一种新的阻抗型电压跌落发生器设计

针对现有的阻抗型电压跌落发生器模拟电网电压跌落深度受限制的问题,提出一种基于串并联电阻、三相抽头变压器与限流电抗器等配合使用的电压跌落发生器拓扑结构。利用变压器副边不同抽头与电阻的组合模拟不同的电压跌落深度,设计的变压器限流电抗器在电压跌落和恢复期间投入,防止抽头电压等级切换而造成的电压冲击。基于50 kVA的电压跌落发生器样机实验结果表明,依据国家光伏太阳能及风能低电压测试标准,该设计可准确模拟不同等级的对称及不对称电压跌落,跌落暂态响应平稳无冲击,满足低电压穿越测试要求。

Design of a New Impedance Voltage Sag Generator

It is limited for the impedance voltage sag generator(VSG)to simulate the depth of grid voltage sag. Aiming at solving this problem, this paper proposes a topology structure of voltage sag generator based on series parallel resistor, three-phase tap transformer, and current limiting reactor. The voltage sag depth is simulated by combining different taps and resistors on the auxiliary side of the transformer. During the voltage drop and recovery period, the designed transformer current limiting reactor is put into operation to avoid the voltage impact caused by the switching of tap voltage level. Experiments on the 50 kVA voltage drop generator prototype show that according to the national low voltage test standards for photovoltaic solar and wind power, the generator can accurately simulate the symmetrical and asymmetrical voltage drop at different levels, and the drop transient response is smooth and impact-free, which satisfies the requirements of low voltage ride through test.