Scalable Protection and Self-Healing of Microgrids : Hardware In The Loop Co-Simulation

The design of a reliable protection scheme for microgrids often requires communication between protective devices and microgrid controllers. These communication assisted schemes must be validated in real time with cyber physical co-simulation for successful demonstration. The paper presents such a co-simulation platform between a simulated power system model using RTDS and physical protective devices. The authors have developed a scalable protection scheme with a self healing feature to protect a microgrid with 100% Inverter Based Resources (IBR5). The primary protection of the scheme is programmed in SEL 421-7 relay and backup protection is programmed in MATLAB on a generic computer acting as a microgrid controller. IEC 61850 models are used to communicate between SEL-421 relay and RTDS, TCP/IP communication connects the microgrid controller to RTDS. The paper's focus is to demonstrate the co-simulation platform with real communication links established using both communication protocols. The paper shows the configuration of the IEC 61850 and TCP/IP communications as the interface requires proper hardware and software setup. The real time performance on IEEE 123 node distribution feeder indicates the Hardware In the Loop (HIL) framework as a competent testing environment for the developed protection scheme for microgrids.