Experimental study on ice monitoring method for 10 kV transmission line with tangent tower in alpine landform

Ice monitoring methods were applied for 110 kV and above transmission lines with tangent towers.However,the change in the vertical span is not considered,and a significant difference lies in the tower-conductor structure of 10 kV transmission lines.For this reason,a proposal is made about the ice monitoring method for the 10 kV transmission line with tangent tower in alpine landform,which includes the ice monitoring system based on pressure measurement and corresponding equivalent ice thickness calculating methods.Different methods calculate the vertical span under different height difference coefficients.A finite element simulation model and a simulated ice load experiment system are established based on real conductors and insulators.Experiments and simulations under four simulated terrains are conducted within 2.5–20 mm ice thickness range.The comparison is made between this method and the method without considering the change in vertical span.The results show that the two methods are consistent and the relative errors are lower than�4%in simulation and�10%in experiment when the height difference coefficient is 0.When it is not 0,the relative errors of this method fall between t0.38%and t6.78%in simulation and−6.40%to t6.60%in experiment,while the relative errors of the method without considering the change in vertical span ranges between−11.13%and−20.23%in simulation and−11.65%to−23.20%in experiment.

RRVPE:A Robust and Real-Time Visual-Inertial-GNSS Pose Estimator for Aerial Robot Navigation

Self-localization and orientation estimation are the essential capabilities for mobile robot navigation.In this article,a robust and real-time visual-inertial-GNSS(Global Navigation Satellite System)tightly coupled pose estimation(RRVPE)method for aerial robot navigation is presented.The aerial robot carries a front-facing stereo camera for self-localization and an RGB-D camera to generate 3D voxel map.Ulteriorly,a GNSS receiver is used to continuously provide pseudorange,Doppler frequency shift and universal time coordinated(UTC)pulse signals to the pose estimator.The proposed system leverages the Kanade Lucas algorithm to track Shi-Tomasi features in each video frame,and the local factor graph solution process is bounded in a circumscribed container,which can immensely abandon the computational complexity in nonlinear optimization procedure.The proposed robot pose estimator can achieve camera-rate(30 Hz)performance on the aerial robot companion computer.We thoroughly experimented the RRVPE system in both simulated and practical circumstances,and the results demonstrate dramatic advantages over the state-of-the-art robot pose estimators.