Online monitoring device for turn-to-turn short circuit of voltage transformer

Abstract

The invention relates to an online monitoring device for turn-to-turn short circuit of a voltage transformer. The online monitoring device can be used for monitoring the turn-to-turn short circuit of an electromagnetic voltage transformer on line, monitoring primary admittance at high precision by using a magnetic potential balance principle and further reflecting the turn-to-turn short circuit fault of the electromagnetic voltage transformer. The online monitoring device comprises a data acquisition element, an A / D (Analogue / Digital) conversion element, a data processing system and an upper computer; a sampling resistor is connected to the tail end of a primary high-voltage coil of the voltage transformer in series; a divider resistor is connected to a group of low-voltage coils of a secondary winding of the voltage transformer in series; the sampling resistor and the divider resistor are respectively connected with the A / D conversion element; through the computed processing of the A / D conversion element and the data processing system, the sampling precision of the system can reach over 10<-4> , and thus the defect that the precision of a current signal monitored by a straight through current transformer cannot meet the requirement is improved and the turn-to-turn short circuit fault of the electromagnetic voltage transformer can be better reflected.

Description

technical field [0001] The invention relates to an inter-turn short-circuit online monitoring device of a voltage transformer, specifically for high-voltage electromagnetic voltage transformers or power transformers, based on the principle of magnetic potential balance, using a high-precision measurement admittance method to detect inter-turn short-circuit faults, belonging to Electrotechnical measurement and detection technology field. Background technique [0002] Turn-to-turn short circuit of winding high-voltage electrical equipment (transformer and transformer) is a very serious accident. According to data statistics, inter-turn short-circuit faults of transformers account for about 50% to 60% of large-scale transformer faults. At present, relevant research has been conducted on inter-turn short-circuits of winding equipment at home and abroad. For transformers, the specific research methods are as follows: [0003] (1) Use primary and secondary winding voltage and cur...

AI Technical Summary

Problems solved by technology

Its shortcomings are: the calculation method of excitation impedance is complicated; by sampling the current and voltage transformers connected to the transformer, the sampling accuracy can only reach 10 -3 ; Since the number of turns of the primary winding of the electromagnetic voltage transformer is much more than that of the transformer, the change value of the excitation admittance when the turns are short-circuited is much smaller than that of the transformer. Therefore, this method cannot be adapted to the protection of the electromagnetic voltage transformer.

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