Electric power systems in most developing countries, especially Ethiopia, are fed by radial distribution systems (RDSs), which serve as the final link between the high voltage transmission system and the consumers. In this paper, a fuzzy logic optimization method was presented for the efficient location of voltage regulators (VR) and capacitors in distribution systems (DSs). An investigation of Gondar power distribution system was performed specifically at the Gondar feeder in Gondar, Ethiopia which has 60 nodes with a total capacity of 3.413 MW. The Gondar distribution system (DS) is classified into different zones for the purpose of proper operation and supply of electricity. The minimum bus voltage is 0.8515 p.u., while the active and reactive power losses of the feeder are 377.75kW and 222.51 KVAR respectively. Voltages and power loss (PL) indices of the DS nodes were modeled using fuzzy membership functions. A fuzzy expert system (FES) containing a set of heuristic rules was used to determine the voltage regulator (VR) and capacitor placement suitability index. The load flow analysis of the system was simulated using NEPLAN MATLAB software before and after recompense. The effectiveness of the results obtained from both the voltage regulator and capacitor placement optimality using the proposed method are presented and compared.

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Washing machines (WMs) are common household appliances that help to save time and effort used in brushing and washing clothes. It is a common practice to use manually operated WMs, and based on their uses, WMs are classified into top and front open cloth washing machines, which operate based on an automatic control mechanism. In this paper, we present the design and simulation of an Arduino fuzzy logic-based WM control system, with an emphasis on improvement in its operating algorithm. Simulations were performed to determine the optimal time the WM takes to wash clothes, the maximum number of clothes the WM can wash per time, the acceptable dirtiness level of cloths, and the type of clothes that the machine can wash. The number of clothes to be washed, the degree of dirtiness, and the type of clothes govern the fuzzy logic control process adopted by the WM. The output voltage of the WM varies as the degree of dirtiness of the water varies from 0 to 1.95 V for very dirty water output from washed clothes and varies from 4 to 4.89 V for low-contaminated water. Another constraint considered was the load current, which increased as the number of clothes increased. The WM’s operation time is determined by the amount of voltage and load current used during its operation. As a result, the control of the WM is dependent on the dirtiness level of the clothes and the amount of load.

BackgroundOne of the new technologies in generating power near the distribution system is called distributed generation which has supportive and destructive characteristics to the power system protection. One of the destructive characteristics of distributed generation is increasing the level of fault current to the protective equipment of the power system. In addition to increment of fault, it also alters the radial nature of the power distribution system and cause the power bidirectional rather than unidirectional. Integration of distributed generation to the distribution network causes increment of fault current effect, reliability drop, and affects security of protection system. The level of failure of protection be contingent on type, size, location and number of distributed generation. This fault current can cause a great damage to the electrical equipment with the miss operations of protective devices. The main aim of this paper is analysis of the fault current level to the protection of distribution network due to the integration of distributed generation which concerns on solar distributed generation, wind distributed generation and combination of solar and wind distributed generations at a time. This paper conducts the analysis for the increment of fault current by the integration of distributed generation and its impact on distribution network protection. ResultsThe analysis and the modeling are conducted on the 15KV distribution network of the radial feeder in Debre Markos town. This paper has covered the ling to ground, line to line and three phase fault analysis and their impact on the protection of distribution system for the wind and solar distributed generation types. After the integration of the distributed generation the fault current is increased by 0.529KA for three phase, 0.74KA for line to ground, 0.467KA for line to line and 0.523KA for line to line to ground. ConclusionsThis paper confirms designing distribution network without forecasting the future demand of electric power users give the protection equipment additional requirement. As the result, the fault current after the integration of distributed generation to the distribution network have great value in terms of power system protection.