System and method for detecting state of secondary circuit of current transformer for metering

Abstract

The invention provides a system and a method for detecting the state of a secondary circuit of a current transformer for metering. The detection system comprises a high frequency voltage signal generation unit, an oscillation and resonance detection unit and a current detection unit which are serially connected between the current transformer for metering and an electric energy meter. The detection method detects the state of the secondary circuit by steps of measuring a practical current value, comparing the practical current value with a measured current value obtained by the electric energy meter, measuring an oscillation frequency value, comparing the oscillation frequency value with an oscillation frequency standard value, inputting high frequency voltage to the secondary circuit and detecting the practical high frequency voltage value of the secondary circuit. The detection system can be independently installed in the secondary circuit, is simple and reliable in structure, and can timely detect required data of the state of the secondary circuit of a detected current transformer. The detection method is more reliable, achieves real-time detection of the state of the secondary circuit of the detected current transformer, and provides a reliable data source for identification of the normal operation state and the open circuit state and analysis of the state of the secondary circuit.

Description

technical field [0001] The invention relates to a detection system and method of a current transformer, in particular to a detection system and method of a secondary circuit state of a current transformer for measurement. Background technique [0002] The electric energy metering device mainly consists of a voltage transformer, a current transformer, a secondary circuit and an electric energy meter. The open circuit, short circuit and series connection of components in the state of the secondary circuit are very important for electric energy measurement. In the system, the system voltage amplitude is relatively stable, so the detection of the secondary circuit and voltage transformer status can be realized through the monitoring of the system voltage. However, the magnitude of the current amplitude changes with the magnitude of the load, so the detection of the loop state cannot be realized through the detection of the magnitude. [0003] At present, there are some methods...

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Problems solved by technology

However, the magnitude of the current amplitude changes with the magnitude of the load, so the detection of the loop state cannot be realized through the detection of the amplitude.

[0003] At present, there are some methods to determine the state of the loop by detecting the minimum value of the resonant frequency. However, in actual use, this method is not suitable for a current transformer with a small transformation ratio; Detect high-frequency signals, measure high-frequency signals through sampling resistors, and judge the state of the secondary circuit of the current transformer according to the change of the amplitude; but in actual use, it is almost impossible to pass the open circuit and normal working state of the current transformer The problem of distinguishing frequency changes, especially for large ratio current transformers

At the same time, it is not suitable for independent installation for the state detection of the secondary circuit, and it has false status reports, and the application effect is not ideal.

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