Research On Multi-objective Reactive Power Optimization Of Distribution Network Including Small Hydropower

Energy is the material basis of national economic development.With the shortage of fossil energy and the concept of sustainable development,actively seeking green,clean,low-carbon,and efficient renewable energy is the strategic policy for my country’s energy development.As a green and clean energy source,small hydropower has made important contributions to alleviating the problem of energy shortage and environmental protection.However,runoff small hydropower has weak self-regulating ability and is easily affected by seasonal fluctuations.During the dry season in winter,the electric energy generated by small hydropower decreases sharply and the load increases.,Due to the long transmission distance and weak electrical connection of small hydropower,the voltage at the end of the power grid is low.Safe and stable operation of the network.Reactive power optimization of the distribution network connected to small hydropower can improve the voltage quality of the distribution network,reduce network losses,enhance the absorbing capacity of small hydropower,and give full play to the positive role of small hydropower.This paper summarizes the research status of distribution network with small hydropower,and focuses on the reactive power optimization model of small hydropower distribution network and the optimization solution method.By establishing a small hydropower grid-connected model,theoretically analyze the voltage distribution characteristics,network loss,and voltage and reactive power adjustment principles,and conduct simulation analysis of small hydropower with different grid-connected capacities,different grid-connected locations,and different operating modes.It can be seen from the simulation results that the grid-connected capacity,grid-connected location and operation mode of small hydropower have important influences on the network loss and voltage distribution characteristics.The principle and related concepts of the multi-objective problem processing method based on Pareto optimal solution are analyzed,and the basic principle of particle swarm optimization algorithm is expounded.Lack of ergodicity and diversity,the convergence performance of the algorithm decreases,and it is easy to fall into the local optimum,which makes the diversity and distribution characteristics of the obtained Pareto optimal solution set worse.In this paper,an adaptive chaotic multi-objective particle swarm algorithm based on black hole mechanism is proposed.In the initial stage of the algorithm,Henon map is used to initialize the particle swarm to enhance the ergodicity of particles and improve the diversity of understanding.By introducing random black hole mechanism,The search ability of the global optimal particle neighborhood expands the optimization radius;the improved adaptive parameter adjustment strategy is adopted to adaptively adjust the optimization ability in the early and late stages of the algorithm,improve the convergence performance of the algorithm,and make it easier for the algorithm to find the global The optimal solution is obtained,and finally a Pareto optimal solution set with strong selectivity,good diversity and uniformity is obtained.The reactive power optimization problem of distribution network with small hydropower involves multi-variables,multi-objectives and multi-constraints.It is a typical hybrid nonlinear programming problem.The traditional reactive power optimization model is usually established with a single objective,or adopts fuzzy theory and weights.The idea of transforms the multi-objective problem into a single-objective problem for solving,and the optimization results have great limitations.For this reason,this paper constructs a reactive power optimization model with the minimum of network loss and voltage deviation as dual objective functions from two aspects of economy and safety and stability of power grid operation.Based on Matlab software and using the improved algorithm in this paper,the IEEE-30 node model and the actual distribution network model with small hydropower in a certain area in southern Shaanxi are used to simulate and analyze the established reactive power optimization model,and a set of diversity and The Pareto optimal solution with good uniformity proves that the algorithm has good convergence performance and global search ability,and after optimization,it can effectively reduce the system network loss,improve the voltage qualification rate,and provide decision makers with optional reactive power optimization results,which has a certain reference value for the research on reactive power optimization of distribution network connected to small hydropower.