What is Power Quality?

Report
Power Quality, Harmonics and Accuracy
April 2013
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 fault
recording, waveform capture and more
Power Quality Parameters
Frequency
Voltage Variations
Voltage Flicker
Voltage Dip
Power Quality Parameters
Interruptions
Temporary Overvoltage
Transients
Power Quality Parameters
Unbalance
Harmonics
Interharmonics
Harmonics
+
f ( x )  sin(x )
=
sin(5 x )
f ( x) 
5
sin (5 x )
f ( x )  sin (x ) 
5
IEEE1159-EN50160 Levels
IEEE 1159
No. Categories
EN50160
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
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
Momentary
9
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
100 ( V 2  V 3  ..... V n )
2
THD(V) 
THD(I)
100 (
2
V
I
2
2

I
I
2
3
2
(% )
1
 .....
I
2
n
)
(% )
1
IN, VN – Individual Harmonics of order N
‫‪TDD - Total Demand Distortion‬‬
‫(‪ - TDD )I‬נותן אפשרות להעריך את הנזקים הנגרמים ע"י הרמוניות בזרמים‪.‬‬
‫) ‪ I 3  ..... I n‬‬
‫‪2‬‬
‫)‪(%‬‬
‫‪2‬‬
‫‪max demand‬‬
‫‪2‬‬
‫‪I‬‬
‫‪2‬‬
‫‪I‬‬
‫( ‪100‬‬
‫‪TDD(I)‬‬
‫כאשר ‪ - I max. demand‬ערך מקסימלי של זרם הנמדד במחזור‬
‫זמן של ‪ 15‬דקות או ‪ 30‬דקות לתקופה כוללת של שנה‪.‬‬
‫פרמטר – ‪ %THD I‬לא נותן אפשרות להעריך את הנזקים הנגרמים‬
‫ע"י הרמוניות בזרמים כי הוא לא מתייחס לזרמים נומינליים וכאשר‬
‫הזרם ברשת נמוך הוא נותן הערכה לא נכונה‪.‬‬
‫מסיבה זו בתקן ‪ IEEE‬עבור זרמים מוגדר פרמטר ‪.% TDD‬‬
K-Factor
K factor   I
n
h1
2
h
2
h
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
Frequency
The Utility
Voltage variations
Load changing
Sync. loads,
Fast PF correction
Voltage flicker
Load changing, mainly
welding
Fast PF correction
Voltage dip
Motor 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
Unbalance
Unbalanced loads,
transformer phase shift
Balance the loads
Non linear loads, resonance
Active/passive filtration,
detuned capacitors,
Improved VFD operation
Harmonics
Solutions
Agenda
 What is Power Quality
 Improving Power Quality
 Power Quality in SATEC products
 Accuracy Standards
The Full Range of Electricity Management Solutions for Every Application
ExpertPower™ Server
(Service Edition)
PAS
ExpertPower™
Server (Pro Edition)
Internet
LAN
ETC2002
RS232/422/485, Profibus, TCP/IP,
Dialup modem, GPRS, RF, USB
EM132/3 PM130 PLUS PM135
Modbus RTU, ASCII, DNP3.0, Modbus/TCP,
DNP3/TCP, Profibus, IEC 61850, IEC 60870
BFM136
C192PF
PM172
EM720
EM920
PM180
ezPAC
Substation
Automation
Asset Management
Power Measurement
Fault Recording
Energy Efficiency & Cost Allocation
Revenue Metering
Energy Management & Billing
Smart Grid & Demand Response
Multi-Tenant Submetering
COMMERCIAL & INDUSTRIAL
PM174/5
Power Quality Analysis
ALL
UTILITIES & RENEWABLE
 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
Worst Case
Category
Frequency Variations
Voltage Dips
Long interruption
Transient Overvoltage
Transient Undervoltage
THD
Individual
Individual
H15
Individual
H17
Individual
H19
Individual
H23
Individual
H25
Harmonic H5
Harmonic
No. of
Events
67
122
1
133
Event
No.
1809
1986
1979
2263
Date
19/07/2006
19/07/2006
24/12/2006
15/03/2007
Time
17:10.9
14:39.2
25:55.9
55:18.3
Value
48.44
69,180
3,778
180,131
142
3
2024
1998
02/01/2007
24/12/2006
46:43.8
12:16.9
143,127
.6 ms
0.73
24:43 min
9
2271
31/03/2007
28:28.9
2.2
2:16 hrs
2
1984
24/12/2006
13:01.6
0.6
19:60 min
2
1986
24/12/2006
13:01.6
1.14
23:59 min
3
1987
24/12/2006
12:16.9
1.39
24:43 min
3
1992
24/12/2006
12:16.9
1.11
24:43 min
3
1994
24/12/2006
12:16.9
1.17
24:43 min
3
493
1980
24/12/2006
12:16.9
1.97
24:43 min
Duration
16:3 m
890.0 ms
5:10 hrs
.6 ms
Harmonic
Harmonic
Harmonic
Harmonic
Individual Harmonic H4
Total
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 
TPF 
DPF
1  THD i2
 DPF = Displacement Power Factor (Cos φ)
 TPF = True Power Factor (incl. harmonics)
Conclusion – practically there is no unity Power Factor.
Meter Class 0.5 Accuracy
IEC 62053-11
CT Class 0.5 Accuracy
IEC 60044-1
Power Factor
Error of 45 minutes
1.00
0.92
0.50
0.015%
0.52%
1.14%
System Accuracy
Power
Meter
0.8%
System
Accuracy
1.58%
CT
0.75%
Phase
Shift
1.14%
U ( x  y  z)  U 2 ( x)  U 2 ( y)  U 2 ( z)
Meter Class 0.5S Accuracy
IEC 62053-22
CT Class 0.5S Accuracy
IEC 60044-1
Power Factor
Error of 30 minutes
1.00
0.004%
0.92
0.50
0.34%
0.76%
System Accuracy
Power
Meter
0.6%
System
Accuracy
1.09%
CT
0.5%
Phase
Shift
0.76%
HACS – High Accuracy Current Sensors

SATEC devices has
numerous amplitude and
phase calibration points
System Accuracy
Power
Meter
0.6%
System
Accuracy
0.6%
CT Included
Phase
shift Included
Comparison
Class 0.5S
Class 0.5
Class 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
IEC 62053-11 62053-22 61000-4-30
Accuracy Standard Pyramid
Class A
Class S
Class 0.2S
Class 0.5S
Class 0.5
Class 1
Class 2
%Readings
Not included:
Class B – meaningless
Class 0.1, 0.2 – only for CTs
%FS (Full Scale)
No stated accuracy
Min. Acceptable
SATEC
Empowering the Smart Grid
www.satec-global.com

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