EHV Transmission

You can have distance protection Schemes at your end as provided at th TNEB Substation, so that the faulty feeder alone tripped on Both ends, leaving the healthy feeder to feed to your loads.(/p)

If numerical relay protection is used, you may have to enable parallel feeder protection settings additionally for correct operation of protection System,

Both bus section isolators can be kept closed, If one feeder is capable of handling your total load.

Dear Sir

Pl clarify the following:

1) If both the supplies are from the same section on 110 kV side then where is the question of having a buscoupler in between ?

2)How many incomers does the 11 kV switchgear has?If you are planning to close the buscoupler then u may have to defeat mechanical and electrical interlocks(which might be detrimental to the equipment/personnel) to close the buscoupler.

3)If you are closing the buscouplers (assuming the supplies are being derived from either side of the buscoupler ) on the EHV side(may not be under your control,since u are telling it is TNEB substation) and HV side you might actually be paralleling the sources,which would result in catastrophe, in the event of a fault on any one of the involved lines.

4)However, the distance protection /OC/EF are available to isolate the fault.Nevertheless it is risky and not recommended in SOPs.

Regards

Switch off the both breakers of failed feeder. Now put ON the 11KV B/C only.

Your live feeder can be protected by Directional O/C-E/F and other Trf protection with Partial Differential and LBB.