Design And Analysis Of New Short Circuit Ground Wire Clamper For EHV Transmission Lines

Short circuit ground wire is one of the necessary personal safety devices to protectelectrician by grounding transmission lines and has a large market demand. Shortcircuit ground wire is composed of short circuit wire, ground clamper, wire clamper,etc, and the wire clamper is the key component. At present, the commonly used wireclamper has the defects such as difficulty in assembly/disassembly and unreliability inconnection with transmission lines. To overcome these problems, a new kind of shortcircuit ground wire clamper applicable to the EHV transmission line was designed,which had the advantages of easy assembly and disassembly, large clamping force, andreliable and steady connection with transmission lines. The main research work is asfollows:(1) According to the use condition of short circuit ground wire for the EHVtransmission lines, the functional requirements of new wire clamper were confirmed.The clamper could clamp and loosen through wireless remote control, and couldloosen and reset through pulling insulating rope under the condition of clampingtransmission line. On this basis, the possible ways and means were analyzed.(2) According to the basic functions of clamper that must be realized, three typesof different transmission mechanisms: gear-driven mechanism, vertical screw-drivenmechanism and horizontal screw-driven mechanism were put forward throughdivergent thinking. After comparative analysis, the horizontal screw-driven mechanismwith three classes force amplifier was selected as the final implementation plan.(3) Structural design of the new wire clamper was carried out according to theselected final implementation plan. With the bended clamp handle, the deflective angleof clamp handle was symmetric relative to the radius direction of screw throughout thestroke, and accordingly, the size of the mechanism was reduced and the force wasimproved. Because of the innovative structure adopting clearance fit between thetransmission parts and the screw, and half-nuts moving in the transmission slot along the radial direction of screw, the clamper could not only clamp and loosen driven bythe screw rotating in both directions, but also loosen and reset by pulling half-nutsunder the condition of clamping transmission line.(4) The drive motor, the screw pair, the reset spring tension and the pulling forcewere determined on the basis of mechanics analysis of the clamper.The prototype of the designed new wire clamper in this paper has be produced,passed tests and applied for a patent. At present, a company is prepared for batchproduction.