基于典型故障限流措施的输电系统可靠性评估

摘要

The fault current limiting measures used in current power grid can control the short-circuit current effectively, and reduce the power distribution reliability and security margin of the system. With the continual increase of the short-circuit current levels,it′s necessary to research the more effective alternative method. The basic fundamental of HVDC and traditional short-circuit current limiting measures are analyzed to establish the corresponding AC/DC current equation and reliability evalua-tion model. The effect of the DC power control on status adjustment link after Monte Carlo fault is considered in evaluation pro-cess. The system reliability indexes are compared under the influence of different measures. The affects of HVDC installation lo-cation and DC capacity on reliability are studied. The simulation results show that,in comparison with the traditional measures changing the system structure such as bus segmentation and cut-off transmission line,the HVDC has higher system reliability un-der the same current limiting effect.%当前电网采用的故障限流措施虽有效控制了短路电流,但也同时降低了系统的安全裕度和供电可靠性,随着短路电流水平的不断提高,迫切需要研究更有效的替代方法.根据传统限流措施和HVDC的基本原理分析,建立相应的交直流潮流方程和可靠性评估模型,在评估过程中考虑直流功率控制在Monte Carlo故障后状态调整环节的作用,对比各措施影响下的系统可靠性指标,并在此基础上研究HVDC安装位置和直流容量对可靠性的影响.仿真结果表明,相比母线分段、开断线路这类改变系统结构的传统措施,HVDC在相同的限流效果下具有更高的系统可靠性.