Reliability evaluation of distribution transformers considering the negative and positive effects of rooftop photovoltaics

Rooftop photovoltaics (RPVs) have an impact on the ageing failure rate and reliability of transformers. The advantages and disadvantages of different penetrations of rooftop photovoltaic on the reliability of the transformers are studied. For the first time, the adverse effects of high penetration of RPVs on the transformer failure and power system reliability are examined. Regarding the growing interest in the widespread use of renewable energies on account of global warming, studying the negative effects of DG units presence is so important to predict the future of power system conditions. Monte Carlo simulation is used for the probabilistic nature of clearness index and reliability evaluation. Well-being criteria that show the different operation modes of the power system is used to identify the at-risk, marginal and healthy mode of the power system in the presence of different penetrations of rooftop photovoltaic. The results show that the maximum penetration of rooftop photovoltaic for improving the reliability of the power system is 5 kW per house in the feeder of Isin in Bandar Abbas, in Iran.