Optimal Dispatching Method For Sending-end Grid With High-proportion New Energy Considering Transmission Plan Flexibility

With the rapid development of new energy,long-distance transmission through transmission channels has become an important way for new energy consumption.How to improve the transmission capability has become an urgent problem.However,the traditional power transmission plan is made based on the principle that the energy of the transmission plan keeps constant,which fails to fully consider the random fluctuation characteristic of the new energy.It is difficult to meet the consumption demand of new energy transmission under the total transfer capability of the transmission channels,which causes the obstruction of new energy transmission during the period of large availability of new energy.Therefore,it is urgent to study the optimal dispatching method for sending-end grid with high proportion new energy considering transmission plan flexibility,so as to improve the ability of new energy transmission consumption.Firstly,this paper analyzes the problem that the transmission consumption of high proportion new energy sending-end grid is blocked.With increasing proportion of new energy integrated to the grid,restricted by the local load far less than the capacity of new energy,the demand for new energy transmission increases.As a result,the transmission power of the transmission channels exceeds the total transfer capability during the period of large availability of new energy,and the transmission power is too low during the period of little availability of new energy,showing the phenomenon of"high power and low energy ",which lowers the ability of new energy transmission consumption.Secondly,this paper studies the mechanism of high-proportion new energy sending-end grid dispatching plan optimization to improve the new energy transmission capability.Based on the traditional transmission planning method,the flexibility relationship between energy and power is analyzed.Then,based on the flexibility characteristic of the transmission plan,this paper proposes to reduce the conventional power output during the period of large availability of new energy,so as to minimize the peak transmission power of the transmission channels.In addition,in the period of little availability of new energy,the conventional power output will be increased,so that the transmission power of the transmission channels will be increased.This enables the transmission channels to achieve" Peak Load Shifting" and effectively improves the capability of new energy transmission consumption under the rigid condition that the transmission energy of the transmission plan keeps constant.Thirdly,this paper proposes an optimal dispatching method considering the transmission plan flexibility.aiming at the characteristic of new energy output prediction and dispatching plan in different time scales in the high proportion new energy sending-end grid.In the day-ahead time scale,a multi-objective optimization model is established,considering the constraints of constant transmission energy and total transfer capability of transmission channels,taking the maximum energy consumption of new energy and the minimum operation cost of conventional power as the objectives,and then the model is solved.In the intraday time scale,based on the day-ahead optimal dispatching plan and intraday new energy output prediction,taking the maximum power of new energy transmission as the objective,a new energy power dispatching optimization model of the new energy sending-end grid is established and solved.In addition,based on the difference between the peak value of transmission power demand and the total transfer capability of the transmission channels,the start-up threshold of day-ahead dispatching optimization is obtained,and if the threshold is greater than 0,the day-ahead dispatching plan needs to be optimized.Based on the difference between the intraday transmission power demand and the total transfer capability of the transmission channels,the start-up threshold of the intraday dispatching optimization is obtained,and if the threshold is greater than 0,the intraday dispatching optimization needs to be carried out.Then the day-ahead and intraday optimal dispatching methods are formed.Finally,the actual operation data of a power grid is used for simulation,which verifies the feasibility and effectiveness of the optimal dispatching plan optimization method of high-proportion new energy sending-end grid considering the flexibility of transmission plan proposed in this paper.