500 kV变电站直流电源系统级差配合特性分析及建议

文中以某500 kV变电站直流电源系统交接试验中保护电器的越级跳闸为例对级差配合进行分析。首先，通过梳理直流电源系统各参数间的约束关系，对该工程级差配合存在的问题进行了研究；然后，根据该工程具体设备配置和整改难度，提出以减少直流分电柜进线段电缆截面的方法来控制短路电流水平进而实现上下级保护的级差配合。所提整改方案实施后通过了级差配合试验。

Characteristic Analysis and Suggestion for Stage Difference Coordination of DC Power Supply System of 500 kV Substation

Taking override trip of protective device in DC power supply system of a 500 kV substation during hand-over test for example,the stage difference coordination is analyzed. Firstly, according to the constraints on parameters of DC power supply system, the problems existing in stage difference coordination is studied. And then, based on the detailed configuration and rectification difficulty, a solution is proposed to realized the stage difference coordination between upper-stage protection and lower-stage protection by reducing the DC cable section to control short-sircuit current level. Finally, the effectiveness of the proposed method is verified by experiments.