Review of inverters PQ controls to improve LV networks hosting capacity via Monte-Carlo simulations including inverter dynamics

Due to the rapid increase in residential PV capacity, it gets increasingly difficult for the distribution 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. In collaboration with Belgian DSOs and with realistic input data representing Belgian feeders, dedicated Monte-Carlo analyses were performed to investigate mitigation measures, among which the PQ control of residential inverters. The principle of this mitigation measure is to apply a dedicated control to the inverters since they can control their active and reactive power output to some extent. By either reducing their active power output or absorbing some reactive power in parallel of the active power production, the voltage level can be reduced and inverter tripping due to overvoltages can be avoided. Different types of controls have been assessed and their relative efficiencies compared. The inclusion of the inverters’ dynamic behaviour (i.e. disconnection and reconnection dynamic) had an important impact on the outcome of the assessment. Ultimately, the droop control on the reactive power provided the best results in terms of increased inverter production and equity among prosumers, while the droop control on the active power showed counterproductive results.