power quality standards roadmap - ieee-sagrouper.ieee.org/groups/scc22/files/2005-09-14 pq roadmap -...

Roadmap For Power Quality Standards Development

IEEE PCIC 2005Production Technical SessionSeptember 14, 2005Denver, Colorado

IEEE Power Quality Standards

Coordinating Committee (SCC22)

Authors:

David B. Vannoy, P.E., Chair

Mark F. McGranghan, Vice Chair

S. Mark Halpin, Vice Chair

D. Daniel Sabin, Vice Chair

William A. Moncrief, P.E., Secretary

IEEE POWER QUALITY STANDARDS COORDINATING COMMITTEE

(SCC22)

The PQ Standards Roadmap

What is the role of PQ standards?

What about North American vs International Standards?

What needs to be in PQ standards?

What are the existing standards?

What’s being done now?

What needs to be done?

How do we get the rest of the way?


(SCC22)

The Role of PQ standards

Role - Provide a common basis for evaluating PQ concerns,

system performance, and equipment performance

Goal – Achieve coordination

between the characteristics of

the power system and the

requirements of end use

equipment


(SCC22)

Role of PQ Standards, cont.

Definitions, Indices

Measurement and monitoring procedures

(standardized characterization)

Benchmarking (expected power quality levels)

Power Quality Guidelines and Limits “Compatibility

Levels”

– PQ requirements for the supply system

– PQ immunity for equipment

– PQ disturbance generation limits for equipment

and customer systems

Application guidelines (including economics)


(SCC22)

Who develops PQ standards?

Power Quality Standards in North America

– IEEE (mostly PES & IAS)

Generally not equipment specific

– Voluntary compliance

– SCC22 (PQ Standards Coordination)

International Power Quality Standards

– International Electotechnical Commission (IEC)

Electromagnetic Compatibility (EMC) Standards

– Individual countries may adopt as performance requirements


(SCC22)

IEEE Power Quality Standards Activities

IEEE Power Quality Standards Coordinating Committee (SCC22)

– Created in 1991 as coordinating body for Power Quality Standards

within IEEE

– Historically focused primarily on Power Quality Standards

Development in IAS and PES

– Provided home of last resort for standards projects not within

scope of other sponsoring societies

– More recently adjusted focus to include international Power Quality

Standards efforts

– Membership consists of persons actively involved in Power Quality

Standards Development


(SCC22)

SCC22 Scope

The Committee is responsible for coordinating IEEE activities related to the quality of electric power as it affects equipment, users, utilities, power and communications systems. This scope also includes development of guides, recommended practices, standards, common definition of terms and phenomena. The SCC22 will identify needed standards within the area of power quality and locate sponsors within IEEE to undertake the development of such standards including designation of appropriate Working Groups (Subcommittees) to serve as the sponsor for the project.


(SCC22)

IEEE Power Quality Standards Activities, cont.

Industry Applications Society– Color Books – IEEE Std. 1100 Emerald Book

Joint IAS/PES Standards – IEEE Std 519-1992 – Harmonic Distortion

– IEEE Std 1436 – Power System and Process Equipment Compatibility

– IEEE P1564 – Voltage Sag Indices

Power Engineering Society– IEEE Std 1159 – Monitoring Power Quality

– IEEE Std 1250 – Equipment Sensitive to Voltage Disturbances

– IEEE P1409 – Custom Power

– IEEE Std 1453 – Flicker


(SCC22)

IEC Power Quality Standards Activities

Subcommittee 77A – Low Frequency Phenomena, of IEC

Technical Committee 77: Electromagnetic Compatibility

IEC 77A Power Quality Related Working Groups

– WG 1 – Harmonics and other Low frequency disturbances

– WG 2 – Voltage Fluctuations (flicker) and other low Frequency

Disturbances

– WG 6 – Low Frequency Immunity Tests

– WG 8 – Electromagnetic Interference Related to the Network

Frequency

– WG 9 – Power Quality Measurement Methods


(SCC22)

Structure of basic and generic EMC Standards - IEC

Part 1: General (IEC Pub 61000-1-x)

– fundamental principles, definitions, terminology

Part 2: Environment (IEC Pub 61000-2-x)

– description, classification and compatibility levels

Part 3: Limits (IEC Limits 61000-3-x)

– emission and immunity limits, generic standards

Part 4: Testing and measurement (IEC Pub 61000-4-x)

– techniques for conducting

Part 5: Installation and mitigation (IEC Guide 61000-5-x)

– installation guidelines, mitigation methods and devices

Part 6: Generic and Product Standards (IEC Pub 61000-6-x)

– immunity levels required for equipment


(SCC22)

PQ Concerns

Steady State Power Quality Characteristics– Voltage regulation

– Unbalance

– Harmonics and Interharmonics

– Flicker

Disturbances– Voltage sags (dips) and swells – RMS variations

– Transients

– Momentary interruptions

– Outages (reliability)


(SCC22)

Voltage Regulation and Unbalance

Power system constantly adjusting to changes in

load

Long duration voltage variations result from these

changes.

Best expressed with profiles and statistics

– Undervoltages and overvoltages

IEEE Std 1159 defines long duration as those > 1 minute

ANSI C84.1-1995 limits: +6%, -13%

EN 50160 limits: +/-10%, 95% of 10 minute values for a week


(SCC22)

Voltage Regulation


(SCC22)

Voltage Unbalance

– Unbalance

ANSI C84.1-1995 limit: 3% Maximum at the meter under

no load conditions

Motors operating between 1% and 5% unbalance should

be derated

EN 50160 limit: 2% for systems with three phase load,

3% for systems with single phase load, 95% of 10

minute values for a week


(SCC22)

Flicker

Voltage fluctuations associated with flicker usually do not exceed

ranges specified by C84.1

Result in visible fluctuation in light intensity

North American defacto Standard “GE Flicker Curve” recently

replaced with IEEE 1453 that is based on IEC 61000-4-15

IEC flicker meter output

– Pst Short term flicker severity - made up of 10 minute samples

– Plt Long term flicker severity - made up of 12 successive Pst

values

3

12

1

3

12

1

j

stlt jPP


(SCC22)

Flicker, cont.

Comparison of 120 volt and 230 volt flickermeter weighting

curves (Pst =1 curves for rectangular variations)


(SCC22)

Flicker –What is needed?

Method of applying flicker limits to end users,

taking into account circumstances of

individual systems

Application guidelines for characterizing

impacts of individual users and loads

Economics – where is best place to correct

flicker problems?


(SCC22)

Harmonics and Interharmonics

Voltage Harmonic Distortion

– Interaction of harmonic currents with system impedance

– IEEE 519-1992 IEEE Recommended Practices and Requirements for

Harmonic Control in Electrical Power Systems

End users limit harmonic currents injected into system

Suppliers control harmonic voltage distortion addressing resonances

Guidelines for acceptable levels of voltage distortion on the utility system at

the Point of Common Coupling (PCC)

Maximum Individual

Harmonic Component (%)

Maximum

THD (%)Bus Voltage

69 kV and below 3.0% 5.0%

115 kV to 161 kV 1.5% 2.5%

Above 161 kV 1.0% 1.5%


(SCC22)

Harmonics and Interharmonics, cont.

Voltage Harmonic Distortion, cont.

– At end use location 8% VTHD normally acceptable

– IEC 61000-2-2 compatibility level for LV and MV systems is 8%

– Power factor correction capacitors and non-linear loads on the

same bus often result in resonances

Current Harmonic Distortion

– Harmonic current limits dependent on the strength of the system

at point of connection (ratio of IL to ISC)

– Total Demand Distortion where:

In = magnitude of individual harmonic components (rms

amps)

n = harmonic order

IL = maximum demand load current (rms amps)

TDD

I

I

n

n

L

2

2100%


(SCC22)


IEEE 519-1992 Harmonic current limits for individual end users expressed in %

of rated load current


(SCC22)


EN 50160 limits based on IEC 61000-2-2 compatibility levels

– Individual harmonic component limits up to 25th harmonic

– Total Harmonic Voltage Distortion – 8%

Evaluated using measurement procedure in IEC 61000-4-7

– Uses 3 second periods, combined to obtain 10 minute values

– Limits based on 95% of 10 minute values during an assessment period of

one week

Revision to IEEE Std 519-1992 will propose adopting the IEC

measurement procedure


(SCC22)


Interharmonics– Those harmonic components that are not integer multiples

of the fundamental

– New revision to IEEE Std 519-1992 will include

recommended limits for interharmonics

Voltage limits are based on lamp flicker with a PST=1.0 using

the measurement techniques described in IEEE Std 1453 and

IEC 61000-4-30

Current limits may be calculated using the specific voltage limit

and the system impedance at the PCC


(SCC22)

Harmonics and interharmonics –What is needed?

Common method of measurement and assessment

Benchmarking of international harmonic levels

Method of assessing impact of individual customers (harmonic

source location)

Limits and practical methods of implementation

Interharmonic limits and assessment methods

Higher frequency limits and assessment methods

Economics – where to solve distortion problems?


(SCC22)

Transients

Normally refers to fast (sub cycle) changes in the system voltage or current waveform

ANSI/IEEE C62.41-1991 IEEE Guide to Surge Voltages in Low Voltage AC Power Circuits

– Defines transient environment

– Specifies test waveforms

Measured by triggering on abnormality involved– Peak magnitude

– Rate of rise

– Change in waveform

IEEE 1159-Characterization of typical transient waveshapes– Oscillatory transients

– Impulsive transients


(SCC22)

Transients, cont.

Capacitor switching waveform one of the most important oscillatory

transients

– Created when capacitor Is energized


(SCC22)

Transients, cont.

Capacitor switching transients can be either attenuated or

amplified based on the system impedance

Effects:

– ASDs trip

– UPS transfer to backup power source

– Worst case component damage


(SCC22)

Transients What is needed?

Equipment performance for a wider variety of

transient characteristics (e.g. response to

capacitor switching transients)

Methods of characterizing system

performance

Application guidelines for transient control


(SCC22)

Voltage sags and interruptions

Defined as short duration voltage variations according to IEEE

Std 1159 and IEC definitions

Best characterized by RMS Voltage vs. Time

– Can be characterized by voltage Magnitude, and Duration voltage

is outside specified limits Example Voltage Sag Waveform from Field

Measurement

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 70 80 90

100 110 120

Time (Seconds)

%

0 25 50 75 100 125 150 175 -150 -100 -50

0 50

100 150

Time (mSeconds)

%

Duration 0.117 Sec

Min 74.70 Ave 94.11 Max 98.58 Ref Cycle

48462


(SCC22)

Voltage sags and interruptions, cont.

Voltage Sags typically caused by a fault on the power system

Can be experienced over a significant area

Voltage returns to normal on unfaulted portion when fault is

cleared

Typical duration 6 cycles (100ms) dependent on protection

philosophy

Voltage magnitude during sag dependant on distance from the

fault and system characteristics


(SCC22)


IEEE Std 1346 provides methodology for economic evaluation power conditioning equipment based on the expected sag performance of the power supply system and equipment sensitivity

– Contour plot of sag magnitude and duration

– Superimpose equipment sensitivity to obtain estimate of number of times process will be disrupted

1 2 4 6 8 1 0 2 0 3 0 4 0 5 0 6 0 1 8 0 3 0 0 >3 0 0 0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

D u ra tio n (C y c le s )

Ma

gn

itu

de

(%

)

In te rru p tio n a n d S a g R a te P ro b a b iltie s a s a F u n c tio n

o f E v e n t Vo lta g e M a g n itu d e a n d D u ra tio n

0 -5 e v e n ts p e r

s ite p e r y e a r

1 0 -1 5 e v e n ts

1 5 -2 0

5 -1 0 e v e n ts p e r

s ite p e r y e a r


(SCC22)


Work under way to define indices for characterizing voltage sag

performance – IEEE P1564

Voltage sag agreed to be characterized by the remaining

voltage, i.e., voltage sag to 70%

One method under consideration – System Average RMS

(Variation) Frequency Index (SARFI)

– Average number of voltage sags experience each year with a

specified characteristic

– SARFIX Index includes all voltage sags where the minimum

remaining voltage was less than x.


(SCC22)


Average SARFI statistics for US distribution system

17.7

27.3

49.7

0

5

10

15

20

25

30

35

40

45

50

Avg

. N

o. o

f E

ve

nts

per

Ye

ar

SARFI-70 SARFI-80 SARFI-90

Avg. SARFI Statistics for US Distribution Systems


(SCC22)

Voltage sags and interruptions –What is needed?

Common method of measurement and assessment (indices)

Benchmark performance as a function of system characteristics

Statistical methods of characterizing performance Application guidelines for performance improvement

options (e.g. IEEE 1409) Equipment performance standards (e.g. SEMI F47) Economic evaluation with a system perspective


(SCC22)

Future Direction for Power Quality Standards

Benchmarking efforts have provided initial basis for defining

expected power quality performance of supply systems

Need statistical means of characterizing performance to permit

better risk analysis for end users

Equipment manufacturers must provide sensitivity of equipment

to power quality variations

Monitoring of power quality should be standard part of system

monitoring for both supplier and user

Need tools to help find optimum design based on system

performance and equipment sensitivity


(SCC22)

Compatibility Levels, cont.

Compatibility levels

– Basic expectation for supply system performance

– Basis for equipment design for immunity to supply system power

quality variations

– EN 50160 “Physical characteristics of electricity supplied by public

distribution systems” – Voltage Characteristics

Harmonics

Voltage fluctuations

Unbalance

Interruptions

Voltage Dips


(SCC22)

Compatibility Levels, cont.

Planning Limits

– Established by Utilities for

comparison with actual power

quality levels

– Problem indicated if planning

limit exceeded

– Need margin between planning

level and required voltage

characteristics

Equipment Immunity

– Equipment should be capable of operating within full range of possible

power quality levels

– Need margin between immunity level and required voltage characteristics

Compatibility level

Assessed level

Disturbance magnitude

time

Equipment immunity test levels

Utility planning levels


(SCC22)

Compatibility Levels

Steady State characteristics

– Trends, statistical distributions

– Defined by a range of values


(SCC22)

Standards needed for each type of PQ Concern

Compatibility

Levels

Customer System

Impact Limits

System

Performance

Expectations

Measurement

and Assessment

Methods

Customer System

and Equipment

Immunity

Requirements

Equipment PQ

Limits

System Solutions and

their implementation

Customer and

equipment solutions

to limit impact on

system

Customer and

equipment solutions

for immunity

improvement


(SCC22)

What should we do?

Participate in IEEE Standards Development

Participate in IEC Standards development to make sure the standards

apply to North American systems (SCC22 has official Category D

liaisons on the following IEC SC77A working groups)

– WG1 – Mark Halpin

– WG2 – Rao Thallum

– WG6 – Alex McEachern

– WG8 – Mark McGranaghan

– WG9 – Erich Gunther

Develop Application Guides


(SCC22)

Application guidelines -How to apply the standards

IEEE Std. 519.1 - Harmonics

IEEE Std. 1346 - Voltage sags


(SCC22)

Roadmap example - harmonics

Definitions, Indices(updates in progress)

IEEE 1159

Monitoring and

Characterization

(updates in progress)

IEEE 1159

Benchmarking

EPRI DPQ

Miscellaneous projects

Need coordinated effort

Compatibility and Limits

(updates in progress)

IEEE 519

Application Guides

IEEE 519.1

Harmonic source location

Harmonic filters

Active filters

Economics


(SCC22)

Compatibility is the Goal of Power Quality Standards Development

Questions

IEEE – IEC Standards Cross-reference


(SCC22)

Voltage regulation and unbalance

IEC 61000-2-2

IEC 61000-2-4

IEC 61000-2-12

EN 50160

IEC 61000-4-27

(unbalance)

IEC 61000-4-30

ANSI C84.1

Regulations from

individual states

ITIC and other

equipment standards


(SCC22)

Flicker

IEC 61000-2-2

IEC 61000-2-4

IEC 61000-2-12

EN 50160

IEC 61000-3-3

IEC 61000-3-5

IEC 61000-3-7

IEC 61000-4-15

IEEE 1453


(SCC22)

Harmonics and Interharmonics

IEC 61000-2-2

IEC 61000-2-4

IEC 61000-2-12

EN 50160

IEC 61000-3-2

IEC 61000-3-4

IEC 61000-3-6

IEC 61000-3-9 (interharmonics)

IEC 61000-4-7

IEC 61000-4-13 (immunity)

IEEE 519

IEEE 519.1

IEEE 1159

Filter Design


(SCC22)

Transients, cont.

IEC Standards similar to

C62.41 standards

Lightning performance and

insulation coordination

ANSI/IEEE C62.41

Lightning performance

standards and insulation

coordination standards

IEEE 1100

UL 1449


(SCC22)

Voltage sags and interruptions

IEC 61000-2-8

IEC 61000-4-11 (immunity

testing)

IEC 61000-4-30

CIGRE SC36

IEEE 1564 (voltage sag

indices)

IEEE 1346 (compatibility)

ITIC (equipment immunity)

SEMI F47 standards

(equipment immunity)

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