基于补偿电压复合极化量的自适应距离继电器

方向阻抗继电器通常采用单一电压如正序电压作为极化量,其动作特性固定不变,不能自适应过渡电阻的变化.当高压输电线路发生单相经高阻接地故障时,过渡电阻可能导致阻抗继电器的稳态超越.在提高阻抗继电器自适应过渡电阻能力的同时,为避免因过渡电阻引起的不正确动作,利用补偿电压随过渡电阻变化的特性,提出了由补偿电压构成的复合电压作为极化量的阻抗继电器.在电压平面和阻抗平面分析了该继电器的动作特性,并以300 km线路500 kV双端电源系统为模型进行了仿真验证.理论分析和仿真计算表明该继电器具有较强的耐过渡电阻能力.

Adaptive Distance Relay with Combined Polarizing Quantity Based on Compensated Voltage

Mho relay usually takes a single voltage as polarizing voltage such as positive sequence voltage. In this way, its operating boundary is fixed and operating characteristic cannot adapt to fault resistance. To enhance the adaptive capability against fault resistance, a second voltage quantity changing with fault resistance should be introduced to form a composite vector of multiple polarizing voltages that is able to track the trajectory of fault resistance. Hence this paper proposes a new composite polarizing voltage consisted of a part of compensated voltage and the primary polarizing voltage that is the pre-fault voltage at the location of the setting impedance. To overcome transient overreaching problem, a part of the primary polarizing voltage is also introduced to the compensated voltage to adjust the protective zone to fault clock. The paper investigates the operating characteristics of the adaptive distance relay in the voltage plane and the impedance plane. The performance of the relay has been demonstrated on a two-source 500 kV system with 300 km line, Theoretical analysis and simulation show that the relay has good resistive tolerance.