Distributed load control of autonomous renewable energy systems

Autonomous renewable energy systems such as wind, solar, and micro-hydro re quire control methods to maintain stability, due to the real time variation of input energy and load, while maximizing the use of renewable energy. Th is paper describes the application of load control using a novel frequency and voltage-sensing device. The device uses a low cost microcontroller to m onitor the system frequency and voltage. Load switching is carried out base d on this information. Software was developed for frequency and voltage measurements and tested on a 18 kW, single phase, 50 Hz, micro-hydro system, A fuzzy control system w as then developed which makes intelligent load switching decisions using in puts from the measurement algorithms coupled with expert knowledge expresse d in the form of control rules, This load control system was then tested on the same micro-hydro system and on a site powered by a 60 kW, 3 phase, 50 Hz wind turbine only.