Research On High-voltage Cable Line Intelligent Monitoring System

With speed up of the urbanization process, urban space becoming crowded andel ectricity load increasing rapidly. To meet the growing demand of electricity and tosave the city space, many cities begin cable distribution lines Shimoji transformation.Achieving condition monitoring and on-line fault location for the large number ofpower cable line to improve reliability has became an inevitable trend.Firstly, the development process of existing surveillance systems is reviewed.Then system architecture is designed. Considering the characteristics of the cable linethe distributed measurement and wireless communication is used to improve theinput-output ratio. The main station and monitoring terminal is designed based on thesystem atchitecture to meet the functional requirements of actual sceneSecondly, summarized advantages and disadvantages of the existing distributionnetwork cable line fault location method and make intensive study of the on-line faultlocation algorithm. Analysis the transient signal propagation characteristics in thethree-core power cables deeply, then take out the distibuted transient signal acuisitionprogram.Transient signal content coefficient is defined with the Hilbert-huangtransform to characterize the distortion of initial traveling wave. Then sequencemonitoring points with the coefficient. Take data from monitoring points intothree-terminal fault location formula in the sequence order to find out the fault branchand section. On this basis, considering the accuracy characteristic of the D typetravelling wave fault location principle, choose data from monitoring points nearestand most symmetric to the fault points to locate the fault point accurate. So thedeviation brought by signal attenuation can be minimized. Traveling wave velocity inexperience is replaced by real-time measured velocity to improve accuracy. Thedistribute measurement offers redundant data. Fault location flexibility androbustness can be significantly improved. Plenty of EMTP simulation results showthat the accuracy is approximate to off-line methods, can meet the actualrequirements.Finally, facing two typical types of cable line at present, presents a simplifiedarrangement of monitoring points fault location scheme to take account of investmentconstraints, improve cost performance. Simulation results show that add monitoringpoints to get redundant information can effectively improve the fault locationaccuracy and success rate. The distributed measurment and fault location algorithm isflexible and practical.