Analysis Of Static Voltage Stability Characteristics And Optimal Allocation Of FACTS For AC/DC Hybrid Power System

In recent years, the construction of HVDC power grid in China has developed rapidly. Due to the huge transport capacity, it is needed attach great importance to safe operation and stability control of the system as well as sufficient accident expectation and variety of countermeasures analysis, and these topics above brought new challenges and research issues to the management and production of the grid. With the continuous development of AC/DC hybrid power system, how to ensure the safe and stable operation of system caused widespread concern in domestic and foreign scholars. To achieve this goal, FACTS provides new control technology and effective means. For a large power grid, the application effect of FACTS depends largely on whether its configuration in the power grid is reasonable. With the stable operation demand of power grid, how to choose the access location, type and capacity of FACTS is an urgent problem to be solved.This paper relies on the horizontal issues’The research on Large scale AC/DC hybrid system static voltage stability characteristics analysis and countermeasure’of Henan Power Grid Corporation, and takes the±800kV UHVDC from Hami to Zhengzhou and Henan power grid as research object, presenting the research results of static voltage stability characteristics analysis and FACTS optimal configuration of AC/DC hybrid power system. The main contents are as follows:(1)The system loadability index utilized to evaluate static voltage stability level of AC/DC hybrid power system was defined. The impact on static voltage stability characteristics of Henan power grid under different DC system converter control modes was analyzed theoretically. The operation modes of Henan power grid after UHVDC from Hami to Zhengzhou putting into operation were subdivided and calculated, the optimization analysis of DC system control modes were also be done before obtaining the system best operation modes under different DC transmission power conditions.(2)The view that FACTS ideal access location should be a collection of optimum installation location which including different nodes and lines was pointed out. The SVC and TCSC, which have been both widely used in China power grid, were chosen as research objects. For the purpose of finding weak buses and key lines in grid, this paper proposed the approach by using modal analysis method and sensitivity analysis method respectively to obtain bus participation factors and line sensitivity coefficients. And according to priorities of installing FACTS on nodes and lines, the FACTS access locations could be selected.(3)The multi-objective optimization mathematical model under consideration of system static voltage stability and FACTS investment costs was established. In order to solve the problem of improving system static voltage stability level as well as reducing investment costs, this paper proposed chaos self-adaptive evolutionary algorithm based on the improvements of NSGA-II algorithm in generating the first generation population and genetic operators.(4)Based on the proposed FACTS access location selection methods and chaos adaptive evolutionary algorithm, the optimal configuration of FACTS were carried out and the recommendation for FACTS configuration programs of different DC transmission power were given by using Henan power grid after UHVDC from Hami to Zhengzhou putting into operation as research object. The access location selection, capacity and relevant parameters settings of SVC and TCSC were sorted. The results above could provide the reference to decision-makers to evaluate FACTS investment and construction.