No abstract

Hidden defects in transmission lines can be detected by X-ray. Through the simulation of different voltage/current tests in the laboratory, the live detection test of digital X-ray detection equipment was carried out and the detection tests under the live condition of 110kV transmission line carried by unmanned aerial vehicle, the maximum tolerable voltage of X-ray digital imaging equipment during live operation was determined. By using the electric field finite element simulation, the affected field intensity detected by the equipment is 360kV/m, and the spatial field intensity distribution of ac transmission lines with different voltage levels is given, which provides a reference for selecting reasonable electric field shielding measures for the live operation of X-ray digital imaging equipment.

Overhead lines for wind power transmission in the southern region have the characteristics of large tower-line elevation, across thick ice areas, harsh natural environments, and difficult maintenance. Unpredictable line breakage accidents often occur, affecting the stability of the social power supply. This paper designs and introduces a technology based on intelligent perception technique for online monitoring of the earth wire, which can realize long-term real-time online monitoring of the state of the earth wire of overhead lines and solve the problem of line monitoring from wind power transmission and fault inspection and troubleshooting. Now the test and monitoring work of an overhead transmission line has been completed during the ice period, and the test results show that the technology has good monitoring performance.

By macroscopic observation, composition analysis, mechanical properties test, SEM, energy spectrum, overall grip tensile test and finite element mechanics calculation method, the strain clamp steel anchor corrosion failure of a 500 kV transmission line is analysed. The results show that the corrosion of steel anchor for 31 years are the result of the natural corrosion, steel anchor corrosion rate is accelerated due to the galvanic corrosion, crevice corrosion, stress and damaged surface of the galvanized layer, and achieve C4 environment (zinc 2.1–4.2 um per year, carbon steel 50–80 um per year). The hardware are qualified. It is suggested to replace the steel anchor with yellow rust on the surface after 5 years, and to reevaluate the next maintenance cycle of the gold fittings without yellow rust on the surface at present, and replace it when the corrosion depth reaches 10%. Before replacement, all fittings should be monitored, especially steel anchor.

The failure cause of the fracture in wave trap hanging ring in A-phase fault tripping of a 220kV line was analyzed by using macroscopic inspection of fracture, chemical composition analysis, hardness test, metallographic structure analysis and fittings load calculation. The results show that the main causes of hanging ring fracture were unqualified material and welding quality.