# Impacts of integrating solar PV power to an existing grid. Case Studies of Mölndal and Orust energy distribution (10/0.4 kV and 130/10 kV) grids.

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Abundance existence of solar energy from the sun on the globe has brought potential for rapid growth of solar photovoltaic (PV) rooftops/power plants connection to existing grids at transmission and distribution levels. The connections are likely to bring impact challenges of integration and operations of the grids by utility companies. The steady state integration impacts of solar PV power to existing grids were studied with focus on the distribution grids of Mölndal energy (10/0.4 kV) residential distribution grid and Orust energy (130/10 kV) distribution grid. The steady state impacts on voltage level, voltage profile, voltage drop, losses, line loading and voltage stability on the distribution grids were studied. The study approached the integration impacts by comparison method of the distribution grids without solar PV power integrated, with solar PV power integrated and with different penetration levels (0%, 30%, 60% and 90%) of integrated solar PV power with aid of simulation software NEPLAN, Paladin Designbase and PVSyst for solar PV power production for the grid areas. The impacts study revealed that integration of solar PV power for the distribution grids studied in general caused an increase in voltage profile, voltage level, decrease in voltage drop and losses, and improvement in steady state voltage stability of the studied grids. In addition, integration of rooftop PV systems caused a decrease in line loading of feeder cables while integration of large ground utility PV systems caused an increase in line loading of the feeder cable/line to the coupling substation to the grid. The increase in PV power penetrations caused similar latter results in voltage level, voltage drop and voltage stability. However, the grid losses decreased for 40% penetrations level and below for Orust energy distribution grid. The losses started to increase at penetrations higher than 40%. From these results, there is a limit to how much maximum PV power (hosting capacity) a grid could allow. For the grids under study, the hosting capacities were determined. Hosting capacities of 30%, 40% and 25% penetration levels were found for Mölndal area 1, Mölndal area 2 and Orust area distribution grids.

**Nyckelord: **Solar Integration, Grid Impacts, Hosting Capacity, Solar PV power, NEPLAN, Paladin designbase, Steady State Voltage Stability, Distribution Grid.

Publikationen registrerades 2015-06-25. Den ändrades senast 2015-06-25

CPL ID: 218826

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