新能源同步机并网系统惯性特性的理论和实验研究

Theoretical and Experimental Study of Inertial Characteristics for the Synchronous Motor-Generator Pair

针对高比例新能源电网存在的惯性降低问题,提出了新能源通过驱动同步电动机-同步发电机(motor-generator pair, MGP)后并网的新方式;详细描述了MGP系统的结构及工作原理,推导了MGP并网系统和同容量的真实火电机组转动惯量的定量关系,得出了在同容量下MGP的转动惯量约为火电机组的66%的结论;建立了5kW的MGP实验系统,并设计了MGP、单个发电机组和同容量的火电机组三种工作模式,在可编程负载中设置相同的负荷扰动,分别测量三种工作模式的频率响应曲线,对比结果说明了相比相同质量块的单个发电机组和相同容量的火电机组,MGP能更好的抑制系统的频率波动,可以为系统提供足够的真实惯性响应,为提高高比例新能源电网的稳定性提供了全新的解决方案。

Aiming at the problem of low inertia existing in high proportion new energy grid, the synchronous motor-generator pair system was proposed as a new grid connection mode. The structure and working principle of MGP system are described in detail, and the quantitative relationship of real inertia between MGP system and thermal power units with the same capacity is deduced. The conclusion is that the inertia of MGP is about 66% of that of thermal power units with the same capacity. The 5 kW MGP experimental system is established, and three working modes of MGP, single generator unit and thermal power units with the same capacity are designed. Setting the same load disturbance in the load, the frequency response curves of three modes are measured respectively. The comparison results show that MGP can better suppress the frequency fluctuation of the system than a single generator with the same mass block and a thermal power unit with the same capacity. It can provide enough real inertia response for the system and provide a new solution for improving the stability of the high-proportion new energy grid.