Model reference adaptive control add-ons for hydro turbine speed governors

Hydroelectric power plants have an important place in electricity generation through renewable resources in the world. Hydroelectric power plants account for about 20% of the total installed capacity of the power plants throughout the world. Also in Turkey, this rate is slightly higher and hydroelectric power plants constitute 32% of the total installed power. Due to the fact that the hydroelectric power plants could be activated in minutes and could react in seconds to supply-demand imbalances occurring in the electricity grid, hydroelectric power plants feed the peak load and are used as reserve-supplying plants in contrast to the base load supplied by the thermal and nuclear power plants. As the presence of wind and solar power plants with an intermittent generation profile increases in the electricity grid, the generation need that these type of power plants could not supply is satisfied by the hydroelectric and natural gas power plants for the reliable operation of the electricity grid. Speed regulators in hydroelectric power plants regulate the amount of water entering the turbine runner and adjust the turbine speed for network synchronization and active power output in parallel operation. The speed regulators must be operated correctly for the rapid start-up of the unit and for the stable generation of the electricity after mains synchronization. Primary frequency control is the fastest frequency control method in order to keep the network frequency deviations within the certain limits which is a result of the difference between the generation and consumption occurring in the network. Primary frequency control is provided by the automatic response to frequency deviations via the speed governors. The speed governor controller, which is tuned according to the rated values, shows poor performance in the presence of the disturbing effects such as the water level changes in the reservoir and tailwater, the operation of other units in the plant. This low performance causes the unit to prolong the network synchronization time, fail to maintain the given target active output power rating in a stable manner or to contribute to the primary frequency control in the desired way. Adaptive control methods could be applied to determine the effects of such disturbing effects on speed regulator performance and to correct the negative results of this effect. It is aimed to develop adaptive add-ons for the speed and active power output controls of the speed regulator in order to adapt the unit rapidly to changing power plant conditions and to perform the desired performance. In order to develop the adaptive control add-ons, a non-linear hydroelectric power plant model is established in the simulation platform using the characteristic values for two different power plants. The dynamic models are validated through the field tests. In addition, reference models for which the desired performance is processed are formed for the speed control and primary frequency control. The developed adaptive control add-ons are first applied in simulation environment. Then the add-ons are tested in the software-in-the-loop simulation environment with the actual controller code. Finally, field tests are performed and the functionality and performance of the add-ons under field conditions are evaluated. It has been observed that the adaptive add-ons developed in this study have corrected the poor performance of the classical PI controller in the presence of disturbing effects in accordance with the reference model.