Voltage Control of Rural Networks by Virtual Power Plant

A Virtual Power Plant is a cloud-based distributed combination of generators, loads and Energy Storage Systems which are connected in a manner that allows them to operate in unison while being geographically dispersed amongst an electricity network. This research project measures network voltage changes during charging and discharging of batteries on a trial Virtual Power Plant on the North Coast of New South Wales. The area has a high penetration of photovoltaic generation and features light loading supplied by a mix of three wire, two wire and Single Wire Earth Return feeder constructions. Customers within the trial area have installed incentivised Energy Storage Systems through a partnership with Essential Energy, the Australian Renewable Energy Agency, Reposit Power and the Institute for Sustainable Futures. This research utilises Essential Energy infrastructure and Reposit Power aggregator control systems to measure the voltage regulation capability of power dispatch used as means to defer or avoid major network investment. A series of active power charges and discharges, termed dispatch tests are performed. The Virtual Power Plant aggregator software is used for scheduling and voltage recording devices are used for measurement at various locations within the trial network area. Real-world testing is compared against load flow analysis to verify simulation against measured behaviour. A model is used to simulate scenarios which use both active and reactive power. Real-world Virtual Power Plant testing confirms active power dispatch can be utilised for voltage regulation on high resistance rural networks. Reactive power dispatch expands voltage control on areas with low resistance supply. Load flow analysis is used to construct a voltage sensitivity matrix which can be used to optimise member commitment. An increased reliance on low voltage asset data accuracy in distribution networks is identified for accurate modelling of Virtual Power Plant behaviour. An algorithm to optimise unit commitment and automate Virtual Power Plant response to network constraints is essential