Research On The Control Of Three-phase Load Unbalance Based On Intelligent Switching-phase Switch And SVG

Under the three-phase four-wire system of China's low-voltage distribution network,due to the difference in the behavior of a large number of single-phase power loads,the three-phase load unbalance i n the low-voltage distribution station area is becoming increasingly serious,which seriously affects the safety and economic operation of the distribution network.Intelligent switching-phase switch and Static Var Generator(SVG)are often used as automation devices to control three-phase unbalance.These two devices are also starting in three-phase unbalance management to a good governance effect.In the process of governance,it is not only necessary to consider whether the power quality after the governance meets the requirements of the power sector,but also how to install the two devices to maximize the governance effect.Therefore,the reasonable configuration of the commutation switch and SVG in the low-voltage distribution network can not only improve the power quality and ensure the safe operation of the distribution network,but also increase the operating income of the distribution network.This article is based on the cooperation of commutation switch and SVG to control the three-phase load unbalance.First,the three-phase load imbalance is adjusted and treated by installing the commutation switch,and then on the basis of this,the three-phase unbalance is further controlled by installing SVG.The intelligent switching-phase switch can switch the phase sequence of the single-phase user's load under the condition of continuous electricity,and distribute the user's load evenly to each phase,so as to realize the three-phase balance.In this paper,by analyzing the existing intelligent switching-phase switch management methods,in order to address the shortcomings in the configuration of the commutation switch,a method for selecting the installation configuration of the commutation switch based on particle swarm optimization is proposed.Firstly,a three-phase unbalance calculation formula is established from user electricity data,and considering the number of times of switch,a multi-objective mathematical model is established.By solving the multi-objective mathematical model,the frequency of users with different loads participating in commutation is determined.Determine the installation position of the intelligent switching-phase switch according to the frequency of load users participating in commutation.This paper analyzes the shortcomings o f the traditional SVG compensation configuration method,and proposes a method based on the combination of clustering method and negative sequence current for SVG configuration and installation.First,establish an association matrix according to the topological structure of the distribution station area,reduce the dimension of the high-dimensional matrix established by the multi-dimensional scaling method,and use the clustering method to partition the distribution station area according to the electrical distance,and then according to Negative sequence current calculates the center of gravity of the load and determines the installation position of SVG in each zone,so as to determine the compensation point of SVG.After the position of compensation point is determined,the compensation capacity calculation needs to be carried out.In consideration of investment income and other aspects,a multi-objective mathematical model for determining the compensation capacity is established,which is solved by the particle swarm optimization algorithm to determine the installation capacity of the SVG.The method is applied to the modified IEEE33 node distribution network,which verifies the feasibility and effectiveness of the proposed method.