针对高速铁路牵引网所采用的全并联AT供电方式,提出一种基于电流特征的高速铁路供电臂联跳保护方案。从理论上推导不同区段故障时的全并联AT牵引网短路电流表达式,分析并联接线对电流分配的影响。当变电所与AT所之间故障时,变电所的电流比和AT所功率方向可以反映故障线路;当AT所与分区所之间故障时,功率方向可以反映故障线路。在变电所配置电流比和过电流保护,AT所和分区所配置方向过电流保护,利用联跳信号将整个供电臂保护构成一个整体,实现了故障的快速隔离。通过Matlab/Simulink对各种故障类型和故障位置的仿真,验证了该方案的选择性和快速性。理论分析和仿真结果表明,该保护方案实现简单,不同保护之间无需同步,能够快速隔离故障供电臂。
For the cross-coupling AT feeding network of high-speed railway, an inter-tripping protection scheme for feeding system based on current features was proposed. Firstly the theoretical expressions of the fault currents at different sections were derived, and the influence of cross-coupling line on current distribution was analyzed. When a fault occurred between substations and AT posts, the ratio of substation line currents and the power direction of AT post could reflect the fault section. Similarly, the power directions of AT post and section post could also reflect the fault section when a fault occurred between AT post and section post. Therefore the protection based on current ratios and overcurrents were equipped in substations, and directional overcurrent protections were equipped in AT posts and section posts. A link signal was used to inter-trip all the relays on the same feeding sections. The selectivity and speediness of the scheme were verified by the simulation results of different-type and different-location faults. The theoretical analysis and simulation results show that the protection scheme is simple and can quickly isolate the faulted feeding sections, each protection criteria has no requirement to synchronize with others.