A Rapid Diagnosis Method for Fault Types of Transfer Grounding Devices in Distribution Networks

Abstract

The invention provides a fault type quick diagnosis method for a power distribution network transfer grounding device. A power distribution network neutral point voltage transformer TV detects neutral point shift voltage U<N> and a stable increment Delta U<N> and Delta U<N> is compared with a power grid neutral point shift voltage fault increment standard value Delta U<Q>. When Delta U<N> is greater than or equal to Delta U<Q>, a zero sequence compensation branch circuit switch QF1 is closed. A zero sequence compensation branch circuit current transformer TA measures current stable increment Delta I<0> and Delta I<0> is compared with a zero sequence compensation branch circuit increment standard value as in the description. If Delta I<0> is greater than the zero sequence compensation branch circuit increment standard value, a power distribution network single-phase grounding fault is determined. If Delta I<0> is smaller than or equal to the zero sequence compensation branch circuit increment standard value, the single-phase grounding fault is excluded. After the zero sequence compensation branch circuit switch QF1 is closed, if Delta U<N> is smaller than Delta U<Q>, or when Delta U<N> is greater than or equal to Delta U<Q> and after a resonance elimination branch circuit switch QF2 is closed, Delta U<N> is smaller than Delta U<Q>, the fault is determined as power grid ferromagnetic resonance fault. After the zero sequence compensation branch circuit switch QF1 and the resonance elimination branch circuit switch QF2 are closed, if Delta U<N> is greater than or equal to Delta U<Q>, the fault is determined as zero sequence parameter dissymmetry fault.

Description

technical field [0001] The invention belongs to the field of rapid diagnosis method and processing of single-phase grounding fault type of distribution network, and is mainly used for rapid judgment of fault type when a distribution network transfer grounding processing device handles distribution network faults. Background technique [0002] There are many types of faults in the distribution network, but there are mainly single-phase ground faults, ferromagnetic resonance faults and asymmetric disconnection faults. When these faults occur, they will cause the neutral point displacement voltage of the distribution network to rise, and many distribution networks When the grid grounding processing device handles distribution network faults, its main basis is the rise of the neutral point displacement voltage of the distribution network, especially the distribution network transfer grounding processing device is used to close the grounding switch of the faulty phase in the subst...

AI Technical Summary

Problems solved by technology

[0002] There are many types of faults in the distribution network, but there are mainly single-phase ground faults, ferromagnetic resonance faults and asymmetric disconnection faults. When these faults occur, they will cause the neutral point displacement voltage of the distribution network to rise, and many distribution networks When the grid grounding processing device handles distribution network faults, its main basis is the rise of the neutral point displacement voltage of the distribution network, especially the distribution network transfer grounding processing device is used to close the grounding switch of the faulty phase in the substation. The method of transferring the fault current is used to deal with single-phase grounding faults in the distribution network. If the fault type is misjudged, for example, ferromagnetic resonance or asymmetric disconnection of the power grid has caused the neutral point displacement voltage of the distribution network to rise. , and the distribution network transfer grounding processing device mistakenly believes that a single-phase grounding fault has occurred, and closing the grounding switch of a certain phase to the ground will cause processing errors, and even cause accidents in severe cases. Therefore, it is necessary to find a A rapid diagnosis method for a distribution network fault type, which can be quickly diagnosed when a fault occurs in the distribution network, and then processed quickly and accurately

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