| With the increasing depletion of traditional fossil energy sources,all countries are vigorously developing clean energy such as wind power and photovoltaic.However,wind power and photovoltaic are the substantial randomness,intermittency,and uncertainty.These characteristics bring certain difficulties to the dispatch and operation of the power system.Concentrated solar power with thermal energy storage system can achieve energy transfer.With the dispatchability of concentrated solar power with thermal energy storage system,wind power and photovoltaic can be reasonably dispatched to improve the power system’s ability to consume and absorb wind power and photovoltaic and reduce wind and light abandonment.Soft open point(SOP)can adjust active power and reactive power and plays a crucial role in power regulation,voltage support,fault isolation and fault recovery of distribution network at the same time.In order to improve the dispatching and grid-connected capacity of new energy,enhance the comprehensive economic benefits,and reduce the voltage offset and fluctuation of the distribution network,this thesis proposes a two-layer optimization model of considering the joint work of concentrated solar power with thermal energy storage system and SOP.The model needs to study the dispatching and grid connection of new energy,so this thesis divides the model into two layers for research.The main content of this thesis is as follows:(1)The upper-layer model in this thesis focuses on the dispatchability of concentrated solar power with thermal energy storage system.In the upper planning of the distribution network,according to the load demand,the upper-layer model takes the minimum operation cost as the objective function,and establishes the optimal scheduling strategy of wind power,photovoltaic and energy storage system by accessing concentrated solar power with thermal energy storage system.The output curves of wind power,photovoltaic,energy storage system and concentrated solar power with thermal energy storage system under this strategy are obtained to provide the energy basis for the SOP research of lower-layer model.By comparing and analyzing the costs of both scenarios with and without concentrated solar power with thermal energy storage system,the feasibility and superiority of the participation of concentrated solar power with thermal energy storage system in wind power and photovoltaic dispatch is demonstrated.(2)The lower-layer model in this thesis focuses on the effect of SOP on power transmission and voltage excursions in the distribution network.In the lower planning of the distribution network,the lower-layer model integrates the results of the upper layer scheduling strategy into the lower-layer distribution network.It takes the minimum network loss and voltage offset as the objective function.It optimizes it through the cooperative control of the SOP,on-load tap changer and capacitor banks to realize the distribution network’s economic operation and reduce its voltage offset and fluctuation.The original lower-layer model belongs to a non-convex and nonlinear model.Therefore,it is trans-formed into a linear model,the quadratic cone model,and the rotated quadratic cone model,and the auxiliary variables are introduced and remove the absolute value to rapidly and accurately produce the solution of the model improve the solution efficiency.A comparison and analysis of four scenarios-no SOP,one SOP,two SOPs and four SOPs-demonstrates that as the number of SOPs increases,the voltage excursions at the nodes are reduced,the voltage fluctuations are smoother,the loss costs of the network are effectively reduced and the security of the network is effectively improved.(3)The model is simulated and analyzed in a modified IEEE33 node system.The results show that the model proposed in this thesis ensures the economy of the grid while improving the voltage stability. |
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