探究无功控制回路对构网型并网逆变器暂态稳定性的影响

Investigating the Impact of Reactive Power Control Loops on the Transient Stability of Grid-Forming Inverters

随着全球能源结构的转型和环境保护意识的提升,作为一种高效、环保的能源利用方式,基于新能源的分布式发电系统正逐渐在电力系统中占据重要地位。而随着分布式发电系统渗透率的不断提高,电网的等效惯性不断降低,严重影响电力系统的频率稳定。因此,虚拟同步控制应运而生,其通过模拟传统旋转同步发电机的动态特性,能够对电网补偿惯性和等效阻尼。虽然虚拟同步机(Virtual Synchronous Generators,VSG)的小信号稳定控制已经得到广泛的研究,但其无功回路对系统的大信号暂态稳定性的影响仍需进一步研究。文中首先对构网型并网逆变器无功回路对其暂态稳定性的影响进行了理论分析,在此基础上列举了三种能够有效改善并网逆变器暂态稳定性的方法;最后,通过MATLAB/Simulink平台对其进行了仿真验证。

With the transformation of the global energy structure and the improvement of environmental protection awareness,as an efficient and environmentally friendly way of energy utilization,the distributed generation system based on new energy is gradually occupying an important position in the power system.With the continuous improvement of the penetration rate of distributed generation system,the equivalent inertia of the power grid continues to decrease,which seriously affects the frequency stability of the power system.As a result,virtual synchronous control has emerged,which can compensate for inertia and equivalent damping of the grid by simulating the dynamic characteristics of traditional rotary synchronous generators.Although the small signal stability control of virtual synchronous machine(Virtual synchronous generators,VSG)has been widely studied,the influence of its reactive power loop on the transient stability of the large signal of the system still needs to be further studied.In this paper,the influence of the reactive circuit of the grid-connected inverter on its transient stability is analyzed theoretically,and on this basis,three methods that can effectively improve the transient stability of the grid-connected inverter are listed.Finally,the simulation was verified by MATLAB/Simulink platform.