new technologies to facilitate increased levels...

NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO FACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASED LEVELS LEVELS LEVELS LEVELS OF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENERATIONATIONATIONATION

CONTRACT NUMBER: DG/DTI/00039/05/00

URN NUMBER: 06/1829

The DTI drives our ambition of ‘prosperity for all’ by working to create the best environment for business success in the UK. We help people and companies become more productive by promoting enterprise, innovation and creativity.

We champion UK business at home and abroad. We invest heavily in world-class science and technology. We protect the rights of working people and consumers. And we stand up for fair and open markets in the UK, Europe and the world.

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NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO NEW TECHNOLOGIES TO FACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASEDFACILITATE INCREASED LEVELS LEVELS LEVELS LEVELS OF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENEROF DISTRIBUTED GENERATIONATIONATIONATION

CONTRACT NUMBCONTRACT NUMBCONTRACT NUMBCONTRACT NUMBER ER ER ER

DG/DTIDG/DTIDG/DTIDG/DTI/000/000/000/00039/05/0039/05/0039/05/0039/05/00

URN NUMBERURN NUMBERURN NUMBERURN NUMBER: 06/1829: 06/1829: 06/1829: 06/1829

This work was commissioned and managed by the DTI's Distributed Generation Programme in

support of the Technical Steering Group (TSG) of the Distributed Generation Co-ordinating

Group (DGCG). The DGCG is jointly chaired by DTI and Ofgem, and further information can be

found at www.distributed-generation.gov.uk

ContractorContractorContractorContractor

P B Power

The work described in this report was carried out under contract as part of the DTI Technology Programme: New

and Renewable Energy, which is managed by Future Energy Solutions. The views and judgements expressed in this report are those of the contractor and do not

necessarily reflect those of the DTI or Future Energy Solutions.

First published 2006

Crown Copyright 2006

Page ii

Project Steering Group SummaryProject Steering Group SummaryProject Steering Group SummaryProject Steering Group Summary

To implement the recommendations of the DTI/Ofgem report on Embedded Generation, a

Distributed Generation Co-ordinating Group (DGCG), together with a supporting Technical

Steering Group (TSG) was established. A number of workstreams were formed by the TSG -

one of which, Workstream 5 (WS5) is focussed on long-term network solutions. An issue

addressed by WS5 was to establish what new technology was likely to become available by

2010.

WS5 commissioned a Report, via Future Energy Solutions, from PB Power with the following

principal objectives:

1. To identify what new technologies are available or emerging (in UK and world-wide) to

facilitate increased levels of Distributed Generation (DG) in the time frame to 2010; and

2. To provide a summary of the status of emerging technologies to help inform decisions about what further work might be appropriate in this area.

The Report considered network-related technologies - including primary and secondary plant,

telecommunications and IT. Generation-related technologies were omitted except where they

formed part of a wider network solution. In compiling the Report the authors considered

technologies that may not yet be fully developed, commercially available, or are cost effective

but which would have the potential to be so by 2010.

The Report identified that the technologies likely to have the most impact on the connection of

additional generation were super-conducting fault current limiters, in-line voltage regulators,

micro-grid controllers and reactive power compensators such as SVCs, FACTs and STATCOMs.

Some of these technologies would be commercially available well before 2010, other may be

still at the ‘demonstrator’ stage by that time.

In commissioning the Report it was not the intention of WS5 to provide an exhaustive list of

emerging technologies, research, development and demonstration projects and initiatives

being undertaken by manufacturers. The intention was to understand what new technologies

were emerging to inform decisions on what might be done to eliminate barriers for the

introduction of DG. Whilst particular new technologies might be noted as being developed by

a certain manufacturer, it should not be interpreted as being solely developed by that

manufacturer or to be the only new technologies being developed by that manufacturer.

A number of areas were identified where additional work may be required to remove potential

barriers to the connection of additional generation. The successful connection and operation of

large quantities of distributed generation will require a high-speed reliable communications

network to be established. No standards were identified which cover communications

protocols between the substations and remote devices on the distribution system.

The Distribution Working Group (DWG) of the Energy Network Steering Group (ENSG) will

need to consider the issues raised in the report and ensure that they are taken into account in

scoping work programmes.

The WS5 P10 Project Group

Page iii

CONTENTSCONTENTSCONTENTSCONTENTS

Page No.Page No.Page No.Page No.

1. INTRODUCTION................................................................................................................1

2. STUDY METHODOLOGY..................................................................................................3

2.1 Literature Searches ...................................................................................................3

2.2 Internet Searches.......................................................................................................3

2.3 Questionnaires and Interviews ................................................................................3

3. INTERVIEWS AND QUESTIONNAIRES...........................................................................5

3.1 Interviews ...................................................................................................................5

3.2 ABB .............................................................................................................................5

3.3 AREVA.........................................................................................................................6

3.4 Econnect.....................................................................................................................6

3.5 Remsdaq.....................................................................................................................7

3.6 University of Manchester .........................................................................................7

4. PRIMARY PLANT TECHNOLOGIES.................................................................................8

4.1 Introduction................................................................................................................8

4.2 Transformers..............................................................................................................8

4.3 Overhead Lines and Cables....................................................................................11

4.4 SVCs, FACTs and STATCOMs................................................................................14

4.5 Switchgear and Fault Current Limiters .................................................................16

5. SECONDARY PLANT TECHNOLOGIES.........................................................................20

5.1 Introduction..............................................................................................................20

5.2 SCADA Systems and Substation Automation.....................................................20

5.3 Communications Systems......................................................................................25

Page iv

6. PRIMARY PLANT RESULTS SUMMARY ......................................................................28

6.1 Transformers............................................................................................................28


6.3 SVCs, FACTS and STATCOMs ...............................................................................32


7. SECONDARY PLANT RESULTS SUMMARY................................................................36


8. CONCLUSIONS...............................................................................................................38

8.1 Transformers............................................................................................................38


8.3 SVCs, FACTS and STATCOMs ...............................................................................39



8.6 Communications Systems......................................................................................40

8.7 Others .......................................................................................................................40

8.8 Summary..................................................................................................................41

9. REFERENCES...................................................................................................................43

Appendix A – Study Brief

Appendix B –Questionnaire sent to Manufacturers

Appendix C –Responses from Manufacturers

Page v

Executive SummaryExecutive SummaryExecutive SummaryExecutive Summary

PB Power was commissioned by the DTI to identify new or emerging technologies that

would have the potential to allow increased levels of distributed generation to be

connected to the network up to 2010. The review covered primary and secondary

plant infrastructure, communications and IT.

The work was carried out in two stages. The first stage comprised literature searches,

internet searches, discussions with manufacturers and research institutions, as well as

information gathering from PB Power specialists. This information gathering stage

was a world wide review to identify significant R&D activities and products which may

be applicable to the UK distribution system. In addition, any overseas practices which

may be beneficial to the UK system were also identified.

Interviews were undertaken with four manufacturers and one university in order to

gain a better understanding of their R&D activities, identify any research gaps and find

any barriers to the development of systems necessary to allow the connection of

distributed generation.

The second stage of work reviewed all of the data collected during the first stage. The

results were classified by technology and rated according to their ability to allow the

connection of additional generation. The likely benefits and timescales for

implementation of each technology were also provided. Cost data has not been

presented due to the lack of data provided by the various manufacturers and

institutions.

The review identified that the technologies likely to have the most impact on the

connection of additional generation before 2010 were super-conducting fault current

limiters, in-line voltage regulators, micro-grid controllers and reactive power

compensators such as SVCs, FACTs and STATCOMs.

Super-conducting fault current limiters would allow the connection of generation into

networks where fault levels would otherwise be exceeded. In-line voltage regulators

have been demonstrated to allow additional generation to be connected by improving

the voltage regulation on the system. These are not widely used in the UK but are

considered to provide significant benefits. First generation micro-grid controllers will

soon be available which will provide a control interface between generators and the

primary substations to enable system voltages to be controlled more accurately.

Reactive power compensators have been used to allow the connection of distributed

generation but their application may be limited due to the relatively high unit cost.

A number of areas were identified where additional work may be required to remove

potential barriers to the connection of additional generation. The successful

connection and operation of large quantities of distributed generation will require a

high speed reliable communications network to be established. No standards were

identified which cover communications protocols between the substation and remote

devices on the distribution system.

Page v i

GlossaryGlossaryGlossaryGlossary

ACCC Aluminium Conductor Composite Core

ACSR Aluminium Core Steel Reinforced

AVC Automatic Voltage Control

CERTS Consortium for Electric Reliability Technology Solutions

CHP Combined Heat and Power

DC Direct Current

DCHP Domestic Combined Heat and Power

DFIG Doubly Fed Induction Generator

DG Distributed Generation

DNO Distribution Network Operator

DTI Department of Trade and Industry

EMS Energy Management System

ENA Electricity Networks Association

EPRI Electric Power Research Institute

EPSRC Engineering and Physical Sciences Research Council

ESQCR Electricity Safety, Quality and Continuity Regulations (2002)

FACTS Flexible Alternating Current Transmission System

FCL Fault Current Limiter

GTI Gas Technology Institute

HSE Health and Safety Executive

HTS High Temperature Superconductor

HV High Voltage

HVDC High Voltage Direct Current

IEE Institution of Electrical Engineers

Page v ii

IEC International Electro technical Commission

ISDN Integrated Service Digital Network

IT Information Technology

MEMS Micro Electromechanical Systems

MVAr Mega Volt Amperes Reactive

MW Megawatts

NGC National Grid Company

NREL National Renewable Energy Laboratory

PLC Programmable Logic Controller

PV Photo Voltaic

R&D Research and Development

RTU Remote Terminal Unit

SCADA Supervisory Control And Data Acquisition

STACOM STATic COMpensator

SVC Static Var Compensator

TCP-IP Transmission Control Protocol - Internet Protocol

UI Universal Interface

VAR Volt Amperes Reactive

XLPE Cross Linked Polyethylene

1.1.1.1. INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

PB Power was commissioned by Future Energy Solutions, acting on behalf of the DTI,

to undertake a study into new distribution technologies.

The scope of the study was intended to identify new or emerging technologies that

would have the potential to allow increased levels of distributed generation to be

connected to the network, as detailed in the study brief contained in Appendix A. The

technologies to be covered included: -

• Primary and secondary plant infrastructure including

o Switchgear

o Transformers

o Overhead lines and cables

o SVCs, FACTs devices etc

o Fault current limiters

• SCADA systems including

o Telecommunications

o IT

o Substation automation

Only network related technologies have been covered, generation related technologies

have been omitted except where they form part of a wider system, for example in a

microgrid system.

All the technologies investigated were to have the potential to be commercially viable

or cost effective by 2010. Any technologies that were in use elsewhere in the world

have been included, technologies already in use in the UK have been largely excluded.

The study has been undertaken by investigating a number of sources as follows: -

• Literature review

• Internet searches

• Discussions with other PB Power Specialists

• Questionnaires and interviews with manufacturers

References to published material and websites are provided at the end of this report.

The manufacturers’ questionnaire is presented in Appendix B whilst written responses

are contained in Appendix C.

The results of the research have been classified into different functional groups to aid

comparison between similar technologies. The potential advantages and

disadvantages have been identified, as well as timescales for availability and benefits

where available. Costs have not been included in this study as none were available for

products in development and few were provided for products currently available. PB

Power did, however, take a view on which technologies were likely to be commercially

available and cost-effective by 2010, based on the published literature and the

interviews with manufacturers.

2.2.2.2. STUDY METHODOLOGYSTUDY METHODOLOGYSTUDY METHODOLOGYSTUDY METHODOLOGY

2.12.12.12.1 Literature SearchesLiterature SearchesLiterature SearchesLiterature Searches

The literature searches were based on three sources: -

• Public domain material identified in the project scope

• Public domain material currently held by PB Power

• Public domain material obtained from the internet searches

The documents obtained were checked for references to new technologies as well as

manufacturers, research programmes and references to other work. Useful references

were then followed up to increase the spread of the search.

Colleagues within PB Power and Parsons Brinckerhoff in the US, UK and Australia

were contacted to identify new technologies and also existing technologies employed

outside of the UK.

2.22.22.22.2 Internet SearchesInternet SearchesInternet SearchesInternet Searches

A number of search techniques were utilised to identify potential material for input to

the literature searches and manufacturers questionnaires. These included: -

• Internet search engines

• Manufacturers’ web sites

• The IEE Discussion Forums

The results of the internet searches led to literature reviews, further internet searches

as well as providing more detailed information on manufacturers, their products and

R&D activities.

2.32.32.32.3 Questionnaires and InterviewsQuestionnaires and InterviewsQuestionnaires and InterviewsQuestionnaires and Interviews

A list of manufacturers was compiled from the results of the literature and Internet

searches. Two questionnaires were then compiled as detailed in Appendix B. One

was sent to companies with a UK office and the second questionnaire was sent out to

companies with no UK offices.

Where possible meetings were arranged to discuss the questionnaire, outline the

companies’ product development plans and determine the types of products that the

companies expected to develop and be in production before 2010. Meetings were

held with the following companies: -

• ABB

• AREVA

• Remsdaq

• Econnect

Discussions were also held with a variety of other companies and institutions that

were either developing or marketing distribution products. The data requested was

product dependent but included budget costs and product specifications. The results

of these enquiries are contained in Appendix C. The companies and institutions

contacted were as follows: -

• Eve Group Ltd (UK) / Composite Technology Corporation Inc (US)

• University of Canterbury (NZ) / CanterburyTX (NZ)

• Wilson Transformers (UK) / Dynamic Rating Equipment (AUS)

• American Superconductors

Approaches were also made to the following companies but at the time of writing the

report, no response had been received.

• Southwire

• Waukesha Electric

• Nexans

3.3.3.3. INTERVIEWS AND QUESTINTERVIEWS AND QUESTINTERVIEWS AND QUESTINTERVIEWS AND QUESTIONNAIRESIONNAIRESIONNAIRESIONNAIRES

3.13.13.13.1 InterviewsInterviewsInterviewsInterviews

Interviews were conducted with four manufacturers to discuss their current R&D

programmes and products. Specific technology details have been documented in

sections 4 and 5 whilst the outcome of more general discussions is detailed below.

An interview was also conducted with Prof. N Jenkins and Prof. G Strbac of the

University of Manchester.

3.23.23.23.2 ABBABBABBABB

Discussions were held at ABB’s Stone offices on the 12 October 2004. ABB are

engaged in a wide range of R&D activities including: -

• Primary plant e.g. switchgear, transformers, circuit breakers, fuses and

cables etc

• FACTs technologies, including HVDC Light

• Insulation materials

• Test procedures

• Sensor technologies

• Materials technologies including nanotechnology

• SCADA and EMS systems

Due to the wide range of R&D activities undertaken by ABB, only those of most

relevance to increasing generation capacity on distribution systems have been

considered. These are described below and in sections 4 and 5.

• SVCs, FACTs and STATCOMs, detailed in section 4.4

• Switchgear and fault current limiters, detailed in section 4.5

• SCADA Systems and Substation Automation, detailed in section 5.2

• Nanotechnology

o ABB is working in partnership with the Rensselaer Nanotechnology

Institute in New York to develop improvements in materials

technologies. It is envisaged that this will produce materials with

improved mechanical and electrical properties giving lower losses,

enhanced insulation characteristics, improved electromagnetic

performance as well as giving cost and weight savings. No details

were provided in relation to potential products, production dates or

costs.

• Microelectromechanical Systems (MEMS)

o ABB is working in partnership with three overseas institutions to

develop MEMS for sensors and instrumentation based on integrated

circuit technology. No specific applications were provided although

the technology is expected to benefit the power industry. No details

were provided in relation to potential products, production dates or

costs.

A number of other issues were discussed and these are summarised below: -

• The lead-time from the inception of a research or development project to

the availability of a commercial product can be 10 years or more. The

development of a new product would have to be at an advanced stage now

in order for it to be available before 2010.

• Research is generally market led. If a market cannot be identified then there

is little chance of undertaking any required R&D. Some form of feedback

from network operators is therefore required in order to identify potential

markets and needs early enough to allow products to be developed.

• Any requirement to comply with UK-specific standards (e.g. ENAs Technical

Specifications) as opposed to international IEC standards increases

production costs and reduces the scope for product development.

3.33.33.33.3 AREAREAREAREVAVAVAVA

Discussions were held at AREVA’s Stafford offices on the 13th October 2004. AREVA’s

current R&D activities of interest to this study are described in sections 4, 5 and other

issues are described below: -

• As with ABB, the R&D activities are generally market led. Both AREVA and

ABB stated that with no clear indication of the future of the distribution

systems, it was difficult to identify market needs.

• Any requirement for UK specific standards was also considered to raise

issues with regard to global product development.

3.43.43.43.4 EconnectEconnectEconnectEconnect

Discussions were held at Econnect’s Hexham offices on the 20 October 2004.

Econnect’s current R&D activities of interest are described in sections 4 and 5.

3.53.53.53.5 RemsdaqRemsdaqRemsdaqRemsdaq

Discussions were held with Remsdaq at PB Power’s Manchester offices on the 7

October 2004. Remsdaq’s current R&D activities of interest are described in sections 4

and 5.

3.63.63.63.6 University of ManchesterUniversity of ManchesterUniversity of ManchesterUniversity of Manchester

Discussions were held with Prof. N Jenkins and Prof. G Strbac at the University of

Manchester on the 15 November 2004. The results of these discussions are contained

in sections 4 and 5 with other general issues described below: -

• The requirement for energy storage system was not considered to be

necessary before 2010, due to insufficient levels of wind generation and

high costs making the technology prohibitively expensive, and suitable for

only the most valuable loads.

4.4.4.4. PRIMARY PLANT TECHNOPRIMARY PLANT TECHNOPRIMARY PLANT TECHNOPRIMARY PLANT TECHNOLOGIESLOGIESLOGIESLOGIES

4.14.14.14.1 IntroductionIntroductionIntroductionIntroduction

This section presents the results and analysis of the various searches for new

technologies applicable to primary plant.

The primary plant technologies have been classified under the following groups: -

• Transformers

• Overhead lines and cables

• SVCs, FACTs and STATCOMs

• Switchgear and Fault Current Limiters

The results of the research for each group are presented in the following sections.

Generation related technologies have been excluded from these studies.

The range of equipment considered is from 240V up to and including 132kV.

4.24.24.24.2 TransformersTransformersTransformersTransformers

The main area of R&D for transformer design is in the development of

superconducting windings. These utilise high temperature superconducting (HTS)

material cooled by affordable liquid nitrogen.

4.2.14.2.14.2.14.2.1 DevelopmentsDevelopmentsDevelopmentsDevelopments

4.2.1.14.2.1.14.2.1.14.2.1.1 AREVAAREVAAREVAAREVA

AREVA is currently developing several new transformer technologies. Solid-state tap

changers are under development. These could be retrofitted to existing transformers

or could be fitted to new transformers. The main advantage could be the improved

reliability and lower maintenance requirements over existing mechanical devices. It is

expected that the tap changers would have full reverse power capability.

A two-position tap changer is also being developed for smaller distribution

transformers. This would give an increased range of operation by providing low/high

load positions, winter/ summer or load/generation positions. It was not disclosed

whether these could be retrofitted to existing transformers with off-load or fixed taps.

No details of the tap step size were provided. A large step size may restrict operation

in order to comply with Engineering Recommendation P28.

4.2.1.24.2.1.24.2.1.24.2.1.2 Other Companies and InstitutionsOther Companies and InstitutionsOther Companies and InstitutionsOther Companies and Institutions

The EPSRC SuperGen Initiative1 claims limited benefits from superconducting

transformers. The main benefits are from the reduced size and reduced

environmental hazards. Due to the high efficiency of conventional transformers the

reduced losses of HTS transformers are not considered a major advantage.

The University of Canterbury (NZ) is in the process of developing an HTS transformer

in conjunction with CanterburyTX2. A resonating high voltage transformer has already

been constructed and utilised for testing other HV transformers. Advantages of the

HTS transformer are the use of liquid nitrogen as both a coolant for the HTS windings

and as a dielectric as opposed to oil. This reduces the environmental hazards and fire

risks. A special core design substantially reduces stray electric and magnetic fields,

thereby reducing interference with other equipment. The current carrying capacity is

higher, meaning that a HTS transformer could have four times the rating of a

conventional identically sized transformer. Voltage regulation is improved due to the

lower leakage reactance reducing the requirement for a tap changer. Fault levels

would be increased however. No cost indications or expected manufacturing dates

have been given.

Waukesha Electric Systems (US)3 is also developing an HTS transformer in its

dedicated R&D facility. Few details are given other than the perceived benefits of

reduced size and weight, no environmental or fire safety hazards, extended lifetime,

greater efficiency and 100% continuous overload capability. No cost indications or

expected manufacturing dates have been given.

SF6 insulated transformers are currently available from Mitsubishi Electric Ltd4. They

are available over a voltage range of 11kV to 33kV with a reduced footprint compared

to conventional dry-type transformers.

Dynamic Ratings (AUS)5 has developed dynamic transformer rating equipment that

provides the ability to utilise the full overload capability of the transformer. Optical

fibre temperature measurement is employed to determine the winding temperature

and provide an input to the dynamic rating and insulation ageing software. The

system provides transformer load monitoring and control, although the method of

controlling the load is not stated. A full system replaces all existing transformer

control equipment, including the AVC control and the pump and fan controls. It can

be fitted to new transformers or retrofitted to existing transformers. Development

work is being undertaken on more advanced equipment. Existing products have

recently been installed on transformers on the Kansas City system in the US and a few

transformers in the UK. Although the technology is not new to the UK, it is not in

widespread use. It is being marketed in the UK by Wilson Transformers Ltd, an

Australian manufacturer.

Cooper Industries6 manufacture in-line voltage regulators for 2.4kV to 34.5kV systems.

These provide a 32 step ±10% tap range with ratings between 33kVA and 1MVA in

both directions. They are placed in series on a distribution circuit and provide

accurate voltage regulation of the downstream circuit section. These devices have

been used by SP Powersystems in North Wales to allow increased amounts of

generation to be installed. They have also been installed by Scottish Hydro on the

11kV and 33kV systems, mainly to control the voltage profile on long circuits. They

have also been used to allow generation to be connected although problems were

experienced when loads and generators were connected onto the same circuit. For

this reason small SVCs are now being installed where required. They have been

included in this report as their use in the UK is not thought to be widespread. In-line

voltage regulators are in more common use in both Northern Ireland and the Republic

of Ireland where loads may be sparser than in Great Britain. Guidance on their use is

provided in ETR 126 ‘Guidelines for Actively Managing Voltage Levels Associated with

the Connection of a Single Distributed Generation Plant’7.

4.2.24.2.24.2.24.2.2 ReviewReviewReviewReview

HTS transformers are currently being developed by a number of companies and

institutions. They have a significantly higher power rating for the same footprint as a

conventional oil-filled or cast resin transformer. This may avoid the need to relocate

existing substations or build additional substations to accommodate load growth.

Fewer substations could therefore supply a wider area or increased load transfers

could be accommodated at lower voltage levels. Lower environmental hazards would

be realised due to the use of liquid nitrogen as opposed to oil, minimising fire risks

and disposal issues.

There would be less requirement for a tap changer on an HTS transformer due to the

lower reactances resulting in a low voltage drop. This would improve reliability by

reducing the maintenance but would also increase fault levels.

Disadvantages envisaged are more expensive cooling arrangements and higher plant

costs due to the use of superconducting materials. Integration into the existing

system would be relatively easy due to the smaller footprint of the transformers,

though space would be required for the cooling equipment. This equipment could

however be common to a number of HTS transformers, cables and other plant such as

fault current limiters (FCLs).

All these developments would allow space to be made available at existing

substations to accommodate additional switchgear or control equipment.

Dynamic transformer rating equipment is currently available and in service on

transformers between 50MVA and 333MVA, allowing closer control of the maximum

transformer load than at present and a possible means of postponing reinforcement

requirements. Potentially dynamic loading could increase the allowable loading by

10% to 20%. This figure would be dependent on ambient temperature, cooling

efficiency and previous loading conditions. Dynamic loading could also reduce the

allowable maximum loading under adverse conditions although under these

circumstances remedial action such as load shedding might be required.

In-line voltage regulators have been shown to allow the connection of additional

generation but are not thought to be widely used in Great Britain.

4.2.34.2.34.2.34.2.3 SummarySummarySummarySummary

The following table summarises the features of the transformer technologies.

ManufacturerManufacturerManufacturerManufacturer Product or Product or Product or Product or

TechnologyTechnologyTechnologyTechnology AvailabilityAvailabilityAvailabilityAvailability Advantages/DisadvantagesAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantages/Disadvantages

Solid State Tap Changer

Under development

No tap wear allowing increased frequency of operation and ‘faster’ voltage control. Full reverse power capability.

AREVA

Two Position Tap Changer

Under development

Provides low/high load or load/generation positions for greater operational flexibility.

CanterburyTX Superconducting Power Transformers

Under development

Lower losses, smaller footprint, no oil required, and high overload capability.

More expensive cooling arrangements.

Tap changer requirements reduced. Possibility of low maintenance but higher fault levels.

Waukesha Electric Systems

Superconducting Power Transformers

Under development

Lower losses, smaller footprint, no oil required, and high overload capability.

More expensive cooling arrangements.

Tap changer requirements reduced. Possibility of low maintenance but higher fault levels.

Dynamic Ratings

Dynamic Rating Equipment

In use

Allows potentially higher loadings to be carried. Insulation ageing calculations also provided. Maximum loading dependent on environmental factors plus previous loading.

Cooper Industries

In-line Voltage Regulators

In use Regulate distribution system voltages, reverse power capability. In very limited use in Great Britain.

Mitsubishi Electric Ltd

SF6 Distribution Transformers

In use Smaller footprint than dry-type transformers.

4.34.34.34.3 Overhead Lines and CablesOverhead Lines and CablesOverhead Lines and CablesOverhead Lines and Cables


Superconductivity is also the main area of development for power cables. J. W. Ekin8

of the National Institute of Standards and Technology, Boulder, Colorado states that

three superconducting cable projects are under construction in the US. The largest is

a 600m, 2400A, 138kV cable being constructed by Nexans and American

Superconductor for the Long Island Power Authority, New York. This is due to be

energised by 2006. A three to seven fold increase in current carrying capacity is given

for an HTS cable over a conventional identically sized copper cable. Cables are of

hollow single core, coaxial or triaxial construction. Ohmic resistance (and losses)

would be decreased which may increase fault levels.

The EPSRC SuperGen Initiative1 claims limited benefits from superconducting cables.

They would reduce the resistive transmission losses but the high costs and inefficient

cooling would make such cables non-competitive compared to conventional

underground cables or overhead lines. There may, however, be an application in

congested urban areas where the higher power densities would allow greater power

transfer along existing cable routes.

Systems that monitor cable core temperature using optical fibres or thermocouples in

order to provide a dynamic current rating are available from KEMA9. Thermocouples

are fitted to existing cables where optical fibres are not available. This is carried out on

a consultancy basis on selected cables. Mathematical modelling is undertaken to

determine the cable performance under dynamic loading conditions and to provide

information on insulation ageing. The Belgian transmission system owner, ELIA, has

installed this system on a 150kV cable circuit in Brussels. Real time temperature data

and overload capabilities can be accessed to allow greater operational flexibility10.

NGC are installing similar technology on the new 400kV, 20km cable between Elstree

and St Johns Wood11. Two optical fibres are built into the cable to provide continuous

temperature monitoring.

There are also developments in overhead line technology. Gap type conductors

incorporate an annular gap between the steel core and the outer aluminium strands.

The conductor is suspended by tensioning the steel core with the aluminium strands

left slack. The conductor sag is therefore a function of the expansion of the steel core.

Higher stringing tensions give lower sags which allow higher currents to be carried.

These conductors are being installed by NGC to uprate existing circuits.

A new overhead line conductor has been developed which is claimed to provide a 1.6

increase over conventional ACSR conductors12. In order to reduce the sag and provide

higher ratings a conventional ACSR conductor is constructed with a pre-tensioned

steel core. After the conductor has been constructed the tension is released in the

steel core which causes the aluminium strands to slacken. During operation the steel

core expands and takes up the slack in the aluminium conductor. This results in a

lower sag and higher power rating. Conventional installation techniques are used

which removes the need for the tower reinforcement that may be required when using

gap type conductors. The new conductor has been used on 34 lines in Japan.

Composite Technology Corporation (US) is producing an ACCC (Aluminium Conductor

Composite Core) conductor that utilises a composite core in place of a steel or

aluminium core13. The first commercial installation was completed in August 2004.

The low thermal expansion coefficient of the core results in lower conductor sag and

thereby allows higher operating temperatures. No special installation techniques are

required. The rating given for an ACCC conductor is 1902A compared to 905A for the

same size Drake conductor (approx 400mm2 ACSR). The allowable operating

temperature is increased from 75°C up to 200°C. Details of the discussions with the

UK representative are given in Appendix C.


Development activities for HTS cables have to date concentrated on the higher voltage

levels and therefore it is envisaged that HTS cables would be most applicable to high

voltage distribution (132kV) initially. Existing urban cable routes could be upgraded

from conventional paper insulated cable to HTS cable giving an increased capacity in

congested cable corridors. It is possible that the technology could be applied in the

future since the 132kV cables currently installed can be short lengths from a terminal

tower to a nearby substation. The additional cost of HTS cables may not provide

sufficient benefits to the DNOs, as old or overloaded circuits could be upgraded using

suitably rated XLPE cables. The cost may also limit the application of HTS cables to

higher voltage levels.

Dynamic conductor monitoring systems are currently available and are in use in

Belgium. They have enabling increased current carrying capability by allowing cable

hot spots to be identified and rectified. The system requires that the monitored cables

are fitted with optical fibres and this may limit the number of applications. An

alternative would be to incorporate temperature measuring fibres during manufacture

although no manufacturers appear to have plans for this.

Composite overhead conductors are currently available and have been installed at a

number of locations. It is envisaged that they have the potential to increase the

capacity of overhead lines by simply replacing existing conductors using conventional

installation techniques and equipment. Composite conductors could be applied at any

voltage level thereby assisting in the relief of bottlenecks, increasing transfer

capacities and allowing increased loads and generation to be connected.

The limitations of the North – South transmission inter-connector may constrain the

connection of new wind generation in Scotland.


The following table summarises the features of the cable and conductor technologies.



Nexans Superconducting Power Cables

Under trial in several installations

Lower losses, higher capacity for similar sized cables. Higher fault levels.

More expensive cooling arrangements (compared to oil/gas filled cables).



KEMA Dynamic Cable Rating Equipment

In use

May not provide significant increase in capacity, requires thermocouples to be fitted to existing cables or installation of new cables. Could be employed on future cables if manufacturers incorporate optical fibre temperature measurement into cables.

Composite Technology Corporation

Composite Overhead Conductors

In use

Higher capacity for similar sized conductor, no special installations requirements, equally applicable at any voltage level.

4.44.44.44.4 SVCs, FACTs and STATCOMsSVCs, FACTs and STATCOMsSVCs, FACTs and STATCOMsSVCs, FACTs and STATCOMs


4.4.1.14.4.1.14.4.1.14.4.1.1 ABBABBABBABB

ABB currently produce FACTS and HVDC Light devices for high voltage transmission

and distribution solutions. ABB is not developing similar devices for use at

distribution voltage levels of 33kV and below as the company does not believe there is

sufficient demand and the relatively high costs would present a significant barrier to

their deployment.

The ABB HVDC Light system provides a DC link of up to 100MW between two remote

AC systems. This has been employed to connect a remote wind farm to the

transmission system in Gottland, Sweden. The cable link is 70km long with a rating of

50MW at 80kV. A DC link was selected due to the difficultly in building a new

transmission line as well as the ability of the system to improve power quality.


AREVA is in the final stages of developing a compact STATCOM, C-STATCOM. The

first equipment is scheduled to go into service at the end of 2005. A single C-

STATCOM cabin has a steady state rating of ±10MVAr and up to five modules may be

combined to give ±50MVAr. The cabins will normally be connected to the power

system via a tertiary transformer winding. Connection voltages are expected to range

from 11kV to 132kV. The reactive power capability provides extremely fast voltage

control improving voltage regulation, flicker and power quality. They can also reduce

post fault oscillations and improve the ability to ride through faults. The addition of

energy storage provides full four quadrant operation. The required output is

maintained over a very wide voltage range whilst the dynamic capability of each

module is twice the steady state rating.

AREVA is also developing a new common range of SVCs that will be available for

tendering at the beginning of the second quarter of 2005. These provide similar

benefits to STATCOMs; however, the STATCOM has some superior characteristics

whilst SVCs provide a lower cost solution.


American Superconductors14 manufacture a range of static and rotary power systems

devices which are described below: -

• D-VAR – Dynamic VAR system similar to a STATCOM. Provides an

‘instantaneous’, continuous source of reactive power. Can be used to resolve

voltage stability issues, increase transfer capabilities, minimise voltage flicker,

improve fault ride through and improve steady state voltage regulation.

Already in use providing up to –37 to 97MVAr of reactive power mainly in the

US. Operates over 480V to 35kV with outputs of 1.0 to 8.0MVAr.

• SuperVAR – an HTS synchronous condenser. Due to the use of an HTS field

winding the unit is more efficient, compact and reliable compared to

conventional synchronous condensers. A ±10MVAr, 13.8kV unit is available

with maintenance costs of <$10k per annum. It provides steady state voltage

regulation, increases system inertia, responds to system transients and

generates no harmonic currents. It also provides a fault level contribution. The

transient rating is up to 8.0pu.

• D-SMES – Distributed Superconducting Magnetic Energy Storage system. Can

inject real and reactive power into the system, up to 3MW and 8MVAr

(18.4MVAR instantaneous) per unit. Fast response provides benefits during

voltage collapse and instability on systems between 69-500kV. The ability to

inject real power into the network may allow generators to ride through more

severe faults or provide a smoother transition to and from island mode

operation.

Scottish Hydro have installed SVCs at the distribution level in order to improve the

voltage control when generators are connected to the system. These are being

installed where in-line voltage regulators do not provide a wide enough range of

operation to accommodate the opposing demands of load and generation.


FACTs technologies provide the opportunity to provide both steady state and dynamic

voltage support for a range of voltages and power levels. Power quality can be

enhanced and the reactive power capabilities could be utilised to reduce network

losses. The dynamic response could provide additional inertia or MVAr/voltage

support to reduce the effect of faults on local generators.

A variety of STATCOM products are available or due to go into production before

2010. These would provide improved steady state and dynamic voltage support for

the network. Some manufacturers provide the facility for injecting real power into the

network to improve the fault ride through characteristics.

Distribution voltage SVCs are being installed by one DNO to overcome the limitations

of in-line voltage regulators.


The following table summarises the features of the transformer technologies.



ABB FACTS, HVDC Light, SVC

In use Provides steady state and dynamic MVAr capability reducing flicker, improving stability and regulation.

AREVA C-STATCOM Q4 2005

Improves system voltage regulation, provides steady state and dynamic reactive capability. Energy storage capability for four quadrant operation.

D-VAR (STATCOM) devices

In use Provides steady state and dynamic MVAr capability reducing flicker, improving stability and regulation.

SuperVAR HTS synchronous compensator

In use

Increases system inertia, no harmonic contribution, provides steady state regulation.

Increases system fault levels.

American Superconductors

D-SMES HTS Magnetic Energy Storage System

In use Provides real and reactive power injection during transients. Fast response.

4.54.54.54.5 Switchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current LimitersSwitchgear and Fault Current Limiters


4.5.1.14.5.1.14.5.1.14.5.1.1 ABBABBABBABB

ABB is continuously developing its range of switchgear products, covering most

distribution voltages. The main area of innovation is considered to be the use of new

or alternative materials. This could lead to more compact cubicles allowing additional

circuits to be installed in existing substations. This may generate interface problems

with existing equipment such as the need to re-route the existing cables. There is also

a possibility that cubicle sizes will increase if the use of SF6 as an insulator is

discontinued due to environmental concerns.

One barrier to the use of a manufacturer’s standard design equipment in the UK is the

requirement for UK specific Energy Networks Association Switchgear Assessment

Panel approval in addition to the internationally recognised standards. The UK-

specific requirements largely stem from the need to meet the requirements of the

ESQCR and the Distribution Code. For example UK equipment typically has more

comprehensive interlocking than continental equipment. DNOs are however

purchasing larger quantities of switchgear from continental manufacturers.

An 11kV solid state circuit breaker has been developed and is installed at a substation

in Switzerland. It is expected that these would operate faster than conventional circuit

breakers. It has not reached the commercialisation state yet due to various issues

including the cooling requirements and cost of the unit.

An intelligent vacuum circuit breaker has been developed for medium voltage

applications. This incorporates all the measurement, protection and control functions

into the circuit breaker truck reducing the cabling required as well as providing an

Internet communications interface. This would allow control and monitoring via a

wide area corporate network or an Internet connection. The smaller size and reduced

number of parts allows space and cost savings. This would allow extra circuits to be

incorporated into existing substations whilst simplifying the installation requirements.


A magnetic type fault current limiter has been developed. The prototype working

voltage ranges will be between 3.5kV and 33kV.


Nexans15 have recently installed a 10MVA capacity HTS fault current limiter (FCL) on

an RWE 10kV network in Germany in May 2004. The next stage of development is for

a 110kV unit. HTS FCLs exhibit rapid resistance or reactance changes above defined

current limits. Excessive current levels force a change of state from superconducting

to resistive which results in a lower fault current. Conventional circuit breakers and

protection relays can then be used to isolate the faulted equipment.

EPRI is sponsoring a project16 to demonstrate an HTS FCL suitable for use on a 138kV

transmission network. The beta test version, currently being developed by Nexans, is

scheduled for installation in 2006 and will then undergo a one to two year test phase.

The EPSRC SuperGen Initiaitive1 anticipates that the first superconducting application

will be for fault current limiters that should be commercially available within 5 years.

They react more rapidly than any circuit breakers and are regarded as essential to

enable the incorporation of distributed generation into the grid system.


Increased levels of distributed generation will typically result in increased system fault

levels. Fault current limiters could be employed to reduce the need to upgrade

switchgear fault ratings, and possibly allow the use of lower rated equipment in order

to reduce costs. It is considered that they could make a significant contribution to

allowing increased generation because of their ability to effectively split the network

or control fault flows.

The future generation of fault current limiters will be fail-safe. HTS FCLs are inherently

fail-safe since the collapse of superconductivity is directly related to the current

density. No external systems are required to initiate operation, indeed failure of an

external system, such as the cooling, causes the FCL to operate.

Development is in the advanced stages with several prototypes in use at various

voltage levels. It is expected that these devices would be available by 2010.

Installation of a FCL could avoid the requirement to replace entire switchboards,

thereby reducing reinforcement costs.

An intelligent 11kV circuit breaker has been developed which incorporates all the

monitoring, control and protection functions inside the circuit breaker truck. All

functions are available via an Internet type interface which reduces installation costs.

New materials technologies are expected to provide smaller switchgear components

due to improvements in insulation properties. This may allow more equipment to be

installed in existing substations.


The following table summarises the features of the FCL technologies.



Switchgear Improvements based on new materials technologies

Not given Smaller cubicle sizes, therefore more feeders per substation

Medium Voltage Intelligent VCB

Now

Incorporates measurement, protection and control functions into circuit breaker truck. Control and monitoring via internet interface.

ABB

Solid State Circuit Breaker

Not given Faster operation and reduced maintenance

AREVA Superconducting Fault Current Limiters

Under development

Failsafe operation, allows system operation at higher fault levels. Can avoid the need for asset replacement. Allows increased levels of generation to be connected.



Magnetic Fault Current Limiter

Under development

Allows system operation at higher fault levels. Can avoid the need for asset replacement. Allows increased levels of generation to be connected.

Fail safe operation.

Nexans Superconducting Fault Current Limiters

Under trial in several installations

Failsafe operation, allows system operation at higher fault levels. Can avoid the need for asset replacement. Allows increased levels of generation to be connected.

5.5.5.5. SECONDARY PLANT TECHSECONDARY PLANT TECHSECONDARY PLANT TECHSECONDARY PLANT TECHNOLOGIESNOLOGIESNOLOGIESNOLOGIES

5.15.15.15.1 IntroductionIntroductionIntroductionIntroduction

This section presents the results and analysis of the various searches for new

technologies applicable to secondary plant.

The technologies covered by secondary plant technologies include: -

• SCADA Systems and Substation Automation

• Communications Systems

Generation related technologies have been excluded from these studies except where

they form part of a wider system.

5.25.25.25.2 SCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation AutomationSCADA Systems and Substation Automation


5.2.1.15.2.1.15.2.1.15.2.1.1 ABBABBABBABB

ABB17 have developed a range of SCADA software and automation equipment which

is currently available and in use around the world. Advanced features are readily

available which allow a fully integrated network management system to be developed.

Optional functionality includes outage management, network planning, optimal power

flow and reliability analysis. Future developments include the integration of real time

software for energy trading whilst Internet technology is used to allow operation from

a wide range of devices.

The range of equipment varies from large centralised SCADA systems to distributed

units for individual substations. Although the equipment is already is use in the UK it

is not thought by the manufacturers that the full capabilities of the various systems are

used. This may be due to the network operators not purchasing the additional

features or not having suitably qualified engineers to take advantage of the increased

functionality. It was considered that developing countries often made better use of the

advanced product features in place of installing additional substation equipment.


AREVA are developing the next generation SCADA and Energy Management

Applications incorporating the specific DER requirements under its e-terra platform.

This is a modularised and fully integrated, object orientated system which

incorporates a wide range of advanced features such as market trading interface, wind

farm prediction and optimal Voltage-VAR Control schemes.

The system will, when complete, allow direct control of all system devices from circuit

breakers to individual wind turbines and FACTS devices. The software incorporates

the required protocol interface to each individual device, employing standard state of

the Art Ethernet TCP-IP OPC and IEC61850 based protocols.

Control is provided at all levels, from individual generator controls, control of a

specific area to system wide voltage and power controls. These controls range from

simple open/close to more sophisticated coordinated distributed MW or MVAR control

schemes incorporatingtap changers, DFIG, Statcom, Micro CHP, and any controllable

loads.. Any type of device could be incorporated into the system providing it had a

suitable interface. This includes any wind turbines or other generators such as PV,

micro CHP etc.

The system operates over a fast Ethernet 100Mbit./s communications network with

peer to peer communication between devices to achieve fast automation within the

plant. The system is also open to include extra software applications required for any

commercially driven control required in the future (for example reactive power

ancillary services).

5.2.1.35.2.1.35.2.1.35.2.1.3 EconnectEconnectEconnectEconnect

Econnect18 have developed a range of solutions to manage voltage rise issues that

allow increased levels of distributed generation to be connected. The principal system

is called GenAVC™ which is designed to improve the voltage regulation on

distribution systems incorporating generators. GenAVC™ works in conjunction with

standard automatic voltage control (AVC) relays on the tap changers of 33kV/ 11kV

(primary) transformers. State estimation software is run on an industrial pc platform

holding a model of the network and receiving inputs of real and reactive power flows

and voltages on all feeders connected to the primary substation, and also inputs of

power and voltage information at the DG site. Two sets of trials are currently

underway, one on a section of 11kV network in EDF Energy’s Eastern network, and one

on United Utilities Carlisle network. Each network contains a DG scheme. Econnect’s

studies indicate that GenAVC™ could double the amount of generation that could be

connected to a network. It is expected to be in production in approximately 12 months.

Other Econnect solutions for voltage rise issues include the GenV™ control system

that can control the MW and MVAr output of a generator to response to the network

voltage. GenV™ is most appropriate for smaller generation projects when the

probable occurrence of constraint conditions due to voltage rise is low.

Econnect’s established range of load controllers for autonomous operation on

islanded networks is being further developed to incorporate embedded

communications ability to control on-site loads. These loads may be controlled as

part of a voltage rise mitigation, or to maximise on-site usage of own generation,

displacing more expensive bought-in energy. These new products will be field tested

in early 2005, with a target for market readiness of September 2005. Both power line

carrier and low power radio communication options will be available to suit a wide

range of applications.

5.2.1.45.2.1.45.2.1.45.2.1.4 RemsdaqRemsdaqRemsdaqRemsdaq

Remsdaq19 are currently marketing an advanced RTU system called CallistoIES which is

currently used by a number of UK utilities and generators. Briefly it provides various

control and monitoring functions for a variety of devices including interfaces to

capacitor banks and wind turbine control systems. Strictly this system is outside the

scope of this study since it is in use in the UK, however it has been included as an

example of existing technologies which could be further developed.

5.2.1.55.2.1.55.2.1.55.2.1.5 University of ManchesterUniversity of ManchesterUniversity of ManchesterUniversity of Manchester

It was considered that the installation of active network management systems would

require the development of more sophisticated software tools, both to provide real

time system operation and to allow the networks to be designed and studied by the

planning departments.

Additional research and development would be required on systems to automatically

dispatch distributed generation on a continuous basis in response to measured

system data. It is likely that active network systems would be autonomously

controlling discrete sections of networks and therefore robust algorithms would be

required. In addition software tools would be required for use by the DNOs and

developers in order to design and study such networks.

The university believes that large numbers of active networks may not be developed

or required before 2010 as there would be limited levels of generation at the lower

distribution voltages (11kV and below).

5.2.1.65.2.1.65.2.1.65.2.1.6 Other Companies aOther Companies aOther Companies aOther Companies and Institutionsnd Institutionsnd Institutionsnd Institutions

The reliability of the DNO’s existing SCADA equipment and communications networks

was seen as a significant barrier to the use of such systems for controlling more

sophisticated networks20. The speed of operation would also make existing

communications channels unsuitable for the control of large number of generators.

A large number of research projects have been identified which are aiming to develop

intelligent micro-grid controllers. A micro-grid controller can be considered as an

advanced RTU which provides a common controller for a discrete section of

distribution network. Features vary but all systems essentially combine an interface to

the various generators, transducers, transformers etc and a controller, or series of

controllers, that co-ordinate the control of generation, local system voltages and

power flows. Some of the various projects are described below: -

• Reliable, Low Cost Distributed Generator/Utility System Interconnect21

Funded by the National Renewable Energy Laboratory (NREL) in conjunction

with GE and Puget Sound Systems. Project objectives are to develop a

standard-compliant generation and grid interconnect to overcome

interconnection barriers, allow reliable system operation and ‘achieve the full

value of distributed generation’. GE are developing a Universal Interconnect

(UI) to provide a standard interface between any plant item and the remainder

of the system. The project includes a micro-grid study from 2004 to test the UI

devices.

• Innovative Distributed Power Interconnection and Control Systems22

Funded by the NREL in conjunction with the Gas Technology Institute (GTI) and

Encorp Inc. Projective objectives are to develop key enabling technologies for

cost effective distributed generation interconnection products, software and

communications solutions by the end of 2005.

• Intelligent Solutions for Distributed Power Technology23

Funded by NREL in conjunction with Orion Engineering Corporation. Research

objectives are to demonstrate a neural network control system for managing

small distributed generation. Orion Engineering has developed a system called

the Distributed Energy Neural Network Integration System (DENNIS) that

effectively aggregates a number of small generators into a single larger virtual

generator. Control of the generator dispatch is based on real time electricity

prices, individual demand profiles, state of discharge of storage devices and

weather conditions (to modify demand data).

• Consortium for Electric Reliability Technology Solutions24 (CERTS)

CERTS is a group of research institutions, headed by the Lawrence Berkeley

National Laboratory, who are undertaking research on micro-grid solutions, as

well as other fields. To date research has focused mainly on micro-grid

modelling tools, dynamic generator characteristic and data collection. Field

trials of a three generator micro-grid installation are planned for 2004 to

validate the research findings. There do not appear to be any plans yet to

produce marketable products.


The reliability and speed of operation of existing SCADA systems and

communications networks are seen as barriers to the control and operation of large

quantities of distributed generation.

The main areas of R&D activities are based around micro-grid network controllers to

actively control a discrete section of distribution network. Simplified versions which

provide limited functionality are currently available and in use, both in the UK and

overseas. The next stage of development could provide ‘Plug and Play’ type

generation interfaces providing an standardised control, monitoring and metering

interconnection to the network. These would interface to micro-grid controllers that

co-ordinate the operation of all the plant on a section of network. Current

programmes indicate that such devices could be available after 2006.

Several SCADA/EMS systems are currently available that provide advanced

functionality. These integrate all the system components and make them accessible

via a database for control and monitoring purposes. Advanced features include wind

speed prediction, wind farm control, network voltage and MVAr control etc. Although

some of these systems are already in use in the UK the advanced features are not

widely used, if at all.

RTU devices are becoming more advanced and provide PLC type functionality. These

would allow greater integration and control of components connected to the

substation. They could implement all the lower level control and monitoring

functionality required for control of the local distribution system in response to higher

level control from a centralised system. Such devices are already being used in the

UK.

Intelligent generation controllers are under development which would provide a co-

ordinated voltage control system for distribution networks incorporating generators.

Optimal power flow routines would be built in to identify the best generator dispatch

based on system loading and predicted wind resources. The system could be used to

provide a localised control system responsible for real time network operation,

communicating at a high level with a centralised DNO control system.

Load controllers are being developed to implement automatic load shedding schemes

for weak and islanded networks. This system may not allow additional generation to

be added to a system.


The following table summarises the features of the SCADA and substation automation

technologies.



ABB SCADA, EMS Systems

In use

Fully integrated solutions with advanced functionality.

DNOs may only be using the basic product features.

AREVA e-terra SCADA/EMS

In use Fully integrated system allowing control over all system devices from individual generators to system wide power control.

Remsdaq CallistoIES In use

Wide variety of communications protocols and media. Interfaces with various plant items, both local and remote. Flexible inbuilt intelligence, possible to automatically schedule generation, change transformer taps etc.

GenAVC Approximately 12 months

Provides voltage set-point adjustment for systems with embedded generators. May double amount of generation that could be connected.

Econnect

Load Controller Approximately 10 months

Automatic control of loads to provide some voltage rise mitigation and/ or maximise on-site usage of energy/ minimum bought-in energy to provide economic benefit.

Range being extended to cover grid connected applications.

5.35.35.35.3 Communications SystemsCommunications SystemsCommunications SystemsCommunications Systems


None of the searches have identified any major developments in communications

technology. This may be because the communications systems are not seen as a

barrier to implementing new technologies. Current products and research use

existing communications technologies such as Ethernet and similar. For example,

AREVA has carried out R&D on new Ethernet Hub technology, to extend Ethernet

100Mbit/s over WAN configurations, and site configurations similar to windfarms.

New products such as the Remsdaq CallistoIES 19 can communicate over a large

number of proprietary protocols (e.g. AREVA K series relays) using virtually any media

such as ISDN, optical fibres, microwave, radio or satellite links.

A wide variety of communications technologies are currently available which can

provide high speed links over a number of media with varying ranges. Ethernet,

optical fibres and microwave links can provide secure high speed communications

channels. Radio links such as Bluetooth can provide short range links within

substations. Although communication links may be sparse in rural areas the range of

existing technologies is considered capable of providing adequate, fast and secure

links between distributed plant items.

Communications channels may need to be established between new and existing

plant in order to take advantage of the latest developments in automation and control

systems.

AREVA questioned whether the existing communications protocols are suitable for

use into the future. The communications protocols must be capable of handling the

wider range of devices that are expected to be connected to the distribution system.

The communications systems must also be capable of handling the larger amounts of

data in timescales that allow an adequate level of network control. It is envisaged that

all devices connected to the system would have to incorporate an industry standard

interface to eliminate compatibility problems between the DNOs and consumers’

equipment.

IEC61850, Communications Networks and Systems in Substations25 provides a

communications system for substation control, monitoring and protection functions. It

covers communications between all substation devices from intelligent circuit

breakers to non-conventional instrument transformers up to the bay level and station

level control functions. No IEC standard was identified which specified a

communications systems for devices outside the substation.

Existing SCADA communications networks are seen as a significant barrier to the

integration of large quantities of distributed generation, as detailed in section 5.2.1.6.


No major communications related research projects or product developments were

identified during the various searches. Existing communications technologies are

being utilised in the development of new products and research activities. The

principal communications barrier is considered to be the physical installation of a

reliable, high speed network using existing technologies, in order to overcome the

limitation of existing systems.

The suitability of the existing communication protocols may need to be examined to

ensure compatibility between the DNOs and consumers’ equipment.


No major R&D projects related to communications technologies have been identified.

The main communications barrier to increasing generation is considered to be

upgrading the existing slow and unreliable SCADA communications networks with a

high speed reliable infrastructure.

Communications protocols may need to be revised to prevent incompatibility between

the wide range of new devices that may be connected to the system. IEC61850

provides a communications standard for all substation components but no standard

was identified to cover the communications required between the substation and

devices located elsewhere on the distribution system.

6.6.6.6. PRIMARY PLANT RESULTPRIMARY PLANT RESULTPRIMARY PLANT RESULTPRIMARY PLANT RESULTS SUMMARYS SUMMARYS SUMMARYS SUMMARY

This sections details the manufacturers and their technologies with likely benefits from section 4 in tabular format. It should be

noted that the results column ‘Potential to Allow Increased Generation’ are subjective. Factors considered when determining the

potential are the ability to resolve voltage regulation, reverse power flow and fault level issues. Technologies which relieve system

bottlenecks have been classified as having a lower potential to allow additional generation to be connected. Perceived costs have

also been taken into consideration.


ManufacturerManufacturerManufacturerManufacturer Product/ Product/ Product/ Product/

TechnologyTechnologyTechnologyTechnology

Potential to Potential to Potential to Potential to

AlloAlloAlloAllow w w w

Increased Increased Increased Increased

GenerationGenerationGenerationGeneration

Applicability Applicability Applicability Applicability

to UK to UK to UK to UK

NetworkNetworkNetworkNetwork

BenefitsBenefitsBenefitsBenefits Implementation Implementation Implementation Implementation

BarriersBarriersBarriersBarriers TimescalesTimescalesTimescalesTimescales

Solid State Tap Changer

Low Voltage range

not known

Lower maintenance, full

reverse power capability,

faster switching, more

frequent tap operation.

Under development Not known

AREVA

Two Position Tap Changer

Medium Voltage range

not known

Gives low/high load or

load/generation tap

positions to accommodate

increased load/generation.

Under development Not known












CanterburyTX Superconducting Power Transformers


not known

Increased substation

capacities due to smaller

footprint.

Product under

development. Cost and

lead time to large scale

production.

Possibility of increased

fault levels.

Not known

Waukesha Electric Systems

Superconducting Power Transformers


not known



footprint.

Product under

development. Cost and


production.

Possibility of increased

fault levels.

Not known

Dynamic Ratings

Dynamic Rating Equipment

Low to

medium All

Allows transformers to be

operated closer to their

maximum ratings

Minimal Available now

Cooper Industries

In-line Voltage Regulators

High 2.4kV to

34.5kV

Improved voltage

regulation of distribution

circuits. Reverse power

capability.

None Available now












Mitsubishi Electric Ltd

SF6 Distribution Transformers

Medium 11kV to 33kV



footprint.

None In use

6.26.26.26.2 Overhead Lines and Cables Overhead Lines and Cables Overhead Lines and Cables Overhead Lines and Cables




AAAAllow llow llow llow








Nexans Superconducting Power Cables

Medium

Initially 132kV

and above

due to costs

Increased circuit capacities,

reduction of voltage

regulation problems.

Lower losses.

Installation costs would

be higher than for

existing cables. Cost and


production.

May increase fault levels.

Not known

KEMA Dynamic Cable Rating Equipment

Low All

Provides actual cable rating

based on installation

conditions.

Could be employed on

future cables if

manufacturers incorporate

optical fibre temperature

measurement into cables

May not provide

significant increase in

capacity, requires

retrofitting to existing

cables or installation of

new cables.

Available now

Composite Technology Corporation

Composite Overhead Conductors

Medium

Initially 132kV

and above

due to cost

Higher ratings possible

without constructing new

circuits. Installation

methods identical to

existing conductors.

Cost – intended to

provide cost saving over

GAP type conductors

Available now

6.36.36.36.3 SVCs, FACTS and STATCOMsSVCs, FACTS and STATCOMsSVCs, FACTS and STATCOMsSVCs, FACTS and STATCOMs




Allow Allow Allow Allow








ABB FACTS, HVDC Light, SVC

Medium 132kV and

above.

Improves steady state and

dynamic performance of

the network

Substation space.

Cost.

Available now

AREVA C-STATCOM Medium 11kV to 132kV

Improves steady state and

dynamic performance of

the network.

Can include energy storage

to give four quadrant

operation.

±10MVAr modules up to

±50MVAr

Substation space.

Cost.

Q4 2005


D-VAR (STATCOM) devices

Medium 480V to 35kV

Improved power quality,

steady state and dynamic

voltage control.

1.0 to 8.0MVAr capability

Substation space.

Cost.

Available now












SuperVAR HTS synchronous compensator

Medium 13.8kV

Improved power quality,

steady state and dynamic

voltage control.

±10.0MVAr with up to

8.0pu transient rating.

Substation space.

Cost.

Available now


D-SMES HTS Magnetic Energy Storage System

Low to

medium 69kV to 500kV

Dynamic delivery of real

and reactive power during

fault conditions allowing

possibility of generator

fault ride though and

islanding.

3MW and 8MVAr

capability.

Substation space.

Cost.

Available now













Switchgear Improvements based on new materials technologies

Not known Not known

More compact switchgear

allowing more circuits per

substation

Development of new

materials Not known

Medium Voltage Intelligent VCB

Low 11kV

Measurement, control and

protection functions all

incorporated into circuit

breaker. Internet type

interface allows remote

control of all functions

None Available now

ABB

Solid State Circuit Breaker

Low Not known Faster operation, reduced

maintenance. Design issues to resolve Not known

AREVA Superconducting Fault Current Limiter

High 3.5kV to 35kV

Allows increased fault

levels and therefore

increased distributed

generation.

Failsafe operation

Not known Not known












AREVA Magnetic Fault Current Limiter

High 3.5kV to 35kV

Allows increased fault

levels and therefore

increased distributed

generation.

Fail safe operation.

Not known Not known

Nexans Superconducting Fault Current Limiter

High Not known

Fail safe control of fault

levels. May reduce

reinforcement costs.

Cost. Substation space.

Cooling equipment.

Possibly 5

years to

commercial

availability

7.7.7.7. SECONDARY PLANT RESUSECONDARY PLANT RESUSECONDARY PLANT RESUSECONDARY PLANT RESULTS SUMMARYLTS SUMMARYLTS SUMMARYLTS SUMMARY

This sections details the manufacturers and their technologies with likely benefits from section 5 in tabular format. It should be

noted that the results column ‘Potential to Allow Increased Generation’ are subjective. Factors considered when determining the

potential are the ability to control increasing quantities of distributed generation. Technologies which relieve system bottlenecks

have been classified as having a lower potential to allow additional generation to be connected.












BarriersBarriersBarriersBarriers TimescTimescTimescTimescalesalesalesales

ABB SCADA, EMS Systems

High All voltages Fully integrated solutions

with advanced functionality.

DNOs may only be using the basic product

features.

Available now

AREVA e-terra SCADA/EMS

High All voltages

Fully integrated system allowing control over all system devices from

individual generators to system wide power

control.

None Available now

Remsdaq CallistoIES High Already in

use

Integrated control and monitoring of multiple

plant items. Wide range of communications protocols

and media

None Available now











BarriersBarriersBarriersBarriers TimescTimescTimescTimescalesalesalesales

Econnect GenAVC Medium 11kV

Can allow up to a doubling of size of DG schemes. Provides adjustment of voltage set points to optimise the network

voltages.

Acceptance of new concept by DNOs.

Development of 5-6MW schemes for 11kV

connection.

Ready for installation end

2005

Econnect Load Controller Low to medium

All voltages. Suited to

islanded and interconnecte

d grids (especially

weak systems)

Automatic load shedding system to mitigate voltage rise issues and maximise use of on-site generated

electricity

Under development September

2005

8.8.8.8. CONCLUSIONSCONCLUSIONSCONCLUSIONSCONCLUSIONS


Superconducting transformers are currently under development with no firm dates or

costs given for production units. It is considered that some units may be available

before 2010. There would be issues arising from the cooling system such as the

increased complexity and requirement for liquid nitrogen supplies. There would be

environmental benefits as insulating oils would not be required. They may allow

additional generation to be connected due to their improved voltage regulation

characteristics, but these would also result in higher fault levels.

Solid state tap changers are being developed which may provide more flexible system

operation. These may allow more generation to be connected if retrofitted to existing

transformers with limited reverse power capability. Costs were not available but it is

expected that production units would be available before 2010.

Two position tap changers may also provide greater system flexibility, especially if

they can replace existing fixed or off load tap changers. These would allow more

generation to be connected due to the larger voltage range. Costs were not available

but it is expected that production units would be available before 2010.

Dynamic rating equipment would allow the full temperature range, and therefore

power range, of transformers to be utilised. This equipment is in use outside the UK

and can be retrofitted. It may allow increased levels of distributed generation, but

only where network thermal capacity starts to constrain the allowable levels of

generation.

In-line voltage regulators have been shown to provide positive benefits and allowed

the connection of additional generation. They are not in widespread use in the Great

Britain but they have been included in this report due to the benefits provided.

8.28.28.28.2 Overhead Lines and CablesOverhead Lines and CablesOverhead Lines and CablesOverhead Lines and Cables

Superconducting power cables have been developed and are undergoing trials. No

costs or production dates were available. They would allow higher powers to be

transferred along the same cable corridor which may have benefits in congested

urban areas. The reduced impedance may allow more generation to be connected but

the advantages over conventional cables are considered to be marginal.

Dynamic conductor monitoring systems are in use outside the UK. They allow an

accurate cable rating to be determined which may increase the power transfer

capability of circuits. These systems may allow marginally more generation to be

connected where there are high levels of connected generation.

Composite overhead conductors would allow existing overhead circuits to be

substantially up-rated. In areas where there is a high concentration of generation their

use may allow more generation to be connected.

8.38.38.38.3 SVCs, FSVCs, FSVCs, FSVCs, FACTS and STATCOMsACTS and STATCOMsACTS and STATCOMsACTS and STATCOMs

A variety of SVC and STATCOM type devices are available and use around the world

and in the UK at transmission voltage levels. Due to the cost these devices are

normally employed at transmission level. Smaller more cost effective devices are

becoming available which would allow improved steady state and dynamic system

performance at distribution voltage levels. They could allow the connection of

additional generation by improving the fault ride through capability and providing

additional voltage regulation. The relatively high costs of these devices are

considered to be a barrier, in the short term at least, to their widespread use in the UK.

Distribution voltage SVCs are being installed by one DNO where in-line voltage

regulators do not provide a sufficient degree of voltage control.


A number of superconducting FCLs are under development. It is expected that these

would be available before 2010. They could allow significant amounts of additional

generation to be connected to systems where there would otherwise be fault level

issues.

Intelligent circuit breakers are available which have all the necessary functionality built

in including Internet type interfaces to allow remote operation. These would not

directly allow more generation to be connected but may make new connections more

cost effective.

New material technologies are expected to provide more compact switchgear

components that may result in the ability to install more equipment in existing

substations. This in turn may allow the connection of more generation.


Several organisations and institutions21, 22, 23, 24 in the US are undertaking R&D on

micro-grid network controllers. These would provide real time control for all active

devices on a section of distribution network. They would provide an interface

between the complexity of the distribution network and the centralised DNO control

system. Such systems should provide a simplified system for connecting a variety of

low voltage generators (DCHP, solar, micro wind etc) into a local distribution system.

Centralised SCADA/EMS systems are being continually developed to provide more

functionality. Advanced features include wind speed prediction, control of individual

generators and wind farms and market modelling. The increased capabilities will

allow additional generation to be more easily integrated into the existing system.

Improved methods of controlling the tap changers of 33kV/ 11kV (primary)

transformers are already developed and undergoing field trials on two distribution

networks. Power measurements are used to control the primary transformer tap

changer to enable the maximum generation to be connected whilst ensuring that all

voltages are maintained within acceptable limits. Studies undertaken to date indicate

that GenAVC™ could double the amount of generation that could be connected to a

network. It is expected to be in production in approximately 12 months.

Intelligent generation controllers are being developed that should allow improved

voltage control for systems incorporating generators. By optimising generator

operation the system should maximise the amount of generation that can be

connected to the system.

8.68.68.68.6 Communications SystemsCommunications SystemsCommunications SystemsCommunications Systems

No major communications related R&D activities were identified as part of this report.

New developments are utilising existing communications technologies to provide the

functionality required.

The main barrier to allowing increased amounts of generation is considered to be the

development of the communications infrastructure to support the needs of the various

technologies. Existing SCADA communications networks are considered to be

unreliable and too slow for the control of significant quantities of distributed

generation. As increased quantities of generation are installed a reliable, high speed

communications network may need to be established in order to provide the DNO

with sufficient levels of control and monitoring.

The suitability of existing communications protocols may need to be examined to

ensure compatibility between the DNOs and consumers’ equipment. IEC61850

specifies a communication standard for substation devices but not for devices located

elsewhere on the distribution system.

8.78.78.78.7 OthersOthersOthersOthers

A first generation expert system has been developed to evaluate connections options

for 11kV networks. Further software development and testing is underway to expand

the range of applicable voltages to 132kV. The system examines the impact of

proposed generation on voltage profiles and fault levels then identifies the most cost

effective connection.

More advanced design and analysis tools will be required in order that developers and

DNOs can design and operate networks comprising active management systems and

high levels of distributed generation more effectively.

8.88.88.88.8 SummarySummarySummarySummary

Most manufacturers’ R&D programmes are market led. Therefore products will only

be developed if a market has been identified. Some manufacturers have reported

issues with identifying customers’ needs and the uncertainty of future energy system

policy changes.

From the reviews undertaken it has been concluded that the most influential

technologies, in terms of maximising the potential for new generation, that should be

available before 2010 are: -

• Super-conducting Fault Current Limiters

o These devices would potentially remove any fault level issues where

additional generation may result in existing switchgear being

overstressed.

• SVCs, FACTS and STATCOMs

o These devices have been used to resolve voltage regulation issues

where generation is present. They can also improve power quality

but their high cost may restrict their application.

• In-line Voltage Regulators (not yet in wide-spread use)

o Although in-line voltage regulators are in use in the UK and therefore

outside the scope of this report, it is considered that they can allow

significant quantities of additional generation to be installed. This,

together with their very limited use in the UK, has resulted in their

inclusion.

• Micro-grid Controllers

o First generation controllers will soon be available which allow

generators to be incorporated into distribution systems whilst

maintaining satisfactory voltage control.

A number of areas were identified where further work may be required in order to

remove any potential barriers to the connection of additional generation. These are: -

• Communications Networks

o The successful connection and operation of large quantities of

distributed generation will require a high speed reliable

communications network to be established.

• Communications Protocols

o No standards were identified which covers communications

protocols between the substation and remote devices on the

distribution system.

The only overseas practice identified by manufacturers as being an improvement on

current UK practice was making fuller use of SCADA/EMS product features to improve

system operation and flexibility. Whilst this may allow additional generation to be

installed and easily controlled, the combination of the existing SCADA and

communications systems employed are not generally considered suitable for

controlling large numbers of distributed generators.

9.9.9.9. REFERENCESREFERENCESREFERENCESREFERENCES

1 EPSRC SuperGen Initiative, Workshop on Future Technologies for a Sustainable Electricity System,

November 2003, http://www.econ.cam.ac.uk/dae/Supergen-workshop/programme.html 2 University of Canterbury website. http://www.comsdev.canterbury.ac.nz/news/2004/040310a.shtml

3 Waukesha Electric Systems. http://www.waukeshaelectric.com/

4 Mitsubishi Electric Ltd, http://www.mitsubishielectric.com.hk/mehk/p&m/MAR/transform/sf6gis.htm

5 Dynamic Ratings Selected by Kansas Utility, T&D World, July 2004

http://tdworld.com/mag/power_dynamic_ratings_selected

6 Cooper Industries, http://www.cooperpower.com/Products/Voltage

7 Energy Networks Association, Engineering Technical Report 126, Guidelines for Actively Managing

Voltage Levels Associated with the Connection of a Single Distributed Generation Plant, August 2004.

8 J. W. Ekin, Superconductors – An Emerging Power Technology, 2004,

http://www.boulder.nist.gov/div818/81803/publications/ekin/GDX(2004).pdf

9 KEMA Dynamic Current Rating Optimisation, http://www.kema.com/

10

Extracting More Value with Intelligent Cable Systems, Transmission & Distribution World, Aug 1

2004 11

S. Sadler, 1600MVA Electrical Power Transmission with an EHV XLPE Cable System in the

Underground of London, CIGRE 2004 12

H. Ishihara, Development of Pre-Stretch Type Up-Rating Conductor to Realise Cost Reductions,

CIGRE 2004. 13

Composite Technology Corporation, www.compositetechcorp.com

14

American Superconductors, http://www.amsuper.com/

15

Nexans, http://www.nexans.com/internet/Welcome.nx

16

Demonstration of a Superconducting Fault Current Limiter, EPRI, Project P122.003,

http://www.epri.com/D2004/

17

ABB, www.abb.com

18

Econnect, www.econnect.co.uk

19

Remsdaq, www.remsdaq.com

20 ScottishPower plc, Network Management Systems for Active Distribution Networks – a Feasibil ity

Study, K/EL/00310/REP, 2004. 21

NREL, Reliable, Low Cost Distributed System Generator/Utility System Interconnect,

www.nrel.gov/publications/

22

NREL, Innovative Distributed Power Interconnection and Control Systems,

www.nrel.gov/publications/

23

NREL, Intelligent Solutions for Distributed Power Technology, www.nrel.gov/publications/

24

Consortium for Electric Reliabil ity Technology Solutions, http://certs.lbl.gov/certs.html 25

IEC61850, Communication Networks and Systems in Substations, 2003

APPENDIX A

Study Brief

New Technologies – To Facilitate Increased Levels of Distributed Generation

Study Brief

Purposes of Study

1. To identify what new technologies are available or emerging (in UK and world-wide) to

facilitate increased levels of Distributed Generation (DG) in the time frame to 2010

2. To provide a summary of the status of emerging technologies to help inform decisions about

what further work might be appropriate in this area.

Approach to Study

The study will be carried out in three stages.

Kick-off Meeting

A draft study brief will be prepared prior to the kick-off meeting. This document will define the scope of

the work required to undertake a structured and well-managed study. The Brief will describe the

approach to the Study; Risks/Dependencies/Assumptions; Quality Assurance etc.

At the kick-off meeting with the WS Project Manager, the study brief will be reviewed and approved,

and the number of manufacturers to be interviewed will be agreed.

Information Gathering

This stage will comprise the bulk of the work. It will include the following activities: -

• Identification of possible manufacturers/contacts and preparation of the questionnaire for the

interview with manufacturers

• Review of international developments from the literature: DTI/DGCG commissioned reports,

IEE, IEEE, CIGRE, Tyndall Centre, EPRI, web sources etc. Note will be taken in particular of

earlier DGCG studies, ‘Survey Study of Status and Penetration Levels of Distributed

Generation (DG) in Europe and the US (stage one and two)’ by KEMA (K/EL/00306/02/REP)

and ‘Network Integration of Distributed Generation: International Research and Development’

by SPRU (K/EL/00307/REP)

• Discussions with specialists within PB Power

• Telephone discussions with academic contacts

• Administration of questionnaires and/or structured interviews with selected manufacturers

This will be a world-wide review. It is envisaged that the technologies to be covered would include

primary and secondary plant infrastructure, telecommunications and IT. These technologies may

not yet be fully developed, commercially available, or be cost effective, compared to more

traditional approaches, but they should have the potential to be so by 2010. Existing technologies

not currently employed in the UK will also be covered. Only network related technologies will be

covered, ie generation related technologies will be omitted. Specific technologies to be addressed

could include wind generator control systems, SVC’s, FACTS and STACOM developments,

superconducting fault current limiters, in-line voltage regulators, substation automation and

integration of generator/voltage control, SCADA systems and associated communications.

Manufacturers to be contacted could include the following: -

1. ABB at Stone, Staffordshire for on-going developments in SVC (to stabilise voltage

fluctuations and provide grid interconnection); FACTS devices for wind generator

connections; Superconducting Fault Current Limiters etc

2. Siemens Power T&D Group at Manchester for developments in substation automation

systems

3. Peter Brotherhood based at Peterborough for innovations in designing and manufacturing

equipment for use in renewable energy applications

4. GE Wind Energy Systems for developments in wind turbines

5. VA Tech T&D for new switchgear developments

6. Eurowind Developments Limited for innovations in wind turbines

7. Alstom at Stafford

8. Thales Information Systems

The manufacturers to be contacted will be determined from the document reviews and discussion

with PB Power specialists in the UK and overseas.

Rev iew and Reporting

The final stage will consist of the following: -

• Review of information gathered and preparation of DRAFT report

• Review of comments from Work Stream

• Preparation of Final Report

The report will include: -

1) Tabulations of manufacturers and their products/technologies.

2) Classification of these technologies into functional groups.

3) Review and discussion of each of these groups of technologies covering:

• their function and applicability to the UK system.

• their potential to integrate more generation

• the ease with which they could be incorporated into existing systems and any issues which would

have to be addressed,

• their l ikely cost/benefit

• the timescales on which they are likely to become available

• a comparison of (advantages and disadvantages of) the different products / technologies

competing within each group

4) Conclusions about the impacts these technologies could have within the timescale of interest.

Information that is commercially sensitive to a manufacturer will be presented in an appendix or

similar and would not be placed in the public domain.

Reports would be produced in either Microsoft Word or Adobe Acrobat format as required by the

workstream.

Assumptions

It is assumed that this work will build on previous reports delivered under the DTI New & Renewable

Energy Programme, and will not go back over the same ground. Material presented in earlier reports

will not have to be reiterated in detail.

Risks

A lot of the input for this report will come from the manufacturers. There will therefore be risks

associated with the quality and timeliness of the information provided. There may also be difficulties in

commercial confidentiality. This will be addressed by contacting the manufacturers ahead of sending

the questionnaire and carrying out a structured interview, in order to identify the correct individual to

approach, and to ensure that the purpose of the exercise is fully understood. The benefits to the

manufacturer in contributing to the report will be highlighted, and any confidentiality concerns

discussed and addressed. Any material which the manufacturers consider confidential will not be

published in the public domain report but may be included in a restricted appendix.

Staffing and QA

The majority of the work will be carried out by a senior engineer, Steve Ingram, who has

experience of carrying out previous studies for the DTI N&RE Programme, and meeting the

requirements of a DGCG workstream.

Guidance and peer review will be provided by Katherine Jackson and John Douglas. Katherine has

managed other DTI N&RE projects, and John has extensive experience of distribution network

technologies.

Timescales

It is intended to produce a Draft Final report by the 24th

September 2004 to allow it to be presented at

the workstream meeting on the 30th September. The Final version of the report will be issued in mid

October, assuming that workstream comments are received within approximately two weeks. This will

depend to some extent on the speed of response of the manufacturers

APPENDIX B

Questionnaires sent to Manufacturers

APPENDIX B –Questionnaires sent to Manufacturers

The following questionnaire was sent out to a number of manufacturers with UK offices.

Manufacturers Questionnaire

We have been asked by the Department of Trade and Industry (DTI) in the UK to establish the status

of the new technologies that could influence the power distribution industry over the next ten years.

The purpose of this study is to identify the potential new technologies that may be applied in the UK

and to enable them to concentrate their R&D funding on technologies that may have a commercial

future.

Specifically the DTI’s requirements are summarised as follows: -

“This will be a world-wide review. It is envisaged that the technologies to be covered would

include primary and secondary plant infrastructure, telecommunications and IT. These

technologies may not yet be fully developed, commercially available, or be cost effective,

compared to more traditional approaches, but they should have the potential to be so by

2010. Existing technologies not currently employed in the UK will also be covered. Only

network related technologies will be covered, ie generation related technologies will be

omitted. Specific technologies to be addressed could include wind generator control systems,

SVCs, FACTS and STATCOM developments, superconducting fault current limiters, in-line

voltage regulators, substation automation and integration of generator/voltage control,

SCADA systems and associated communications.”

We understand from publicity that your company may be involved in product development or R&D

which could enhance the current UK distribution system and allow the connection of increasing levels

of distributed generation.

As detailed in the covering e-mail we would like to meet to discuss your company’s plans for such

technologies. In order that we can have a useful discussion we have compiled some questions,

below, which we would use as a basis for any meeting: -

• Outline any current products which are used in overseas distribution systems which could

benefit the UK system

• Are any products in development that may increase the ability of distribution systems to

accept more distributed generation, or to delay reinforcement?

• If possible, discuss the company’s current areas of research on distribution technologies

• Outline the areas in which the company expects current distribution technologies to develop

over the next five years

• Outline the areas in which the company intends to undertake research over the next five

years

The DTI is actively encouraging increased levels of distributed generation, and therefore the current

distribution system may require significant changes in order to satisfy future needs. Funding may be

available to support any technologies or R&D projects that aim to improve the capacity of the current

distribution system.

We acknowledge that there will almost certainly be confidentiality issues surrounding your research

and products. In order that the DTI gains the most benefit from this study we would be willing to abide

by a confidentiality agreement in order that sensitive information would not be disclosed. Such

information would be included in a report appendix but would not form part of the document released

into the public domain.

The following questionnaire was sent out to a number of manufacturers with no UK offices.

Sirs,

We have been asked by the Department of Trade and Industry (DTI) in the UK to establish the state

of the new technologies that could influence the power distribution industry over the next ten years. The purpose of this study is to identify the potential new technologies that may be applied in the UK

and to enable them to concentrate their R&D funding on technologies that may have a commercial future.

Specifically the DTI’s requirements are summarised as follows: -

“This will be a world-wide review. It is envisaged that the technologies to be covered would include

primary and secondary plant infrastructure, telecommunications and IT. These technologies may not yet be fully developed, commercially available, or be cost effective, compared to more traditional

approaches, but they should have the potential to be so by 2010. Existing technologies not currently employed in the UK will also be covered. Only network related technologies will be covered, ie

generation related technologies will be omitted. Specific technologies to be addressed could include wind generator control systems, SVCs, FACTS and STATCOM developments, superconducting fault

current limiters, in-l ine voltage regulators, substation automation and integration of generator/voltage control, SCADA systems and associated communications.”

We understand from your publicity that you are presently working on dynamic reactive compensation, high temperature superconductor cables and other methods of improving power quality.

Would you be able to confirm that you are still working on these technologies and when they are

expected to reach the commercial market?

We would also appreciate any information about any other exciting areas of research that you are undertaking that could be of interest to the power generation or power distribution industries.

We acknowledge that there may be confidentiality issues surrounding your research and products, but

would of course welcome any high level information that you would be prepared to share.

Many thanks for your time and cooperation

Best Regards

Stephen Ingram

Senior Power Systems Engineer

PB Power Ltd

Energy and Uti li ty Consulting

Manchester Technology Centre

Oxford House

Oxford Road

Manchester

M1 7ED

<mailto:[email protected]>

Direct Line: 44(0)161 200 5203

Fax: 44(0)161 200 5001

APPENDIX C

Responses from Manufacturers

APPENDIX C – Manufacturers Responses

The following pages contain the results of the manufacturers written responses to the various

questionnaires.

Company /

Institution: - University of Canterbury / CanterburyTX

Technology: - Transformers

Products: - High Temperature Superconducting Transformers

The University of Canterbury (NZ) is currently undertaking research into the development of

HTS transformers. CanterburyTX is the company responsible for manufacturing the

prototype and possibly production transformers.

In addit ion to the details obtained from the w ebsite additional correspondence w as

conducted as follows: -

From: Bodger, Pat [[email protected]]

Sent: 30 September 2004 22:44

To: Ingram, Stephen

Subject: RE: DTI New Technologies

Hi Steve

What are the reactance characteristics of an HTS transformer compared to

normal power transformers?

>With respect to leakage reactance it is smaller because of the thinness

and

the flux exclusion effects of HTS wire. You don't get the same leakage

flux.

>With respect to the magnetizing reactance, our partial core transformer

has

a higher reluctance for the magnetic circuit than a conventional full core

transformer. This means a lower magnetizing inductance and hence

reactance.

Hence there is an increase in shunt reactive current going into the

transformer. This is not necessarily a bad thing as it could be useful for

reactive compensation of cable capacitance.

If the reactance is significantly reduced then there may be no need for a

tap changer? Voltage regulation on the LV side may be improved and fault

levels increased.

> In this you are referring to the leakage reactance. I can agree with

your

statements. Voltage regulation on our unit is low relative to a normal

transformer.

Also, would you be able to provide some information with regards to any

future power system related R&D projects which you may be involved in?

> While the HTS transformer is our main thrust, we have developed a

resonant testing transformer and are looking at our HTS transformer as a

reactive compensator and fault current limiter.

Hope these responses are useful, but you may also wish to visit the

department website www.elec.canterbury.ac.nz and look under Research groups

and the Electric Power Engineering Centre and the Power Engineering Group.

These will give you an overview of the extent of our research.

Best regards

Pat

Company /

Institution: - Remsdaq

Technology: - Remote Terminal units (RTUs)

Products: - CallistoIES

Meeting Date: - 7th October 2004

Location: - PB Pow er Offices, Manchester

Remsdaq are a UK based company developing and marketing RTUs to the pow er

generation and distribution business. In addit ion to the interview they provided a w ritten

response to the questionnaire as reproduced below : -

I - Response to Questionnaire

Q1- Outline any current products which are used in overseas distribution systems which could benefit

the UK system.

A1- Remsdaq’s Callisto RTU has been used widely both in Overseas and UK electricity distribution

systems. Please see the attached application summary entitled ‘Callisto in Power Distribution’.

Q2- Are any products in development that may increase the abil ity of distribution systems to accept

more distributed generation, or to delay reinforcement?

A2- Callisto RTU already provides functionality and features applicable to distribution automation and

distributed generation. Please refer to the attached application summary entitled ‘Callisto in Power

Distribution’.

Q3- If possible, discuss the company’s current areas of research on distribution technologies.

A3- Remsdaq places great emphasis on its research and development facil ities, and has a strong

R&D Department. The Company’s development plans are both technology and customer based to

meet the needs of the ever increasing worldwide de-regulated electricity industry.

Current development areas include the next generation Callisto RTU taking advantage of latest

electronics / microprocessor technologies and available components, with an expandable and

innovative hardware platform. Ethernet connectivity and GPRS communications are the latest

additions to the Callisto networking and communication facilities.

Q4- Outline the areas in which the company expects current distribution technologies to develop over

the next 5 years.

A4- Relevant to the RTU element, IEC61850 standard is an important area of development. An area

which also should be looked at is the definition of a 3-phase object within the protocol(s).

Developments / advances in communications technology / systems / equipment will open other areas

for RTU development. These would be expected to include utilising low cost communications media,

communication speeds, and communications security.

Current areas of interest to the distribution network operators include fault condition monitoring and

asset management and control, some of which are already within the RTU capabilities, with further

developments / facil ities are in sight.

Q5- Outline the areas in which the company expects current distribution technologies to develop over

the next 5 years.

A5- Please see A4 above.

II_- Callisto in Power Distribution

1- Selected Callisto features

a)- Callisto is an advanced technology, versatile, and flexible RTU. It can provide most, if not all,

information for the monitoring, control and protection of the electricity network. Utilising a networked

distributed architecture, the RTU can be used in both distributed and concentrated arrangements.

The unit is fully scalable and is suitable for use in RTU applications ranging from small (e.g. pole-

mount) to large (e.g. fully equipped primary transmission and distribution substations). The product is

specifically designed to meet the needs and requirements of the electric utili ty sector, and has been

type tested to stringent EMC and Environmental standards.

b)- Callisto has a fully flexible RTU functionality, which is augmented by its inherent intelligence. The

unit is fully user configurable, and user programmable for automation and logic functions using

IEC61131-3 guidelines. Programmes can be designed with over 1000 logic and arithmetic functions

including PID controllers. RTU Programmes can reside on specific nodes or can be distributed

across the entire remote. Example applications for embedded generation would include load

shedding, generator / load scheduling, and alike (please see 2 below).

c)- Callisto’s transducerless technology allows direct connection of AC signals from VTs and CTs.

Signals are sampled at 128 samples per cycle, with simultaneous (synchronous) sampling of

individual voltage and current phases to allow true rms calculation of voltages and currents to high

levels of accuracy. Using a dedicated DSP (Digital Signal Processor) metering values including real

power, reactive power, total power, kWh, kVARh (import, export, net), are calculated per phase

and in total. Other calculated power parameters include power factor (per phase), supply

frequency, and neutral current.

In addition, power quality and supply analysis data are computed for positive, negative and zero

phase sequence components, and for indiv idual v oltage and current harmonics up to the 50th

and THD (Total Harmonic Distortion) using advanced FFT (Fast Fourier Transform) algorithms for

harmonics calculations.

Analogue Limit Excursions (ALEs) against user defined limits are time stamped and recorded (for

surges, sags, and other transients).

Disturbance recording facil ities within each RTU node allows the recording of disturbances for 12 user

assignable data tracks, each providing 1 second of data, with 3 sets of buffer registers allowing the

storage of multiple disturbances. Such information can be used by the user for disturbance analysis,

network design / optimisation, etc.

d)- Callisto supports a variety of communication media, including fixed circuits, fibre optics, dial up

(PSTN), UHF radio, low power radio, private mobile radio (PMR), power-line carrier (PLC),

Paknet, GSM, Satellite, Ethernet, GPRS, etc.

The RTU has a rich library of communication protocols ranging from industry standard protocols such

as DNP3.0, DNP3.0 I/P, IEC60870-5-101, IEC60870-5-103, IEC60870-5-104, Modbus, to proprietary

protocols (e.g. ABB SPA-Bus, Areva K-series & M-series, Siemens, SEL, GE DFP & DLP, etc.), for

communication with SCADA/EMS/DMS master stations and IED.

A variety of communication topologies and architectures including master-slave, master-master,

multiple master, slave RTUs and IEDs, point-to point, point-to-multipoint, multi-dropped,

backup and redundant bearers, etc. are available with Callisto. RTU redundancy is also available

for mission critical systems.

2- Applications in Distributed / Embedded Generation

a)- At the generator plant the RTU can be utilised for the monitoring and control of local plant. The

RTU can be scaled to suit the plant I/O requirements and where existing RTUs and PLCs are used it

can also be used to interface with such units through a variety of protocols.

The transducerless features can be used to derive direct power measurements and calculate / record

parameters and data such as real and reactive power, total power, kWh, kVARh, (import, export, net)

per phase and total, power factor per phase, supply frequency, power quality and harmonics,

transients and disturbance data. The RTU’s synchronising facilities can be used for synchronisation

of the plant output with the network. The ability of the RTU to readily establish / calculate import and

export of power provides valuable information for load scheduling / forecasting applications.

Automatic control of the plant can be used by utilising the flexible user defined logic applications. The

generator plant RTU can also communicate with (and be remotely controlled from) SCADA/EMS/DMS

master station or ‘master’ RTU(s) (e.g. RTU at primary substation or control centre, etc.). Such

automation would allow automatic connection / disconnection of the generator from the network in

case of defined faults / conditions, at scheduled intervals, due to outage of other duty generators,

network faults, network operational strategies, schedules, supply routings / re-routings, etc.

b)- RTUs at secondary substations, ground mounts, pole-mounts can be employed for the monitoring

and control of plant data and network conditions. Local automation functions can be defined using the

RTU’s flexible user defined logic functions / applications. This could also include automatic

transformer tap changes.

The transducerless configuration can be used to derive direct power measurements and calculate /

record parameters and data such as real and reactive power, total power, kWh, kVARh, (import,

export, net) per phase and total, power factor per phase, supply frequency, power quality and

harmonics, transients and disturbance data.

The RTU can also communicate with (and be remotely controlled from) SCADA/EMS/DMS master

station or ‘master’ RTU(s) (e.g. RTU at primary substation or control centre, etc.) for network

operational strategies, supply routings / re-routings, and alike.

c)- At the primary substation the RTU can be scaled to suit the local I/O requirements and the

communications with its slave RTUs and IEDs. The unit can be arranged in a distributed and / or

concentrated configuration to correspond with the plant requirements.

RTU’s intelligence and user defined logic capabilities can be utilised to define flexible control and

automation strategies for both local and remote control functions. Local automation could include

Line Throw Over (LTO), Bus Throw Over (BTO), under-frequency load shedding, transformer tap

control, etc. Remote automation functions could include network supply routings / re-routings,

generator scheduling, etc. Dependent on the arrangements and network topologies / operations, the

latter can encompass the monitoring and control / automation of large or small sections of the grid.

As a result of the readily available data (including power parameters calculated under the

transducerless arrangement at both the primary substations and its slave satellite RTUs) efficient

control algorithms can be defined to cover a variety of strategies including the control of reverse

power flow in primary transformers, import /export flow control, generator isolation under network fault

conditions, etc.

The RTU’s transducerless capabilities allows the derivation of direct power measurements and

calculation / recording of parameters and data such as real and reactive power, total power, kWh,

kVARh, (import, export, net) per phase and total, power factor per phase, supply frequency, power

quality and harmonics, transients and disturbance data.

The RTU can communicate both upwards to one or more SCADA/EMS/DMS masters and downwards

to ‘slave’ RTUs (e.g. secondary substation, pole-mount and ground-mount RTUs, etc.) using a library

if industry standard and proprietary protocols. A wide range of communications media are supported.

new technologies to facilitate increased levels...

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