Distribution network single-phase ground fault detection method using transient and steady feature fusion

Abstract

The invention discloses a distribution network single-phase ground fault detection method using transient and steady feature fusion. When single-phase ground faults occur under different fault conditions of a resonant ground distribution network system, the steady and transient features of a normal feeder line and a fault feeder line have different time-frequency distribution characteristics, thetransient features are obvious under strong faults, and faults in the distribution network are accurately and reliably detected by using fault transient zero-sequence current time-frequency characteristics. Under weak faults, fault detection is achieved by a zero-sequence current steady quantity feature after the faults. The method solves the technical problem in the prior art that transient zero-sequence current sudden change amount, energy, amplitude and polarity are used for the transient quantity fault line selection method so as to improve line selection effects to different extents; however, after a ground fault, the effect of an arc suppression coil makes the zero-sequence current weak, especially when the intermittent arc grounding occurs, the arc extinguishing is uncertain such that the detection method in the prior art is no longer reliable.

Description

technical field [0001] The invention belongs to the field of distribution network fault detection, and in particular relates to a distribution network single-phase ground fault detection method adopting transient state and steady state feature fusion. Background technique [0002] When a single-phase-to-ground fault occurs in a resonant grounded distribution network system, the line selection method based on single fault information is not very effective in practical application due to the small fault current and unstable arc. In addition, high-resistance faults caused by wires falling to the ground and trees contacting overhead feeders occur frequently, so that there are often missed and wrong selections in actual operation. Compared with the steady state component, the transient component after the fault has a great advantage, and the line selection using the transient quantity has become the first choice for the fault line selection method. [0003] At present, many scho...

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Problems solved by technology

However, after the ground fault occurs, the function of the arc suppression coil makes the zero-sequence current weak, especially when the intermittent arc is grounded, the burning and extinguishing of the arc is uncertain, which makes the detection method of the prior art no longer reliable

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