Demand-based frequency control for distributed generation

Extensive growth in distributed generation (DG) presents challenges for the ability to maintain frequency on the electric power system. There is little impact on frequency stability for small DG penetration. Once DG reaches critical mass, however, the current methodology for generation-based frequency compensation, automated generation control (AGC), may be insufficient to maintain frequency within the bounds for service quality. Some DG units, such as microturbines, are capable of contributing to frequency control. Renewable energy based DG units, such as wind and solar, however, are not controllable and therefore cannot participate in frequency control. In the following cases: Stand alone mini-grids, or a high penetration of DG in interconnected grids, augmenting the capability of DG to provide frequency compensation may be necessary to ensure power quality. This paper investigates demand based frequency control to provide such compensation. Both the technical and economic aspects of implementing demand based compensation are evaluated.