On-line testing method for insulation condition of capacitive current transformer

Abstract

The invention relates to an on-line monitoring method for the insulation condition of a capacitive current transformer. A current transformer is connected with the end panel terminal of the capacitive current transformer and the ground in series; a current meter is connected with the secondary side of the current transformer in series; when the insulation of the capacitive current transformer is normal, the current of the current meter is nearly zero; after water flows into the capacitive current transformer, the end panel, the oil of the transformer and the insulation of the bottom are affected with damp, the leakage current to the ground is increased and flows into the ground through the terminal led out from the end panel, the current value can be read through the current meter which is connected in series, the insulation condition of each capacitive current transformer can be judged by observing the current value and the variation of each capacitive current transformer, and a power off testing and repair schedule can be planed in time. The method is simple, the monitoring is convenient and accurate, on-line monitoring can be performed under the condition that power is not cut, the actual insulation condition of the equipment can be reflected under operating voltage to guarantee the normal operation of the equipment, and the capacitive current transformer can not lose effective supervision.

Description

technical field [0001] The invention relates to a test method for on-line monitoring of the insulation state of a capacitive current transformer. Background technique [0002] In a power system, a current transformer is a current conversion device. It converts high-voltage and low-voltage large currents into small currents with lower voltages to supply meters and relay protection devices and separates meters and protection devices from high-voltage circuits. The structure of the capacitive current transformer is composed of an iron core, a primary winding, a secondary winding, a capacitive screen, a grounding terminal of the last screen, and an insulating support. The number of turns of the primary winding of the current transformer is small, and it is connected in series in the line where the current needs to be measured, and a large measured current flows through it. The number of turns of the secondary winding is large, and it is connected in series in the measuring inst...

AI Technical Summary

Problems solved by technology

[0005] The insulation state of the current transformer for power failure testing is mainly to measure its insulation resistance and dielectric loss factor. Although this test can basically reflect the insulation state of the current transformer, because of the low test voltage (2500V or 5000V for measuring insulation resistance) Megohmmeter, apply 10000V when measuring the dielectric loss), it cannot reflect the real insulation state of the equipment under the operating voltage

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