A dynamic processing method for single-phase transition resistance ground fault in distribution network

Abstract

The invention is a dynamic processing method for a single-phase transition resistance grounding fault in a distribution network. When the neutral point displacement voltage of the power grid is abnormal, firstly compare the magnitude of the neutral point displacement voltage of the power grid, and if it is, it is judged as a low-resistance grounding fault. The phase voltage ratio method can be used to determine the ground fault phase, and the current of the fault point can be transferred by closing the ground switch of the fault phase to ground. At that time, it was a high-impedance ground fault, and the phase voltage ratio method cannot be used to determine the ground fault phase, and the method of closing the ground switch of the fault phase to the ground cannot be used to deal with single-phase ground faults, but directly enters the line selection process, and real-time Detect the displacement voltage of the neutral point of the distribution network, track the development of the fault, and carry out dynamic processing of the fault; once the fault develops, immediately use the phase voltage ratio method to determine the phase selection method of the ground fault, and start the fault current transfer device to transfer the fault current to the ground phase. The grounding switch is closed to the ground to divert the current at the fault point and deal with the single-phase grounding fault of the distribution network.

Description

technical field [0001] The invention belongs to the field of single-phase transition resistance grounding fault processing of distribution network, and is mainly used for judging and dynamic processing of single-phase grounding fault in distribution network. Background technique [0002] Due to the resistance of the fault point to the ground, the single-phase ground fault of the distribution network can be divided into two situations: one is a low-resistance ground fault or a metallic ground fault, and the other is a high-resistance ground fault. For the processing of single-phase ground fault in distribution network, the intelligent processing device for single-phase ground fault in distribution network is used. The gate transfers the fault current at the fault point and clamps the potential of the fault point to zero. At this time, it can not only ensure the safety of the fault point, but also facilitate the insulation recovery of the fault point. It is a good treatment me...

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Problems solved by technology

However, this method is only applicable to metallic grounding or low-resistance grounding faults, because only in metallic grounding or low-resistance grounding faults, the phase voltage of the fault phase is the lowest among the three phases, and phase voltage ratio method can be used to select Phase method to determine the ground fault phase

When the single phase of the distribution network is grounded through high resistance, when the grounding resistance of the grounding point reaches a certain value, the voltage of the faulty phase may no longer be the lowest among the three phases. The method determines that the phase with the lowest voltage is the ground fault phase, and using a fast single-phase ground switch to close the fault relative to the ground may cause a short circuit between phases, and the short circuit point is in the substation, which will cause serious short circuit current impact on the transformer

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