On Site Test Research and Application of Flexible Short-circuit Current Suppression Technology Based on 220kV Fast Circuit Breaker

摘要

The world's first set of 220kV SF6 fast circuit breaker with flexible short-circuit current suppression has been commercialized. In view of this, the basic principle of flexible suppression of short-circuit current is explained, and the coordination sequence and action strategy of fast circuit breaker and conventional circuit breaker are proposed. In order to realize fast opening, the fast eddy current drive technology and the fast identification technology of short circuit fault are introduced. In order to verify the effectiveness of the proposed action sequence and control strategy, a single-phase artificial short-circuit test of 220kV line was carried out. The test results show that when a single-phase short-circuit fault occurs on the 220kV line of the Tianyi substation, the fast circuit breaker realizes the system splitting operation within 20ms and the short-circuit current is reduced from 30.8kA to 24.2kA, which effectively reduce the short-circuit current level. The protection action time of the fast circuit breaker is shortened by 78% and the full breaking time of the fast circuit breaker is shortened by 64.4% compared with the conventional circuit breaker. The research results provide an important reference for the effective development of short-circuit current suppression and 550kV fast circuit breaker.