Identification of RoCoF sensitive areas of power system based on its controlling factors

Abstract

The Rate of Change of Frequency (RoCoF) represents a pivotal parameter used to evaluate the frequency response of power systems. The article aims to present a novel insight on the correlation between RoCoF and its controlling factors by observing its variations across the spatial distribution of the power system network. The analysis may aid power system operators in both real-time and planning stages by allowing them to make informed decisions for system security. Analytical and statistical techniques are employed to identify the factors impacting the RoCoF and to assess the extent of their influence. A Partial Rank Correlation (PRC)-based algorithm is proposed in this paper to capture the sensitivity of the RoCoF. Furthermore, an index is formulated for the identification of the power system network regions most susceptible to RoCoF changes following an event. This index also aids in determining the most suitable locations for placing Inverter-Based Resources (IBRs) as part of the planning procedure. The proposed methodologies were validated using case studies on the IEEE 68 bus system. The results demonstrate the algorithm’s accuracy in predicting RoCoF variations under various contingency scenarios. In the case of a 500 MW load disturbance, RoCoF at bus 37 increased significantly from 0.16 Hz/s in the base case to 0.23 Hz/s—when inertia was reduced in the most sensitive regions.