1. Assumption University Thailand EE4503 Electrical Systems Design Short-circuit Current 1

2. Assumption University Thailand Topics Term & Definition Equivalent Circuits –Voltage Source –Impedance Short-circuit Calculation 2

3. Assumption University Thailand Terms & Definition Short Circuits in Power Systems IEC-60909 Far-from-generator Short Circuit –Usually in transmission systems / end-users –Impedance is constant Near-to-generator Short Circuit –System Impedance changes when the short circuit occurred. 3

4. Assumption University Thailand Terms & Definition Types of Short Circuits Three-phase short-circuit Double-phase short-circuit without earth/ground connection Double-phase short-circuit with earth/ground connection Line-to-earth (line-to-ground) short-circuit 4

5. Assumption University Thailand Terms & Definition Types of Short Circuits 5 http://www.globalspec.com/reference/26006/203279/chapter-4-calculation-of-short-circuit-current-in-a-c-three-phase-hv- systems

6. Assumption University Thailand Terms & Definition Components: DC & AC 6 http://ts-dep.web.cern.ch/ts-dep/groups/el/el_tc/netcomput/neplan0.html

7. Assumption University Thailand Terms & Definition Components of Short Circuit Currents 7

8. Assumption University Thailand Terms & Definition Components of Short Circuit Currents 8

9. Assumption University Thailand Equivalent Circuits 9

10. Assumption University Thailand Equivalent Circuits Impedance: Network Feeder 10

11. Assumption University Thailand Equivalent Circuits Impedance: Network Feeder 11

12. Assumption University Thailand Equivalent Circuits Impedance: Cable 12

13. Assumption University Thailand Equivalent Circuits Impedance: Cable (calculation) 13

14. Assumption University Thailand Equivalent Circuits Impedance: table for PVC cables 14 2.57.4000.155 44.6250.141 63.0830.131 101.8500.121 161.1560.113 250.7400.107 350.5290.103 500.3700.100 Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์ 700.2640.097 950.1950.096 1200.1540.094 1500.1230.092 1850.1000.091 2400.0770.090 3000.0620.089 4000.0510.088

15. Assumption University Thailand Equivalent Circuits Impedance: table for Busway 15 225-6000.13420.0350 8000.08140.0216 10000.07120.0186 12000.05680.0150 13500.04070.0112 16000.03670.0098 20000.02920.0079 Aluminium Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์ 225-6000.07640.0350 8000.07640.0350 10000.06230.0260 12000.04890.0261 13500.04170.0186 16000.03280.0150 20000.02400.0112 Copper

16. Assumption University Thailand Equivalent Circuits Impedance: Transformer 16

17. Assumption University Thailand Short-circuit Calculation Example from CoE 17

18. Assumption University Thailand Short-circuit Calculation Example from CoE 18

19. Assumption University Thailand Short-circuit Calculation Example from CoE 19

20. Assumption University Thailand Short-circuit Calculation Example from CoE 20

21. Assumption University Thailand Short-circuit Calculation Example from CoE 21

22. Assumption University Thailand Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์ http://www.openelectrical.org/wiki/index.php?title=Short_ Circuit_Calculation Calculation of short-circuit currents: Schneider Electric Reference 22

23. Assumption University Thailand Equivalent Circuits Impedance: Transformer (multi-tap***) 23