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Conductor temperature is an important factor that influences the transmission capacity. It is usually assumed that the conductor is an isothermal cylinder in most studies, which is not consistent with the real situation. Due to the difference of air velocity around the conductor, there is a circumferential temperature difference of the conductor. Therefore, a simulation model for temperature was established based on fluid dynamics theory. The circumferential velocity field and temperature field were simulated. Finally, the influence of wind velocity, environmental temperature and current on the circumferential temperature difference was analyzed. The results show that with the increase of wind velocity and environmental temperature, the circumferential temperature difference decreases gradually, while with the increase of current, the circumferential temperature difference of conductor increases continuously.

This article obtained experience from ±800kV direct current project and 1000kV alternating current project power fittings design, manufacturing, construction and operation, combined with ultra high voltage alternating-direct current transmission line suspension string characteristics, throughout optimum design of suspension string, string type 3 dimensional modeling, mechanical characteristics and electrical characteristics simulation analysis and real-model corona characteristic test research, successfully worked out compact type triple-link suspension string and pair fittings, contracted 600mm, which has remarkable economic profits.

The mechanical properties and low-temperature resistance of the 42CrMo steels utilized in electric power fittings after different heat treatments were comparatively investigated. Results indicated that a tempered sorbite with refined structure was obtained in the steels and the mechanical properties and low-temperature resistance were consequently improved after quenching + quenching + tempering and cyclic quenching and tempering, especially after the latter. The product of strength and elongation reached up to 25725 MPa% and the impact energy at -50 °C increased to 48 J after cyclic quenching and tempering as compared to 16562 MPa% and 19 J after conventional quenching and tempering. The 42CrMo steel after cyclic quenching and tempering can be considered as a suitable candidate for connection fittings in electric power transmission line.

UHVDC project will be prepared by JL1X/LHA1-1040/550 aluminum alloy core forming aluminum twisted line to reduce the load on the tower, improves the safety performance of the circuit, and has the function of upgrading line capacity. For such a wire, the domestic currently has no relevant research experience of line pair splicing sleeve, in order to meet the needs of practical engineering, this paper completed the pair splicing sleeve material and a compression ratio development according to the structural characteristics of this guide line; through a splicing sleeve manufacturing and testing, the development of aluminum JL1X/LHA1-1040/550 aluminum alloy core aluminum twisted wire pair splicing sleeve grip strength meets 95%RTS.

The anti-galloping method was proposed for the 6×1520 mm2 large cross section conductor. The galloping model was established by using nonlinear finite element method and considering geometric nonlinear, aerodynamic nonlinear and initial deformation. The galloping characteristics and the critical conditions to excite galloping were obtained for the large cross section conductor. And the anti-galloping effect was also evaluated by using the rotary clamp spacers. The results show that the multi-bundled conductors are more vulnerable to the galloping phenomenon than the single conductors under the same ice and wind conditions. And the galloping characteristics obtained by 1520 mm2 large cross section conductor are basically the same with other cross section conductors. The anti-galloping effect can meet the requirement by using rotary clamp spacer for the 6×1520 mm2 large cross section conductor in the easy galloping areas. And even in the harshest ice and wind conditions, the galloping amplitude can be reduced in the largest extent and the time to excite galloping can be greatly extended.

The analog computation on considering the fluid - structure interaction (without modeling solid deformation) and the large eddy simulation (LES) with the classical Smagorinsky's sub-grid scale model has been adopted for the idealized model. The results show that the solution of this model agrees favorably with experimental data results and that the LES displays an advantage over the simulations. From the simulation for bundled cables, the lift coefficients and the drag coefficients increase as the Reynolds numbers grow in sub-critical region. The upstream cables vibration is induced by Kamen vortex and the downstream cables vibration is due to double influence of the wake interference and the Kamen vortex. With the increase of incidence angles, the drag coefficient of the bundle is largely related to the width of the cables exposed to the fluid and the lift coefficient of the bundle grows while the angles of attack increasing within limits.