Hydroelectric Generator Excitation Experience at Grand Coulee

1. Experience with the motor-driven exciter at the Grand Coulee Power Plant indicates that automatic transfer of power sources to the motor can be successfully done under full load by removing the motor from a faulty power source and reconnecting it to another power source. 2. However, experience also indicates that the best protection is to provide sufficient power sources so that the loss of one source will not cause the loss of excitation. 3. Additional pilot-exciter voltage-regulation equipment has reduced peak voltages on the generators approximately 1.5 kv on a 13.8-kv base with the possibility of reducing this still further by the addition of more resistance in the high-speed lowering relay circuit in the main exciter field.