Coupled Electromagnetic and Thermal Analysis of Single-Phase Insulated High-Current Busducts and GIL Systems

Abstract

This paper presents a mathematical model for the coupled electromagnetic and thermal analysis of the single-phase insulated high-current busducts of circular cross-section geometry and of gas-insulated transmission lines (GIL). The mathematical model, accompanied by a numerical solution procedure, features an exact current distribution in phase conductors and shields of the busduct or GIL system, accounting for the skin and proximity effects, and including the complete electromagnetic coupling between phase conductors and shields. The current distribution is based on the conductor filament method in combination with the mesh-current method. The mathematical model further couples the analysis of current distribution with the computation of (Joule) power losses and subsequent temperature increase in the high-current busducts or GIL systems, accounting for the material properties (electrical conductivity, thermal emission and convection coefficients) as well as for the surrounding ambient properties (ambient temperature, wind and solar radiation influences).

Research on the Calculation Method of Equivalent Parameters of the Core Wire for the High-Voltage GIL Metal Shell Grounded Through the Copper Bar

“…Benato et al (2007) studied the magnetic field coupling relationships among the conductive layers of the GIL in tunnels and analyzed the characteristics of the magnetic field distribution among the conductor layers of each phase, taking the skin effect and the proximity effect of the conductors in GIL into consideration and obtaining two equations about the complex voltage drops in phase conductors and shells. An analytical numerical method is proposed to determine the self-impedance and mutual impedance for the three-phase GIL, for which the so-called "external proximity effect" is also considered (Sarajcev et al, 2013). Benato et al (2002) studied the current and magnetic field distribution characteristics of the metal shell and the core wire of the single-phase GIL according to the geometric structure of the single-phase GIL and analyzed the influence of GIL magnetic field distribution characteristics on GIL impedance parameters.…”

Study on the Gas-Insulated Line Equivalent Model and Simplified Model

“…Progress has been made in the study of parameter characteristics as well as GIL modeling: references [4,5] analyzed the magnetic field distribution among the conductors of the three phases in differing scenarios of GIL laying; reference [6] presents a numerical computation method for determining the magnetic field of the GIL; references [7][8][9][10] examined the electrical characteristics of underground conductors and the influence of the earth on conductor parameters, then proposed a method for solving the impedance matrix of underground conductors; references [11,12] studied the current and magnetic field distribution characteristics of the metallic enclosure and the inner conductor of a single-phase GIL, discussing how this distribution can change the electrical characteristics of the GIL; reference [13] presents results of numerical computation of electrical parameters of the flat and symmetrical three-phase GIL; reference [14,15] presents an analytical numerical method of determination of self and mutual impedances of GIL without taking into account skin and proximity effects as well as taking them into consideration; reference [16] presents a mathematical model of the GIL with taking into consideration skin and proximity effects; reference. [17] proposed a model of a three-phase GIL transmission system with the earth return current considered; reference [18] adopted the finite-element method in building a model of a three-phase GIL system; reference [19] proposed an approximate model based solely on the mutual inductance among the GIL inner conductor and the metallic enclosure; reference [20] suggested a modeling method for the simulation of a long-distance GIL system; and reference [21] adopted the lossless Bergeron model in building a model of a GIL-OHL hybrid transmission system.…”