A Study On Tracking Characteristics Of Power Socket-outlet Insulation

Due to the characteristics of power socket-outlet,they are widely used in all kinds of places.As imperative electrical accessories in every home or office space,the safety and reliability of power socket-outlet is very important.According to the related survey data,electric fire accounted for 30% of the total number of cumulative fire accidents in recent years in China,among which near 80% of fire in urban and rural residential areas was associated with the outlets or circuit.As one of the most common used electrical connection devices in low voltage distribution system,we often find that due to insulation aging or bad contact of power conversion device arc faults tend to occur,either sputtering or intermittent.However,the common power protection devices used in system can not play a protection role,such as air-break switch ect.Consequently,heat generated by continued burning of these arc faults on the insulation materials eventually led to the fire.All along the domestic front-line fire investigators and fire evidence identification experts have little systematic and scientific understanding and study on fire occurance,development,formation mechanism,trace characteristics and igniting rules.We therefore carry out a basic research on tracking characteristics of power socket-outlet insulation,which provides a database and theoretical support for its mechanism and process of discharging.This may contribute a lot to perfecting the theoretical system of electrical fire evidence identification and upgrading the electrical fire investigation level in China.This paper first set up a testing platform of power socket-outlet traces by referencing some related research achievements.Second,based on a large number of statistic analyses of fire cases throughout actual life,several fault coupling programmes have been proposed.Under a dust and wet environment,accelerated simulation of power conversion devices working for a long time has been made.Due to slow damages of electric traces,the areas of two plug holes eventually led to insulation failure and even cause a fire.Based on the electrical parameters,temperature,the sampling and recording of fire environmental parameters,analyses of discharging phenomena at different stages have been figured out.With Nonlinear analysis,thermal analysis and infrared analysis methods,tracking characteristics of arc fault after failure have been exposed and the characteristics of electrical tracking failure process have been summerized.Finally,the fault mode identification has been made by introducing the real cases in life to prove the fire risks of power socket-outlets.This study provided a reference basis for not only investigation and prevention of electrical fires but also the anti-fire design of such products.