Methodology of overhead power transmission line pylons technical state assessment with typical exploitation faults accounted

Structure safety estimation via the results of modal testing is widely used in building field. However, overhead power line pylons are so specialised that it is not possible to expand existing standards so that those could be employed to assess pylon conditions. These standards do not contain any information about the pylon eigenvalues, methodology of full-scaled experiment execution or criteria to differentiate pylons with respect to the extent of the structure defects occurred. This means that it is necessary to develop a dedicated approach to estimating the safety of this type of structures. The method proposed boasts an additional advantage, that is, it takes into account the operating defects that are typical for the type of structures under consideration. The point of this method is comparing the computed and experimentally determined natural frequencies of overhead power line pylons. This comparison enables us not only to detect the defect type present in the structure, but also to find whether it is located closer to the base of the structure or in the latticework on one of the sides. The paper presents the results of using our method for estimating the safety of intermediate towers for a 110 kV overhead power line as represented by the SV-5 segment and states the advantages of using our method when planning real-time inspection of structures, as well as for monitoring select towers constantly.

Modified methodology of computation of admissible continuous currents of plain conductors of overhead transmission lines and catenaries

Methodology provided summarizes published, original and foreign theoretic and experimental data on the subject of heating and cooling of standard and shaped conductors of overhead power transmission line and uses those of them which are most affected to fundamental heat-transfer laws. Computation surface area of standard and shaped wire formulas are given. The common formula of convection heat transfer coefficient is provided, based on wind speed and direction, concerning antiicing mode. Parameters of this formula do not coincide with those existing, as they are based on experimental data on standard and shaped conductors but not on round tubes. Formula of computation of heat transfer power under the influence of solar radiation is given. Summarized formula of admissible continuous current computation is given, all the components have detailed description in the article.

DEVELOPMENT OF A DEVICE FOR DIAGNOSTICS OF INSULATORS

The article proposes an invention that makes it possible to diagnose a damaged insulator under the operating voltage of an overhead power transmission line (OHL) by monitoring the leakage current. A prototype of a diagnostic device was made with which experiments were carried out. The leakage current taken from the shunt structure is converted into a digital signal for processing, transmission and further processing at the substation control room. The monitored value of the leakage current corresponds to the value of the insulation resistance of the insulator.

A novel unit mechanism for serial head-tail alternatively supported robot

Multi-unit serial mobile robot designed for obstacle avoidance, inspection or rescue task, should ideally be able to switch the head and tail as supporting stand to move forward wriggly, be lightweight and low energy consumption, aiming at adapting to complex application environment. This paper proposes a novel robot pitching unit based on a parallelogram mechanism, and a robot with the proposed units taking the task of power transmission line inspection as application background. To reduce unit motor number and weight, a single motor and cable driving(SMCD) method is proposed. The unit architecture and robot prototype are designed. The kinematic model is developed and the supporting stand switch process is presented. According to the force analysis of the unit mechanisms, the driving motor energy consumption calculating methods of the proposed unit and the conventional serial unit are presented respectively. The low energy consumption characteristic of the proposed unit is demonstrated through applications respectively on a 4-unit serial immobile robot model and an inspection robot model for power transmission line. Experiments of unit supporting stand switch and robot prototype crossing obstacles are conducted to verify the unit feasibility. The results of analysis and experiments show that comparing with the conventional units, the whole energy consumption of the robot can be reduced clearly by applying the proposed units, the novel unit is capable of switching the supporting stand, based on which the inspection robot meets the application requirements on overhead power transmission line.