In recent years, the concept of hybrid energy systems (HESs) is drawing more attention for electrification of isolated or energy-deficient areas. When optimally designed, HESs prove to be more reliable and economical than single energy source systems. This study examines the feasibility of a combined dispatch (CD) control strategy for a photovoltaic (PV)/diesel/battery HES by combining the load following (LF) strategy and cycle charging (CC) strategy. HOMER software is used as a tool for optimization analysis by investigating the techno-economic and environmental performance of the proposed system under the LF strategy, CC strategy, and combined dispatch CD strategy. The simulation results reveal that the CD strategy has a net present cost (NPC) and cost of energy (COE) values of $110,191 and $0.21/kWh, which are 20.6% and 4.8% lower than those of systems utilizing the LF and CC strategies, respectively. From an environmental point of view, the CD strategy also offers the best performance, with CO 2 emissions of 27,678 kg/year. Moreover, the results show that variations in critical parameters, such as battery minimum state of charge, time step, solar radiation, diesel price, and load growth, exert considerable effects on the performance of the proposed system. Sustainability 2019, 11, 683 2 of 26 different energy sources to produce a hybrid energy system (HES), which can solve reliability problems and provide an environmentally friendly solution [7][8][9]. Various power sources and storages, such as diesel generators, batteries, and supercapacitors, should be integrated into HESs to improve system stability and smooth out fluctuations [10,11].Sustainability 2018, 10, x FOR PEER REVIEW 2 of 29 problems and provide an environmentally friendly solution [7][8][9]. Various power sources and storages, such as diesel generators, batteries, and supercapacitors, should be integrated into HESs to improve system stability and smooth out fluctuations [10,11]. Figure 2. Commonly used approaches for energy management strategies [14]. Sustainability 2019, 11, 683 3 of 26Although the non-dispatchable RESs necessitate complex systems modeling, they are themselves simple to model without the need for control logic, in which the power is merely produced in direct response to the available renewable energy resources. On the other hand, the dispatchable components, such as the generator and battery, are more difficult to model because they must be controlled to achieve matching of demand and supply properly, and to compensate for the intermittency of the non-dispatchable RESs [16,17]. "Should a generator charge the battery or should excess solar production be responsible for charging the battery only and the generator used only to satisfy the load?" This question has led to some rules that manage the operation of generator and battery energy storage. The load following (LF) and cycle charging (CC) dispatch strategies are used to control generator operation and battery energy storage. Under the LF strategy, a generator produces only e...

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The main reasons for installation of power quality meters in distribution transformer substations are power quality monitoring and global evolution of electrical network towards the 'smart grid'. In case that all measurements from the meters are properly synchronised and centralised, new possibilities of control or evaluation of the network are enabled. This contribution proposes the possibility for an earth fault localisation with the aid of synchronised data recorded on the low-voltage side of the medium voltage/low voltage transformers in compensated neutral distribution networks which are equipped with auxiliary resistor for short-time increasing of the active part of the fault current. The described method uses voltage sags evoked by connecting of the auxiliary resistor for locating the faulty section. The proposed method is tested with the help of numerical model which presents a part of the distribution network.

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