1. PQSynergy TM 2011 Chiangmai
The Impact of Voltage Sag for PEA Area 1(North) Customers in North Industrial Estate
Suwipha Kittitanapisarn. B.Eng(EE) Assist. Chief of Power Quality Section
PEA Area1 (North) Chiang Mai, THAILAND
Provincial Electricity Authority, Thailand
September 2011, Chiang Mai, Thailand

2. PEA Area1 (North) In Overview
The Service Area of PEA Area1(North) is approx. 69,557 km2 , accounting for % of the country.
6 Provinces
80 amphors
592 districts
6,611 villages
4,734, populations
1,534, customers
Provincial Electricity Authority, Thailand 2

3. 41 Substations in Responsibility of PEA Area1 (North) (278 Feeders)
PEA Substation 115/22 kV
MEA
PEA Substation 22 kV
CSA
PEA Switching Substation115 kV
MCA
CKN
Transmission Line 115 kV PEA S
THG
MCN S S
EGAT Substation
FAA
TNG CR
CRA
Customer115 kV S
CUN
CDO
MLA
PAU
WPA
MHA S
MTG
MRM
PYA
PEA Substation 22kV
MTA
PAN
DKA
CHM
CMB
Total 14 Substations
CMD
CMF
CMA
SKP
Cement Thai Lampang Public Co.,Ltd.
CME
LPC
CMC
LNB S
LP-2
PEA Substation 115/22 kV
LPB
HCA
LNA S
LP-1
CEA
Total 27 Substations
NIU
NIA
LPA
CTG S
PAS
PEA Switching Substation 115kV
LNC
BGA
HOA
Total 2 Substations
LIA
TEA

4. The Comparison of Peak Load Year 2011 and 2010MW
1,039.12
991.33
995.73
Higher than = 4.86%
Lower than = 4.85%
Lower than = 3.92%
Lower than = 4.38%
Higher than = 7.83%
Higher than 4.55%
Higher than= 12.5%
Jan
Feb
Mar
Apr
May
June
Jul
Aug
Sep
Oct
Nov
Dec
Year 2010
Year 2011

5. Lamphun Province In Brief
8 Amphors 8 Substations
Power Transformer Capacity 490MVA
Total Load MW
UF %

6. Transmission Loop Line Project in Chiangmai Area
MRM
MRM
Now Open Looped
Peak Load 300 MW 1,630 A
DKA
CMD
CMD
CMF
CMF
CME
CME
SKP
SKP
LNC,NIA,NIU,
LNC,NIA,NIU,
CMC
CMC

7. Introduction North Industrial Estate
NIU Substation
North Industrial Estate Lot2
North Industrial Estate Lot1
NIA Substation
3 Substations
Power Transformer Capacity 240 MVA
Total Load MW
UF %
8 Amphors 8 Substations
Power Transformer Capacity 490MVA
Total Load MW
UF %
LNC Substation
Sahapat Industrial Estate
115kV CMC- LNC

8. Report of Average SAIFI Indices (Accumulated from Jan-June 2011) Compare with Target (Level3) in Year 2011
Lower than 21.47%
Times per customer per year
Industrial Estate
City Municiple
District Municiple
SubDistrictt Municiple
Residental Area
Total
SAIFI Year 2011
Target Year 2011

9. Report of Average SAIDI Indices (Accumulated from Jan-June 2011) Compare with Target (Level3) in Year 2011
Lower than27.35%
Minutes per customer per year
Industrial Estate
City Municiple
District Municiple
Subdistrict Municiple
Residental Area
Total
SAIDI Year 2011
Target Year 2011

10. Voltage Sag (IEEE Std.1159-1995)
To Industrial Customers, a Voltage Sag and Momentary Interruption are equivalent if both shut their process down

11. Fault in Transmission and Distribution Line
While the Fault is in the Transmission System, the Entire Power System, including the Distribution System will experience Voltage Sag and Fault are cleared 3-6 cycles for Fault Detection and Breaker Operation
22 kV
115kV
22 kV/400 V 2500 KVA DYn11
Severity of Voltage Sag depend on Fault Location Fault Sizing Fault Type and Clearing Time of Protection Equipment
Provincial Electricity Authority, Thailand 11

12. Study of Voltage Sag Analysis in North Industrial Estate
Process of Voltage Sag Prediction 1.To Correctly Prepare Single Line Diagram of North Industrial Estate Area from PEA-GIS Phase2 Web Database 2.Performing Short-Circuit Simulations with Sliding Faults which include Line to Line, Line to Ground and Three Phase Faults in Digsilent 14.0 Simulation Program. 3.Calcutaion Magnitude of Voltage Sag at Interesting Load 4.Predict Voltage Sag Duration Time by Characteristic of Clearing Fault of Protection Equipment 5.Compare Characteristic of Voltage Sag for Determine the Need for Power Conditioning Equipment at Sensitive Loads in Customer Area
Provincial Electricity Authority, Thailand 12

13. Theory of Voltage Sag Analysis
V sag = Z 2 + Z f
Impedance Divider
Z 1 + Z 2 + Z f
Provincial Electricity Authority, Thailand 13

14. Transmission Line from CMC to LNC
Provincial Electricity Authority, Thailand 14 14

15. Process to Voltage Sag Analysis
1.Prepare Single Line Diagram from PEA-GIS Phase 2 Web Database
Provincial Electricity Authority, Thailand 15

16. GIS Phase 2
Provincial Electricity Authority, Thailand 16

17. Export Single Line Diagram from GIS Phase 2 as *dz files
Provincial Electricity Authority, Thailand 17 17

18. 3. Merge. dz Files in Digsilent Power Factory Version 14
3.Merge *.dz Files in Digsilent Power Factory Version 14.0 and start to run Sliding Fault Calculation
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19. Voltage Sag from Transmission Fault
*OPTREX is a Customer in North Industrial Estate Lot1
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20. (Continued) Voltage Sag from Transmission Fault
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21. Description Voltage Sag from Distribution Fault
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22. For Parallel Feeder (NIU01,03,05 = 0.49 pu.)
4. The Result For Fault at NIU02 ,5 km. From NIU Substation
3P-Fault=3.63 kA, distance =5km. V=0 pu.
0.14 pu.
For Parallel Feeder (NIU01,03,05 = 0.49 pu.) S
Drissen
0.43 pu.
0.46 pu.
Provincial Electricity Authority, Thailand 22 22

23. Voltage Sag Summary from Distribution Fault
Provincial Electricity Authority, Thailand 23 23

24. (Continued)Voltage Sag Summary from Distribution Fault
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25. Voltage Sag Occurrence Calculation Summary from Transmission and Distribution Fault
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26. Voltage Sag Occurrence Calculation Summary from Transmission and Distribution Fault
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27. How Often for Customers to Meet Voltage Sag?
How Often for Sag 40% at Drissen Co.,Ltd.(NIU02) In 8 Months? Drissen Co.,Ltd. Meet Sag 40% = Uniform Fault Rate x Distance from NIU-Drissen = 0.17 (Faults/km-year) x 1 km = 0.17 sags / 8 Months
Provincial Electricity Authority, Thailand 27 27

28. Installation Dranetz-BMI PX5-400 POWER Analyzer
1.At Chiangmai 3 Substation(CMC) 2.At OPTREX Co.,Ltd.(NIA10) 3.At Drissen Co.,Ltd.(NIU 02)
Provincial Electricity Authority, Thailand 28

29. Power Quality Measurement at OPTREX Co.,Ltd.
3 times for Transient
25 Jul – 26 Jul 2011
Provincial Electricity Authority, Thailand 29

30. Power Quality Measurement at Drissen Co.,Ltd.
Abnormal Harmonic 5th order at Main Capacitor
12 Sep – 15 Sep 2011
Provincial Electricity Authority, Thailand 30

31. Power Quality Measurement at Central Pattana Chiangmai
Two events of Voltage Sag at MDB11 from Jun 2011 Instantaneous( S)
Sag 46%
Provincial Electricity Authority, Thailand 31

32. Conclusion
The Impact of Voltage Sag for PEA Area 1(North) Customers in North Industrial Estate
1. The Result of 1P-Fault in 115 kV Transmission Line (From CMC to LNC Substation) Effects Voltage Sag not less than 0.8 pu. 2. The Result of 1P-Fault in 22 kV Distribution Line (NIU,NIA,LNCSubstation) Effects Voltage Sag not less than 0.6 pu Uniform Fault Rate of LNC Substation (From TR.1) has the Most Value and Implies that at the Same Distance from Substation if Comparing with Other Substation in Industrial Park ,LNC Substation (From TR.1) must have the Most Effect from Voltage Sag
Provincial Electricity Authority, Thailand 32

33. Suwipha Kittitanapisarn.
PEA Area1 (North) Chiang Mai, THAILAND
Provincial Electricity Authority, Thailand