1. G G L Ld L1 L2 L3 L4 L5 T1001 T1002 G5002 G5001 B1 B2 B3 B4 B5 B6

2. BUS_CON.CFG (Fixed file) BUS NO BUS SC IMP (OHM) (OFF LINE) DEV CONN 136.55001123 275.015 349.0100134 435.050022451002 550.01002 655.01001

3. DEV_IMP.CFG (Fixed file) DEV_NOIMPEDANCE (OHM) (X ONLY) 150.5 225.7 330.2 428.5 575.0 100190.5 100290.5 5001120.0 (INCLUDING GT) 5002110.0 (INCLUDING GT)

4. REAL TIME VALUES FROM SCADA BUS_VOL.DAT BUS_NOVoltage in kV 1400 2390 3395 4405

5. NSP OUTPUT FROM SCADA DEV_STS.DAT DEV_NOStatus 1Energised 2 3De-Energised 4Energised 5 1001Energised 1002Energised 5001Energised 5002De- Energised

6. Z SC1 Z SC2 ZLZL BUS 1 BUS 2 INITIAL CONDITION, ZSC1 & ZSC2 INCLUDES EFFECT OF Z L

7. Z1 Z2 ZLZL BUS 1 BUS 2 CALCULATE INTERMEDIATE VALUES OF Z1 & Z2 DURING ITERATION EXCLUDING EFFECT OF Z L Z1 & Z2 COMPUTED BY SOLVING THE FOLLOWING NON-LINEAR EQUATION (LOOKS SIMPLE – TRY SOLVING) ZSC1 = Z1 || ZL + Z2 ZSC2 = Z2 || ZL + Z1 WHERE ZSC1, ZSC2, ZL ARE KNOWN COMPLEX PART OF ALGORITHM

8. Z1 Z2 ZLZL BUS 1 BUS 2 ITERATION RESULT, NEW ZSC1 IS COMPUTED INCLUDING THE EFFECT OF Z L DEPENDING UPON LINE STATUS. IF LINE STATUS IS De-Energised, NEW ZSC1=Z1 other wise NEW ZSC1 = Z1 || Z L + Z2 Z SC1 BUS 1

9. INITIAL VALUES OF ALL BUS SHORT CIRCUIT IMPEDANCE ARE COMPARED WITH THE CALCULATED VALUES, ON REACHING THE TOLERANCES, COMPUTE SHORT CIRCUIT MVA OF EACH BUSES SHORT-CIRCUIT MVA = KV * KV / ZSC Z1 AND Z2 COMPUTATION IS TAKEN FOR LINE ONLY AS EXAMPLE. IN FINITE ELEMENT METHOD – THE PROCESS IS SAME and REPEATED FOR ALL DEVICES CONNECTED TO THE BUS.

10. SHORT-CIRCUIT LEVEL - TO SCADA BUS_SCL.DAT BUS_NOSC MVA 14383 22028 33185 44686