power quality harmonics and accuracy april 2013
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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
Power Quality Parameters
Unbalance
Harmonics
Interharmonics
Power Quality Parameters
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
What is Power Quality
Improving Power Quality
Power Quality in SATEC products
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
What is Power Quality
Improving Power Quality
Power Quality in SATEC products
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
What is Power Quality
Improving Power Quality
Power Quality in SATEC products
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
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