Reactive Power Optimization Of AC/DC System Based On Improved Genetic Algorithm

In order to achieve long-distance and large-capacity transmission,a large number of HVDC transmission projects have been built in China in recent years.Compared with AC transmission,HVDC transmission has gradually become a research hotspot for scholars at home and abroad for its ability to quickly adjust current and power.Under the premise of a large amount of electric energy transmitted by HVDC,optimizing every link of the power grid can create huge economic and social benefits.Therefore,it is of great importance to study the reactive power optimization problems of AC/DC system.With the improvement of the requirements for the operation of the power system,the traditional algorithm with network loss minimum or voltage stability as a single objective function cannot meet the security and economic requirements of the actual power grid.Therefore,how to optimize the control variables reasonably makes the economic and safety of the AC/DC system at the same time optimal,which is an important problem to consider in the research of AC/DC system.The multi-objective reactive power optimization problem of AC/DC system based on improved genetic algorithm is studied in this paper.In the calculation of power flow,the iterative formula of alternating iterative method is derived,and alternating iterative method is chosen in this paper.The corresponding flow program is compiled and verified by the four machine two zone system example.Based on above analysis,in order to minimize both active power loss and voltage deviation,a model of multi-objective power optimization was established.Non-dominated sorting genetic algorithm-II is applied to multi-objective reactive power optimization of AC/DC system,in which DC system variables and AC system variables are optimized together to make two objective function optimal.The corresponding reactive power optimization procedure is programmed and verified by the improved IEEE9 and IEEE30 node examples.The results show that using improved genetic algorithm to solve the reactive power optimization model of AC/DC transmission system can obtain a series of pareto optimal solution sets.Compared with the traditional method to solve the multi-objective reactive power optimization,which is the transforming multi-objective function into single objective function,multi-objective optimization problems can be solved directly by improved genetic algorithm.The improved genetic algorithm is simple,and the problem of effecting of optimization result due to the impropriate weight values is avoided.