基于分布参数模型的混合输电线路精确测距及重合闸方案的研究

Research on accurate fault location and re-closing scheme for hybrid transmission line based on distributed parameter model

华东镇海-舟山500 kV线路工程采用复杂的电缆-架空线混合输电线路,发生故障时无法准确对故障位置进行定位,且现有的重合闸方案无法实现自动识别架空线路故障并投入重合闸。文章提出一种基于分布参数模型的混合线路故障测距方案。该方案采用正序故障分量,利用混合线路各段准确参数,分别采用线路两侧电气量计算沿线各点的电压有效值。根据两侧电气量计算的故障位置电压有效值相等的特点,对故障位置进行准确计算。且针对实际工程对重合闸的需求,提出一种故障位置区段定位方法。该方法通过比较用两侧电气量计算的电缆和架空线交界处电压有效值,对故障所在区段进行定位,以实现故障点位于电缆线路时不重合闸,故障点在架空线时重合闸。仿真结果表明,采用华东镇海-舟山500 kV线路工程各段准确参数,各故障位置、各故障类型测距误差均不大于2.5%或±1 km,测距结果不受过渡电阻影响,且可实现自动识别架空线故障并投入重合闸。

A complex cable-overhead hybrid transmission line was used in the Zhenhai-Zhoushan 500 kV line project in East China,which cannot be located accurately in the event of a fault and cannot realize the automatic identification of the failure of the overhead line and re-closing.This paper proposes a fault location scheme which is suitable for cable-overhead hybrid transmission lines.In the scheme,the positive sequence fault component is adopted,the accurate parameters of each section of the hybrid line are used,and the voltage amplitude of each point along the line is calculated by using the electrical quantities on both sides of the line.According to the characteristics that the voltage amplitude of the fault location calculated by the electrical quantity on both sides is equal,the fault location is accurately calculated.According to the requirements of re-closing in practical engineering,a fault location section location method is proposed.The voltage amplitude at the junction of cable and overhead line is calculated with the electrical quantities on both sides of the line,and the fault section can be located by comparing the two voltage amplitudes.After the fault section is located,it can prevent the malfunction of re-closing when the fault occurs in the cable,and realize the reclosing when the fault point is in the overhead line.The simulation results show that when the accuracy parameters of each section of the Zhenhai-Zhoushan 500 kV line project are used,the fault location accuracy of each fault location and fault type is no more than 2.5%or±1 km.The distance measurement result is not affected by the transition resistance,and the method can identify overhead line faults automatically and put into re-closing.