Research On Three-phase Unbalance Treatment In Distribution Area

The three-phase four-wire system has been widely used in low-voltage power distribution network in China.In recent years,due to the increasing unevenness of user load time and space distribution,the problem of three-phase unbalance between distribution stations has become more and more prominent.The three-phase unbalance has a great impact on the quality of the power supply system,and there is a greater risk to the safe and stable operation of the system.This paper aims to solve the three-phase unbalance problem in the power distribution area in a city,and conducts the research on the optimization strategy of load balance for distribution network,and applies it to the power distribution area in a city to improve the power quality in this area.First,this paper introduces the background of the research and the significance of solving the three-phase unbalance problem,and discusses the previous research on three-phase unbalance control at home and abroad,as well as three common three-phase unbalance governance solutions.Second,an investigation was carried out on the current situation of the power distribution area in a city,and the reasons for the three-phase imbalance in the area were discovered and the existing hazards were explained.By comparing the characteristics,advantages and disadvantages of the three governance measures,it is found that the electricity consumption period in rural areas in China is relatively regular,the consumption is not large.Meanwhile,the number of new users is small and automation is difficult to popularize.Therefore,manual phase modulation is feasible.and practical in that area.In order to address the three-phase unbalance problem of the distribution area in a city,this paper takes the degree of three-phase unbalanced current as the optimization object,and the sequence of the load phase as the optimization variable.Based on the dynamic programming algorithm,the three-phase user allocation is performed to establish a load optimization model for the distribution area of the power grid.In this model,the combination relationship of user phase is optimized acts as the output.In addition,a low-voltage power distribution area in a city is utilized to perform commutation operations,based on the commutation scheme derived from the proposed load balance optimization model.The experimental results show that,by using the commutation operations of the load balance optimization strategy of this paper,not only the number of commutation times of the meter but also the unbalanced degree of three-phase load is effectively reduced.As a result,the goal of optimizing the three-phase unbalance current is achieved and the situation three-phase unbalance in the area is got better.Finally,from the aspect of the plan design,construction acceptance,and operation and maintenance of the entire operation process of the distribution area,this paper makes suggestions for governance of the three-phase unbalance in the distribution area of a city.