This paper investigates system identification algorithms for modal identification of frame structures, such as a suspension bridge and an overhead transmission line-crossing frame, using ambient vibration measurements. The modal identification procedures include two novel blind source separation (BSS) algorithms, complexity pursuit method (CP) and generalized eigen decomposition method (GED), based on modern signal processing technology. Here, the frequency response function (FRF) method is introduced as an important reference to verify the effectiveness of the CP algorithm and GED algorithm. The effectiveness and accuracy of both types of algorithms are verified by numerical simulations and experiments on a suspension bridge. In addition, an engineering application of these two BSS methods is successfully implemented in an overhead transmission line-crossing frame. The results show that the two novel BSS learning rules (CP and GED) are capable of successfully identifying modal parameters of the civil structure under ambient excitation.

The spacer is an important component of a transmission line and can effectively prevent wires from whipping each other and inhibit vibration. Given the complex installation conditions of multi-split lines, the installation of spacers is mainly achieved through manual work, which has the disadvantage of heavy labor intensity and a high risk factor. The robots that install two-split and four-split spacer bars cannot be applied to the complex operating conditions of six-split transmission lines. In order to improve the installation efficiency of spacers and reduce operating costs and risks, a new type of spacer-installing robot was researched based on the six-split transmission lines in this paper. Through the theoretical analysis of the wire’s arc sag, the moving device of the robot was designed. In order to improve the operating efficiency of the robot, the storage and feeding device of the six spacers was designed. A planar arm with the ability to assemble the spacer was designed. The overall design of the robot was completed by integrating the design of each unit. Through the experimental test, the results indicated that the robot was capable of installing six spacers at once, the maximum moving slope was 15 degrees, and the error rate in the spacer installation was 2.33%, which matched the manual installation of the spacers. The robot provided new ideas for the design of new transmission line engineering equipment and expanded the scope of the application of robots in the power industry.

Aiming at the problems of high cost, large floor area and nondisassembly of traditional transmission line crossing equipment, it is particularly necessary to study and apply the detachable foundation with low cost, high reuse rate and good environmental protection performance in transmission line crossing equipment. Therefore, the maximum load combination form of detachable foundation is obtained by studying the load form of foundation of transmission line crossing equipment. At the same time, combined with the characteristics of overturning trend of transmission line crossing equipment, we design the arrangement form of detachable foundation cap and foundation screw anchor that meet the bearing capacity requirements. The design of flange seat connection form in detachable foundation can not only realize the detachable purpose of screw anchor and foundation cap, but also adjust the problem of installation difficulty caused by the inclination of screw anchor after construction drilling. After the simulation check, the maximum stress of the foundation bearing platform is 206.2 MPa, and the maximum stress of the bolt strength used for reaming holes is 335 MPa, all of which meet the material allowable requirements under the safety factor. The research of detachable foundation can realize the reuse of crossing equipment of transmission lines, and has good economic benefits.

External impact load resistance of self-elevating (self-supporting) crossing frames (hereinafter referred to as "crossing frames") is one of the important mechanical properties. The risk and cost are high for studying the influence rule of a single parameter on external impact loads on crossing frame carrier cables by test method. To explore the influence rule of the dropping wire position, dropping wire height, crossing distance and wire type on impact loads, the parametric modeling method for wires impacting crossing frames is studied. The simulation results show that the working condition where dropping wires are in the middle of the crossing frame is the most dangerous, and the impact loads rise with fluctuation with the increase of the dropping wire height. Due to the randomness of impact, the crossing distance and wire type have no obvious effect on the change of impact loads.