Prediction And Monitoring Of Power Lines Icing Thickness And Experimental Study On Icing Bond Strength

The icing of power lines may cause conductor galloping,wind deflection,ice shedding jump,etc.,and cause flashover,trip,damage of fittings and insulators,broken line and even tower collapse,which is a major hidden danger threatening the safe operation of power lines.The research on the prediction and monitoring of equivalent icing thickness of power lines is of great significance to the prevention and control of icing disasters,and the research on the mechanical properties of icing is also very important.In this paper,the meteorological prediction model and mechanical monitoring model of equivalent icing thickness of power lines are established,and the data of Wudang Gang comprehensive monitoring system are used to verify.The nominal normal bond strength test device of true conductor icing is designed and developed,and the icing bond strength under different working conditions is measured.1.Power lines’ equivalent icing thickness prediction model.The basic types of icing and icing growth mechanism are analyzed and discussed.It is considered that the classical icing prediction model under a single meteorological condition is difficult to meet the actual needs.The effective meteorological boundary conditions between different icing types are summarized,and a model which can distinguish and predict the type and thickness of icing that vary with meteorological conditions in the whole icing cycle is proposed.The model can directly reflect the trend of equivalent icing thickness of power lines with time development by using the conventional meteorological data which is easy to obtain and adopts the method of hourly calculation and superposition.2.Monitoring method of equivalent icing thickness based on tension / inclination of insulator string.Based on the analysis of Jiang model and Yang model,adopt reasonable assumptions and consider the necessary objects,taking the intermediate support as an example,taking the axial tension and inclination of insulator string as the basic parameters,the equivalent icing thickness of power lines considering strain caused by icing load is proposed.The overall moment balance equation which can be applied to the intermediate support is established and solved.3.Power lines’ icing comprehensive monitoring system and model validation.This paper introduces an on-line monitoring system of power lines,which is composed of mesoscale automatic meteorologic station,video online monitoring device,icing online monitoring terminal and their respective master station system in Wudang Gang mountain area of Shengzhou City,and analyzes the monitoring data in recent two years.The accuracy of the meteorological prediction model of equivalent icing thickness in Chapter 2 is verified by the calculation of environmental meteorological data obtained by the monitoring system,and the effectiveness of the mechanical monitoring model of equivalent icing thickness in Chapter 3 is verified by using the monitoring data such as tension and inclination of insulator string.4.Experimental study on nominal normal bond strength of true Conductor.a set of test device for nominal normal bond strength test of true conductor icing is designed and developed.In order to have a deeper understanding of the mechanical properties of power lines’ icing,the test is carried out under various working conditions to obtain the influencing factors and correlation degree of bond strength between conductor and icing,and compare with the test results of other researchers.It can provide reference for more accurate analysis and calculation of and deicing,and play a guiding role in mechanical deicing.