Improving LV networks hosting capacity via the use of batteries – a Monte-Carlo analysis

The rapid increase in residential PV capacity is causing significant overvoltage issues, making it challenging for the grid t o absorb power during peak hours. This triggers inverter stalls as a security measure, causing concerns to Belgian DSOs and preventing prosumers from injecting power into the grid. In collaboration with Belgian DSOs and via the use of metered consumption and injection data, dedicated Monte-Carlo analyses were performed to investigate mitigation measures, via parametric simulations focused on the issue at hand. The focus in this paper is put on the use of batteries to improve LV networks hosting capacity. This approach was implemented to study different questions arising from the use of BESS: e.g., optimal ratings and location, use of P-Q capability of the BESS,… Results from thousands of simulations highlighted that a single three-phase 45 kWh/15 kVA/phase BESS installed at the end of the feeder can regulate voltage mainly by implementing phase-balancing, i.e. absorbing power on a phase and injecting it on another, with very limited storage (< 1.5 kWh) in most of the simulated cases. With these ratings, a simple Q control algorithm also allows to regulate voltage in > 99% of the cases. The upside is the net-zero energy exchange limiting the battery energy capacity requirements. However, this is achieved at the expense of higher kVA requirements due to the high R/X ratio of distribution networks compared to the transmission level.