过渡电阻对多相补偿阻抗元件影响的分析及对策

Analysis on Impact of Transition Resistance on Multi-Phase Compensation Impedance Element and Its Countermeasures

介绍了一种不受系统振荡影响的多相补偿阻抗元件,利用序分量法分析了线路单相经过渡电阻短路时该多相补偿阻抗元件的动作特性,分别从保护区内、区外以及反向故障3个方面分析了过渡电阻对该多相补偿阻抗元件的影响。针对该多相补偿阻抗元件在保护区内耐受过渡电阻能力较弱,而保护区外及反向耐受过渡电阻能力较强的特点,提出通过对单相距离继电器动作判据引入偏移角,以及引入零序电抗继电器来克服过渡电阻对多相补偿阻抗元件的影响,同时引入以正序电压为极化量的阻抗继电器来解决零序电抗继电器的稳态超越问题。PSCAD仿真结果表明了该措施的有效性。

A kind of multi-phase compensation impedance element that is not impacted by power system oscillation is proposed. Using sequence fault components, the operation characteristics of the multi-phase compensation impedance element under the single-phase earth fault of transmission line via transition resistance is analyzed; the impacts of transition resistance on the multi-phase compensation impedance element under different fault conditions, i.e., inside the protection zone, outside the protection zone and the fault in the reverse direction, are described. In allusion to the feature of the multi-phase compensation impedance element, namely its weak transition resistance endurance capability inside the protection zone and strong transition resistance endurance capability outside the protection zone, it is suggested to overcome the impact of transition resistance on multi-phase compensation impedance element by leading the offset angle into the operation criterion of single-phase distance relay as well as leading in zero-sequence reactance relay, meanwhile, it is also suggested to overcome the steady-state overreach of zero-sequence reactance relay by leading impedance relay that takes positive-sequence voltage as the auxiliary polarization voltage. The effectiveness of the suggested measures is verified by results of simulation based on PSCAD.