System stability and inertia

Executive Summary

This document presents the position of GO15 members on the main challenges and the most promising enabling solutions to enhance the stability of low inertia and power converters-dominated power transmission systems. It introduces a comprehensive classification of the main phenomena influencing power system stability, examining research directions and promising technologies and methodologies for improving dynamic grid performance in the presence of large-scale adoption of distributed power converter-based generators.

The concept of power system stability is re-examined, taking into account the potential effects arising from the large-scale replacement of conventional synchronous generators by distributed generation systems based on renewable energy sources. Particular attention is paid to critical issues facing modern power systems, including decreasing inertia and vulnerability to dynamic disturbances on multiple time scales, and their potential impacts on the stability, flexibility, and resilience of power systems. The paper includes a detailed analysis of the most promising enabling technologies for improving system stability.

Moreover, the document summarizes and discusses the results of surveys submitted to GO15 members on power system inertia and stability, presenting best practices and providing valuable insights.

Finally, the document makes few recommendations at three levels: policy and planning, regulatory and technical. The significant penetration of converter interface generators (CIGs) requires substantial revisions to conventional policies governing the planning, operation and regulation of power systems [65]. Several countries have witnessed the negative effects of the rapid growth of CIGs connected to the grid, underlining the importance of defining and implementing corrective actions to improve grid flexibility and mitigate the impact on power system stability and security.