Research on Node Inertia and Frequency Distribution Characteristics of Renewable Energy Power Systems

With the continuous increase in the proportion of new energy generation, a significant number of renewable energy units are being integrated into the power grid through power electronic converters. This integration has led to substantial changes in the inertia characteristics of the power system. Overall, system inertia has decreased, and frequency stability issues have become increasingly prominent. This paper begins with an analysis of inertia characteristics and explores the application of inertia assessment and zoning methods in conjunction with the dynamic distribution patterns of frequency. First, the inertia characteristics of power system nodes are introduced, along with a definition of equivalent node inertia in the power grid and the methods for inertia analysis. Next, the frequency stability characteristics are examined, and the impact of system inertia on frequency stability is discussed through key indicators. Finally, simulations based on the IEEE 39-node system are conducted to validate the frequency dynamic response under the integration of new energy sources. The simulation results indicate that inertia plays a critical role in maintaining power system frequency stability, and the high penetration of new energy significantly affects this stability. Low-inertia systems exhibit slower frequency recovery and larger frequency deviations. This research provides a foundation and reference for addressing the challenges to frequency stability posed by low-inertia issues in renewable energy power systems.