Virtual Synchronous Generator: Parameter Sensitivity Analysis

In this paper, the concept of virtual synchronous generator (VSG) which provides grid following converters the dynamic frequency support capability is analyzed. A frequency controller that responds to both frequency deviation and frequency derivative generates the active power reference required to emulate the droop response (DR) and inertial response (IR) characteristics similar to a traditional synchronous generator (SG) for the VSG. First, a theoretical validation of the impact of DR and IR of the VSG unit on frequency response is presented. Then, the influence of the VSG parameters, i.e., (a) DR and IR gains, (b) active power reserve, (c) response time and (d) frequency controller deadband on the frequency stability of a medium voltage microgrid (MG) during load step events has been analyzed using simulation. The minimum frequency (fmin) and maximum rate of change of frequency (RoCoF
max
) are used as the transient stability performance indicators. The studies are performed in the DIgSILENT PowerFactory simulation platform.