Electrical Computer Engineering

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    ASSESSMENT AND ENHANCEMENT OF THE TRANSIENT STABILITY OF DFIG BASED WIND FARM USING ANFIS (A Case Study of ADAMA II Wind Farm)
    (Hawassa University, 2021-12-18) TESFAYE BELAY
    Wind power is the greatest existing and used form of renewable energy in the world. Mixing the different wind farms to the national grid introduces new challenges regarding power system stability, among power system stability concerns; transient stability is one that significantly affects the grid. The objective is to assess and enhance the transient stability of DFIG based on wind farms, to model PI control for speed and slip control generator, to improve transient stability using thyristor control series capacitor (TCSC), to conduct during pre-fault, during fault, and post fault conditions. The methods to gathering data are through review of different papers, by asking the site workers, preparing questions for the worker, and from nameplates of equipment. The result consists of four conditions, the first condition is pre-fault conditions, the systems have no disturbance, the second condition is during a fault condition, all systems are disturbed, the third condition is posted fault conditions in this systems have no disorder and the fourth is the improvement of the systems by using TCSC, TCSC is injecting reactive power to the fault area and remove the fault from the systems or back to normal operations. Generally, stability has contained three scenarios pre-fault, during the fault, and post-fault condition. In Matlab Simulink, the pre-fault and post-fault have no disturbance, but during fault conditions, the systems disturbed and the disturbed systems are solved by TCSC at the improved conditions of the systems.
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    TRANSIENT STABILITY IMPROVEMENT OF DOUBLY FED INDUCTION GENERATOR-BASED VARIABLE SPEED WIND ENERGY CONVERSION SYSTEM USING FLSTATCOM
    (Hawassa University, 2023-10-21) ELIAS EJIGU
    The "doubly fed induction generator (DFIG)" is the most extensively utilized technology for wind power generation because of its adaptability to changing wind speeds and ability to capture more wind energy. However, issues like transient stability posed hurdles for the grid because wind energy has a fluctuating nature, faults, load fluctuations occur, and electronic devices are required to connect wind turbine generators to the grid. Capacitor banks are used in the research region to address the aforementioned issues and improve the variable-speed wind production system's transient stability. The investigation shows that the capacitor banks are incapable of maintaining the grid code during any kind of network fault. This demonstrates how crucial it is to use FACTS devices to increase the wind-generating system's transient stability. In this dissertation, a shunt flexible alternative current transmission system device called a static synchronous compensator (STATCOM) can offer technical solutions to enhance the overall performance of wind energy conversion systems through the creation of a suitable controller. The Thesis also presents the STATCOM control system and its effectiveness. ANFIS-controlled STATCOM is examined in this Thesis before being compared to that of STATCOM controlled by fuzzy logic. The adaptive ANFIS control approach is faster to speed control, better at responding to voltage fluctuations, and better at tracking the reactive current reference, according to simulations performed using MATLAB on grid-connected DFIG systems. Finally, the ANFIS based STATCOM is critical in assuring the stability of power systems in the case of large disruptions and break down