Multi-objective voltage optimisation trade-off assessment for coupled HV and LV networks

Real-time HV and LV network voltage optimisation and control are receiving significant attention from both academia and industry as a means of reducing consumer power consumption and increasing the capacity for utilization of low carbon technologies. In this study, a multi-objective optimisation problem involving the twin objectives of HV network loss reduction and LV network energy consumption reduction is considered. The potential trade-off that may exist between these two objectives is investigated using a detailed openDSS simulation of a coupled HV/LV network in the greater Manchester area in the UK. Optimisation of the voltage control devices is performed using a warm start oriented discrete coordinate descent method with a decomposition weighting technique employed to assess the trade-off between the objectives. The results show that, while a trade-off does exist, the much larger scale of LV energy reduction compared to the increase in HV losses means that the latter dominates the optimisation. When the objective functions are given equal weighting an 8.3% and 10.1% reduction is achieved in LV energy consumption and HV energy loss, respectively, compared to nominal operation.