Power distribution network fault section positioning method based on FDM

Abstract

The invention discloses a power distribution network fault section positioning method based on a FDM. The method comprises the following steps: firstly developing various measurement point zero-sequence currents after a single phase ground fault is existent in the power distribution network based on a generalized Fourier decomposition method (FDM) so as to obtain a series of orthogonal and mutually-independent Fourier intrinsic band functions (FIBFs) with self-adaptivity; and then defining Fourier-Hilbert spectrum (FHS) based on various band functions, and further constructing transient energydensity functions of various measurement point zero-sequence current after the fault based on the marginal spectrum, and forming fault positioning criterion. Through the positioning method disclosedby the invention, the effective technical support can be provided for the quick and accurate positioning of the single-phase ground fault of the power distribution network, and the positioning methodhas good engineering practical value.

Description

technical field [0001] The invention proposes an FDM-based fault section location method in a distribution network, which belongs to the technical field of electric power system relay protection. Background technique [0002] The country has invested heavily in the construction and transformation of the distribution network. The goal of the "Distribution Network Action Plan" is to achieve a power supply reliability rate of more than 99.947%. The distribution network construction requires high standards, new technologies, and good results. The distribution network is directly oriented to users, has a wide coverage area, and has a complex environment. It is very important to quickly locate a fault. [0003] At present, when a single-phase ground fault occurs in the power distribution system whose neutral point is grounded through the arc suppression coil, the line voltage continues to maintain symmetry, which can greatly improve the reliability of power supply. This grounding ...

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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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