Risk-Based Dispatch For Power System Including Wind Farms

Energy is the material basis of human activity. The modern era is facing gradual depletion of traditional energy with increasingly serious environmental problems, which creates new opportunities for the widespread use of wind power and also brings new challenges for the economical dispatch of power systems. The original security-constrained economic dispatch is hard to manage the increasing uncertainty and decreasing controllable power in today’s power systems. It is realistic to introduce the risk index which characterizes the uncertainties into the economical dispatch model.In this paper, wind speed is taken as time series, using ARMA to predict wind power and transfered into wind power. The results show that ARMA model established can accurately predict wind speed trends thus provide a reasonable reference for economical dispatch.In order to make better use of generating capacity of the system and get the power system reach the optimal economic and security point, this paper focus on the traditional security-constrainted economic dispatch (SCED) and build a new risk-based and security-constrainted economic dispatch (RBSCED) model through the introduction of two coordination factors Kc and KR where Kc improves the economical efficiency and KR improves the security. Then three scheduling models are set to meet different scheduling demands.Considered that the new RBSCED model is large-scale and there are numerous constraints in it, it is difficult to solve it directly. Consequently, Benders decomposition strategy is adopted and transform the original problem into a two-layer nested Benders decomposition problem. The algorithm improves the practicality and operability of the new RBSCED model.Finally, the above algorithm is applied in standard IEEE30 case, according to the existing load forecasting results, SCED and three models of RBSCED are conducted in numerical example. Results show that compared to SCED, three models of RBSCED have outstanding performance in risk reduce and operational safety improvement and ESM and HEM also show excellent economic performance. On this basis, ESM model is conducted and the cost curve and the risk curve can show RBSCED (ESM) has outstanding performance in economy and safety. Then the accuracy of the prediction of wind power is taken into consideration, feasibility of the new RBSCED model is proved.