基于状态坐标分析的高压直流输电线路保护方案

针对现有高压直流输电线路保护可靠性偏低的问题,提出了一种基于状态坐标分析的高压直流输电线路保护方案。在直流线路电流和电压的坐标系中,定义以直流线路2端的电压值和电流值为坐标的点为状态坐标,通过对直流线路故障后状态坐标变化的分析发现,直流线路区内和区外故障后2端状态坐标的变化具有明显的差异,据此构建直流输电线路的保护判据。通过PSCAD仿真验证,结果表明,所提的保护方案具有可靠性高、易于整定和耐受过渡电阻能力强等诸多优点。

A Scheme of HVDC Transmission Line Protection Based on the State Coordinate

Targeting low protection reliability of HVDC transmission lines, a protection scheme for HVDC transmission lines based on state coordinate analysis is proposed in this paper. Firstly, the coordinate system based on DC line current and voltage is built and the point whose coordinate is the voltage and current at both ends of DC line is defined as the state coordinate. By analyzing the change of state coordinates of HVDC lines after faults, it is found that there are obvious differences in the state coordinates between the two ends of the DC transmission line, and based on this, the protection criterion of HVDC transmission lines is established. The PSCAD simulation results show that the proposed protection scheme has many advantages, such as high reliability, easy tuning, and strong resistance and so on.