Stochastic Assessment of Voltage Unbalance Mitigation by Home Battery System in Low Voltage Grid with Single-Phase Solar Power Generation

Abstract

Modern electrical power system is evolving to a smarter and agile system, which will support society's sustainable development. The low voltage grid should be capable of withstanding new challenges such as reverse power flows and voltage unbalance (VU) caused by distributed generation. In this paper, the mitigation possibilities of the VU caused by single-phase-connected photovoltaics (PV) are analysed with Tesla Powerwall 2 battery energy storage systems (BESS) added to the grid. Three different BESS phase connection strategies are modelled and the VU is assessed with Monte Carlo Simulation (MCS). A low voltage distribution grid in Sweden is considered with different PV and BESS penetration levels and the applied method for VU assessment is validated. Simulation results reveal the effectiveness of VU mitigation by connecting PV and BESS to the same phase.