Electric signal amplitude and phase angle measurement method for low-voltage protection device

Abstract

The invention discloses an electric signal amplitude and phase angle measurement method for a low-voltage protection device. The method comprises the following steps: acquiring an original sampling point electric signal of the low-voltage protection device; filtering the original sampling point electric signal by using a filter to obtain a filtered sampling point electric signal; performing discrete Fourier transform on the filtered sampling point electric signal to obtain a calculation amplitude and a calculation phase angle of the sampling point electric signal; and correcting the calculated amplitude and the calculated phase angle of the electric signal of the sampling point by using the amplitude compensation coefficient and the phase angle compensation coefficient of the filter to obtain the corrected amplitude and phase angle. According to the invention, the accuracy of the amplitude phase angle can be improved while the interference signal is filtered out, so that the low-voltage protection device is prevented from maloperation when the electromagnetic compatibility test is carried out.

Description

technical field [0001] The invention relates to a method for measuring electric signal amplitude and phase angle of a low-voltage protection device, and belongs to the technical field of signal measurement of secondary equipment in a power system. Background technique [0002] Based on the embedded microcomputer protection device, it has been widely used in various factories, stations and other places of the power system. During the working process of the protection device, it is necessary to accurately measure the voltage and current signals in the power system. At present, the discrete Fourier algorithm (DFT) is commonly used to process the voltage and current signals, and measure the voltage and current amplitude and phase angle, so that the protection device appears in the power system. In the event of a fault (overcurrent, overvoltage, undervoltage, etc.), it can effectively jump off the faulty part to protect the safe and stable operation of the entire power system. ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem that DFT cannot accurately measure the amplitude and phase angle of the electrical signal in the low-voltage protection device in the prior art, the present invention proposes a method for measuring the amplitude and phase angle of the electrical signal in the low-voltage protection device, without changing the original sampling frequency Under the premise, filter, DFT and correct the electrical signal of the low-voltage protection device, filter out the peaks and burrs in the signal while ensuring the accuracy of the amplitude and phase angle, and suppress the possibility of misoperation of the low-voltage protection device from the source

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