Analysis And Prediction Of Chaotic Characteristics Of Transmission Line Icing Time Series

The icing of power transmission lines seriously threatens the safe operation of the power grid.Severe ice coating may cause wire galloping,insulator flashing,disconnection,tower collapse and other accidents,causing the entire transmission network to be paralyzed,causing incalculable losses to the entire national economy.Forecasting the icing condition of the transmission line can give early warning,effectively guide the deicing work and avoid the occurrence of disaster accidents.The transmission line icing system is a nonlinear system and exhibits some chaotic behavior.The monitoring values of the wire temperature and micrometeorological factors and the calculated values of the equivalent ice thickness were measured by the ice monitoring system.The chaotic characteristics of the ice thickness and the main factors affecting the ice coating were analyzed,and the chaotic property of the time series was calculated.The Lyapunov exponent proves that the thickness of ice coating and the main influencing factors of ice coating have chaotic characteristics,and the chaos theory can be applied to ice prediction.The phase inversion of the main influencing factors of ice thickness and ice coating was carried out,and the multivariate phase space reconstruction prediction model was constructed.The local ice method was used to predict the thickness of ice coating.The specific research work of this paper is as follows:(1)According to the static equation of the transmission line in the vertical plane and the wind deviation plane,and the static equilibrium equation of the ice-covered conductor in the vertical direction of the wind deflection plane,the equivalent ice thickness calculation model is obtained.The parameters required for the ice-covered monitoring system to calculate the temperature of the ice-covered wire,the micro-meteorological environment and the thickness of the ice coating are collected,including the tension of the wire,the inclination angle of the insulator string and the wind angle.(2)Analyze the chaotic characteristics of the thickness of ice coating and the main influencing factors of ice coating.The grey integrative correlation analysis method was used to find out the main influencing factors of ice coating.The phase space reconstruction theory was used to reconstruct the phase space of ice thickness and air temperature and air temperature with large correlation with ice thickness.The delay time and the embedding dimension are made.The maximum Lyapunov exponent method is used to identify the chaotic nature of the ice thickness and the influence factors of ice coating.(3)Establish an ice prediction model based on multivariate phase space reconstruction.Due to the similarity between the wire temperature and the air temperature two-dimensional reconstruction map,the dynamic system information contained in the two is similar.Therefore,the temperature of the wire with greater correlation with the thickness of the ice is introduced into the prediction model,and the wire temperature and the thickness of the ice are established.An icing prediction model for multivariate phase space reconstruction.The ice monitoring data of a certain area in Yunnan was selected as the research object.The localized method was used to predict the ice thickness of the transmission line.Finally,the error value of the prediction result of this model was compared with the error value of the BP neural network prediction result to verify the multivariate.The effectiveness of the ice prediction model for phase space reconstruction.In this paper,based on the large amount of actual monitoring data of the ice monitoring system,based on the analysis of the chaotic characteristics of the ice-covered time series,the ice thickness prediction model of multi-variable phase space reconstruction is established.