输电线路论文：高压输电线路光纤分相电流差动保护的研究.doc

输电线路论文：超高压输电线路光纤分相电流差动保护的研究 【中文摘要】基于光纤的数字式分相电流差动保护,已成为输电线路理想的主保护。但在实际运行中尚存在一些问题,如CT饱和、负荷电流、分布电容电流及双端数据同步等问题,都可能使保护误动或闭锁。文章针对目前光纤电流差动保护在实际运行中所面临的几个问题进行了分析,特别对分布电容电流和双端数据同步展开了研究。对国内外几种典型动作判据进行了总结。针对CT饱和的问题,深究了产生它的原因,并指出光电式电流互感器可以解除这一瓶颈。对重负荷下负荷电流对差动保护的影响,基于故障分量的差动保护可以有效的避免其影响,但故障分量存在时间短且较难提取。针对超高压长线路分布电容电流的影响,特别是对T接线路有无并联电抗器补偿进行了分析计算并进行了仿真,得出时域暂态补偿优于稳态补偿,但在空载合闸等情况下仍无法完全补偿。针对双端数据同步,引入装置“时钟差”的概念,以传统的“乒乓对时”为主,辅助以电气量对时,可以解决由于双端保护收、发数据延时不同,引起差动保护产生不平衡差流甚至保护误动的问题。基于贝瑞隆线模法的分相电流差动保护,通过比较同侧电流量而非异侧电流量,从模型上克服了分布电容电流的影响；采样值差动保护具有动作速度快、计算量小的优点,且具有“天然的”抗CT饱和的能力；而基于贝瑞隆模型的采样值差动保护兼具了两者的优点,文章分单相与三相进行了详细的推导计算,对一些典型故障作了仿真验证,证明了此判据的有效性与优越性。最后,对全文内容进行了总结,并对下一步的工作进行了展望。 【英文摘要】Fiber-based digital current differential protection, has become the ideal main protection of transmission line. However, there are still some problems in actual operation, such as CT saturation, the load current, the distributed capacitance current and double-end data synchronization problems, be likely to make protection maloperation or closure.This paper analyzes several problems which exist in actual operation of optical fiber current differential protection, especially researches distributed capacitance current and double-sides data synchronization.It summarize several typical criterion of the domestic and abroad. It researches its reasons about the problem of CT saturated, and points OECT can solve this problem. Fault- based component current differential protection may avoid the effect of load current, but exist time of fault component is very short and more difficult to extract. For the effect of EHV long lines for the distributed capacitance, especially to T circuit, is analyzed and simulinked whether the shunt reactor, concluded that domain transient is better than the steady-state compensation, but it could not still compensate fully in the case of no-load closing and other.For the double-end data synchronization, the introduction of device “Clock poor” concept, based on the traditional “ping-pong time”, aid