for Southern Thailand Network Engineering Level 4 Control and Protection System Department Electricity Generating Authority of Thailand

Transcription

1 Design and Implementation of RLS Scheme for Southern Thailand Network by Mr.Yossawin Bureetan Engineering Level 4 Control and Protection System Department Electricity Generating Authority of Thailand

2 Outline 1. Introduction 2. Previous Protection Scheme 3. Power System Analysis 4. Transient Stability Studies 5. Installation of the Protection Scheme 6. Post Event Analysis 7. Conclusion

3 Network Configuration of Southern Thailand - Network configuration before 2011 To PKK 500 kv 230 kv BSP2 BSP 115 kv Power Flow From Central Region CP RN LSN RPB SRT KN TP PK2 PK1 PN KA PP BDN NT TS PU LR HY1 STU Main Load RA SKL HY2 CHN KNE SDO YL2 PTN YL1 BLG NW SUK GURUN BST

4 Problem Solving Method - The previous RLS Scheme System Information To PKK 500 kv BSP2 230 kv BSP 115 kv Areva - Tie-Lines Power Flow - Generation in Southern system - HVDC Status TP PK2 RN SRT RPB PN PK1 LSN KA CP Trip Signal PP LR BDN TS KN PU STU NT Control Box RA SKL HY2 HY1 SDO GURUN KNE CHN YL2 BST HVDC Run Up/Back PTN YL1 BLG Load dshedding (81 Cases Table) NW SUK

5 Current Network Configuration BSP2 CP Changing in Southern Thailand To PKK Network after 2011 BSP Network configuretaion Load Increament RN LSN RPB SRT KN PK3 TP P PN2 N PK1 PK2 500 kv 230 kv 115 kv KA PP BDN NT TS PU RA LR SKL CHN HY HY1 2 PTN STU SDO KNE YL1 YL2 BLG GURUN BST NW SUK

6 Power System Analysis Condition for Steady State Study Load Condition is divided into 3 condition - Evening Peak Load - Day Peak Load - Light Load System Disturbance :Only large disturbance will be investigated, Ex. - CHN Power Plant Full Block Trip (700 MW) - CHN Power Plant Half Block Trip (350 MW) - KA Power Plant Trip - HVDC Trip while importing 300 MW - Central to Southern Tie-Line Trip 2 Circuits - Tie-Transformer 500/230 kv BSP2 Trip

7 Part of study Part 1 Part 2 Part 3 After the system disturbance, the System can remain stable without any protection Scheme response After the system disturbance, the system can remain stable with only the action of HVDC Run Up/Run Back After the system disturbance, the system can remain stable with HVDC Run Up/Run Back and Rapid Load Shedding

8 Studies Result from Part 1 Part 1 : Maximum Pre-condition Tie-Line Power Flow which, After the system disturbance, the System can remain stable without any protection Scheme response. HVDC (+300) CHN (700) KA (300) CHN (350) Tie Line (N-2) KN-CC Bus Evening Day Light

9 Studies Result from Part 2 Part 2 : Maximum Pre-condition Tie-Line Power Flow which, After the system disturbance, the system can remain stable with only the action of HVDC Run Up/Run Back CHN (700) KA (300) CHN (350) Evening Day Light

10 Load Shedding Point Selection The appropriate load shedding point are selected using V-P Characteristics. ti The slope of V-P Characteristic of each load points indicate the weakness of that load points at that condition. V V critical Stable Unstable P

11 Weak point in the system To PKK 500 kv BSP2 BSP 230 kv 115 kv CP Weak Load point PK3 TP PK2 RN SRT RPB P PN2N PK1 LSN Selected Load Shedding Point KN PP BDN NT TS KA LR PU RA STU SKL CHN HY HY1 2 PTN SDO KNE YL1 NW YL2 BLG SUK GURUN BST

12 Studies Result from Part 3 Part 3 : Amount of load shedding which, After the system disturbance, the system can remain stable with action of HVDC Run Up/Run Back and Load Shedding Tie Line Flow Load Shedding (MW) Light Day Evening

13 Transient Stability Studies In studies result from transient stability studies, 2-example cases are shown Case 1: CHN full block trip (700 MW) at tie-line flow 400 MW Case 2: CHN full block trip (700 MW) at tie-line flow 700 MW

14 Transient Stability Result : Case 1 Case 1 : CHN Full Block Trip ( 700 MW) : Tie-Line Flow 400 MW T = 1 s : Fault T 1.4 s : HVDC Run up T = 1.1 s : Clear Fault

15 Transient Stability Result : Case 2 Case 2 : CHN Full Block Trip ( 700 MW) : Tie-Line Flow 700 MW T = 1 s : Fault T 1.4 s : HVDC Run up T = 1.2 s : Shed HY2 = MW T = 1.1 s : Clear Fault

16 Special Protection Scheme Operation - The Scheme Operation to prevent system instability after large disturbance To PKK BSP2 BSP Tie-line Flow Areva RN SRT RPB TP PN PN2 PK3 PK1 PK2 KA LSN CP Trip Signal KN PP BDN TS LR PU STU NT Control Box HVDC Run Up/Back RA HY1 SKL HY2 SDO GURUN KNE Load (200 ms) If Tie-line Flow > 700 MW and CHN full block trip 500 ms Load CHN YL2 BST PTN YL1 BLG NW SUK Load2 Shedding 500 kv 230 kv 115 kv Load1 Shedding

17 Special Protection Scheme Operation

18 Special Protection Scheme Installation BSP2 To PKK BSP Tie-line Flow Areva 500 kv 230 kv 115 kv RN SRT RPB TP PN PN2 PK3 PK1 PK2 KA LSN CP Trip Signal KN PP BDN TS LR PU STU NT Control Box HVDC Run Up/Back RA HY1 SKL HY2 SDO GURUN KNE Load (200 ms) If Tie-line Flow > 700 MW and CHN full block trip CHN YL2 BST PTN 500 ms Load YL1 BLG NW NCC Monitor and Control Signal SUK Load1 Shedding Load2 Shedding

19 Challenge and Suggestion The delay of the construction cause delay of scheme installation. Number and location of the communication device have to be consider to minimize the scheme installation cost while remaining effective scheme operation. Changing of load point impact amount of load shedding when the scheme operate. In the scheme installation, the previous scheme was removed then the new scheme was installed. The function of scheme operation during that period had to be able to protect the system from black/brown out.

20 Example Event On 5 th March 2012 : Transmission Line 230 kv SKL2 HY2 KNE cct. 1 and 230 kv HY2 KNE cct. 2 trip while central to southern tie-line flow 442 MW from Central to Southern System and HVDC was importing power 30 MW from Gurun to KNE

21 Special Protection Scheme Operation The event occur in the evening Tie-Line Flow 442 MW RPB-H:232.5 KN-CC:645.6 KK-T :74.3 CHN Full Block 710 MW No KA HVDC Ex. 30 MW BLG-H:73.3

22 Special Protection Scheme Operation

23 Measurement Value from Post Event Ang(TPR)-Ang(KNE) degree Tie-Line Flow 763 MW SRT 1.00 PN 0.98 PN PK KA 0.98 TS 0.99 NT 0.98 No CHN HY PK PK KNE 1.00 HVDC Im. 245 MW

24 Study Result Ang(TPR)-Ang(KNE) degree Tie-Line Flow 929 MW SRT 0.98 PN 0.93 PN PK KA 0.95 TS 0.96 NT 0.97 No CHN HY PK PK KNE 1.00 HVDC Im. 245 MW

25 Actual Value Study Result

26 Actual Value Study Result

27 Conclusion In Southern Thailand Network, a special protection scheme was installed to prevent black out after large disturbance. When the scheme is trig, the scheme will send run up/back command to HVDC and load shedding command to load point simultaneously. After getting the shedding command, load at each will be shedded only when the voltage at that bus is low. Post event analysis show that the scheme can prevent the system black out when large disturbance occur. The load shedding, after the scheme action, can be avoided by controlling of the tie-line flow.

28 Thank you