Quantitative Analysis Method of Stability Ability for Renewable Electric Energy Delivery System

Abstract

One mainstream approach to alleviate insufficient voltage support in renewable-energy power delivery systems is to introduce a portion of grid-forming (GFM) inverters. However, the distinct characteristics of grid-following (GFL) and grid-forming (GFM) controls complicate the quantitative assessment of system stability capability. To address this issue, this paper proposes an amplitude mapping-based method for quantitatively evaluating stability capability, yielding a simple and practical analytical expression. Specifically, we introduce the idea of assessing system stability through waveform-amplitude stability. Based on this concept, the mathematical model of the renewable-energy delivery system is established, and the expression of the stability capability index (SA) is derived. Next, the impacts of key parameters on SA are analysed, and the critical GFL–GFM power ratio is quantified. Finally, the theoretical findings are validated through case studies.