相控真空断路器投切空载变压器的应用研究

INVESTIGATIONS ON SWITCHING IDLE POWER TRANSFORMER WITH PHYSING VACUUM CIRCUIT BREAKERS

关合空载变压器所产生的励磁涌流容易引起继保装置误动、绕组机械应力增大及电能质量降低等。采用选相合闸技术在铁心中的预感应磁通与剩磁相等时刻投入变压器,可以有效地削弱励磁涌流。该文分析了变压器空载投切的暂态过程及限制励磁涌流的策略,仿真分析及相关试验结果表明选相控制的永磁机构真空断路器很适于选相分合闸的实现。

The inrush currents generated by the energization of unloaded transformer have unfavorable effects such as protective relay misoperation, imposed sever mechanical stresses on the transformer windings and reduced power quality of the system. Controlled transformer switching can potentially eliminate these inrush currents and the optimal instant to energize the transformer is when the “prospective” flux is equal to the residual flux. This paper analyses the transient process of energizing unloaded transformer and introduces several strategies for controlled energization. Both simulation and experimental results in laboratory indicate that phase-control vacuum circuit breakers with permanent magnetic actuator can be used to realize the controlled switching.