System and implementation method for monitoring grounding current of transformer core on line

Abstract

The invention aims at disclosing a system and implementation method for monitoring grounding current of a transformer core on line. The method comprises the following steps: analyzing data acquired by a fast Fourier transform algorithm (FFT), converting a time domain signal into a frequency domain signal, and then sequentially calculating power frequency signal amplitude values and harmonic wave amplitude values; then carrying out analysis processing by the system according to the effective values of the power frequency signal amplitudes and the effective values of the harmonic wave amplitudevalues in a current signal to determine power frequency current values and harmonic wave current values in the grounded transformer core at the moment, thus users can determine whether the transformer core is subject to multipoint grounding. The invention has the advantages that field data copy can be realized conveniently by means of an output module, and field system parameters can be set by means of a display module and a keyboard module, so that field data can be acquired conveniently and system parameters can be set under the condition of communication interrupt or inconvenient communication line installation, thus debugging and installation can be carried out conveniently, and the purpose of the invention is realized.

Description

technical field [0001] The invention relates to an on-line monitoring system and an implementation method thereof, in particular to an on-line monitoring system for transformer iron core grounding current based on a DSP algorithm and an implementation method thereof. Background technique [0002] At present, in the power supply system, the power transformer is the most important electrical equipment in the power system. Once a fault occurs during operation, it will cause serious consequences to the power system; If the transformer core is grounded at two points or multiple points, a current loop will be formed between the transformer core of the power transformer and the earth. The maximum current in the current loop can reach dozens of amperes, which will cause partial overheating or even burning of the transformer core. [0003] At present, there are mainly three methods for judging whether the transformer core in a power transformer has multi-point grounding: the electric...

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Problems solved by technology

[0006] The purpose of the present invention is to provide an online transformer core grounding current monitoring system and its implementation method. Aiming at the above-mentioned deficiencies in the prior art, it overcomes the defect that the high-order harmonics in the current signal cannot be analyzed, and the collected voltage signal is based on The method of mathematical transformation converts the time-domain signal into a frequency-domain signal, and then calculates the current value of each harmonic in turn, providing the data of each harmonic in the transformer core grounding current, and adding the local operation mechanism and local data Export, etc., greatly improving the adaptability of the equipment

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