Sag Measurement Method of Wind-Induced Vibration for Uniced Overhead Power Line via Laser Rangefinder and Angle Monitoring

The sag of overhead power lines is an important indicator of the construction quality and safe operation of power lines. If the sag is too large or too small, it will threaten the safety of the lines and lead to serious power grid accidents. Existing sag measurement methods have problems such as high manual labor intensity, complex deployment, and high operational requirements. This article considers the influence of wind-induced vibration, establishes a wind-induced vibration model and measurement model, and proposes a sag measurement method that combines laser ranging and angle sensors. The proposed method can be applied to actual engineering scenarios such as daily maintenance of power line sag, on-site construction, and small-scale monitoring. When the laser is perpendicular to the wire, the horizontal angle \theta _{\mathrm {vertical}} recorded by the angle sensor is an important parameter for calculating the 3-D coordinate data. In this work, a nonparametric estimation method is introduced for the first time to calculate the angle. In the 2-D plane, the improved progressive sample consensus (PROSAC) algorithm and the adaptive random sample consensus (RANSAC) algorithm are used to double filter the error points in the measurement data under the influence of wind-induced vibration, a 3-D model of the power line is fit, and the stochastic gradient descent (SGD) method is used to find the lowest point of sag and finally calculate the tangent sag. Experiments have proven that the calculation accuracy of the method in this work meets the requirements of the industry. It has the characteristics of convenient deployment, safety, and stability, which improves the safety and efficiency of overhead power line sag measurement work.