power quality harmonics and accuracy april 2013

April 2013

Power Quality, Harmonics and Accuracy

Agenda

What is Power Quality

Improving Power Quality

Power Quality in SATEC products

Accuracy Standards

What is Power Quality? Definitions of the quality of the supplied voltage (what about the current?)

Usually referred in negative contexts – power quality problems Measurement

– IEC 61000-4-7 Voltage Flicker

– IEC 61000-4-15 Harmonic Measurement

– IEC 61000-4-30 Measurement Accuracy (“Class A”, “Class S”)

– IEC 62052/3-11, 22, 23 Energy Accuracy (“Class 0.2S”, “Class 0.5S”)

Power Quality

– BS:EN 50160: In use worldwide, in favor of the utilities, voltage only,statistical standard

– IEEE 519 and IEEE 1159: American standards, practical point of view

– GOST 13019: Russian standard, very comprehensive

– G5/4: British standard for Harmonics (also current)

– Customized: Allows the user to select the best of all, including faultrecording, waveform capture and more

Frequency

Voltage Variations

Voltage Flicker

Voltage Dip

Power Quality Parameters

Interruptions

Temporary Overvoltage

Transients


Unbalance

Harmonics

Interharmonics


Harmonics

+ =

5

)5sin()sin()(

xxxf

5

)5sin()(

xxf )sin()( xxf

IEEE1159-EN50160 LevelsIEEE 1159 EN50160

No. Categories Typical Spectral Content

Typical Duration Typical Voltage Magnitude

Short Duration Variations

Instantaneous

7 Sag 0.5-30 Cycles 0.1-0.9 pu <1 sec

8 Swell 0.5-30 Cycles 1.1-1.8 pu No

Momentary

9 Interruption 0.5 Cycles-3s <0.1 pu <1 sec

10 Sag 30 Cycles-3s 0.1-0.9 pu No

11 Swell 30 Cycles-3s 1.1-1.4 pu No

Temporary

12 Interruption 3 s-1 min <0.1 pu No

13 Sag 3 s-1 min 0.1-0.9 pu No

14 Swell 3 s-1 min 1.1-1.2 pu No

Long Duration Variations

15 Interruption, Sustained >1 min 0.0 pu Yes

16 Undervoltages >1 min 0.8-0.9 pu Yes 10 min

17 Overvoltages >1 min 1.1-1.2 pu Yes 10 min

THD-Total Harmonic Distortion

IN, VN – Individual Harmonics of order N

(%).....(

THD(I)

(%).....(

THD(V)

IIII

VVVV

n

n

1

22

3

2

2

1

22

3

2

2

)100

)100

ITDD-

I max. demand -

–THD I

IEEETDD

TDD - Total Demand Distortion

(%))100

max

22

3

2

2

IIII

demand

n.....(

TDD(I)

K-Factor

n

hh hIK

1

22factor

Agenda




Accuracy Standards

Should we Care about Power Quality?

Comprehensive Research in Europe in 1400 sites at 8 countries reports that 20% experience the following:

Computer lockouts (20%)

Light flickering (22%)

Electronic card failures (18%)

Power Factor correction system failures (17%)

Failures in high load switching (16%)

Neutral conductor overheating (12%)

Unexpected breaker operation (11%)

Power meters inaccurate readings (6%)

And of course excess losses and downtime

Causes and Solutions

PQ Problem Major Sources Solutions

Frequency The Utility

Voltage variations Load changingSync. loads, Fast PF correction

Voltage flickerLoad changing, mainly welding

Fast PF correction

Voltage dipMotor and other load startups

Motor starters, VFD, Fast PF correction

Interruptions The Utility

Overvoltage Over PF compensation Fast PF correction

Transients Connections, Switching Controlled switches

UnbalanceUnbalanced loads, transformer phase shift

Balance the loads

Harmonics Non linear loads, resonanceActive/passive filtration, detuned capacitors,Improved VFD operation

Agenda




Accuracy Standards

RS232/422/485, Profibus, TCP/IP,

Dialup modem, GPRS, RF, USB

Modbus RTU, ASCII, DNP3.0, Modbus/TCP,

DNP3/TCP, Profibus, IEC 61850, IEC 60870

ETC2002

COMMERCIAL & INDUSTRIAL

Multi-Tenant Submetering

Power Measurement

Energy Efficiency & Cost Allocation

Energy Management & Billing

Asset Management

C192PFBFM136 PM172 PM174/5 EM720 EM920 ezPAC

PAS

PM130 PLUS

LAN

ExpertPower™

Server (Pro Edition)

The Full Range of Electricity Management Solutions for Every Application

EM132/3

SubstationAutomation

UTILITIES & RENEWABLEALL

Power Quality Analysis

Fault Recording

Revenue Metering

Smart Grid & Demand Response

PM135

Internet

ExpertPower™ Server

(Service Edition)

PM180

Built in analysis to international power quality standards such as EN50160, IEEE1159, G5/4 and GOST

Automatic alerts for preventive maintenance

From simple compliance chart to sophisticated expert analysis screens

EN 50160 Summary Report

List of Events

Event

No. Date Time Value Duration

Frequency Variations 67 1809 19/07/2006 17:10.9 48.44 16:3 m

Voltage Dips 122 1986 19/07/2006 14:39.2 69,180 890.0 ms

Long interruption 1 1979 24/12/2006 25:55.9 3,778 5:10 hrs

Transient Overvoltage 133 2263 15/03/2007 55:18.3 180,131 .6 ms

Transient Undervoltage 142 2024 02/01/2007 46:43.8 143,127 .6 ms

THD 3 1998 24/12/2006 12:16.9 0.73 24:43 min

Individual Harmonic H5 9 2271 31/03/2007 28:28.9 2.2 2:16 hrs

Individual Harmonic

H15 2 1984 24/12/2006 13:01.6 0.6 19:60 min

Individual Harmonic

H17 2 1986 24/12/2006 13:01.6 1.14 23:59 min

Individual Harmonic

H19 3 1987 24/12/2006 12:16.9 1.39 24:43 min

Individual Harmonic

H23 3 1992 24/12/2006 12:16.9 1.11 24:43 min

Individual Harmonic

H25 3 1994 24/12/2006 12:16.9 1.17 24:43 min

Individual Harmonic H4 3 1980 24/12/2006 12:16.9 1.97 24:43 min

Total 493

Category

No. of

Events

Worst Case

EN50160 Compliance Trends

ITI (CBEMA) Curve

Deep Analysis of a Dip

TDD at 22kV

High Individual Harmonics

Agenda




Accuracy Standards

Full Scale (FS) vs. Reading

FS Full Scale, error in percents from the maximum

rating

Example:

Meter with 0.5% FS accuracy connected to 1000A

transformer, the error is 5A. In 500A load the accuracy

is 1% (5/500)

Reading = Error from the measured value

In the above example, the 0.5% error will be also in low

load, which means 2.5A only

Accuracy vs. Standard

Various measurement conditions– Load

– Harmonics

– Power Factor

– Frequency

– and more…

Various ambient conditions

– Temperature

– EMC (the device and the accuracy)

– Humidity

– and more…

Tests by independent lab

Accuracy stability over time

(SATEC is approved for 8 years)

Power Factor and Cos

DPF = Displacement Power Factor (Cos φ)

TPF = True Power Factor (incl. harmonics)

Conclusion – practically there is no unity Power Factor.

21 iTHD

DPFTPF

Meter Class 0.5 AccuracyIEC 62053-11

CT Class 0.5 AccuracyIEC 60044-1

Power Factor 0.92 0.50

Error of 45 minutes 0.015% 0.52% 1.14%

Power Meter

CT

Phase

Shift

System Accuracy

1.58%

System Accuracy

)()()()(222

zUyUxUzyxU

Meter Class 0.5S AccuracyIEC 62053-22

Power Factor 0.92 0.50

Error of 30 minutes 0.004% 0.34% 0.76%

CT Class 0.5S AccuracyIEC 60044-1

Power Meter

CT

Phase Shift

System Accuracy

1. %

System Accuracy

HACS – High Accuracy Current Sensors

SATEC devices has

numerous amplitude and

phase calibration points

Power Meter

CT -Included

Phase shift -

Included

System Accuracy

%

System Accuracy

Comparison

Class 0.5 Class 0.5SClass 0.5S

with HACSes

(or direct connection)

Power Meter Accuracy 0.8 0.6 0.6

CT Accuracy 0.75 0.5 Included

Phase Shift 1.14 0.76 Included

System Accuracy 1.58 1.09 0.6

Accuracy is for Engineers,Money is for Decision Makers

1000 kVA transformer

80% load

0.90 Power Factor

0.15 US$/kWh

The difference between

0.6% to 1.58% equals to

US$ 9,272 each year

Accuracy Standard Pyramid

Class A

Class S

Class 0.2S

Class 0.5S

Class 0.5

Class 1

Class 2

%Readings

%FS (Full Scale)

No stated accuracy

--

-IE

C

-

Min. Acceptable

Not included:

Class B – meaningless

Class 0.1, 0.2 – only for CTs

SATECEmpowering the Smart Grid

www.satec-global.com

power quality harmonics and accuracy april 2013

Documents

supplied voltage

voltage flickeriec

class siec

measurement accuracy

energy accuracy class

class b meaninglessclass

russian standard

british standard