Analysis of the voltage control capability of energy harvesting networks

At times of high generation levels from distributed generators (DGs), there may be a paucity of conventional generators still synchronised to the transmission system. These synchronous machines have traditionally been the power system's principal source of controllable reactive power. If DGs are operated at inductive power factors, total reactive power absorption at distribution system bulk supply points may be highest at times when the transmission system is least equipped to supply it. On the Irish power system, new DGs (typically windfarms) may be connected in a clustered fashion to a new transmission node. This paper will show how the aggregate reactive power capabilities of these clustered DGs may be characterised. Of particular importance is how the cluster can respect distribution system operating limits while also providing reactive power support to the transmission system.