Dynamic modeling of anti-islanding protection scheme of inverter-based generator for transient stability analysis

Abstract

Distributed generators connected to electric power distribution networks are prone to to operate islanded after contingencies. Islanding occurs when a portion of the distribution system becomes electrically isolated from the remainder of the power system (main substation), yet continues to be energized by distributed generators. The current industry practice is to disconnect all distributed generators immediately after the occurrence of islands. There are many techniques developed to anti-islanding protection of distributed generators, in the case of inverter-based DGs, the positive feedback-based anti-islanding methods have gained wide acceptance. These methods use the deviations of voltage frequency and/or magnitude from normal values as positive feedback signals to influence the operation of inverter-based DGs. The essential idea is to destabilize a DG when it is islanded, which facilitates the detection of islanding condition by frequency and voltage-based relays. Since the positive feedback scheme is a destabilizing force, it is important to develop tool to analyze the stability of distribution networks with multiple generators with positive feedback anti-islanding protection. Thus, the objective of this project is to develop a family of dynamic, non-linear models to represent these devices in transient stability programs.