report on completion of deliverable 8.2 installation of

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LCE-04-2017 Innovation Action

An Integrated Platform for Increased FLEXIbility in smart TRANSmission grids with

STORage Entities and large penetration of Renewable Energy Sources

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 774407

Report on Completion of Deliverable 8.2 – Installation

of Power Flow Control Devices in Greece

Reporting Date

31/05/2019

Report on Completion of Deliverable 8.2

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Table of Contents

Table of Figures 3

Table of Acronyms 4

1. Purpose of this Report 5

2. Variation in Deliverable 8.2 5

3. Power Flow Control Devices 5

4. The Mobile Container 6

5. Communications 7

6. Line Selection 8

7. Outage No 1 – Installation of Support Structures and Preparation of Overhead Lines 10

8. Preparation of the Mobile Container 11

9. Preparation of the Communications 13

10. Outage No 2 - Installation of the PFC devices 15

11. Establishment of the Communications 15

12. Demonstration of the PFC Devices 16

13. Summary 17


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Table of Figures

Figure 1 : Electrical schematic of Power Guardian .......................................................................... 5

Figure 2 : View of the Mobile Container, mounted on a trailer and towed by a tractor unit ....... 6

Figure 3 : View of the inside of the Mobile Container ..................................................................... 7

Figure 4 : Schematic of Communications Arrangements for the Project ....................................... 8

Figure 5 : Contingency Without PFC Devices ................................................................................... 9

Figure 6 : N-1 Contingency with PFC Devices ................................................................................... 9

Figure 7 : Support Structures .......................................................................................................... 10

Figure 8 : Condutors with Insulators and Jumpers Installed ........................................................ 11

Figure 9 : PFC Devices Above the Roof of the Mobile Container .................................................. 12

Figure 10 : Connections from PFC Devices to Support Structures Installed ............................... 13

Figure 11 : Communications Cabinet .............................................................................................. 14

Figure 12 : Completed Installation of the Mobile Container ......................................................... 15

Figure 13 : Line Current Response at Different Levels of Injection ............................................. 16


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Table of Acronyms

EMS Energy Management System

ESO Electrical System Operator, the Bulgarian electricity transmission operator

IPTO Independent Power Transmission Operator S.A., the Greek electricity transmission operator

PFC Power Flow Control


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1. Purpose of this Report

This report explains the steps that were taken to complete Deliverable 8.2 – the installation of Smart Wires Mobile Container incorporating six Power Guardian Power Flow Control (‘PFC’) devices at IPTO’s substation at Megalopolis.

The installation was undertaken in two phases. First, an outage was taken to prepare the overhead lines in order that the PFC devices could be connected, and subsequently a second outage was taken to install the PFC devices themselves. During each outage, power to the line was turned off to ensure a safe working environment.

2. Variation in Deliverable 8.2

Deliverable 8.2 originally envisaged the installation of PFC devices in Bulgaria during 2019 with redeployment to Greece the following year.

IPTO had identified a substation for the project and a 150 kV line on which to install the PFC devices at Megalopolis in the Peloponnese, but subsequently discovered that a new 400 kV line, connecting into that substation and due to be introduced into service in late 2019, would significantly reduce the power flows on the 150 kV line. Since the PFC devices require a minimum level of current to operate (128 amps) and a higher level to inject reactance into the line (255 amps) there was a risk that current levels on the line would not meet these requirements after the new 400 kV line entered service, leading to the project being unable to be undertaken in Greece.

As a result, and with the agreement of ESO, the Bulgarian transmission operator on whose network the PFC devices were originally to be installed first, it was decided to install initially in Greece and then subsequently to install in Bulgaria.

3. Power Flow Control Devices

The PFC devices used in this project are Smart Wires’ Power Guardians, model 390-850. These units increase the reactance on power lines on which they are mounted by injecting magnetizing reactance generated by an internal transformer into the lines on command. Each Power Guardian 390-850 is capable of injecting a minimum of 427m.

PFC devices are installed in series and the number of devices installed will depend on the volume of reactance required. The units operate by generating reactance in the secondary of the transformer, which can then be injected into the line when a switch is opened. The Silicon Controlled Rectifier then causes the reactance to be injected. The internal electrical schematic is shown in Figure 1.

Figure 1 : Electrical Schematic of the Power Guardian


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The PFC devices can be controlled in number of ways. They can be programmed to turn on when a certain level of current is seen on the line. The control arrangements can be integrated into the Energy Management System (‘EMS’) of the utility deploying them allowing direct control through the EMS. For this project, given the short duration that the PFC devices will be installed in both Greece and Bulgaria, it was agreed that the PFC devices would be controlled through a laptop computer at the System Operations Centre of whichever transmission utility operated the network of the country in which the Mobile Container was then installed.

4. The Mobile Container

The Mobile Container has been developed from a standard 40-foot (12.2 metre) shipping container and contains the PFC devices and provides a means for their transportation. The Mobile Container can be transported by sea on container vessels and on land by being placed on a trailer and pulled by a tractor unit.

The Mobile Container contains all other tools and equipment required to install the PFC devices.

Figure 2 shows a view of the Mobile Container as it was brought to the installation site, and Figure 3 shows the inside of the Mobile Container before it was unpacked ahead of the PFC devices being deployed. One Power Guardian can be seen on the right-hand side of the Container (above the red structure) as it is stored during transportation.

Figure 2 : View of the Mobile Container, mounted on a trailer and towed by a tractor unit


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Figure 3 : View of the inside of the Mobile Container

5. Communications

Communications between the PFC devices and the laptop referred to in Section 3 above is first through encrypted ISM (Industrial, Scientific, Medical) radio signals. The ISM frequencies are radio bands reserved for the use of radio frequency energy for industrial, scientific and medical purposes other than telecommunications.

The ISM signals are collected by a radio antenna connected to a PowerLine Coordinator, a device that manages the secure wireless link between the PFC devices and a PowerLine Gateway, which provides for operation and management of the PFC devices and supports multiple communications approaches. In this case, the next stage of communications is by secure GSM (telecoms) signal to a secure website located in Europe. The laptop computer is able to communicate with the secure website through a proprietary program called SmartInterface and thereby control the PFC devices.

Figure 4 is a schematic of the communications arrangements.


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Figure 4 : Schematic of Communications Arrangements for the Project

6. Line Selection

The Mobile Container was selected to be installed in the Peloponnese Region of Greece, in the High Voltage Substation at Megalopolis.

Initially, simulations were conducted using PSS/E grid planning software in order to assess the expected impact of the PFC devices. After identifying a post-contingency overload, IPTO modelled the Mobile PFC application on one of two short 150 kV parallel single-circuit overhead transmission lines to increase the line’s impedance. The results of this study indicated that a deployment of Mobile PFC devices could reduce loading on this particular line by 17%. The Mobile PFC application reduces the thermal overload by increasing the line’s impedance and pushing power to other under-utilised lines.

Figures 5 and 6 below demonstrate the expected impact of the PFC devices on the selected line.


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Figure 5 : Contingency Without PFC Devices

Figure 6 : N-1 Contingency with PFC Devices


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Figure 5 shows that the selected line faces overload during a contingency. The PFC devices allow for the redirection of the power flow, as shown in Figure 6, by reducing the current on the line by 17%.

Installation of the Mobile Container

7. Outage No 1 – Installation of Support Structures and Preparation of Overhead Lines

Before commissioning the first outage, some preparatory works took place in the substation. Specifically, concrete bases were built above ground in the substation in order to accommodate the installation of support poles that will hold the cables connecting the PFC devices to the network. The construction of these structures lasted around 15 days.

Afterwards, during the commission of the first outage, on May 7 and 8, insulators were added to the lines in order that the lines could be ‘broken’ from an electrical perspective to allow the PFC devices to be connected to the network.

The support structures each comprise a concrete base with a lattice tower structure bolted to the top of it and with a post insulator then mounted on top of the lattice tower. Figure 7 shows some of the support structures before the cables were connected.

Figure 7 : Support Structures

The overhead line conductors were prepared for the installation by having insulators placed in between sections of conductor. These prevent current flowing along the line, so to maintain the flow of electricity on the line after this first outage was completed, jumpers (small sections of conductor) were connected to the line outside where the insulators had been installed to maintain the circuit. Figure 8 shows the conductors, with the insulators installed after the work undertaken in the first outage had been completed. Due to space considerations, IPTO needed to tap into the overhead line mid-span where the overhead line transitions from being a vertical-stacked to a horizontal configuration at the substation gantry.

Support Structure

Post insulator

Lattice tower

Concrete base

Concrete base


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These spatial and configuration challenges led the team to develop a clever, yet simple means of tapping into the overhead line while maintaining the necessary phase-to-phase electrical safety clearances.

Figure 8 : Condutors with Insulators and Jumpers Installed

8. Preparation of the Mobile Container

Preparation of the Mobile Container started on May 14. The Mobile Container was brought to the place where it was to be installed in the substation, between the support structures described in Section 7.

It was decided not to commence preparation of the Mobile Container during the first outage to avoid any risks that might arise through setting up the Mobile Container whilst other work was being undertaken on the overhead lines immediately above.

The steps taken to prepare the PFC devices for connection to the grid were:

▪ Remove certain of the roof panels on the Mobile Container (to allow the PFC devices to be lifted

up above roof level);

▪ Raise the PFC devices (in pairs) so that they just protruded slightly above the roof;

▪ Bring the insulators that will support the PFC devices beneath the devices themselves and bolt

the two items together;

▪ Raise the insulators and PFC devices into their installation position;

▪ Secure the insulators into position by bolting the support structure used to raise the insulators

inside the Mobile Container.

The PFC devices and the insulators were raised by an electric lift built into the Mobile Container. A small mobile generator was used to provide electrical power to the lift.

Figure 9 shows the Mobile container with four PFC devices fully deployed and two more protruding slightly above the roof.


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Figure 9 : PFC Devices Above the Roof of the Mobile Container

The day before the connection of the PFC devices to the grid, connections from the PFC devices to the top of the support structures were installed. Figure 10 shows these connections.


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Figure 10 : Connections from PFC Devices to Support Structures Installed

9. Preparation of the Communications

The communications hardware (comprising PowerLine Coordinators and PowerLine Gateways – two of each were installed, one as a primary and the other as a backup) together with other supporting equipment (such as a power supply) were installed in a small waterproof metal cabinet close to the Mobile Container. The cabinet had poles attached to it to support the radio and GSM antennae. Figure 11 shows the cabinet.


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Figure 11 : Communications Cabinet


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10. Outage No 2 - Installation of the PFC devices

Installation of the PFC devices took place on May 14. The steps that were taken were as follows:

▪ The power to the line was turned off at around 7 AM;

▪ The jumpers (maintaining the power flows on the line after the insulators were installed) were

removed;

▪ New jumpers were attached to the lines;

▪ The other ends of the jumpers were attached to the support structures, thereby completing the

connection to the PFC devices;

▪ The systems Operator was advised that the line could be returned to service at 12.30 PM, after

an outage of just 5½ hours.

Figure 12 shows the completed installation.

Figure 12 : Completed Installation of the Mobile Container

11. Establishment of the Communications

After power had been returned to the line, establishment of the communications began.


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Initially, the current level was on the margin of the PFC devices being able to operate and the systems operator kindly increased the current to 180 amps. This allowed communications to be established and all of the preliminary checks of the comms system to be undertaken and for Smart Wires to confirm that the comms was working properly.

After the check was completed, the results of the installation process and a manual of operation were presented to IPTO’s engineers in the National Dispatching Centre. Shortly afterwards, a live demonstration took place, and the PFC devices successfully managed to reduce power flows on the selected line.

12. Demonstration of the PFC Devices

As mentioned above, on May 16, a presentation took place in IPTO’s premises and, afterwards, the PFC devices were tested live by Smart Wire’s and IPTO personnel.

Figure 13 shows the results of this short demonstration .

Figure 13 : Line Current Response at Different Levels of Injection

Initially, the current level was not sufficient for the PFC devices to enter injection mode. This was expected, as in May the electrical demand is at its lowest values, which was one of the reasons why this month was selected for the installation. This prompted IPTO’s dispatchers to take out a parallel line in order to increase the current and allow the devices to inject reactance. In Figure 13, the line’s current is shown, scaled between 0 and 1. The x-axis represents a time step of 9 seconds.

At first, one PFC device on each phase was used to inject 50% of the nominal reactance on the line. Afterwards, these devices were turned back to monitoring mode, and, subsequently, both devices on each phase were turned to injection mode, generating 100% of the nominal reactance on the line.


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Manual mode of operation was used in all cases. In both injection cases, the line’s current instantly dropped, showcasing the device’s ability to redirect power flow to adjacent lines. Percentage-wise, when both devices on each phase were in injection mode, the reduction in line current seen was around 30 %.

13. Summary

The installation was completed successfully to the schedule that had been established and agreed between the parties. There were no reportable incidents, or indeed incidents of any nature, arising during the undertaking of the works described in this report.

The PFC devices will be in operation for at least six months and will be tested regularly by IPTO, provided that the minimum current requirements are met. IPTO’s team is expected to establish a methodology of testing the PFC devices, specifically, IPTO’s engineers plan to test both the manual and automatic operation of the devices. Additionally, case studies are being developed that will showcase the impact of the device under various operational circumstances, both normal and under contingency.

report on completion of deliverable 8.2 installation of

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