交流整流发电机保护开关的双向非一致短路分断机理研究

The DC electric power system of modern ship uses AC rectifier generator as the system source and supplies power to loads through static DC-AC invertors. A topology of bidirectional non-uniform hybrid vacuum DC circuit breaker based on zero voltage principle and zero current principle is proposed in order to solve the problem of selected protection of AC rectifier generator in such a system. When short circuit occurs in the generator side of the circuit breaker, the breaker must cut off the circuit immediately. And the zero current method is applied which is able to cut off fault current with maximum di/dt of 20 A/μs within 10 ms. However, when fault occurs out of the generator, the circuit breaker has to undergo the fault current with peak current of 70kA/5ms and cut off the fault current in the decay period after a short time delay. The zero voltage method is used in this condition and faults that occur in the load and the main copper bar can be differed. A high speed contact driving mechanism is design in combined of a high speed electro-magnetic repulsion mechanism, a permanent magnetic mechanism and a spring mechanism. Equivalent vacuum dielectric recovery tests in all working condition are performed and the control strategy can be optimized upon the tests. A practically technology of bidirectional non-uniform hybrid vacuum DC circuit breaker can be achieve based on the breakthrough of the all key techniques.

现代舰船直流电力系统采用交流整流发电机作为系统电源，并通过固态逆变器向负载供电。这种系统中，发电机保护开关面临发电机侧短路时瞬动和电网侧短路时耐受后延时分断的矛盾。针对此问题，本项目提出一种双向非一致混合型真空直流断路器方案，当保护开关的发电机侧发生短路故障时，采用强迫换流关断方法，在10ms内切断初始上升率为20A/μs的短路电流；当保护开关的电网侧发生短路故障时，断路器能够耐受峰值70kA，峰值时间5ms的短路电流冲击，并在电流的衰减阶段采用自然换流关断原理关断短路电流，以区分负载故障与配电母排故障，实现选择性保护。设计基于高速电磁斥力机构、双稳态永磁机构和弹簧连接机构的高速触头驱动机构，进行断路器各运行工况下的等效真空介质恢复试验，在此基础上对断路器控制策略进行优化。在突破各关键技术的基础上获得实用化的双向非一致混合型真空直流断路器技术，为舰船电力系统的安全、稳定运行提供技术保障。

针对现代舰船直流电力系统交流整流发电机保护断路器面临的发电机侧短路时瞬时分断高上升率短路电流和电网侧短路时短延时分断的不同要求问题，本项目提出了一种双向非一致混合型真空直流断路器的拓扑结构，采用强迫换流关断原理关断发电机侧短路时高上升率短路电流，采用自然换流关断原理实现电网侧短路时短延时保护以及正常工作电流的分断。设计基于高速电磁斥力机构、双稳态永磁机构和弹簧连接机构的高速触头驱动机构，进行断路器各运行工况下的等效真空介质恢复试验，对断路器关断的三个换流过程进行分析，得到了该拓扑结构的最佳连接形式，该连接形式下正、反向关断电流的利用率分别为100%和83%。设计了1 kV/2.5 kA混合型断路器样机，并进行了正、反向关断试验，实现了正向8 kA的自然换流关断和反向初始上升率为20 A/μs的短路电流强迫换流关断。试验结果表明所提出方案的有效、可行和分析准确、可信。突破了各关键技术并获得实用化的双向非一致混合型真空直流断路器关键技术，为舰船电力系统的安全、稳定运行提供技术保障。