Background In order to solve the problems of single influencing factors and inconsistency of subjective experience of multiple experts under different working conditions in the evaluation of existing cross-river transmission corridor schemes, a cross-river transmission corridor scheme evaluation method based on hierarchical analysis has been proposed in this work. Methods Firstly, six evaluation indices, including planning and important facility areas, environmentally sensitive points, geological conditions, hydrological conditions, safety and economy, have been established to construct a system for assessing the impact factors of cross-river transmission corridors. Then, the hierarchical analysis method has been combined with the improved grey correlation analysis to synthesize the weight judgement values of multiple experts, construct a unified scoring system for the weights of qualitative and quantitative indexes, effectively improve the stability of the indexes' weights, and realize the scientific assessment of the cross-river transmission channel scheme. Finally, the engineering scheme of a cross-river transmission channel has been evaluated. Results Through practical engineering analysis, the selected cross-river transmission channel using this method has been found to be consistent with the actual project. Conclusion The results have shown that the method could effectively achieve the evaluation of various cross-river transmission channel schemes by comprehensively considering a variety of factors in the selection of cross-river corridors for transmission lines and effectively protecting the empirical roles of different experts.

The study of the influence factor of transmission line scattering and its influence law is the key to developing the transmission line passive interference suppression strategy. Therefore, the line-surface geometric model of electromagnetic scattering of transmission lines is constructed in this paper. The method of moments ( MOM ) built in Feko simulation software is used to solve the induced current on the surface of transmission lines and the scattered electric field generated by it. Taking the ±800kV Xiangjiaba-Shanghai ultra-high-voltage direct current (UHVDC) transmission line as an example, the effects of the ontological structural features such as transmission line ground wire, line span, and tower height on the scattered electric field of the transmission line were investigated. The results show that the ground wire and tower insulation have little effect on the induced currents on the surface of the transmission tower, the scattered electric field at the observation point is less with the increase of the transmission line distance, and the scattered electric field at the observation point decreases with the increase of the height of the transmission tower. The findings of this paper can provide a reference for the protection of passive interference of transmission lines.

To obtain the electromagnetic scattering characteristics of transmission lines, we conducted a multi base tower scaled model experiment in an outdoor open experimental field at the China Shipbuilding Research and Design Center (hereinafter referred to as 701 Research Institute) in Wuhan, Hubei Province, to measure the scattering field of transmission lines under different conditions. At the same time, the experiment verifies the correctness of the equivalent principle of generalized closed systems, verifies the applicability of the fast algorithm for electromagnetic scattering characteristics of transmission lines based on MBPE technology to the calculation of high-frequency and broadband scattering characteristics, and verifies that MBPE technology is suitable for solving the scattering field of short wave frequency band ultra-high voltage transmission lines under different spans, tower numbers, and other conditions.

The static performance of transmission line span tower space steel network structure is relatively well studied, but the dynamic performance research lags behind, which has become an important factor limiting its general promotion. In this paper, a combination of numerical and analytical methods is used to carry out a modal analysis of the spatial steel network structure of transmission line towers. The vibration patterns and self-oscillation frequencies of two types of tower structures, spanning towers and ordinary towers, are analysed. The dynamic characteristics of the spatial steel mesh structure of the spanning tower are obtained, laying the foundation for the subsequent analysis of the dynamic performance of the transmission line spanning tower.

Background: The research in this paper aims to address the effect of large-span AC lines on ion currents in parallel DC lines. This paper proposes an algorithm for solving mixed ion flow fields based on meshless radial point interpolation, which can accurately solve the ion flow field of large-span AC-DC parallel lines. Methods: The shape function of the traditional meshless method is modified by polynomial radial point interpolation so that the shape function can satisfy the Kronecker-δ function property at the point where the boundary constraints are to be imposed so as to meet the requirements of directly applying the boundary constraints; Combined with the influencing factors of the AC line on the mixed ion flow field, the mixed ion flow field and the ion current density value was obtained. Results: Using the proposed algorithm, the relative error of ion current density can be reduced to 4.5%, and the relative error of ion flow field can be reduced to 24%. Conclusion: The simulation results are consistent with the measurement results, which proves the correctness and practicability of the mixed ion flow field solution algorithm based on meshless radial point interpolation.

Due to the complexity of the spatial layout of metal equipment in the substation, the traditional geometric modeling method cannot accurately calculate the 5G channel loss in the substation. Due to the short wavelength of the 5G signal, it can be seen as ray propagation. Therefore, this paper introduces the basic idea of ray tracing algorithm. Based on the geometric optics theory of ray propagation, the reflection point and diffraction point are determined by using the spatial geometric characteristics of signal reflection and diffraction, and the effective channel path of 5G signal in substation is traced. Then, the energy loss caused by the reflection and diffraction of the signal is calculated by the electromagnetic reflection theory and the consistent diffraction theory. Combined with the relationship between the free space loss and the electric field change of the 5G signal on the transceiver path, the solution method of the 5G channel loss in the substation is derived.