(1) When single-phase grounding fault occurs in the distribution system, the alarm bell of the insulation monitoring device in the substation rings, and the light plate "×× bus grounding" lights up. Neutral point grounding through arc suppression coil, and "arc suppression coil action" light plate.
(2) When the generator is faulty, the voltmeter of the insulation monitoring device indicates that the voltage of the fault phase is reduced or close to zero, and the voltage of the other two phases is higher than the phase voltage or close to the line voltage. For stable grounding, the voltmeter indicates no swing. If the voltmeter pointer swings back and forth, it indicates intermittent grounding.
(3) When arc grounding produces overvoltage, the non-fault phase voltage is very high, and the voltmeter pointer hits the head. At the same time there is also a voltage transformer fuse break, serious will burn out transformer.
But in some cases, the power distribution system has not occurred grounding fault, the insulation of the system is not damaged, but due to the asymmetrical state, insulation monitoring will also give out grounding signal, which often cause misjudgment and power failure search.
Wuhan Xinshengneng Technology Co., LTD
