Multi-objective Reactive Power Optimization In Area Power Grid Based On Improved Tabu Search Algorithm

The reactive power optimization is an effective approach to make the power system operate securely and economically, which is also a significant measure to reduce the power loss and enhance the voltage quality, and is of great significance in theoretical research and practical application. The target of reactive power optimization is to ensure the security of power system and to undertake power supply with the minimum power loss and maximum voltage stability on the condition of satisfying reliability and power quality standard of power system. When solving the reactive power optimization problems, the traditional methods on reactive power optimization have some flaws. But the meta-heuristic algorithms in modern times can solve the discrete, non-convex and nonlinear problems, which presents the new methods for reactive power optimization in power system.The advantage and disadvantage of traditional reactive power optimization methods as well as some meta-heuristic algorithms are summarized. The main parameters'setting method and algorithm flow are introduced, and the improvement on the traditional Tabu Search algorithm is made as follows: Conditionally release the records in Tabu table. According to practical operation traits in area power grid, this paper discusses in detail how the improved Tabu Search algorithm is applied to reactive power optimization in area power grid. During the process of this algorithm being applied to reactive power optimization in area power grid, control variables consist of the voltages of high side voltage bus in power plants and the reactive power load of high side voltage bus in 220 kV and 500kV substations, adopted in binary hybrid coding mode. And the length of the experiment neighborhood is the same as the length of the binary codes for control variables. The analysis of the"before restrict"of the control variables and the sensitivity analysis for those control variables are carried out conveniently to shrink the solution space, and the computational efficiency is improved. The paper adopts"first in first out"queue management method to manage the Tabu table. And the size of Tabu table equals to fifty percent of the whole length of the binary code string. The convergence criterion of quitting iterative is used to control the execution time of the Tabu algorithm.On the basis of analysis of the voltage stability analysis methods, a reactive power optimization model, in which the minimum active power loss and the maximum margin index are regarded as the two objectives, is constructed. The two objectives are mixed by way of the nearest distance ideal point method, and the final optimization solution which considers the two objectives can be obtained.An application program is written by VC++6.0 in this paper, Simulation results based on IEEE₁4 node system indicate that, not only is the improved Tabu search algorithm suitable to solve reactive power optimization in area power grid, but also the reactive power optimization based on the improved Tabu search algorithm in area power grid which takes static voltage stability into account is practicable and effective.