Location method of single-phase ground fault section in distribution network based on esmd

Abstract

The invention relates to an ESMD-based method for locating a single-phase ground fault section of a distribution network, which includes the following steps: (1) judging whether the zero-sequence voltage value of the bus bar exceeds the limit, if so, perform step (2); if not, then Return to step (1); (2) collect the zero-sequence current signal within 1 / 2 power frequency period after the failure of each measuring point; (3) perform ESMD decomposition on the collected zero-sequence current signal to obtain a series of eigenmodes Function IMF and margin function R; (4) Construct the fault transient energy function describing the oscillation intensity of transient zero-sequence current waveform from the intrinsic mode function IMF and margin function R obtained by ESMD decomposition; (5) Based on the fault The transient energy function is normalized by constructing the logic judgment function of the fault section; (6) Combining with the distribution network topology to determine the fault section. The invention can show excellent adaptability to grounding faults under different grounding modes, different transition resistances and different fault angles, and is easy for engineering realization.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to an ESMD-based method for locating a single-phase ground fault section of a power distribution network. Background technique [0002] When a single-phase ground fault occurs in the non-effectively grounded system, the line voltage continues to maintain symmetry, which can greatly improve the reliability of power supply. At present, the distribution network of major foreign developed countries is gradually shifting to the arc suppression coil as a whole. non-effective ground mode transition. However, in this kind of neutral point grounding system through the arc suppressing coil, because the arc suppressing coil compensates the capacitive current of the distribution network to a certain extent, the current distribution law of the entire distribution network has undergone a major change after the fault occurs. Locating and troubleshooting has brought ...

AI Technical Summary

Problems solved by technology

Judging from the actual use effect in recent years, the overall effect of the line selection and positioning method based on the steady-state quantity is not good, because it is easily affected by factors such as the neutral point grounding method, transition resistance and unstable arc, and has low sensitivity and is prone to misjudgment; A significant disadvantage of the signal injection method is that it requires a substantial increase in investment, and this method cannot fundamentally solve the problem of high-impedance ground faults; the transient method has been favored by academics in universities and manufacturers of electric wave recording devices in recent years, mainly because arc suppression The object of coil compensation is power frequency current, and it has no significant compensation effect on some high-frequency currents in the transient transition process. Based on this starting point, a series of technical solutions for fault line selection and location based on transient method are proposed, but based on different theories There are considerable differences in the effects and applicability of the transient line selection and positioning methods

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