Method and apparatus for on-line monitoring over voltage

Abstract

The invention provides an over-voltage on-line monitoring method used for solving the problems during electric network over-voltage monitoring. The invention adopts the technical proposal as follows: a hardware system comprises a voltage transformer, a signal conditioning and protection circuit, a data acquisition card and an industrial control computer, which are sequentially connected; the industrial control computer is used for collecting in real time the secondary lateral over-voltage signal of the voltage transformer by the data acquisition card; according to the voltage transfer function of the voltage transformer and the signal conditioning and protection circuit, the quick inversion and restoration computation is performed in combination with the saturation characteristic of the voltage transformer; and finally, the voltage type is determined by comparing the waveform of the voltage transformer primary lateral voltage acquired from the computation with various over voltage types stored in the database. The invention is capable of capturing in real time and storing the temporary over voltage waveform of a power system so as to provide reliable data for analyzing the cause of equipment accidents in the power system. Moreover, the invention is characterized by simple hardware structure and reliable operation.

Description

technical field [0001] The invention relates to a method and a monitoring device for on-line monitoring overvoltage of a power grid, which belong to the technical field of monitoring. Background technique [0002] With the rapid development of the power system, the influence of overvoltage on the safety of the power grid has attracted more and more attention. In recent years, insulation accidents of electrical equipment in the power grid have occurred from time to time, and the cause of the accident is difficult to find out directly. Only effective online monitoring methods can be used to completely and accurately record the waveform and various parameters of the fault overvoltage when the overvoltage occurs. Only in this way can we provide accurate data for understanding the overvoltage situation before and after the accident and the impact on the grid voltage during the accident, and provide reliable basis for technicians to analyze the cause of the accident. [0003] At ...

AI Technical Summary

Problems solved by technology

These three methods all have obvious disadvantages: for the first monitoring device, due to the saturation characteristic (non-linearity) and frequency-off effect of the PT under the action of the high-frequency signal of the overvoltage, the voltage signal extracted by the secondary port is serious. Distortion, cannot be used directly, otherwise the distortion is serious

Although the second and third types can truly reproduce the overvoltage of the primary system, because the voltage divider it uses is directly connected to the primary bus or the ground terminal of the capacitive equipment, the site changes are large, the construction is difficult, and the voltage divider The fault itself will also bring many adverse effects to the power station.

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