电压跌落故障半实物模拟方法研究

Research on hardware-in-loop simulation method for voltage sag

为了在光伏电站、风电机组、虚拟同步机等低电压穿越测试过程中精确模拟电网各种电压跌落故障,提出频域内故障电压目标相量的直接合成方法,搭建基于MicroLabBox实时仿真单元和物理变流装置的半实物实时仿真平台。针对电力系统中典型电压跌落故障(包含三相对称故障和三相不对称故障),在MicroLabBox中利用故障电压特征相量合成三相故障电压调制信号,经AC/DC/AC两级PWM变流电路生成故障电压,避免了应用对称分量法的分解与合成运算过程,大大降低了控制算法运算量。实验结果表明,该半实物模拟平台可生成各种类型的故障电压,跌落深度、故障起止时间设置灵活,动态响应速度快。

In order to accurately simulate various voltage sags in the power grid during the low voltage ride-through test of photovoltaic power plants,wind turbines,virtual synchronous generator,etc.,a direct synthesis method of fault voltage target vector in the frequency domain is proposed.A hardware-in-the-loop real-time simulation platform is built based on the MicroLabBox which is a real-time simulation unit and physical control device.For typical voltage sags in power systems（including three-phase symmetrical faults and three-phase asymmetric faults）,three-phase fault voltage modulation signals are synthesized in the MicroLabBox by utilizing the fault voltage characteristic vector.Then,the fault voltage is generated after AC/DC/AC two-stage PWM converter.In this way,the decomposition and synthesis process of symmetric component method is avoided,and the calculation amount of control algorithm is greatly reduced.The simulation results show that the semi-physical simulation platform has a fast dynamic response and can generate various types of fault voltages.The drop depth and the start and stop time of faults can be set flexibly.