Hysteresis loop measuring method of current transformer

Abstract

The invention relates to a hysteresis loop measuring method of a current transformer. The hysteresis loop measuring method includes steps of (1) boosting and reducing voltage of a secondary coil of the current transformer slowly by working-frequency voltage before measuring hysteresis loop, so as to demagnetize the iron core of the current transformer to ensure it in the zero-flux state; (2) testing excitation characteristics of the current transformer by 0.5 Hz low-frequency voltage source, and integrating voltage and time in real time so as to obtain a magnetic flux curve of the iron core of the current transformer; (3) measuring the magnetic flux curve of the current transformer under the 0.5 Hz voltage and drawing the hysteresis loop, and reading remanence coefficient of the current transformer on the hysteresis loop, so as to obtain accurate and reliable measuring results of the remanence coefficient. The hysteresis loop measuring method is an effective method for measuring hysteresis loop of the current transformer and is accurate, reliable and convenient to operate, accurate and reliable data can be quickly acquired, and the required instruments are small and portable and very applicable to the field.

Description

Technical field [0001] The invention belongs to the field of power measurement, in particular to a method for measuring the hysteresis loop of a current transformer. Background technique [0002] The measurement error performance of the current transformer is mainly determined by the core material and performance of the current transformer. When the turns ratio is fixed, the smaller the excitation loss of the current transformer, the higher the accuracy level of the current transformer can be. The core loss of the current transformer is mainly determined by the core loss and hysteresis loss. The core loss depends on the current transformer core material coefficient, the frequency and amplitude of the current signal, and the core loss can be calculated by a fixed formula. But there is no exact formula to calculate the hysteresis loss. The size of the hysteresis loss is proportional to the area surrounded by a cycle of hysteresis loop. By comparing the graph of the hysteresis loop...

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Problems solved by technology

[0004] Since the excitation performance of the iron core of the current transformer is closely related to the size and material of the iron core of the current transformer, and the difference is very large, the voltage and current required to make the current transformer enter a saturated state under power frequency are very different. , for a current transformer with a very large core size and a large number of turns, its saturation voltage may reach more than 10kv, and its saturation current may reach 2A. The required equipment is very large and heavy, and the output power will double once the transformer reaches saturation, the test process is very dangerous and difficult to implement

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