Sub Station Abstract -(Part-2)

 

Sub Station Capacity & Short Circuit Current Capacity:

As per GERC

VoltageSub Station CapacityShort Circuit Current
400 KVUp to 1000 MVA40 KA  (1 to 3 Sec)
220 KVUp to 320 MVA40 KA  (1 to 3 Sec)
132 KVUp to 150 MVA32 KA  (1 to 3 Sec)
66 KVUp to 80 MVA25 KA  (1 to 3 Sec)
33 KV1.5 MVA to 5 MVA35 KA (Urban) (1 to 3 Sec)
11 KV150 KVA to 1.5 MVA25 KA (Rural) (1 to 3 Sec)
415 V6  KVA to 150 KVA10 KA  (1 to 3 Sec)
220 VUp to 6 KVA6 KA  (1 to 3 Sec)

 Sub Station Capacity & Short Circuit Current Capacity:

As per Central Electricity Authority

VoltageSub Station CapacityShort Circuit Current
765 KV

4500 MVA

31.5 KA for 1 Sec
400 KV

1500 MVA

31.5 KA for 1 Sec
220 KV

500 MVA

40 KA for 1 Sec
110/132 KV

150 MVA

40 KA or 50 KA for 1 Sec
66 KV

75 MVA

40 KA or 50 KA for 1 Sec

 Minimum Ground Clearance and Fault Clearing Time:

VoltageMin. Ground ClearanceFault Clear Time
400 KV8.8 Meter100 mille second
220 KV8.0 Meter120 mille second
132 KV6.1 Meter160 mille second
66 KV5.1 Meter300 mille second
33 KV3.7 Meter 
11 KV2.7 Meter 

 Bus bar Ampere Rating:

For Phase Bus barAluminium 130 Amp / Sq.cm or 800Amp / Sq.inch.
For Phase Bus barCopper 160 Amp / Sq.cm or 1000Amp / Sq.inch
For Neutral Bus barSame as Phase Bus bar up to 200 Amp than Size of Neutral Bus bar is at least half of Phase Bus bar.

 Bus bar Spacing:

Between Phase and Earth26mm (Min)
Between Phase and Phase32mm (Min)
Bus bar Support between Two Insulator250mm.

 Sound Level of Diesel Generator (ANSI 89.2&NEMA 51.20):

KVA

Max. Sound Level

<9 KVA40 DB
10 KVA to 50 KVA45 DB
51 KVA to 150 KVA50 DB
151 KVA to 300 KVA55 DB
301 KVA to 500 KVA60 DB

IR Value of Transformer:

IR Value of Transformer

Voltage

30°C

40°C

50°C

>66KV

600MΩ

300MΩ

150MΩ

22KV to 33KV

500MΩ

250MΩ

125MΩ

6.6KV to 11KV

400MΩ

200MΩ

100MΩ

<6.6KV

200MΩ

100MΩ

50MΩ

415V

100MΩ

50MΩ

20MΩ