The Impact of the Imbalance Netting Process on Power System Dynamics

Abstract

This paper discusses the imbalance netting process (INP) between control areas (CAs) that was developed due to the high costs of balancing energy. The main objective of INP is to net the demand for balancing energy between the participating CAs with opposite signs of interchange power variation. However, INP incorporates a frequency term; hence, it affects the frequency response of participating CAs inherently, which is not discussed in the literature. Therefore, the impacts of INP on the frequency quality and provision of load-frequency control (LFC) are shown thoroughly with dynamic simulations of a three-CA testing systems, in addition to an eigenvalue analysis of a two CA system. It is shown clearly herein that INP changes the eigenvalues of the system matrix, which results in decreased damping of the entire power system. Furthermore, the simulation results confirmed that INP reduces balancing energy, releases regulating reserve and reduces the unintended exchange of energy; thus, LFC performance indicators were improved. However, the impact of INP on frequency quality is not so explicit, since cases exist of frequency quality improvement and deterioration.