Improving LV networks hosting capacity via manual phase switching of households – a Monte-Carlo analysis

Due to the rapid increase in residential PV capacity, it gets more and more difficult for a Low Voltage grid to absorb power at peak hours due to overvoltage issues, causing concerns to DSOs and prosumers who are temporarily unable to inject power into the grid. Monte-Carlo simulations were performed to statistically assess the benefits of using manual phase switching of households as a mitigation measure. The best implementation approach was also investigated. Based on typical LV feeder scenarios found in Belgium, it was shown that a single 1ph switch can already provide a significant gain in voltage reduction . However, 3-wire networks are by nature less prone to unbalance-related issues and stand thus less to benefit from phase switching. A concrete decision-making criterion for the relevancy of a 1ph switch was found: should the unbalance between each phase’s maximum yearly voltage be larger than 6% or should the average of the phases’ maximum yearly voltage be smaller than 1.08pu, a targeted 1ph switch would be useful and advisable. The smaller the average voltage, the higher the chance that a single 1ph switch will solve the overvoltage issue altogether. The best choice for a 1ph switch is a household from the phase with the highest maximum voltage to the phase with the lowest maximum voltage, the farthest along the feeder as possible.