适用于并网系统低电压穿越的电压检测算法

随着新能源并网发电系统大规模的接入,电网从运行安全的角度制定了严格的并网标准。其中,低电压穿越标准要求新能源发电系统具备低电压穿越能力,从而能够在电网故障情况下对其提供支撑。提出了一种适用于新能源并网发电系统低电压穿越的快速电压检测方法,该方法由基于同步参考系锁相环与2个并列运行的检测模块组成,快速检测模块根据追踪的电压最大值点与过零点可在短时间内快速检测出电网电压跌落,准确检测模块则可以在复杂电网情况下得出精确的电压跌落幅度,为并网系统准确、快速响应电网需求提供了有力支撑。仿真与实验结果验证了该方法的有效性与准确性。

A Voltage Detection Method for Low Voltage Ride Through of Grid-connected System

With the large-scale of renewable energy resources connected to the grid, strict grid codes are formulated to ensure grid safety. Of the grid codes, the low voltage ride through (LVRT) regulation requires that the new energy generation system be capable of LVRT so as to be able to provide the grid with support during grid fault. This paper proposes a fast voltage detecting method suitable for the new energy grid-connected system. The method consists of the traditional three-phase phase locked loop and two voltage detecting modules that can quickly detect the grid voltage sag in a short time according to the maximum voltage point and zero crossing point. And accurate detection of module makes it possible to obtain the precise voltage sag range in the case of a complex power grid, which provides a powerful support for grid-connected system to accurately and quickly respond to the grid demand. The validity and accuracy of the proposed method is verified by simulation and experimental results. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2011AA05A301).