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The feasibility and potential assessment (PA) of solar PV energy is one of the key factors in identifying the most promising areas for the installation of solar PV stations. It determines the useful energy generated in the given area. This paper assesses the solar energy distribution and PA in the North Shewa administration zone. Based on the data collected and analysis made, it is found that more than 80% of the North Shewa areas are suitable for the solar energy generation for off-grid and on-grid systems. Hence, the solar potential of the North Shewa zone completely fulfills the standards of sunshine, solar radiation, and temperature. That is, most of the areas have solar radiation of 5.2 kWh/m2, and daily sunshine is greater than 7 h. The maximum energy production is found in December in Shewa Robit, Mehal Meda, Eneware, Debre Berhan, Alem Ketema, and Sela Dengay with 175.35 kWh, 188.18 kWh, 180.78 kWh, 189.54 kWh, 175.78 kWh, and 189.63 kWh, respectively. This is a good opportunity for investors to invest in solar PV electricity generation. It will solve the issue of electricity supply to the community, which currently relies on wood and fossil fuels. It also highlights the positive opportunities for the future implementation of solar energy.

Most of developing country including Ethiopia distribution systems has received considerably less of the attention to reliability modeling and evaluation than have generating and transmitting systems. Now a day life is directly or indirectly depends on electric power so that utility should deliver reliable power every day for 24 hours and each year for 8760 hours to satisfy human needs and to perform their works as much as possible with less economy. This paper focuses on enhancement of distribution system of Debre Berhan distribution network. The reliability assessment has been done on four feeders of 15kV and 33 kV to assess the performance of the existing system and to predict the reliability analysis for the future. The interruption data of two years 2017-2018 G.C has been used as a base year. Different alternatives have been assessed using heuristic (trial and error) method and the alternative with low SAIDI, SAIFI and EENS with a reasonable cost has been preferred. The reliability of the Debre Berhan distribution system has been enhanced significantly by implementing reliability improvement solutions that are justified economically. Even if the uncertainty of the input data is taken into account, SAIFI has been reduced by 77.33% as compared with the average reliability indices values of the system in the base years. In the similar way SAIDI and EENS have been decreased by 80% and 77.77% respectively.

Wind power is one of the most promising renewable energy resources and could become a solution to contribute to the present energy and global warming crisis of the world. The commonly used doubly fed induction generator (DFIG) wind turbines have a general trend of increasing oscillation damping. Unless properly controlled, the high penetration of wind energy will increase the oscillation and affect the control and dynamic interaction of the interconnected generators. This paper discusses power oscillation damping control in the automatic generation control (AGC) of two-area power systems with DFIG wind turbines and Matlab code/Simulink interfacing optimization methods. The differential evolution (DE) optimization technique is used to obtain the controller gain parameters. In the optimization process, a step load perturbation (SLP) of 1% has been considered in Area 1 only, and the integral of time weighted absolute error (ITAE) cost function is used. Three different test studies have been examined on the same power system model with non-reheat turbine thermal power plants. In the first case, the power system model is simulated without a controller. In Case Study 2, the system is simulated with the presence of DFIG and without a controller. In Case Study 3, the system is simulated with a PID controller and DFIG. Most of the studies available in the literature do not optimize the appropriate wind penetrating speed gain parameters for the system and do not consider the ITAE as an objective function to reduce area control error. In this regard, the main contribution and result of this paper is—with the proposed PID+DFIG optimized DE—the ITAE objective function error value in the case study without a controller being 6.7865, which is reduced to 1.6008 in the case study with PID+DFIG-optimized DE. In addition, with the proposed controller methods, the dynamic system time responses such as rise time, settling time, overshoot, and undershoot are improved for system tie-line power, change in frequency, and system area controller error. Similarly, with the proposed controller, fast system convergence and fast system oscillation damping are achieved. Generally, it is inferred that the incorporation of DFIG wind turbines in both areas has appreciably improved the dynamic performance and system stability under consideration.

Electric power should deliver a predicable per condition for the technological, economic, and political development of any countries and it is vital for each individual. Power outage is series problem in Ethiopia at the hole of distribution network. This is due to frequent interruptions and much time service restoration. That is why most customers of Ethiopia have their day-to-day activities highly affected and they are strongly complaining to Ethiopia electric utility daily. But this power outage affected customer cost and the Ethiopian utility. In most developing countries including Ethiopia, distribution systems have received considerably less of the attention to reliability modeling and evaluation than have generating and transmitting systems. Life is directly or indirectly dependent on electric power so a utility should deliver reliable power every day for 24 hours and each year for 8,760 hours to satisfy human needs and to perform their works as much as possible with less economy.