Current Status and Fault Issues in PEA's Networks

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Current Status and Fault Issues inPEA’s Network

Wirote Buaklee

Deputy Director of System Planning Department

Provincial Electricity Authority, Thailand

September 29, 2015

Joint TNC-CIGRE & IEEE-PES Seminar



Topics

I. Overview of PEA Power System

II. Overview of PEA Fault Calculation

III. Current Status of Fault Level

IV. Problem and Issue on Fault Current

2



I. PEA Power System Overview

Substation 534 substations

Sub-Transmission 11,414 ckt-km

Distribution 296,809 ckt-km

Control Center 13 centers

PEA 2014

3



No. of Customers 17,679,995 Cust.

Energy Sale 116,501 M-unit

Electrified Village(%) 99.98

4

PEA Service Information

PEA 2014

Peak Demand 17,724 MW



SAIFI : 6.46 occ/cust/yr

SAIDI : 217.89 min/cust/yr

LOSSES : 5.46 %

5

PEA Service Information

PEA 2014



6

Current Status of SPPs in PEA System

Area Project SellingPower(MW)

InstalledCapacity

(MW)

North

5

191.00

202.50

Northeast 10 394.50 485.40

Central

41

2,664.30

4,082.43

South 3 220.20 253.56

Total 59 3,450.00 5,023.89

Sept 2015



Fuel Type

Connected Non-Connected

Project Power (MW) Project Power (MW)

Biomass 126 775 123 725

Biogas 127 222 97 183

Solar 251 922 176 964

Waste 18 43 38 206

Wind 6 9.65 8 50

Hydro 6 1.2 9 14

Other 2 4.5 2 18

Total 536 1,977 453 2,160 7

Current Status of VSPPs in PEA System

Source: Alternative Energy Encouragement Division on Sept 2015



Status of VSPPs Interconnected to PEA System

39.2%

11.2%

46.6%

2.2%

0.5% 0.1%

0.2%

Solar922 MW

Biogas222 MW

Biomass775 MW

8

Wind 9.65 MW

OTHERS 4.5 MWWaste 43 MW

Hydro 1.2 MW

Status : Sept 2015



II. Overview of PEA Fault Calculation

• Objective: equipment selection and protection

coordination.

• Annually Calculation

• Use IEC60909-2001 Method with “c-voltage

factor” equal to “1.0”

• Get EGAT driving point data from “System

Operation Department” as a source of PEA

power system

• Only Initial symmetrical short circuit current:

Ik” value will be calculated

• In the future, Peak short circuit current: Ip will

also be calculated

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Example of PEA Short Circuit Report

10



Typical Configuration Between EGAT and PEA

• 22/33kV Control Station

• 115kV Substation

11

EGAT

PEA 22-33 kV

EGAT

PEA 115 kV

PEA Substation

115 kV Customer

G 115 kV SPP

G VSPP



PEA Standard of Rated Short Circuit

12

Type VoltageLevel

Breaking Current(kA_rms)

Making Current(kA_peak)

Circuit Breaker

115

31.5/40

80/100

22/33

25

63

LBS/ RCS

22

12.5

31.25

33 10 25

Recloser

22

12

31.25*

33 10 25*

RMU 22/33 16 40

* Assumed value due to lack of data



III. Current Status of Fault Level: All PEA Service

Area

13

3-Phase Fault(kA) Max Min

115 kV 38.46 0.86

22/33 kV

20.06

2.20

532

2 0

315

5513

0

100

200300

400

500

600

<50% 50-80% ≥80%

N o . o f S u

b s t a t i o n

Isc/Icb

22 kV

115 kV



Current Status of Fault Level: Northern Region

14


115 kV 22.46 0.86

22 kV

12.10

2.52

108

0 0

60

2 00

20

4060

80

100

120

<50% 50-80% ≥80%

N o . o f S u

b s t a t i o n

Isc/Icb

22 kV

115 kV

Nakhon Sawan Area



Current Status of Fault Level: Northeastern Region

15


115 kV 18.05 1.39

22 kV

13.23

2.68

102

2 0

59

1 00

20

40

60

80

100

120

<50% 50-80% ≥80%

N o . o f S u

b s t a t i o n

Isc/Icb

22 kV

115 kV

Nakhon Ratchasima Area

Udon Thani Area



Current Status of Fault Level: Central Region

16


115 kV 38.46 1.39

22 kV

20.06

3.93

223

0 0

133

52

11

0

50

100

150

200

250

<50% 50-80% ≥80%

N o . o f S u

b s t a t i o n

Isc/Icb

22 kV

115 kV

Rangsit Area

Ayutthaya AreaSaraburi Area

Amata Area

Ao Phai Area

Leamchabang Area



Current Status of Fault Level: Southern Region

17


115 kV 36.72 1.44

22/33 kV

10.77

2.20

99

0 0

63

0 20

20

40

60

80

100

120

<50% 50-80% ≥80%

N o . o f S u

b s t a t i o n

Isc/Icb

33 kV

115 kV

Ratchaburi Area



IV. Problem and Issue on Fault Current

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• 13 substations have a high fault level

• PEA has no remedial actions/plans to mitigate the problem

• High fault current will reduce both security and quality of supply

• There are a lot of approaches to control the short circuit current

• Network Reconfiguration

• Bus Splitter

• Install Fault Current Limiter (FCL) such as Current Limiting Reactor (CLR),

Is-Limiter, Solid State FCL(SSFCL) Superconducting FCL(SCFCL) and

Magnetic FCL (MFCL)etc.



The Status of FCL Technologies

19•

A Neumann, “Application of Fault Current Limiters”, Department for Business Enterprise & RegulatoryReform(BERR), 2007.



Thank you



Characteristics of short-circuit currents

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Documents

Current Status and Fault Issues in PEA's Networks