电力电子变压器在有源配电网无功优化中的应用

尽可能地降低配电网中节点电压的偏差，是配电网运行的基本要求。为实现对节点电压的有效控制，提出利用电力电子变压器通过对其一次侧和二次侧电力电子变换器的脉宽调制控制(Pulse Width Moderation, PWM)，改变其一次侧和二次侧潮流的方法加以解决。为此，构建了含分布式电源、储能元件和电力电子变压器在内的有源配电网无功优化模型，并运用粒子群优化算法进行求解。仿真结果表明，含电力电子变压器的有源配电网无功优化后的网损，低于采用有载调压变压器(On-Load Tap Changer, OLTC)对应网络无功优化后的网损；且其节点电压与额定值的相对偏差也优于后者，从而说明了在有源配电网中应用电力电子变压器，利用其灵活的无功调节功能，能提高配电网的运行水平。

Power electronic transformer applied to optimization of reactive power in active distribution system

To reduce nodal voltage deviation in distribution system is basic requirement for an active distribution system (ADS) operation. In order to control nodal voltage, power electronic transformer (PET) is proposed. With the help of PWM (pulse width moderation) control at the primary side and the secondary side respectively, power flow at the both side of PET is regulated. Therefore, the optimal passive flow model of an active distribution system is built, which is composed of distributed generators, storage devices and power electronic transformers. Then particle swarm optimization (PSO) is adopted to solve the problem. Simulation results reveal that power loss in the active distribution network is less than that in the same network with on-load tap changer (OLTC) transformer. Meanwhile, the relative error of nodal voltage is less than the latter, which demonstrate that power electronic transformer applied to the active distribution system could improve the operation level with its flexible regulation ability of passive power.