Earthing Calculation for Switchyards and Substations

Product Description

The object of a good grounding system is to provide under and around the site a surface which shall be at a uniform potential and be as near zero or absolute earth potential as possible. This is to ensure that no human being in the vicinity is subject to shock or injury on the occurrence of short circuit or of development of other abnormal condition in the equipment. The basic design criteria of a properly designed gounding system are meant to :

1. Stabilize circuit potential with respect to ground and limit the overall potential rise.

2. Protect life and property from over-voltage.

3. Provide low impedance path to fault currents to ensure prompt and  consistent operation of protective devices during ground faults.

4. Keep maximum voltage gradient along the surface inside and around the plant site within safe limits during ground faults.

While carrying out the earthing calculation, we check the following :

a. Calculated step potential is below the tolerable value.

b. Calculated touch potential is below the tolerable value.

c. Ground system resistance is below 1 ohm.

d. Ground potential rise is limited to 5kV or so.

We can deliver earthing calculations and layout drawings with BOQ as per IEEE 80 or CBIP manual or IS 3043.