摘要
在±800kV特高压直流系统中,换流变压器套管SF6压力表计发生接点粘连时,跳闸回路将会启动换流器单元紧急停运,使换流器单元退至备用状态。为消除这一缺陷,方案一在SF6压力低跳闸回路1、跳闸回路2中分别并入继电器K205、K305,改造后的信号回路和跳闸回路可以对单一元件拒动或误动进行监视,并正确启动跳闸功能;方案二增加一对机械表计接点,采用三选二的逻辑,可以很好地解决机械表计、继电器的拒动和误动问题;方案三通过告警回路与跳闸回路串联的方式,并与现场运行实际结合,从而避免了接点粘连而引起换流器单元紧急停运的情况。比较可知,方案二具有较大优势和使用价值。
In the ± 800kV UHVDC system, the SF6 low pressure trip circuit will start the function of emergency switch-off sequence （ESOF） in order to make the inverter unit return to the standby status when the SF6 pressure gauge terminals of the converter transformer valve bushing stick together. In order to eliminate the defects, the first scheme is to stall relay K205 and K305 in parallel with the trip cir- cuit 1 and trip circuit 2 respectively, then the improved sig- nal circuit and trip circuit can monitor refusing action of sin- gle element or misoperation, then to start trip function cor- rectly. The second scheme is to increase a couple of new me- chanical contacts, then the question of refusing action and misoperation of mechanical contacts and relays can be avoi- ded by using of three out of two logic. The third scheme is to combine with real operation situation through series con- necting warning circuit and trip circuit, which can avoid in- verter unit ESOF caused by the contacts adhesion. The com- parision shows that the second scheme is the best one.
出处
《现代电力》
北大核心
2014年第1期83-88,共6页
Modern Electric Power
