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Method and device for recognizing over-voltage fault types of power distribution network

A technology of fault type identification and distribution network, which is applied in the direction of fault location, measuring device, fault detection according to conductor type, etc., can solve the problems of distribution network overvoltage fault, low accuracy rate, long duration, etc. Strong interference ability, high recognition accuracy, and less calculation time

Inactive Publication Date: 2017-09-12
STATE GRID FUJIAN JINJIANG POWER SUPPLY +1
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Problems solved by technology

In the actual operation of the power distribution system, both ferromagnetic resonance and single-phase ground faults will lead to overvoltage faults in the distribution network. Such faults last for a long time, easily cause equipment damage, and cause many insulation accidents.
Distribution network overvoltage faults include resonant overvoltage and single-phase-to-ground fault, and the types of resonant overvoltage include fundamental frequency resonance, high-frequency resonance and frequency division resonance, and the fundamental frequency resonance overvoltage waveform is highly similar to that of single-phase-to-ground fault , the existing detection technology cannot automatically and accurately distinguish fundamental frequency resonance, high frequency resonance, frequency division resonance and single-phase grounding fault, more is judged by manual experience, the efficiency is low and the accuracy rate is not high, and misjudgment often occurs, which is not conducive to Take appropriate containment measures for the distribution network system and the treatment of maintenance personnel

Method used

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  • Method and device for recognizing over-voltage fault types of power distribution network
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  • Method and device for recognizing over-voltage fault types of power distribution network

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Embodiment Construction

[0041] Such as figure 1 and figure 2 As shown, the identification method of distribution network overvoltage fault type includes the following steps:

[0042] A. Monitor the zero-sequence voltage of the distribution network. When the zero-sequence voltage exceeds the limit, obtain the sampling data x(t) of the zero-sequence voltage waveform. Among them, the conditions for determining the zero-sequence voltage to exceed the limit are: is the phase voltage;

[0043] B, carry out EMD decomposition to x (t) to obtain a plurality of IMF signals, calculate the correlation coefficient C of each IMF signal and x (t), get the IMF signal with the largest correlation coefficient C as the main mode component y (t);

[0044] Among them, the calculation formula of the correlation coefficient C is: In this calculation formula, x(i) is the sampling value of the i-th point of x(t), y(i) is the sampling value of the i-th point of a certain IMF component, and N is the number of sampling...

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Abstract

The invention provides a method for recognizing over-voltage fault types of a power distribution network. The method comprises the following steps: acquiring zero sequence voltage waveform sampling data x(t); taking an IMF (Intermediate Frequency) signal with a maximum correlation coefficient C as a principle mode component y(t); calculating a marginal spectrum h(omega) of the y(t); judging that a frequency dividing resonance fault occurs when an energy ratio of a frequency band of 10-40Hz in h(omega) exceeds 50%; judging that a high-frequency resonance fault occurs when an energy ratio of a frequency band of 100-150Hz in h(omega) exceeds 50%; otherwise calculating overall similarity S of the x(t) and standard single-phase earth fault zero sequence voltage waveform; judging that a fundamental resonance fault occurs when S is smaller than a preset similarity threshold K, otherwise judging that a single-phase earth fault occurs. The method disclosed by the invention is capable of automatically recognizing the over-voltage resonance type and the single-phase earth fault, simple in algorithm, less in calculation time, high in anti-jamming capability and high in recognition accuracy.

Description

technical field [0001] The invention relates to a method and a device for identifying an overvoltage fault type of a distribution network. Background technique [0002] The distribution network is an intermediate link connecting power stations, substations and end users. It is at the end of the power system and generally refers to a power network with a voltage level of 35kV and below. The distribution network has a wide range of distribution, numerous network branches, and complex structure. Its biggest feature is that it is directly connected with users and can intuitively reflect the user's electricity consumption requirements in terms of safety, quality, and economy. In the actual operation of the power distribution system, both ferromagnetic resonance and single-phase ground faults will lead to overvoltage faults in the distribution network. Such faults last for a long time, easily cause equipment damage, and cause many insulation accidents. Distribution network overvo...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 高伟陈立纯陈永往郭谋发肖旭锦吴建嘉廖宁叶清琳吴俊峰
Owner STATE GRID FUJIAN JINJIANG POWER SUPPLY
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