Impact of large scale PV deployment in the sizing of urban distribution transformers

With the increasing deployment of solar systems in buildings in urban environments, a future scenario of high photovoltaic penetration is expected to produce impacts on the distribution grid. One of the challenges relates to the power balance at the power transformers, which might not have sufficient spare capacity to accommodate the solar electricity feed in. In this work, we estimate the power balance at the transformers in a small urban area of Lisbon, Portugal, considering full deployment of PV, installed on rooftops and building façades. The PV potential is estimated through two different approaches: the simplified Peak power method, which considers the typical peak power of a module and the available area, and the more labour-intensive Irradiance method that accounts for hourly time step solar irradiance and demand data or simulations.
The main findings of this work point out that the Peak power method has limited success if PV facades are to be considered. Moreover, a high PV penetration scenario leads to a locally less resilient grid, hence a solar PV factor was proposed to account for future deployment of PV systems in urban environments.