The Integrated Modeling For Clean Energy And Operation Mode Interaction In Hydropower-rich Power Grid

In southwest China with very rich hydropower resources,as the large-scale construction of giant cascade hydropower plants and small hydropower plants(SHPs),there forms several typical hydropower-rich power grids,such as Yunnan and Sichuan.Since the hydrological similarity in the same region,the large hydropower plants(LHPs)and SHPs share the synchronized water inflows.In flood season,the LHPs and SHPs are bundled for sending out under limited transmission capacity,causing lots of spilled water and also affecting power grid security,and other intermittent power sources such as wind power further increase the transmission pressure.Therefore,how to achieve an integrated modeling among LHPs,SHPs and wind power,so as to improve the power grid security and also reduce spilled water,has becoming a key issue in theory and practice for hydropower-rich power grids.Besides,with the large-scale delivery of hydropower and other clean energies,hierarchical dispatching departments are involved in the scheduling process and their interaction is very close and frequent.How to design an efficient operation mode interaction strategy is an important technical means to ensure the accuracy and efficiency of integrated simulation analysis.Given these practical engineering problems,this dissertation takes the integrated modeling for clean energy and operation mode interaction strategy in hydropower-rich power grid as the main research line,and further carrys out the studies including coordinated operation model of large/small hydropower and wind power,paralleled power flow transfer checking analysis and integrated visualization interaction strategy.The main achievements can be wrapped up by the following points:(1)To solve the problems such as transmission congestion and high operation risk for LHPs and SHPs caused by multistage transmission limits in hydropower-rich power grid,a short-term coordination operation model for LHPs and SHPs considering both the reliability and economy of power systems is proposed based on optimal power flow theory.Four objcetives,including minimizing water consumption for LHPs.maximizing clean energy accommodation,minimizing system loss and minimizing system Loss Of Load Probability(LOLP),are considered in the proposed model.During the calculation process,for better description of the power system reliability,it is evaluated based on the real-time state of power system and simulated by the Monte Carlo method.To ensure the effectiveness of the initial solution of particle swarm optimization algorithm(PSO),the load of cascade hydropower is split into small parts and redistributed.Besides,the gradient tolerance of constraints is also considered to utilize the available information of infeasible solutions.Simulation results of local power grid in Yunnan province show that the proposed model can effectively mine the regulation potential of LHPs,so as to coordinate the operation of LHPs and SHPs,and improve the power system reliability and hydropower absorption.(2)The rapid growth of wind power in hydropower-rich power grid has greatly increased the complexity on scheduling,and the fluctuation characteristics of wind power and SHP make it worse.For this,a short-term optimal operation model for LHP,SHP and wind power considering uncertainty is bulit with the objective of maximizing the total clean energy accommodation.Firstly,to describe the space dispersion and time fluctuation of SHP and wind power,their group effection and output prediction error distribution characteristics are analyzed.And fuzzy clustering algorithm is employed for constucting differnent generation scenarios,and for each scenario,the prediction error distribution is estimated by nonparametric kernel method.Then,based on improvements in terms of initialization mechanism,self-adaptive evolution pattern and mutation search strategy,the improved Bacterial Colony Chemotaxis(IBCC)based on stochastic simulation is proposed for solving the model.Finally,an engineering application of northwest Yunnan province is studied.The result shows that the regional total clean energy accommodation can be increased by the coordination optimization of LHP,SHP and wind power,making good use of provincial power grid platform's coordination advantage.By balancing the operational risk and economic benefit,decision maker could get better operation modes which conform to actual requirement.(3)With the large-scale sending out of hydropower and other clean energies and the deepening degree of power grid interconnection,the threat of power flow transfer for power system operation is increased.Thus,to achieve a rapid and accurate power flow transfer cheking analysis for actual large-scale power system,a parallelization method is proposed.On the basis of parameter analysis,automatically fault set and results parsing,power flow transfer checking analysis is carried out in batch,in which the topology of network is checked by depth first search(DFS)algorithm and the reasonableness of power flow calculation is also determined automatically.Furthermore,in a parallel framework based on Fork/Join,the batch method is performed in a multi-core parallel way by dividing task into smaller subtasks recursively using "divide-and-conquer" algorithm.Simulation results of New England test system firstly validate the proposed method's accuracy,and practical application for the Yunnan power grid is also tested and its high practicality and efficiency is thus demonstrated.(4)To overcome the disadvantages during the operation mode interaction for hydropower-rich power grid,such as difficulty in authority management,unable to realize data sharing and automerge,lack of visualization support,and so on,an integrated visualization interaction strategy is proposed.Firstly,the bottleneck of interaction is carefully explored,and an adaptive intelligent analysis method is proposed,so as to ensure the consistency of the basic equipment parameters.Then,based on the graph theory,the topological network of equipments and graphics are respectively established and they can be related according to actual electrical connection of different devices.Thus,a visualization geographical wiring diagram platform is built,on which operation modes could be scheduled by interactive operations including parameter maintenance,simulation analysis,results show and so on.Furthermore,under closed-loop process control,the interaction process is standardized,and the overload power is also adjusted considering fairness.Successful application for operation mode interaction in Yunnan power grid shows that the proposed strategy is practical in application and can remarkably improve efficiency.It is helpful for other similar interaction problems.Finally,summarize the content of the whole study and some problems to be further studied are discussed.