Research Of Breeze Vibration Characteristics Of Overhead Transmission Lines In Cold Environment

In the northern region of China,the climate is complex and variable,often accompanied by strong winds,and the environmental conditions are harsh.The minimum temperature in winter can reach-58℃.Under the influence of low temperature and wind,overhead transmission lines are in vibration state for a long time.At present,most of the research on the strength of wind induced vibration of conductors focuses on ambient temperatures,but the research on the strength of wind induced vibration of conductors in low-temperature environments is not sufficient,and it is difficult to ensure safe operation in low-temperature environments.In low temperature environments,the ambient temperature in which the wires are located is relatively low and often in a windy state.Metal objects have the characteristics of thermal expansion and cold contraction,making the tension and internal stress of the wire different from those under normal temperature.Due to the influence of low temperature environment,the temperature of the conductor is significantly different from that in normal temperature environment with a certain current carrying capacity.Temperature will have an impact on the stress of each layer inside the wire,and the change in wire stress will affect the self-damping of the wire,thereby affecting the strength of the wire’s breeze vibration.At the same time,most studies on the temperature field,stress,and breeze vibration of the conductor use simplified models to analyze the entire conductor,but the detailed analysis is not sufficient.In response to the above issues,the research content of this article is as follows:(1)Based on the basic principle of heat balance and based on the cross-sectional structure of the conductor,a numerical simulation method is used to establish a temperature field analysis model for the conductor.The temperature field of the conductor under different low temperature environments(-50℃～-30℃),wind speed,and current carrying capacity is calculated,and then the radial temperature distribution of the conductor is analyzed.The temperature field of the conductor under different low temperature environments is analyzed.The effects of low temperature environment,wind speed,and current carrying capacity on the temperature field of the conductor are analyzed.(2)Based on the axial tension equation of the conductor,the stress of the conductor under different loads and temperatures is calculated.The stress field model of the conductor is established based on the three-dimensional solid structure of the conductor.The influence of different loads and ambient temperature on the stress and strain of the conductor under cold environment(-50℃～-30℃)is calculated by numerical simulation method.(3)Based on the energy balance method,the energy balance equation of the overhead transmission line is established,and the temperature and stress characteristics of the conductor under cold environment are considered,and the relationship between the vibration amplitude and frequency of the conductor under different loads,cold environment and terrain factors is analyzed.The influence of different conditions on the strength of the conductor breeze vibration is analyzed.