Research On Power Flow Equilibrium Control Of AC Transmission Network Based On FACTS

The distribution of electric energy and load is uneven in our country,the western power supply is abundant,and the electric load is mainly concentrated in the eastern coastal area,which forms the pattern of China's power transmission from the west to the East.It brings great challenges to China's power transmission.With the economic development,the grid is also booming,but the power construction speed is still faster than the grid grid construction,this situation increased the power transmission task.In addition,the distribution of tidal power distribution in AC transmission network also limits the power flow capacity of the whole system,resulting in the western power and the waste of resources.Therefore,it is very important to explore the trend distribution of AC transmission network and to improve the power transmission capacity of AC transmission network.In this paper,the distribution of power flow is analyzed,and the improvement measures are put forward.According to the power flow evaluation index of transmission network,the configuration of UPFC is guided.Finally,the optimal operation scheme of UPFC power distribution is obtained.The main research contents and results are as follows:First of all,this paper studies the distribution of tidal current in AC transmission network and its influencing factors.Through the analysis of the current situation of AC transmission network in China,it is concluded that the main reason for the transmission capacity of AC transmission network is the uneven distribution of transmission power flow,and the uneven distribution of power flow in the transmission network is very common.the power flow distribution phenomenon is analyzed theoretically,and the power flow distribution is mainly affected by the power supply mode and network structure.In the case study of the central China power grid,the simulation results show that the power flow regulation can be realized by the change of the start-up mode and network structure.Secondly,the tidal current entropy of AC power distribution trend evaluation index is put forward.The traditional transmission network trend evaluation mainly adopts the maximum transmission capacity,but the obtained maximum transmission capacity may cause some line overload,some line light load,reduce the system safety performance.Based on the trend distribution of transmission network,this paper puts forward the index-tidal current entropy to evaluate the power flow balance of transmission network.Considering some important transmission lines,a weighted entropy is proposed,which provides a new idea for the power flow evaluation of transmission network.Finally,the trend adjustment characteristics of different types of FACTS devices are proposed,and the optimal configuration scheme of UPFC is proposed.FACTS can be divided into three types:parallel type,tandem type and hybrid type.In this paper,the characteristics of three different types of typical devices are studied,and the model of the corresponding device is established.The power flow entropy is used to calculate the sensitivity of the UPFC series control parameters,and the UPFC device is configured according to the sensitivity and the value of the power flow entropy.According to the characteristics of Hubei AC transmission network,the key lines are selected for UPFC configuration,and the UPFC configuration is realized according to the sensitivity and the entropy value,and the distribution of tidal current distribution is solved.Finally,the optimal distribution of power flow in Hubei power grid is realized.