Stability Analysis Of Transmission Line Conductor Galloping And Wind Loads Of Ice Cover

With the development of China’s economy, advances in technology and substantially increase in people’s living standards, it is obvious that the electricity is of more and more importance. However, the security and stability of the transmission line of electricity is very important as the carrier of electricity transmission. Transmission line system as a tall flexible structure system vulnerable to impact loads by the wind, ice and other disasters, the destruction of the2008snowstorm Icing, and in some parts of the hurricane weather line are very serious. These loads from the disasters are bad influence on the security and stability of the transmission line. According to these environmental factors and the structural characteristics of the transmission line system, it is the common line disasters that Icing dancing in the wind loads and wind load on the system vibration.This article will analyze the wire covered ice makes dancing characteristics in the wind load and the impact of the towers and lines system, but also lines system vibration analysis in the strong wind load. Specifically do the following:(1) Description of the wind load, wind loads on the degrees of the wind profile, three-dimensional turbulent wind fluctuating wind power spectral characteristics and so on. Wind load theory and the formula of the load calculation. Focus on analysis of the simulation of fluctuating wind load, the use of trigonometric series superimposed harmonic synthesis simulation of fluctuating wind load in the time-domain method for modeling wind load. Instance220kV the SZ3Ma Feng line-straight line tower is simulated in order to compare to the regulatory of the Davenport spectrum, and compares the results.(2) Transmission line conductors of static, dynamic analysis. Static:the use of catenaries’derive the sag of the wire, the formula of line length, tension, etc., on this basis, through an example to calculate the wire in different meteorological environmental loads (wind, ice, temperature) conditions, the wire tension and shape changes. The results of the wire tension and shape are less influence from temperature and wind speed, but temperature of the ice covered, ice co.ver thickness is the main factor of the wire tension and shape change, dynamic:three degrees of freedom to find the wire mechanical model, and solving the three-dimensional mechanical model; vibration wire vortex shedding probability presented to the wire, and then calculate the vortex shedding frequency, and obtained the natural vibration frequency of the wire is distributed more widely, because the wind load easily changes in the vortex shedding frequency changes, frequency changes very easily with a natural frequency of wire vibration order of frequency overlap and resonance.(3) Wire of ice cover dancing mechanics model and after dancing makes influence on the line structure. Building single degree of freedom mechanical model from wire of ice covered dancing can not fully reflect the characteristics of the ice cover conductor galloping through some model assumptions and the derivation of some of the wiring-related mechanical parameters, the establishment of the Icing after dancing three degrees of freedom mechanical model. On the basis of calculation of the ice cover wire tension, drawn two (level of tension wires and suspension point of the vertical direction tension) tension to increase the proportion of ice cover conductor galloping half-wave number of odd and even. At the same time, to analyze the relationship between ice cover conductor galloping alternating tension variation and the vibration amplitude, the draw tension variation of ice cover conductor galloping with the increase of the span increases, decreases with the sag increases. The maximum displacement is less than the Eiffel Tower in the conductor galloping permit displacement-based tower vibration amplitude amplification factor value must be less than the amplitude of the licensed amplification factor value of probability is the Tower of reliability. Proposed the design method of the reliability of this transmission line system in the ice cover conductor galloping occurs.(4) Finite element analysis of the line system of transmission line towers for wind loads. Finite element analysis method should be applied. The combination power transmission tower and tower line system of an inverted tower instance from the law of vibration response on the towers and lines system from the natural frequency of the wire. Analysis of wind load as the overload the destruction of the transmission line system, the first analysis of the failure stress of the tower components and wire disconnected the line for the tower system stability analysis of the system in both cases, come to the wind load caused by the system vibration lead to the conclusion of the tower component on failure, to provide support for the tower of strength design.