On-line detection method for inter-turn short-circuit fault of secondary winding of current transformer

Abstract

An on-line detection method for inter-turn short-circuit fault of a secondary winding of a current transformer comprises the following steps of obtaining a resistance value Z2 of the secondary windingof a TA; measuring a secondary current under different primary current power factors before the TA is put into operation, calculating and using the sinusoidal quantity they represent to construct a standard trajectory cluster under a normal state; after the TA runs for a period of time, measuring secondary side current data under the different primary current power factors, and constructing a corresponding elliptical trajectory cluster; comparing and analyzing the constructed elliptical trajectory cluster and the trajectory cluster, and determining that the secondary winding may have an inter-turn short-circuit fault when three characteristics of the inter-turn short-circuit fault are found in the elliptical trajectory. The method provided by the invention can effectively detect whether the current transformer winding has an inter-turn short circuit fault in a state without power failure, and provides a reference for the power failure overhaul and maintenance of the current transformer.

Description

technical field [0001] The invention relates to the field of on-line detection of secondary winding faults of current transformers, in particular to an on-line detection method for inter-turn short-circuit faults of secondary windings of current transformers. Background technique [0002] The importance of current transformer (abbreviated as TA) in power system is self-evident. Its efficient, reliable and trouble-free operation is the prerequisite for accurate electrical measurement and correct protection action. However, in the long-term operation of current transformers, due to short-circuit electromotive force, overload, thermal effect and aging of insulating materials, etc., the inter-turn insulation of the secondary coil is often damaged, resulting in inter-turn short circuit faults. Turn-to-turn short circuit will affect the accuracy of electrical measurement and the correctness of relay protection action, which will bring unnecessary economic losses to the power syste...

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Problems solved by technology

However, the application of this technology in current transformer TA fault detection has not been reported

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