Method and system for power grid to detect reasons of voltage sag incident

Abstract

The invention provides a method for a power grid to detect the reasons of a voltage sag incident. The method includes the steps that historical data are extracted and subjected to discretization according to preset analysis parameters; the categorical attributes of voltage sag are set, and the historical data are classified to form a sample set, wherein the categorical attributes include the voltage sag phase, amplitude, duration time, occurring time and transmission characteristics; Apriori calculation is carried out on the sample set, a support degree value larger than a preset threshold value is obtained, Apriori calculation is carried out according to the support degree value, a credibility value lager than a preset second threshold value is obtained, and a voltage sag strong correlation rule knowledge base is formed; a decision-making tree is obtained through an ID3 algorithm; the reasons of current voltage sag of the power grid are determined according to the decision-making tree. The method and system for the power grid to detect the reasons of the voltage sag incident avoid depending on the waveform, excavate strong correlation rules in historical voltage sag incidents based on analysis of the historical data and through multiple characteristic values, and predict the possibility of voltage sag in the future.

Description

technical field [0001] The invention relates to the technical field of power system power quality detection, in particular to a method and system for detecting the cause of a voltage sag event in a power grid. Background technique [0002] With the development of science and technology and industry, many industrial users with a high degree of automation have higher and higher requirements for power quality. In production or information technology enterprises, since most devices and single-chip-based digital controllers or power electronic devices are very sensitive to various electromagnetic interferences, very slight disturbances in the power grid will cause the above products to fail to work or some functions to decline , making the enterprise suffer huge losses. [0003] At present, the ideal power signal has a three-phase sinusoidal waveform with fixed frequency and amplitude. However, in real life, due to circuit faults, asymmetry of lines and equipment, and startup of...

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Problems solved by technology

[0005] However, the traditional technology based on experiments and simulations has shortcomings. The shortcomings are: 1. The power grid is far more complex than the simulation system, and the simplified model cannot completely simulate the real system, resulting in errors; 2. The voltage in the power grid is temporarily The sag detection equipment can only detect the sag amplitude and duration of the voltage sag, and cannot record the waveform with a large amount of data, which leads to deviations in the cause analysis of power quality events

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