A Realization Method of Phase-shifting Transformer Differential Protection

Abstract

The invention discloses an implementation method for phase-shifting transformer differential protection. The implementation method is characterized by comprising the following steps specifically: step SS1, collecting winding current of each side of a transformer in real time; step SS2, converting each winding current in the low voltage side into the high voltage side, and shifting to a step SS3; step SS3, calculating differential current according to the converted current; and step SS4, judging whether the differential current is higher than an action threshold or not, if so, cutting off the transformer by the differential protection action. The implementation method for the phase-shifting transformer differential protection is suitable for common electric transformers as well as phase-shifting transformers with multiple windings, random connection groups and random phase differences; and the implementation method has extremely high universality, and solves the problem that the existing phase-shifting transformers (including rectifier transformers) cannot realize the differential protection caused by difficulty in calculating the differential current.

Description

technical field [0001] The invention relates to a method for realizing differential protection of a phase-shifting transformer, belonging to the technical field of electrical engineering relay protection. Background technique [0002] In industrial fields such as aluminum electrolysis, alkali electrolysis, salt electrolysis, and chemical industry, rectifier phase-shifting transformers are widely used. The phase-shifting transformer has the following three functions: ① realize the phase shift of the primary and secondary side line voltage to eliminate harmonics; ② transform to obtain the required secondary side voltage; ③ realize the electrical isolation between the rectifier and the grid. [0003] The special function of the phase-shifting transformer determines its special electrical structure. Unlike ordinary transformers, the secondary winding of the phase-shifting transformer usually has multiple groups. According to the different phase-shifting windings, phase-shifting...

AI Technical Summary

Problems solved by technology

Due to the large number of windings on the low-voltage side of the phase-shifting transformer and the variable internal transformation ratio, its impedance is not easy to calculate, so the setting of the given value is troublesome.

In addition, quick-break overcurrent cannot reflect faults such as inter-turn short circuit inside the transformer, high-impedance grounding in the area, etc., so the sensitivity of the protection is low

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