Transformer zero sequence differential protection self-checking system and method

Abstract

The invention relates to a transformer zero sequence differential protection self-checking system and a transformer zero sequence differential protection self-checking method. The transformer zero sequence differential protection self-checking system comprises a first current transformer module, a zero-sequence current transformer module, a second current transformer module, a signal conditioningmodule, a signal processing module, a power module and a display and input module, wherein secondary current signal output ends of the first current transformer module, the zero-sequence current transformer module and the second current transformer module are connected to an input end of the signal conditioning module separately, an output end of the signal conditioning module is connected to an analog quantity sampling input port of the signal processing module, a communication port of the signal processing module is connected with a communication end of the display and input module, and thepower module supplies power to the signal conditioning module, the signal processing module and the display and input module respectively. The transformer zero sequence differential protection self-checking system and the transformer zero sequence differential protection self-checking method improve the zero sequence differential polarity verification efficiency, improve the operation reliabilityof zero sequence differential protection, prevent maloperation accidents after transformer zero sequence differential operation, and reduce the operation cost; and the transformer zero sequence differential protection self-checking method is simple in operation and is convenient and practical.

Description

technical field [0001] The invention belongs to the technical field of zero-sequence differential protection, and in particular relates to a self-checking system and method for zero-sequence differential protection of a transformer. Background technique [0002] As an important part of AC power transmission technology, the transformer converts AC power into different voltage and current levels through the principle of electromagnetic induction, and completes the energy transmission from the power source side to the load side. When faults such as short circuit occur in the transformer and its lines, the insulating oil in the transformer is subjected to high temperature and arc action, and a large amount of flammable mixed gas is generated, resulting in a sharp increase in the pressure in the oil chamber. In severe cases, the transformer may explode, causing severe damage to personnel and equipment. It is a big threat and has a great negative impact on the social economy. The...

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Problems solved by technology

[0011] 1) The method of verifying the zero-sequence differential protection circuit through the ground fault outside the area is effective, but its shortcoming is that the zero-sequence differential protection cannot be put into operation with the transformer at the same time, and it is necessary to passively wait for the fault outside the area, and the zero-sequence differential protection It may be withdrawn for a long time, and the role of zero-sequence differential protection cannot be played in time

[0012] 2) The verification method of main transformer no-load closing solves the problem that the main transformer zero-sequence differential protection cannot be put into operation at the same time as the main transformer, but it still does not solve the problem of zero-sequence differential protection circuit verification during operation. This verification method requires protection professionals to have a good theoretical basis and practical experience in order to make a correct analysis, and the actual operation is difficult

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