On the Impact of High Penetration of Rooftop Solar Photovoltaics on the Aging of Distribution Transformers

This paper investigates the effect of increasing the penetration of Rooftop Solar Photovoltaics (PVs) on a Distribution Transformer's (DT's) Loss of Life (LOL). The modeling of the secondary distribution system is introduced and the Markov chain Monte Carlo is used to probabilistically estimate the hourly loading on a DT while the LOL is estimated based on the DT's thermal model. The results have shown that the minimum impact on the DT's LOL may be only achieved at 60% penetration of PVs that can be considered as the maximum permissible solar PVs penetration level.