It is assumed that a feeder is in the energized condition and the operating sequences described below are of
a general nature for GIS.In all cases applicable safety and specific operating rules shall be observed.
Sequence of operation for isolation of a feeder:
- The feeder circuit breaker is switched to the open position [see Figure(a)]. This unlocks the disconnect switch.
- The feeder disconnect switch is switched to the open position [see Figure(b)].Verify by viewing.
- The feeder is now isolated on bus side.
Sequence of operation for feeder grounding:
- Verify circuit is de energized by means of the integrated voltage detector/indicator.
- The grounding switch is switched to closed position [see Figure(c)]. Verify by viewing.
- Close the feeder circuit breaker [see Figure(d)].
- Lock feeder circuit breaker in closed position according to manufacturer’s O&M manual.
- The feeder is now grounded through the circuit breaker on the line side.
In figure shown switching arrange between breaker and earthing switch in a medium voltage GIS switchgear.