特高压长线路可能在线路中间接入并联电抗器,从而有效补偿线路电容电流,抑制空载线路过电压。提出了在特高压长线路中间带并联电抗器时的线路分相电流差动保护原理。该原理基于输电线路的贝瑞隆模型,分析推导了区内外故障时各相动作量的表达式。理论分析与仿真验证都证明新原理不受长线路分布电容电流的影响,具有很高的灵敏性和可靠性。
Shunt reactor could be installed in the middle segment of the UHV transmission line, in order to compensate capacitive current of transmission line and limit over-voltage of line without load. This paper proposes a novel principle of segregated phase current differential protection in UHV long distance transmission line with shunt reactor installed in the middle segment. Based on Bergeron model of transmission line, this paper presents and analyzes expression of operating quantities of each phase. Theoretical analysis and simulation prove that the proposed protection principle will not be affected by distributed capacity current of transmission line and has higher sensitivity and reliability.