Development Trends and Future Prospects of Hydro-Turbine Control Systems

Hydropower system is considered to be a matured technology if it consists of fixed speed synchronous generators, simple rectifier (AC-DC) based excitation, well established hydraulic structures, mechanical components and their control systems. This system is confined to single input (speed/frequency) and single output (gate opening) control, which is enough for a generator operating independently at constant head and driven by a Francis type turbine having fixed blade angle. But the hydropower system is complex now in view of variable speed induction generators, multi-megawatt voltage source power electronic converters and coordinated control system for hydraulic governor for compensating wide variation in water head, and low frequency power oscillations. Therefore, there is a critical necessity for advanced modeling and control techniques for optimum utilization of hydropower plants. This paper gives an overview of various models and different types of controllers (linear and non - linear) designed for hydraulic turbine control system. Further, future scope and design challenges associated with the hydropower control system are illustrated.