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Reclosers and fuses are the commonplace protective devices in distribution networks. A recloser can prevent long-time outages by clearing temporary faults before operation of the fuses in the system. Thus, it decreases the rate of long-term outages and improves system reliability and power quality. Despite positive features of reclosers, each operation of a recloser causes a momentary voltage interruption that exacerbates power quality. Nowadays, power quality issues have become more important because of the increasing use of sensitive equipment to voltage interruptions. According to the mentioned concerns, it seems necessary to set reclosers to strike a balance between power quality and the effectiveness of fuse saving scheme. Thus, we proposed a method to set reclosers. Due to the random nature of faults, the proposed method is stochastic based on the Monte Carlo method. The proposed method determines the optimal number of operations, reclosing intervals, and protection zones. The proposed method efficiency is evaluated according to the simulation results, and the proposed method is capable of establishing an optimal trade-off between power quality and protection efficiency.

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Abstract:Power converters have been widely employed in power systems to enhance the quality and magnitude of the power drawn from renewable energy sources. An LCL filter for connection of an inverter to the grid is often used to mitigate the harmonics generated by the inverter. Based on different design methodologies, optimal parameters of LCL filters tend to vary in wide ranges. This paper describes a new approach to an LCL filter used for minimizing the harmonic currents. A phase shifting transformer is inserted into the structure of an LCL filter to minimize the harmonic current. The procedures and techniques described in this paper are particularly suited for the grid-connected photovoltaic energy systems.