Ancillary services from a residential community - a Norwegian case study

Energy communities are emerging, often with the motivation to increase self-consumption of renewable energy such as photo-voltaic (PV) panels. A high number of PV panels in a community could create a high feed-in of power to the distribution grid, hence creating challenges for the distribution system operator (DSO), required to respect voltage limits. The aim of this study is to address these challenges by presenting a method to use such PV converters in a community to provide two ancillary services to the DSO: loss minimization and voltage support. Loss and voltage sensitivity factors are computed using a forward-backward sweep method. These factors are used in loss minimization and voltage droop control to estimate reactive power. This allows for maintaining a close to optimal voltage profile while keeping the losses low with little computational effort. The method is applied in a Norwegian case study, using residential meter data. The study shows that the ancillary service from a community with reactive power control capabilities highly depends on the control philosophy, R/X ratio of the network lines and seasonal variations of the load in the network.