基于三相联动断路器的空载变压器选相关合

Controlled Closing of Unloaded Transformer With Ganged Three-operated Circuit Breaker

选相关合技术可以有效抑制空载变压器励磁涌流,常规的合闸策略只适用于可分相操作的断路器,基于三相联动断路器的选相关合策略少有研究。为此,分析了空载变压器选相关合策略的基本原理,研究了基于三相联动断路器的空载变压器合闸暂态过程中铁芯动态磁通的变化规律,并提出针对三相联动断路器的选相关合策略;基于PSCAD/EMTDC软件对所提选相关合策略进行仿真,仿真结果证明了此技术的有效性;搭建动模试验平台,对空载变压器进行了随机关合、选相关合试验。仿真和试验结果表明:随机关合产生的励磁涌流高达6.3倍额定电流;而针对三相联动断路器采用所提选相关合策略进行选相关合,空载变压器产生的励磁电流可抑制到额定电流的2倍,抑制效果明显。

Controlled switching technology can effectively suppress the inrush current of unload power transformer. Conventional switching strategy only works with independent-pole-operated circuit breakers. There are few researches about controlled switching strategy for three-pole-operated circuit breakers. For this reason, we analyzed the basic principles of controlled switching strategy for unload transformers, studied the change rules of dynamic core flux during the energization of unloaded power transformers with ganged three-operated circuit breakers, and proposed a controlled switching strategy for ganged three-operated circuit breakers. Based on the PSCAD/EMTDC software, the proposed controlled switching strategy was simulated, and the simulation results prove the effectiveness of this technique. The experimental platform was built, and the tests of random and controlled switching were conducted for unloaded transformers. The simulation and experimental results show that the inrush current caused by random switching is 6.3 times the rated current. For the ganged three-operated circuit breaker, the proposed controlled switching strategy is used to energize, the unload transformer magnetizing current can be suppressed to 2 times the rated current, and the suppression effect is obvious.