A method for locating ground faults in distribution network

Abstract

The invention discloses a distribution network grounding fault locating method. The method comprises the steps that 1, by means of distribution automation terminals including but not limited to a DTU, an FTU, a fault indicator and the like which are installed on a circuit, currents of all phases on the circuit can be measured, and each terminal can achieve the communication function with a distribution master station; 2, when a single-phase grounding fault occurs in a distribution network system, the distribution automation terminals can calculate sudden changes of the currents of all the phases before and after the fault and transfer the sudden changes to the distribution master station; 3, the distribution master station calculates a sudden change of a longitudinal current of each phase between every two adjacent nodes according to the uploaded phase current sudden changes of all nodes, the sudden changes of the longitudinal currents are subjected to normalization, grounding fault locating is achieved according to a normalization value of the sudden changes of the longitudinal currents, and the fault locating point is displayed in a dynamic topological graph of the distribution master station. According to the distribution network grounding fault locating method, a circuit section subjected to the single-phase grounding fault can be accurately selected out, distribution network grounding fault section locating is achieved, and the defect that a pure current sudden change is influenced by power grid scale and grounding fault conditions is overcome.

Description

technical field [0001] The invention relates to the field of distribution network fault processing, in particular to a distribution network grounding fault location method. Background technique [0002] The neutral point of 6~66kV distribution network mostly adopts non-effective grounding methods, mainly including two methods: neutral point ungrounded and neutral point grounded through arc suppressing coil. It still maintains symmetry, so it can continue to supply power to the load for a short time, but because the ground fault current is small, it brings difficulties to fault location and affects the efficiency of fault repair. [0003] At present, the ground fault location technology is mainly divided into passive method and active method according to the source of the characteristic quantity. The passive method uses the signal after the ground fault occurs as the characteristic quantity to realize the fault location, including The characteristic quantity of itself is clo...

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Problems solved by technology

[0002] Most of the neutral points of 6-66kV distribution network adopt non-effective grounding methods, mainly including the neutral point ungrounded and the neutral point grounded through the arc suppression coil. When a single-phase ground fault occurs, due to the line voltage between the three phases It still maintains symmetry, so it can continue to supply power to the load for a short time, but due to the small ground fault current, it brings difficulties to fault location and affects the efficiency of fault repair

[0003] At present, the ground fault location technology is mainly divided into passive method and active method according to the source of the characteristic quantity. The passive method uses the signal after the ground fault occurs as the characteristic quantity to realize the fault location, including the The characteristic quantity itself is closely related to fault conditions such as grounding point transition resistance and initial fault phase angle, which leads to the fact that the actual application effect of this type of method is not very ideal; the active method is to artificially inject signals into the equipment after the ground fault occurs. The power grid injects specific current signals and detects specific signals to achieve fault location. On the one hand, this type of method requires additional equipment, and on the other hand, the injected specific signals are easily affected by the complexity of distribution lines and the harmonic content of the power grid. Therefore, the application effect of this type of method is also not good.

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