Distribution Feeder Based Virtual Power Plants for Power System Frequency Support Services

Distributed energy resources (DERs), such as solar-photovoltaic (PV), wind and battery energy storage systems (BESSs) have gained popularity in the last two decades due to the strong drive to reduce greenhouse gas emissions. Most of these generation sources are non-conventional renewable energy sources, and one of the important common traits of all these DERs is that they are connected to the grid via a power electronic interface. These power electronic interfaces have decoupled the electro-mechanical dynamics of the source from the electrical dynamics of the power grid, which has resulted in reduced system inertia, and thus frequency stability. This paper has proposed a frequency support strategy using a virtual power plant (VPP) comprised of DERs located at the distribution feeder level. The frequency support strategy was developed considering several factors, such as BESS rating, state-of-charge (SoC) and fault-level at the DER location. The effectiveness of the control scheme has been proved under various operating scenarios and control conditions.