Article: On Small Signal Frequency Stability under Virtual Inertia and the Role of PLLs

Link: https://www.mdpi.com/1996-1073/11/9/2372

I am glad to share the article that we have published. This paper presents the results of a comprehensive analysis on studying the role of PLL on the maximum virtual inertia provision from the virtual synchronous generator (VSG). It addresses the key questions i.e., how the faster frequency measurement can increase the maximum virtual inertia potential from VSG and how it can be quantified. This paper is focused on the PLL based frequency measurement approaches due to their wide application in the industry and the delay in the frequency measurement is defined by the cut-off frequency of the PLL low pass filter that is generally added to PLL to suppress the harmonics. We provides a methodology for evaluating the virtual inertia limitations from stability perspective due to delays in frequency measurement and processing. The research is useful for the case studies of power systems where the inertia from conventional generation is declining and is replaced by the virtual inertia.