Site Selection of a Grid Substation
The site selection of a Grid Substation is the first and most important activity. This needs meticulous planning, foresight, skillful observation, and handling so that the selected site is technically, environmentally, economically, and socially optimal and is the best suited to the requirements.
Table of Contents
Points of consideration
The main points to be considered in the selection of a site for the construction of a Grid Substation are given below:
The site selection of a grid substation should be such that it is as near to the load center as possible. This helps in the optimization of the line length of the distribution lines, which results in high uptime of the lines.
However, being the continuous source of hissing noise, the transformers and reactors should be designed according to suitable country standards set by the competent authority for the reduction of noise pollution and to avoid public resentment.
For ease of proper orientation of bus bars and feeders, the selected site should be square or rectangular in shape.
The site should be far away from obstructions (big trees, high-rise buildings), to permit an easy and safe approach/termination of high voltage overhead transmission lines.
The site should be free from master plans/layouts or future development activities to have free line corridors for the present and in the future.
The site selection should be such that, it remains easily accessible to the public road to facilitate transport of materials and equipment.
The site should be near a town but away from municipal dumping grounds, burial grounds, tanneries, and other obnoxious areas.
Consideration should be given to air-suspended pollutants and salts as these can potentially harm the insulation of the substation.
Preferably the site should have a fairly leveled ground. This facilitates a reduction in leveling expenditure.
Tourist spots and important sites must be avoided as the towers can hamper the scenic beauty of heritage sites.
The site selection of a grid substation should be above the highest flood level (HFL) so that there is no waterlogging. Water logging at the site of electrical installation can result in hazards.
The selection of the site should be such that it is sufficiently far away from areas where police and military rifle practices are held.
The site should have as far as possible a good drinking water supply for the station staff.
The site selection of a grid substation should be such that the proposed Substation is not in the vicinity of an aerodrome. The distance of a Substation from an aerodrome should be maintained as per regulations of the aerodrome authority. Approval in writing should be obtained from the aerodrome authority in case the Substation is proposed to be located near an aerodrome.
The site should have sufficient area to properly accommodate the Sub-Station buildings, structures, equipment, etc., and should have sufficient area for future extension of the buildings and/or switchyard.
Area of land required for substation according to voltage levels
The typical requirement of land for the construction of a Sub-Station is as under:
| S.No. | Voltage Class of GSS | Required Area (Typical) |
| 1 | 400 kV AIS with Staff Colony | 20.0 Hectare |
| 2 | 220 kV AIS with Staff Colony | 6.0 Hectare |
| 3 | 220 kV Hybrid GIS | 2.0 Hectare |
| 4 | 220 kV GIS | 1.0 Hectare |
| 5 | 132 kV AIS with Staff Colony | 3.5 Hectare |
| 6 | 132 kV Hybrid GIS | 0.5 Hectare |
| 7 | 132 kV GIS | 0.25 Hectare |
Note
One Hectare is equal to 10,000 Square meters
or, One Hectare is equal to 2.47105 Acre.
