Synthetic Inertia for Frequency Regulation of Electric Grid using Modular-Multilevel Converter

Abstract

The massive integration of renewable energy sources with little or no inertia has imposed several challenges to the emerging electric power systems. Renewable Energy Sources (RESs) solely with the conventional grid may not solve different problems of the hybrid energy system. Frequency stability and inertia variation are the two major difficulties which can lead to under frequency load shedding and cascaded outages. To mitigate these issues different control aspects have to be considered like creating a virtual source that can extract the stored energy and compensate the required power during the first few seconds of the abnormal conditions. This paper describes an analysis of frequency regulation by using a Virtual Synchronous Generator (VSG) concept. The Modular Multilevel Converter (MMC) has been used for providing the virtual/synthetic inertia in view of increased penetration of converter interfaced RESs. Various case studies have been simulated in a real-time digital simulation environment to analyze the frequency stability and inertial response of the power system during transient conditions.