(1) If the voltage difference between the two poles of a 220V DC system exceeds 40V or the insulation drops below 25KΩ, or if there is a significant change in the voltage of any pole of a 48V DC system to ground, it should be considered as a DC system grounding. (2) After a DC system is grounded, the cause should be immediately investigated. Based on the indication of the grounding selector device, the day's work, weather conditions, and the insulation status of the DC system, locate the grounding fault point and eliminate it as soon as possible. (3) When using the pull-out method to locate DC grounding, at least two people should be involved, and the DC interruption time should not exceed 3 seconds. (4) Push-pull checks should start with circuits that are easily grounded, followed by accident lighting, anti-misoperation locking device circuits, outdoor closing circuits, indoor closing circuits, 6-10kV control circuits, other control circuits, main control room signal circuits, main control room control circuits, rectifier equipment, and battery circuits. Aviation ground power 2, 36V aviation power 1, 400Hz frequency converter power 7, 115/200V power 2, 27V DC power.
(V) After a battery assembly fuse blows, it should be immediately inspected and handled, and appropriate measures should be taken to prevent the loss of power in the DC bus. (VI) When a DC energy storage capacitor is punctured or its capacity is insufficient, it must be replaced promptly. (VII) In the event of an internal fault causing the DC charging device to trip, the backup charging device should be immediately activated to replace the faulty one, and operating parameters should be adjusted promptly. (VIII) When a DC power system equipment experiences a short circuit, or voltage drops in AC or DC, the cause should be quickly identified, the fault rectified, and backup equipment utilized or other measures taken to restore normal DC system operation as soon as possible. (IX) In the event of an explosion or open circuit in a battery assembly, the main fuse or air circuit breaker should be promptly disconnected, and backup equipment used or other measures taken to eliminate the fault and restore normal operation. If there is no backup battery assembly, the charging device should be used to run the DC system load during the accident handling period. If the charging device does not meet the requirements for circuit breaker closing capacity, the power supply to the closing circuit should be temporarily disconnected, and it should be restored to operation promptly after the accident is handled.
