采用虚拟电压匹配的含双馈型电源电网暂降源定位

分布式新能源的大量接入和电力电子器件的广泛使用极大地改变了电力系统的暂态响应特性,使得以不含分布式新能源的电网作为研究对象的传统暂降源定位方法不再适用。基于双馈电源的故障机理特性提出一种新的暂降源定位法,首先建立了双馈风力发电系统的不对称故障数学模型,推导不同变换器控制策略下的机端电压统一解析式,分离电压暂态特征分量,指出稳态分量包含暂降位置信息;其次定义了虚拟电压用以表征故障位置信息,提出并网点和其他测点虚拟电压的计算和获取方法;最后采用各测点的虚拟电压构成待识别模式,与预设故障形成的典型暂降模式群进行匹配,确定暂降位置,并在含双馈电源的IEEE 33和IEEE 118节点系统中验证了文中定位法的可行性和有效性。

Sag Source Positioning of Power Grid With Doubly Fed Power Supply Based on Matching Typical Mode of the Virtual Voltage

The large amount of access in distributed new energy sources and the wide use of electronic devices have greatly changed the transient response characteristics of the power system, making the traditional sag source locations no longer applicable for a grid without distributed new energy. A new sag source location method based on the fault mechanism of doubly fed power supply is proposed. Firstly, the asymmetric fault mathematical model of doubly fed wind power generation system is established: The unified analytical expressions of terminal voltage under different converter control strategies are derived;the transient characteristic components of voltage are separated, and the steady-state component containing the information of sag position is pointed out. Secondly, the virtual voltage is defined to represent the fault position information, and the computation and acquisition of the virtual voltages at the grid connection points and other measured points are proposed. Finally, the virtual voltage of each measured point is used to form a to-be-identified pattern, which is matched with the typical sag pattern group formed by the preset faults. The sag position is then determined, and the feasibility and effectiveness of this positioning method are verified in the IEEE 33 and the IEEE 118 node systems with doubly fed power supplies.