Transformer bushing CT polarity test device based on elimination of impedance and electric arc influence

Abstract

A transformer bushing CT polarity test device based on elimination of impedance and electric arc influence is composed of a CT primary lead access circuit and a CT secondary lead access circuit; the CT primary lead access circuit adopts a triode to construct a switch circuit; the CT secondary lead access circuit is composed of an operational amplifier for amplifying the CT secondary current and obtaining more accurate test result. The transformer bushing CT polarity test device tests the amplified CT secondary current and ensures the test result to be accurate and reliable.

Description

technical field [0001] The invention relates to a polarity testing device for a current transformer, in particular to a polarity testing device for a current transformer which reduces the effect of coil inductance by amplifying the secondary induced current of the current transformer. Background technique [0002] The function of the current transformer is to convert the primary current with a large value into a secondary current with a small value through a certain change, which is used for protection, measurement and other purposes, and to isolate primary equipment and secondary equipment. For all directional relay protection, such as 110KV line zero-sequence directional protection, distance protection and main transformer differential protection, the correctness of CT polarity is extremely important. In production, due to the incorrect connection of the polarity of the CT, the power failure accidents caused by the misoperation and refusal of the protection device often oc...

AI Technical Summary

Problems solved by technology

The limitation of this method is that the primary current is already very small, and at the same time, when the coil passes through the current, it will generate magnetic flux, and the magnetic flux of the coil will change. According to Lenz's law, an induced electromotive force in the opposite direction will be induced, which will cause The current of the coil is reduced, and the CT secondary induced current will be even smaller. It is difficult to observe the deflection of the pointer in the actual experiment.

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