同相供电系统中负载突变时的电流检测方法

In phase change in load current monitoring method in power system research

在同相供电系统中负载突变时,传统检测方法在检测基波有功电流及无功电流时存在一个时间缓冲,这影响电网侧基波有功电流及无功电流的检测效果,可能导致无法及时对负载侧的无功与谐波电流进行补偿。基于上述问题,提出一种Scott平衡变压器结合平衡变换装置的同相牵引供电系统工作模式。通过两相平衡变压器特有的供电方式分析两相电压与电流,采用两相电路瞬时无功功率理论对整个单相基波有功与无功电流信号进行功率检测。通过对整个单相电路的有功电流进行功率分解,得到在基波突变情况下的负序量,再结合基波稳定下的正序量,使其在负载突变时的动态检测性能明显提高。仿真与理论的综合分析验证了该方法的合理性。

When itoccurs load mutation in cophase power supply system,conventional detection method in detecting the fundamental active current and reactive current will exist a time buffer,which in turn directly affects the detection effect of fundamental active current and reactive current at power grid side.It may lead to not timely compensate the reactiveand harmonic current in load side.Based on the above problems,this paper proposed a Scott balance transformer combined balance transform device of cophase traction power supply system mode.The two-phase voltage and current analysis Through the special power supply mode of the two-phase balance transformer.According to the instantaneous reactive power theory of twophase circuit,the whole single-phase fundamental wave active and reactive current signals aredetected.Theactive current in the whole single-phase circuit is decomposed.Thus,the amount of negative sequence can be obtainedin the case of mutation,and then the positive sequence under the condition of fundamental wave stability is recombined with the negative sequence.Therefore,the dynamic performancegets greatly improved when it occurs load mutation.Simulation and theoretical comprehensive analysis verify the rationality of this method.