考虑虚拟电阻局限的电网电压跌落 VSG 暂态稳定性提升

The virtual resistance (VR) scheme can effectively suppress the synchronous resonance (SR) during virtual synchronous generator (VSG) grid-connection, but it will deteriorate the system transient stability performance, especially among high-voltage lines, larger line inductance will further exacerbate its deterioration. In response to the above contradictions, firstly, the power-virtual power angle curve is plotted based on power flow model, then the transient stability of VSG is described quantitatively by maximum power angle overshoot, total deceleration area and minimum initial power angle. Thereafter, with the goal of increasing the maximum power angle overshoot and total deceleration area, it is proposed to improve the transient stability of the system by reducing the equivalent active power reference and increasing the equivalent reactive power reference in the event of voltage sag fault, and a combination of adjustment coefficients in the stability domain is provided at the same time. Finally, a simulation model is built on the Matlab/Simulink platform. The results show that when the inherent large line inductance of the high-voltage lines and the VR is taken into account, the improved VSG control strategy can significantly enhance the transient stability performance of the system, and has a good application prospect.