Study On The Unbalanced Problems And Mitigation Approaches In The Qiaotou Low Voltage Grid

The low voltage grid in China at this stage,the connection mode of the residents is single-phase connection,and the power system network is usually three-phase connection,difference of the connection mode leads to the unbalanced three-phase distribution.Three-phase unbalance will bring great negative impact on the grid.Unbalanced load will lead to increased power loss in power system,the harm of electrical equipment and lines,affect the transformer output,resulting in low voltage,seriously affect the quality of power supply,affect the normal operation of the power equipment at the same time.By remediating the three – phase unbalance problem in low-voltage grid,Can improve the voltage pass rate and power supply quality,For the safety of the transformer,power consumption and long-term stable operation to provide protection,Consolidate the safe and stable operation of the grid.In this paper,three phase unbalance problem in the Qiaotou low voltage grid by taken as the object of study.The study of the three phases of unbalanced problem was carried out.It mainly includes:1.Analyze the characteristics of the three-phase unbalance of the Qiaotou low-voltage grid,From the factors of the grid structure,load factor and user types,analysis the causes of unbalanced in the Qiaotou low voltage grid.And find that the three phases of the low-voltage grid in Qiaotou have some regularity.Find a regular association relationship with seasons,time,load rates,and user types.Through field investigation and data analysis,summarizes the main reasons for three-phase unbalance of Qiaotou grid,and points out the deficiencies in the current routine management measures.2.The three-phase unbalanced compensator and automatic phase changing device are adopted to govern the three-phase unbalanced problem.By analyzing the basic principles of the two technologies,Selected installation site,and through the project to achieve.After analysis and field application check,two new technologies have obvious effect on the three-phase unbalance.The three-phase unbalanced compensator is the best to improve the unbalance of main lines.The adjustment surface of automatic phase inverter is wide,and its cost-effective.Suitable for large-scale renovation.Through the study of the paper,For the Qiaotou low-voltage grid capacity of 100 kVA and above transformers are equipped with reactive power compensation device features.Concluded that the automatic phase commutator is more suitable for the conclusion of the three-phase imbalance of Qiaotou grid.