Stresses on Grounding Switches During Opening

The stresses upon grounding switches under the following conditions are examined: out of two parallel AC lines, one is carrying its rated current and the other is isolated and grounded at both ends by means of grounding switches. Under these conditions, the grounding switches must carry the induced steady-state current. When grounding is cancelled, they must interrupt the induced current and withstand the transient recovery voltage (TRV). The value of the current and the TRV depend upon the sequence of opening of the grounding switches.