An economic load dispatch of wind-thermal power system by using virtual power plants

摘要

The use of renewable energy sources, such as wind power, is of major importance in future power grids for economic and environmental reasons, while the intermittent and stochastic nature of such energy brings challenges to system dispatch. Application of the virtual power plant (VPP) concept is one of the promising ways to improve utilization of renewable power. Among the many issues of practically using VPP, the aggregated output characteristics of a set of generators have not been well studied yet. In this paper, a two-phase economic dispatch model considering the aggregated VPPs is presented for wind-thermal power systems. In phase 1, outputs of VPPs consisting of several wind and thermal generators are decided by the grid operator, with characteristics of such VPPs obtained by aggregating those of individual generators. Then in phase 2, an output dispatch is performed among individual generators within each VPP by its aggregator. The model of the above two phases are both solved by using linear programming methods, and numerical tests are performed on a 3-bus system by using CPLEX. Results show that compared with conventional economic dispatch models, our model leads to substantial improvements in wind power utilization, and lower generator costs.