高压架空-电缆混合线路电容电流补偿方法研究

Research on Capacitive Current Compensation Method for High Voltage Overhead-cable Hybrid Line

为提高架空-电缆混合线路纵差动保护的灵敏度和可靠性,提出了一种分段电容电流补偿方法。首先,获取混合线路两端的电压、电流值,依据架空线路的分布参数线路模型计算出架空与电缆分界处的电压值;然后对架空线段、电缆段分别进行电容电流补偿;进而利用补偿后的电流实现纵差动保护。利用PSCAD/EMTDC建立了500 kV架空-电缆混合线路模型,考虑了故障类型、故障位置及过渡电阻等因素进行了大量仿真计算,仿真结果验证了所提方法的有效性。

For improving the sensitivity and reliability of longitudinal differential protection for overheadcable hybrid line,a kind of piecewise capacitive current compensation method is proposed.First,the voltage and current on both ends of the hybrid line are obtained,and the voltage at the boundary of the overhead line and the cable are calculated in accordance with the line model of distributed parameter of the overhead line.Then,the overhead line section and the cable section are respectively compensated with capacitive current,thus the current after compensation is used to achieve longitudinal differential protection.PSCAD/EMTDC is used to set up 500 kV overhead-cable hybrid line model.A large number of simulation and calculation are performed with consideration of such factors as fault type,fault location and transition resistance.And the effectiveness of the proposed method is verified by the simulation result.