Study Of Multi-time Scale Optimal Dispatch Method For Wind Incorporated Power System

The energy resolution has been going on for twenty years. As the most mature and fundamentally commercialized renewable energy source, wind power generation has been growing rapidly all over the world. On the one hand, large-scale exploitation and utilization of wind power has effectively mitigated the dilemma of energy sustainable development and brought about considerable economic benefits, on the other hand, the stochastic, uncontrollable and unpredictable characteristic of wind power output has brought about great challenges for dispatch and operation of the power system. The traditional dispatch mode based on the combination of day-ahead dispatch scheme and automatic generation control (AGC) can no longer meet the requirement of power system dispatch with large-scale wind power incorporated. Given all this, this paper studies the multi-time scale optimal dispatch for wind power incorporated power system and seeks to provide some theoretical basis for reasonable utilization of wind power and its incorporation and dispatch. The main work and achievements of this paper are summarized as follows:Wind power uncertainty treatment method and forecasting model of wind power under different time scales are studied. Scenario technology is adopted in day-ahead stage; a nonparametric and discrete Markov Chain forecasting method is used in the ultra-short-term stage, the method can estimate wind power probability distribution directly within a short time independent of numerical weather prediction system and complex physical information around wind generators to accommodate the need of real-time dispatch. Multi-time scale coordinated optimization dispatch mechanism of day-ahead dispatch, rolling dispatch and real-time dispatch is elaborated, the "robustness" principle of day-ahead dispatch stage is proposed.A multi-scenario robust reserve dispatch mode and robust economic dispatch mode based on "robustness thinking" are proposed, respectively. The robust reserve dispatch method mainly describes units'robust operation trajectory. Then an economic dispatch mode considering coordination of output of conventional thermal and hydro power generation units with their spinning reserves is established utilizing the thinking of min-max robust optimization. Finally the two dispatch modes are synthetically incarnated and the whole robust dispatch model is established adopting two-stage decision-making method, the model is solved based on Benders decomposition and CPLEX linear programming package. Case studies indicate that units' outputs operating under robust operation trajectory can accommodate all wind power scenarios and guarantee the security of the power system under different scenarios; the generation cost under worst case is minimized through robust economic dispatch. Besides, output of units and their spinning reserves are coordinated, the reserve capacity is led to configure reasonably in both space and time, redundant reserve capacity is avoided effectively, and an optimal configuration of system reserve capacity is realized.Aiming at the problem that strong randomness of wind power makes the day-ahead dispatch scheme accuracy decrease rapidly, a rolling rectification strategy for day-ahead dispatch scheme for wind power incorporated power system is proposed, dual rectification functions of hydro and thermal generation costs and wind spillage in the power system are employed and an improved nondominated neighor immune algorithm is put forward to solve the problem. Case studies indicate that the proposed model can further optimize system operation cost during the intra-day dispatch process and enhance the wind power utilization ability of the system. The proposed improved algorithm is based on equal incremental equation method and the units maximum, minimum load, adjust the deviation to define the search space constraints antibodies preference relational model. The convergence rate of the algorithm is remarkably boosted and the local exploitation ability is stronger.A real-time dispatch method based on wind power time series dynamic rectification is presented. The method incorporates the process of wind power time series dynamic rectification into real-time dispatch model, expected error state vector of wind power is calculated dynamically every5-15minutes and the objective function aimed at the rectification of a particle time period is set up. The model is transformed into convex quadratic programming and its Lagrange dual problem to solve owing to convexity of the objective function. Meanwhile, the load allocation factors for real-time units are defined to indicate the initial interior point. Case studies indicate that real-time dispatch enhances the ability of real-time units tracking the fluctuation of wind power, thus optimizing the power system operation economy. The primal-dual affine scaling interior point method is employed to solve the model, the method is of rapid convergence and strong robustness and the computation speed can meet the requirement of real-time dispatch.