Research On Power Grid Operation Mode And Substation Plan For Effectively Improving System Safety And Economy

With the continuous innovation of the power industry technology,the expansion of the scale of the system and the increase of the demand for urban electricity,the grid structure under the power planning has been difficult to meet the requirements of the safe and economic operation of the power grid.System economy is an important index to evaluate equipment utilization and investment efficiency,and it is related to whether the power grid can be healthy,orderly and sustainable development.At the same time,the complicated and changeable operation environment under the large power grid has brought a great impact on the safe and stable operation of the power system.The objective contradiction of security and economy in the development of power grid can be effectively solved by rationally configuring the structure of the power grid and optimizing the changing mode,so as to promote the process of social modernization.Based on the actual operating conditions of the large power grid,this paper firstly points out that the irrational operation mode of the power grid will not only produce reactive circulation,increase the transmission loss,but also bring about a series of security problems including short circuit current level.As the current power load density of large cities is nearly saturated,the economic analysis under different substation shows that the simplified voltage level in the heavy load area can bring great social benefits.Therefore,there is a practical necessity to optimize the operation status and configuration scheme of the existing power grid.This paper then establishes an optimization model of power grid operation mode,which takes account of the economic and current-limiting effects of the power grid.The system total network loss is the target function of the model,and the short circuit current checking is put into the security constraint.In order to improving model efficiency,reducing the number of variables and the size of the constraint number,a dynamic REI equivalent method is proposed,which is suitable for the optimization of the power grid operation,and the strategy of optimizing the operation mode of the power grid under the improved REI equivalent method is formulated.The example simulation of the Kunder system validates the high precision and transient characteristics of the equivalent method,and the simulation of the IEEE-39 node proves that the proposed scheme can effectively select the safe and economical optimization scheme of the operation mode.Finally,the 500 kV/110 kV technology research is carried out to provide a better power supply scheme for some special load demands.First,the necessity and feasibility of the scheme in engineering practice are analyzed from the aspects of equipment selection and manufacturing capability.Through two typical grid structure scenes,their respective application principles and technical and economic analysis are given,and then the new500 k V/110 k V substation scheme is designed for the East Lake high tech Zone in Wuhan.The electrical demonstration results show that the design of the two substation schemes is technically and economically superior.