Modelling of Electronically Interfaced DER Systems for Transient Analysis

For a variety of technical, economical and environmental reasons, the electric power system is receiving small-scale distributed generation (DG) and distributed storage (DS) systems at its low- and medium-voltage levels of operation. Broadly speaking, distributed energy resource (DER) systems can be classified as rotating-machine-based DER systems or electronically interfaced DER systems. This chapter discusses the electronically interfaced DER systems. Using a generic model, the chapter introduces the construction and principles of operation of an electronically interfaced DER system. It examines how different electronically interfaced DER systems can be considered as special cases of the generic model. The chapter also discusses the important transients pertaining DER systems. Finally, the chapter describes the procedures to develop circuit-based simulation models and mathematical models, using the examples of photovoltaic (PV) energy systems and wind energy systems.