A Method for Measuring Dynamic Bending Strain at Suspension Points of Long-Span Transmission Conductors

Abstract

The invention discloses a method for measuring dynamic bending strain of a large-span transmission conductor suspension point. The method comprises the following steps that S1, an aeolian vibration state of a wire is monitored, and a tension sensor is adopted to continuously measure horizontal tension of the wire; S2, an environmental condition of an overhead transmission line is monitored, a windspeed measuring instrument is adopted to continuously measure wind speed when the wire runs; S3, according to the measured wind speed, an energy balance method is utilized to calculate a characteristic parameter of the aeolian vibration of the wire; S4, a solved amplitude and frequency of the aeolian vibration state of the wire are utilized, and known inertial force of the vibration of the wire is substituted to solve the inertial force F when the vibration of the wire is stable, the inertial force F substitutes static fulcrum counterforce in a static bending strain relationship expression atthe suspension point considering the stiffness of the wire to obtain the dynamic bending strain at the suspension point during the aeolian vibration of the wire. The method estimates the dynamic bending strain of the suspension point by measuring the horizontal tension and wind speed of the running of the wire, can more accurately measure a dynamic bending strain value of the large-span transmission conductor to avoid the occurrence of accidents.

Description

technical field [0001] The invention relates to the technical field of on-line monitoring of breeze vibration of overhead wires in the field of electric power, in particular to a method for measuring dynamic bending strain at suspension points of large-span transmission wires. Background technique [0002] Breeze vibration of transmission lines is also called vortex-induced vibration. When a steady wind with a wind speed of about 0.5m / s to 10m / s blows to the transmission line, Karman vortices alternate up and down on the leeward side of the wire / ground wire, causing up-down alternating The variable force acts on the transmission line, causing it to move up and down in a regular wave-like reciprocating motion in the vertical plane. The frequency of breeze vibration is between 3Hz and 150Hz, the maximum amplitude is generally not greater than 1 to 2 times the diameter of the transmission line, and the duration of vibration is generally several hours, sometimes more than severa...

AI Technical Summary

Problems solved by technology

However, according to the comparison of measured data, the linear relationship is affected by factors such as vibration frequency, amplitude, wire tension and stiffness, and may have an error of ±50%.

For the special conductors used in large spans, the impact is even greater, especially when the large-span transmission conductors vibrate in the breeze, the horizontal tension of the conductors cannot be considered to remain unchanged, so the dynamic bending at the suspension point of the large-span transmission conductors cannot be accurately estimated strain

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