System Optimization And Countermeasure Proposal Of Long Distance Wind Power Transmission Model

Over the past few decades,China's economic development has long been highly dependent on coal,oil and other fossil fuels,which results in serious air pollution in both north and central China.In recent years,in order to improve the atmospheric environment and reduce the total carbon emissions,China's government has started to develop clean energy and reduce the proportion of coal in energy consumption vigorously.During the 12 th five-year plan period,the growth of wind power and solar power has increased rapidly in China,and its total installed capacity remained at the top of the world.The development of new energy power is still the focus of the 13 th five-year plan.However,the rapid development of new energy is also faced with problems such as difficulties in absorption and interconnection.The reverse distribution of power demand and supply in China requires the power grid to have the ability of long-distance and cross-regional transmission.Therefore,the key factor to solve the problems of wind power curtailment and light power curtailment is to develop advanced transmission technology with large capacity,high efficiency and long distance,such as UHV,and accelerate the construction of modern power grid system to adapt to large-scale cross-region transmission and the grid-connection of new energy power generation.Due to the large fluctuation and strong randomness of power generation load of centralized wind farms and solar power stations in northern China,and inadequate peak-shaving capacity of power grid,the channel utilization rate of UHV lines are generally lower and the large-scale wind and light curtailment phenomenon still exists.In order to improve the utilization rate of new energy,the utilization rate of UHV transmission channel lines and the overall benefit of power grid,this paper established a set of comprehensive system model of wind-thermal-storage-delivery(WTSD)to solve the problems faced by the development of new energy.The model includes wind farms,thermal power station,pumped storage station and UHV transmission channel lines.Through energy equalization cost accounting and mixed integer programming,the installed capacity of different power facilities can be optimized in different power-demanded situations to achieve the best operation efficiency of power grid.Taking the transmission and power supply in Gansu-Jiuquan as an example,the simulation results show that peak load regulation is required before and after transmission,which can not only reduce the wind power curtailment,but also improve the UHV transmission efficiency.The peak regulations of pumped storage and thermal power have their own advantages and disadvantages,and the complementary peak regulation of pumped storage and thermal power can achieve better peak regulation effect.According to the sensitivity analysis,the key factor determining the wind power curtailment rate and the cost of power is the ratio of power facilities' installation capacity in wind-thermal-storage-delivery system,and the ratio of power facilities' installation capacity is not sensitive to the change of peak adjustment price,but sensitive to the change of the total pumped storage capacity.The simulation results show that the wind-thermal-storage-delivery model plays a good role in guiding the optimal allocation of power facilities and can provide a reference for power development planners.