Mamo, Mengesha (PhD)Getnet, Yalemzerf2018-06-292023-11-282018-06-292023-11-282017-05http://etd.aau.edu.et/handle/12345678/4872Despite a long history of micro hydropower in Ethiopia, locally manufactured low cost frequency controllers are not well developed and are not available off-the-shelf in local market. The frequencies of micro hydropower plants are controlled by electronic load controllers. Unfortunately, these governors have harmonic effect on the system, waste more amounts of water and energy during low power demand. In this thesis, simple, less cost and fast response fuzzy logic based frequency control system is modeled, designed and simulated. The frequency controller controls flow rate of water by acting on electric valves and keep the frequency of the micro hydropower system nearly constant. In addition to this when flow rate is minimum, the controller designed to prevent component from damage by isolating loads from the system. It is observed from the simulation results that the average overshoot for 35% load change is 0.9% and the settling time is 26.85 seconds. Moreover, even for 75% load change, overshoot is only 3.04% and the settling time is 27.65 seconds. It is further observed that energy wasted on the valve is always around zero at steady state conditions. In addition the proposed controller is less expensive, which cost 10-20 USD than ELC which cost 70-120 USD per kilo watt. Generally both the transient and steady state performances are improved with fuzzy controller and the controller works efficiently under all operating conditions. Therefore, this controller can play crucial role for low cost micro hydro power plant development in rural part of Ethiopia. Key Words: Micro Hydropower, Fuzzy Logic Controller, Rural ElectrificationenMicro Hydropower; Fuzzy Logic Controller;Rural ElectrificationThesis