基于暂态功率的高压直流线路单端量保护

针对传统高压直流单端量保护存在可靠性较低的问题,通过计及直流边界、线路频变等因素影响,研究了高压直流线路暂态功率故障特性,提出了基于暂态功率的单端量保护方案。根据暂态功率在正方向区内外故障的频率段差异性,利用高低频段暂态能量比值,构成边界保护元件;针对利用暂态功率频率衰减特征无法区分正反方向故障的局限性,利用暂态功率极性构造方向辅助判据。结合保护启动元件和故障选极元件构成基于暂态功率的单端量保护方案。仿真结果表明,该保护方案能够快速有效地区分直流线路区内外故障,具有一定的抗过渡电阻性能及抗干扰能力,可靠性较高。

Transient Power Based Single-end Protection for HVDC Transmission Line

Aiming at the problem of low reliability of traditional single-ended protection for high-voltage direct current(HVDC)lines, by considering the influence of DC boundary, line parameter frequency variation and other factors, this paper studies the transient power fault characteristics of HVDC lines, and puts forward a scheme of single-end protection based on transient power. According to the difference in the frequency band of fault transient power in and out of the positive direction, using the ratio of transient energy between high and low frequency bands, a boundary protection element is built. Considering the limitation of using frequency attenuation characteristics of transient power to distinguish positive and negative direction faults, a directional auxiliary criterion is constructed by using transient power polarity. Combined with the actuating element and the fault pole element, the single-end protection scheme based on transient power is constructed. The simulation results show that the scheme can distinguish the internal and external faults of DC line area rapidly and effectively, with certain resistance to transition resistance and anti-interference ability, and have high reliability.