Method and system for detecting SAG signal in DVR device

Abstract

The invention provides a method for detecting an SAG signal in a DVR (Discharge Voltage Regulator) device. The method comprises the following steps: a, obtaining the number of sampling points according to preset sampling frequency and power frequency cycle, and setting a cyclic buffer region with the length equal to the number of sampling points; b, obtaining sampling values corresponding to the sampling points in the power frequency cycle and storing the sampling values in the cyclic buffer region according to a sampling time sequence to form an analytic window; c, when the sampling time of a next sampling point is reached, storing the sampling value of the point in the window, discarding the sampling value with the earliest sampling time in the window, and updating; d, performing wavelet analysis on each sampling value in the updated window to obtain a modulus maximum value of the point; e, judging whether the modulus maximum value is more than 0 or not; f, if so, determining that the SAG signal exists and the sampling time of the point is the starting moment of the SAG signal, and otherwise, returning to the step c. By implementing the method, the starting moment and amplitude of the SAG signal can be detected in real time and the purpose of reducing SAG fault detection time delay in the DVR device can be achieved.

Description

technical field [0001] The invention relates to the technical field of SAG detection of high-voltage and high-power power electronic devices, in particular to a method and system for detecting SAG signals in a DVR device. Background technique [0002] With the continuous development of DVR (Discharge Voltage Regulator, discharge voltage regulator) technology, DVR fault detection technology has also made great progress. Among them, SAG (voltage sag) fault is one of the most serious faults, so the detection of SAG signal It is the basis of DVR technology. In the process of SAG signal detection, when a three-phase asymmetrical fault occurs in the power grid, the three-phase asymmetrical voltage is converted into the direct Both the flow rate D and the AC component Q of twice the fundamental frequency converted from the negative sequence component of the fundamental frequency will jump, but in order to obtain a stable detection amount, it is necessary to filter out the negative...

AI Technical Summary

Problems solved by technology

According to the relevant regulations in the industry standard, the DVR response time should be less than 5ms, but many current DVR fault detection methods generally have shortcomings such as detection time delay and large amount of calculation.

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