In recent years, microgrids have become increasingly common in power systems around the world. Microgrids have complex control and operational requirements, thus, a dedicated communication network is often a requisite for its functionality. Due to economic and logistical concerns, it is also desirable to keep the communication system as simple as possible. Among contemporary system automation protocols, the Modbus protocol is generally the simplest one to implement. This paper demonstrates the applicability of Modbus TCP communication in facilitating the control system of a detailed microgrid simulated in a real-time power system simulator.
The simulated microgrid exchanges voltage, frequency, power measurements, breaker statuses as well as power set points of generators with a central control location via Modbus protocol, where a control system continuously monitors the microgrid.
Control centre issues commands depending on the operating conditions of the microgrid such as to switch the microgrid controls from the grid connection mode to the islanded mode, change the protection relay settings groups and activate a load-shedding scheme. Implementation of relevant microgrid controls and Modbus communications are presented using an example microgrid case with the results obtained.