Research On Optimal Allocation And Control Strategy Of DSSC To Promote High Proportion Of New Energy Consumption

In September 2020,president Xi Jinping said that ’A new type of power system with new energy as its main body’ should be built,to promote ’China’s carbon dioxide emissions to peak by 2030,strive to achieve carbon neutrality by 2060’ development goal.To promote the absorption of new energy,improve the safe operation of the power grid,and solve the security and stability problems of the high proportion of new energy grid after being incorporated into the power grid,is an important prerequisite for the early realization of the dual-carbon target.At the same time,with the rapid growth of new energy grid-connected scale,the security of power grid operation is affected,and new energy with intermittent and fluctuating characteristics is easy to be affected by the environment in the process of absorption,the transmission lines are blocked and the power flow is distributed unevenly,which limits the carrying capacity of the new energy and affects the safe and stable operation of the power grid.With the development of power electronic technology,Flexible AC Transmission System(FACTS)has been further studied in regulating power flow and improving static voltage stability,the large capacity FACTS equipment represented by the Static Synchronous Series Compensator(SSSC)can greatly enhance the transmission capacity of the system line,however,its complex structure,large area and high investment cost limit the large-scale application of SSSC in the power grid.Compared with the traditional centralized FACTS equipment,the distributed FACTS equipment represented by DSSC has the characteristics of simple structure,flexible installation and decentralized investment,the problems of static voltage stability and load-bearing capacity of high-ratio new energy grid are solved.In this paper,the static voltage stability and load-bearing capacity of power grid with high proportion of new energy are studied.Firstly,the basic structure and working principle of DSSC are analyzed in detail,based on the equivalent power injection model,the power flow equation including DSSC is constructed,and the influence of high proportion of new energy connected to power grid is summarized,to evaluate the power flow control efficiency of DSSC quantitatively from the static voltage stability of power grid,and to improve the static voltage stability of high-proportion new energy after being incorporated into power grid,the optimal allocation and control strategy of DSSC for improving the carrying capacity of high-ratio new energy grid is proposed.Specifically,the main research work of this paper is as follows:(1)This paper analyzes the basic structure and working principle of DSSC,and the effect of DSSC on power flow control efficiency in actual power grid operation.At the same time,combined with the power flow calculation equation of power grid,a power flow calculation method of DSSC power grid in constant capacity mode is proposed.And the influence of high proportion of new energy connected to power grid is analyzed,a flow chart of DSSC power flow calculation after new energy is connected to power grid is presented.(2)Firstly,based on the new energy electric generator model,the static voltage stability mechanism of the system with high proportion of new energy is analyzed in detail.secondly,the power flow equation is derived from the equivalent power injection model of DSSC.Finally,based on the system power flow calculation equation,a performance evaluation index which can reflect the static voltage stability of the power grid is proposed,and the influence of different proportions of new energy on the overall static voltage stability of the power grid is calculated,the effect of DSSC equipment on static voltage stability at weak nodes of new energy grid is simulated and verified by IEEE-30 nodes.(3)According to the Operation State of the power grid,the index that can reflect the carrying capacity of the power grid is put forward,the DSSC of the access system is planned and configured to maximize the carrying capacity of the system in a single planning cycle.In order to optimize the installation location and quantity of DSSC,the lowest system configuration cost is taken as the target to improve the carrying capacity of the system.The IEEE-RTS79 bus system and the actual power grid simulation are used to verify and analyze the two-stage optimal configuration control strategy.