CONSTRUCTION STANDARDS:
I. |
ERECTION OF 33/11 KV SUBSTATION |
|||||||
1 |
The switchyard must be 300 mm (one foot) high over the highest level of the adjacent area. |
|||||||
2 |
Substation steel structure |
|||||||
152 x 152 mm H type beams/9.1 m PSCC poles |
||||||||
All members shall be with Galvanized M.S. Channel of size 100 x 50 mm. All parts to be hot dip galavanized after fabrication. |
||||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
3 |
i) 3 Nos single phase PT's to be erected on 33 KV bus on the structures. |
|||||||
ii) 1 No. 3-Ph PT to be erected on the structures in 11 KV bus |
||||||||
4 |
33 KV HG fuse set to be erected on independent structure. Arcing homes shall be 25 x 6 mm Tinned coated copper flat. Bimetallic connectors to be provided for giving to conductor at both ends. Horn gap shall be 15 inches. |
|||||||
5 |
Galvanized step Bolts to be provided for the foundation supports of VCB. |
|||||||
6 |
Station DTR with AB switch and H.G fuse set to be erected on structure |
|||||||
7 |
Bolts Nuts shall be hot dip galvanized |
|||||||
8 |
33 KV 800 A AB switch double break shall be errected |
|||||||
9 |
11 Kv side : 11 KV 400 A AB swicth double break shall be errected 9bus Side) |
|||||||
10 |
11 KV 400 AAB switches for feeders shall be errected. |
|||||||
11 |
11 Kv line type LA's to be orected 3 nos each feeder |
|||||||
12 |
Earthing : |
|||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
|
||||||||
13 |
Earth Electrode: 100mm dia (inner dia) 10mm thick and 2.7m long Ci pipe with flange at the top |
|||||||
Earth grid connections between electrodes with 75 x 8mm M.S flat. All joints shall be of but jointing. |
||||||||
Connections between earth grid and equipment (Top connections) with 50 x 6 mm Gi flat. |
||||||||
Back filling with Bentonite soil of 300mm dia metre around the earth electrode (Coke and shall not be used as they are corrosive) |
||||||||
All junctions and raisers in the grid shall be painted with bituman paint and then covered with Hessain tape avoid rusting. |
||||||||
14 |
The combined earth grid resistance shall be less than 1 Ohm. |
|||||||
II. |
ERECTION OF POLES |
|||||||
S.No |
Support |
Size of Concrete |
||||||
1 |
8.0 / 9.01 mts PSCC pole or RS joist / Rail pole |
0.6 x 0.6x 1.5 mts |
||||||
2 |
9.5 mts PSCC/RS joistpole/Railpole |
0.6 x 0.6 x 1.8 mts |
||||||
3 |
11.0 mts spun pole |
0.75 x 0.75 x 2.0 mts |
||||||
4 |
Stay set |
0.45 x 0.45 x 1.265 mts |
||||||
Note : Coping shall be provided for RS joist/ Rail pole Planting depth of pole shall be 1/6th of the total length. |
*****