Online detection method and system of mutual inductor metering error

Abstract

The invention discloses an online detection method and system of a mutual inductor metering error. The method comprises the following steps: injecting an inter-frequency test signal into a secondary side loop of a mutual inductor; collecting a secondary side inter-frequency voltage and secondary side inter-frequency current, and performing calculation according to the secondary side inter-frequency voltage and the secondary side inter-frequency current to obtain equivalent resistance of the mutual inductor; inputting the equivalent resistance of the mutual inductor into a pre-trained BP neuralnetwork model to obtain a mutual inductor error, wherein the BP neural network model is obtained by performing pre-training according to historical data of the equivalent resistance of the mutual inductor and corresponding historical data of the mutual inductor error; the method and system have the advantages of simple calculation and high precision, and are not affected by the environmental interference, no primary side measurement needs to be performed on the mutual inductor, no complicated equipment is needed, and the problems of equipment difficulty and verification difficulty of measuring the mutual inductor error online are solved; and the method and system can be used for performing real-time detection on the error of the dynamic change of the mutual inductor, and the defect of lowinstantaneity of the existing error detection method is solved.

Description

technical field [0001] The invention relates to the field of power metering, and more specifically, to an online detection method and system for metering errors of transformers. Background technique [0002] According to JJG1021-2007 "Power Transformer", the national metrology verification regulation for power transformers, measurement transformers must be periodically tested for errors to ensure that their errors meet the requirements of national metrology regulations. At present, there are two methods for transformer error detection: off-line measurement method and on-line measurement method. Off-line measurement is a method of measuring after the transformer is powered off, commonly used methods such as extrapolation method, small signal test method, etc. Off-line measurement is simple and convenient, but on the one hand, it cannot fully reflect the actual measurement error characteristics of the transformer. On the other hand, most transformers cannot be powered off whe...

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Problems solved by technology

[0003] In order to solve the problems of inaccurate results, bulky and expensive equipment, and difficult calibration of existing transformer error measurement methods in the background technology, the present invention provides an online detection method and system for transformer measurement errors; the method and system pass Different frequency signals are applied on the secondary side of the transformer, and the transfer relationship between the primary side and the secondary side of the transformer is established according to the different frequency voltage and current of the secondary side, and the measurement error of the transformer is obtained by using the BP neural network algorithm; A method for on-line detection of measurement errors of transformers includes:

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