Challenges in Microgrid Control Systems Design. An application case

Microgrids are composed of local adjacent generation, consumption and often energy storage. The main purpose of a microgrid is to increase the quality and reliability of energy supply, ensuring operation both in parallel or isolated from the utility network, and provide economical benefits in the use of energy resources. Controlling the energy balance in the microgrid is one of the most difficult challenges and requires a Microgrid Control System that ensures seamless transition to island operation, automatic generation and load control, resynchronization and coordinated operation with the protection system. Cybersecurity in another aspect that requires increasing attention in the design, operation and maintenance of a Microgrid Control System. The paper describes a Microgrid Control System for the reliable operation of wind turbines and diesel engines coupled to a flywheel electrical storage in an island: multiple permissive-based decoupling schemes, tie-flow controls, and heat load trading features are implemented. Control strategies have been tested with a Real Time Digital Simulator (RTDS) and challenged against different low to turbulent wind gust profiles and low to peak loading.