汽轮机功率负荷不平衡保护改进与参数设置

摘要

An analysis of the malfunction of PLU protection of steam turbines in China shows that the PLU protection based on the mechanical power and the electric power imbalance has malfunction risks caused by grid faults.In order to solve this problem,a simulation model for stability analysis is established by introducing the speed constraint into the PLU protection,and the principles for setting the rotating speed constraints are proposed.Based on the regional power grids,the typical faults are used to configure the speed constraint parameter.The simulation result verifies that this method can effectively prevent the PLU malfunction and improve the reliability of PLU protection.%通过对国内汽轮机功率负荷不平衡保护(PLU保护)误动作的总结分析,指出依靠机械功率和电气功率不平衡量作为PLU保护动作判据过于单一,在电网侧故障时有误动风险.为解决这一问题,将发电机高转速启动条件引入PLU保护并建立了稳定计算用仿真模型,提出了高转速启动定值的配置原则.基于发电机组所在区域电网,采用典型故障方式配置并校核高转速启动定值,使高转速启动定值的设置有据可依.仿真结果表明,该方法可以有效防止电网侧故障引起PLU保护误动,对提高PLU保护动作可靠性、保障电网安全稳定运行具有积极意义.