Research And Application Of Comprehensive Power Quality Control Technology For Distribution Network

In recent years,all kinds of distributed generation are developing rapidly in low-voltage distribution station area,and all kinds of nonlinear loads are increasing rapidly.As a result,the structure of distribution network becomes more complex,low-voltage,three-phase load unbalance and harmonic are easy to be produced,and the power quality problem is easy to be caused.Power quality problems increase and become more and more serious,affecting the healthy operation of equipment and customer perception of electricity.With the development of smart grid and Internet of things(lot),the construction of smart distribution stations has been quickened step by step.The integrated management of power quality has become one of the key problems to be solved in the automation and intelligence construction of distribution stations.This paper studies the common causes of power quality problems such as low voltage,three-phase unbalance and harmonic wave in distribution network,and classifies and analyzes them.In combination with the actual operation of distribution network in Zaozhuang area,a set of governance strategies and corresponding measures are worked out,a comprehensive monitoring system plan for power quality of distribution network is provided,which integrates synchronous data high-density real-time monitoring,operation situation high-quality perception analysis and power quality high-efficiency operation and maintenance management functions,to form a comprehensive solution of power quality for distribution system.(1)A station-line-to-transformer voltage model of distribution network is proposed,according to the voltage target,setting up the voltage adjustment strategy based on decision tree,establishing a full coverage analysis chart,through the monitoring,collection phase,the reason analysis phase,the formulation of measures phase,covering all types of low voltage and control strategy,combining with the actual operation of power grid in Zaozhuang area,solidifying distribution transformer joint gear,verifying operation data,verifying the feasibility of the model and strategy.(2)Based on the analysis of three-phase unbalance in distribution network,the causes of three-phase unbalance are classified and analyzed by enumerating the causes of three-phase unbalance,such as power supply mode,load change and collection problems.On the basis of conventional treatment measures,the three-phase unbalance automatic regulating device based on automatic commutation switch is emphatically analyzed.The advantages and disadvantages of three-phase unbalance auto-adjusting devices,such as commutation switch,capacitance type and power electronic type,are compared.(3)Take the distribution network harmonic as the research object,through the harmonic source,brings the harm consideration,analyzes the harmonic generation reason and the classification,through the source,the process,the environment factor analysis formulates the control measure.Combined with the actual operation of Power Grid,the case of photo voltaic access,concentrated nonlinear load is analyzed,and the operation data before and after treatment are compared.(4)On the basis of the above analysis,a comprehensive management system plan for power quality of distribution network is proposed,through the intelligent device platform,data access platform,operation platform,analysis and display platform four platforms to achieve the distribution network voltage,current and other data on-site collection,regression processing,automatic regulation,statistical analysis and other effectiveness,finally,through the installation of the device and the application of the system,the effect analysis,calculation of its social and economic benefits,discusses the feasibility and necessity of the device.