Substation Earthing

Earthing systems of power plants; Earthing mat and electrodes.

1. Substation Earthing System Earthing Mat Prepared by: Mohammad Injadat

2. The S/S earthing system comprises of:  A grid ( earth mat ) Horizontal buried conductors

3. Functions of grounding system in the S/S Ensure safety of personnel due to electric shocks. Provide grounding path (Neutral grounding). Discharge over-voltages (ground path for surge arrestors). Provide path for faults (Phase-Ground). Provide earth connections to the non-current carrying objects in the s/s.

4. Earthing Mat Buried below ground level Connected conductors If the soil have low resistivity>> the earthing resistance will be low as well. If the soil have high resistivity>> Then we need to insert more conductors in the mesh and connect them closer (To create lower resistance)

5. Earthing spikes (Electrodes) Driven into the ground: connected to the earthing mat Connect it to the; equipment bodies, structures, neutrals, etc

6. The fence, equipment body, tanks, support, structures, towers, structural steelworks, water pipes, etc . should be earthed. 

7. Earth Resistance Value Value of Earthing Resistance Determine the rise of the fault voltage! As well, limit the fault current V = IR

8. Criteria of design S/S earthing system Low step voltage Low touch voltage Low earth resistance

9. Touch Voltage (E-Touch)

10. Step Voltage (E-Step)

11. Substation Grounding