火电机组零功率保护的应用研究

目前大型机组DEH控制中,为了防止功率输出通道中断导致机组剧烈振荡跳闸而采用了功率负荷不平衡逻辑,但该逻辑存在严重依赖有功功率变送器而导致的抗干扰能力差、不能防止误动作等问题.为了从根本上解决机组输出负荷中断事故导致的机组振荡问题,根据实际故障案例研究了火电机组并网前转速控制方式和并网后的负荷控制方式,分析了零功率保护在应对负荷中断事故中的判断准确、动作快速、抗干扰能力强的优点,并探讨了零功率保护的出口方式以及在火电机组中加装零功率保护的必要性,最后建议在火电机组中配置零功率保护.

Application Research of Zero Power Protection for Thermal Power Plants

At present,the logic of power load unbalance is widely used in DEH control system of large thermal power generation unit to prevent the unit from considerable oscillation and tripping when the power output channel is interrupted.However,the logic relies heavily on the active power transmitter,and its weak ability of anti-interference is easy to cause the unit＇s maloperation.To solve this problem,based on the actual fault cases,the speed control mode before unit＇s grid connected operation and load control mode after unit＇s grid connected operation were studied,in which the advantages of zero power protection such as accurate judgment,fast operating and strong anti-interference ability when load interruption happens were analyzed and verified.Moreover,the tripping way and the necessity of zero power protection were also discussed and it was recommended to configure zero power protection in the thermal power unit.