Dynamic Economic Dispatching Strategy Based on Multi-time-scale Complementarity of Various Heterogeneous Energy

Abstract

The grid-connection of large-scale new energy brings tremendous challenges to the economic dispatch of power system and combined operation of complementary system can effectively enhance the new energy accommodation. However, the current day-ahead dispatch models of complementary system have not considered the actual complementary and smoothing effect of the system. Thus, a dynamic dispatch strategy based on multi-time scale complementarity of wind, solar, hydro and thermal sources is proposed. The wind, solar and hydro sources are bundled as a VP (Virtual Power) according to their complementary features. The load tracking index is defined to represent the tracking ability of the VP to load so that the VP can well follow the load curves. Meanwhile, a multi-time scale complementary dispatch model is established, which includes the day-ahead 24-hour plan, the intra-day 4-hour rolling plan and the real-time 15-minute plan. Furthermore, rolling amended wind and solar curtailment constraints are set to make sure that the periods which have larger wind and solar curtailment in the previous time scale dispatch plan have greater wind and solar curtailment up-regulation margins in the next time scale dispatch plan. According to the constantly updated forecast data, the day-ahead plan is amended continually to ensure the good tracking of VP to load and maximize the complementary effect. Results of examples verify that the proposed dispatch strategy can effectively improve the actual complementary and smoothing effect of the complementary system, cope with the dispatch pressure and reduce the generation costs.