Considering continuous power supply conditions, there is currently no effective method for preventing ice disaster, and also some deficiencies of the existing completed short‐circuit ice melting method has been found. Here, taking typical bundled and expanded conductors as the sample, its icing performance was tested and the combined ice‐wind load of tested lines was analysed. Then, a new method of substituting expanded conductors with the same conductive cross‐sectional area for bundled conductors to prevent ice disasters is proposed. Research results showed that: from stagnation point to both sides of crescent‐shaped conductors, local collision rate gradually reduce to 0; under various meteorological factors, there is still a power function relationship between ice thickness of conductors ( D _c ) and the diameter of conductors ( D ); the ice amount of six tested conductors gradually increases with the increase of ice thickness of Rotating Single‐Cylinder Ice Collector ( D _r ), while the ice amount reduction rate reduces first and then increases with D _r ; the combined ice‐wind load ratio of bundled and expanded conductors increases with the increase of wind speed and D _r . Therefore, it is a low‐cost method for improving the anti‐icing capacity of transmission lines and preventing icing disaster once and for all.

Icing degree in the severe icing regions for years is an important factor considered in the anti-icing design of transmission lines. However, there is currently no normalized characterization method for the icing degree of transmission lines, which can be used to record the severity of icing at icing areas over the years and guide the design of transmission lines. This study analyzes collision efficiency of water droplets with various diameters of conductors and investigates the ice accretion law of transmission lines with various diameters under four natural ice types. Therefore, the normalized method of standard ice thickness instead of various ice morphologies is creatively used to characterize icing degree of transmission lines and a lot of field tests which have been done at six natural ice observation stations have verified the effective of the method. The results have shown that: The diameters of conductor and the droplet significantly affect collision efficiency; the relation of standard ice thickness with diameter of conductors for four typical ice types complied with the law of power function. The results can provide important references for the design and external insulation selection of transmission lines in ice region.

This work first proposes a novel flashover model based on the deduced residual resistance of the ice layer. The most important finding of the field icing tests is that the double‐layer ice‐melting water film exists on the inner and outer surfaces of the ice layer. The conductivity of melting water on the inner and outer surface of the ice layer has been measured, and the corresponding surface conductivity has been calculated. According to the proposed flashover model, the ratio η of the resistance of the ice layer to that of the pollution layer gradually increases with the increase of the ratio k of the resistance of the outer surfaces to that of inner surfaces, and eventually approaches saturation. Furthermore, the icing flashover criterion has been modified, and the voltage gradient of the inner surface is less than that of the outer surface. Test results show that the ice flashover voltage is lower than the pollution flashover voltage between 2.18–9.69% and 14.75–20.32% under light ice and semi‐cylindrical ice, respectively. The simulation results based on the proposed model and the classic model are compared with the field test data. Results show that the proposed model could attain a high accuracy of dc flashover voltage and demonstrate the effectiveness of the proposed model.

With the widespread application of composite insulators in transmission lines, exploring the accumulation mechanism of pollution particles on composite insulator surfaces is of importance to ensure the safe and steady operation of the power system. Addressing the current theoretical shortcomings, this study categorises the accumulation process of particles on the insulator surface into three stages, namely ‘spatial motion’, ‘surface collision’, and ‘surface motion’. The motion and rotation velocities in a multi‐physics field are calculated in the spatial motion stage. In the surface collision stage, a parameter called ‘neck height’ is introduced to determine the optimum mechanics theory, and the normal deposition criterion is established. For the surface motion stage, the sliding displacement and rolling displacement on the surface are calculated based on the rotation speed of the particles. A dynamic pollution accumulation model of the composite insulator is established based on the normal deposition criterion and tangential displacement. Finally, numerical simulations are performed by using the finite element method. Simulation results show that the proposed model agrees with the actual insulator pollution accumulation, and the deposition model is still applicable for various types of composite insulators operating in different applied voltages. The deposition probability of particles increases with the increasing particle size. In the surface motion stage, particle displacement increases with particle size and wind velocity.

This work first proposes a novel flashover model based on the deduced residual resistance of the ice layer. The most important finding of the field icing tests is that the double‐layer ice‐melting water film exists on the inner and outer surfaces of the ice layer. The conductivity of melting water on the inner and outer surface of the ice layer has been measured, and the corresponding surface conductivity has been calculated. According to the proposed flashover model, the ratio η of the resistance of the ice layer to that of the pollution layer gradually increases with the increase of the ratio k of the resistance of the outer surfaces to that of inner surfaces, and eventually approaches saturation. Furthermore, the icing flashover criterion has been modified, and the voltage gradient of the inner surface is less than that of the outer surface. Test results show that the ice flashover voltage is lower than the pollution flashover voltage between 2.18–9.69% and 14.75–20.32% under light ice and semi‐cylindrical ice, respectively. The simulation results based on the proposed model and the classic model are compared with the field test data. Results show that the proposed model could attain a high accuracy of dc flashover voltage and demonstrate the effectiveness of the proposed model.