Research On Treatment Technology Of Three-phase Unbalance In Distribution Station Area

At present,the phenomenon of three-phase unbalance in the distribution station area of our country is very common.The unbalance increases the comprehensive loss of the power grid and brings hidden dangers to the safe operation of distribution transformers and electrical equipment.In the low-voltage station area,except for a few loads that use three-phase power,most user loads are randomly connected single-phase power.The load is unevenly distributed and easily fluctuated,which increases the difficulty of three-phase imbalance management.This article aims to study the three-phase unbalance treatment technology in the low-voltage distribution station area.When the unbalance exceeds the limit,adjust the load access phase sequence online,distribute the three-phase load in a balanced manner,and use the commutation switch type three-phase load automatic adjustment device to correct it.Govern the balance problem.Based on the analysis of the basic theory of three-phase unbalance,this article first introduces the overall architecture of the commutation switch type three-phase automatic load adjustment system,and studies the working process of the three-phase automatic load adjustment device.Formulate the commutation principle when the load phase sequence is switched.In order to minimize the voltage and current fluctuations in the commutation process,the phase sequence switching time during load commutation is studied for different load characteristics.The installation position of the commutation device will affect the effect of unbalance adjustment,and the number of installations is closely related to the equipment investment cost.This paper studies the optimal configuration method of the phase commutation device in the station area,comprehensively considers the loss of the station area caused by the three-phase imbalance and the installation and maintenance cost of the phase commutation device,and establishes a mathematical model of the optimization configuration with the goal of maximizing economic benefits.When solving the line loss in the low-voltage distribution station area,the internal loss calculation method of the station area using the typical daily load curve and the forward and backward method is used.The pigeon swarm optimization algorithm is used to solve the configuration scheme of the commutation switch,and the specific calculation process of the algorithm is listed.Finally,the calculation example analysis is completed on the MATLAB simulation platform.When the three-phase load automatic adjustment system balances the load distribution,it is necessary to set a reasonable commutation scheme.This paper studies the phase sequence adjustment method of three-phase unbalanced load,and establishes an optimized commutation mathematical model with the goal of the smallest current imbalance and the smallest number of commutation switches.The adaptive parameters and Cauchy disturbance are introduced to improve the original pigeon flock algorithm,and the improved pigeon flock algorithm is used to solve the load phase sequence adjustment scheme when the three-phase imbalance is the smallest.The effectiveness of this method is verified by MATLAB simulation,and the performance of the improved pigeon swarm algorithm is compared with GA,BA,PSO,ABC,and PIO.In addition,the multi-objective particle swarm algorithm is used to obtain the non-dominated solution set when the three-phase current imbalance on the low-voltage side of the transformer is the smallest and the number of commutation switches is the smallest,and the corresponding load phase sequence is determined according to the different decision requirements of the calculation examples.Adjust the plan.