Fault Current Analysis in a Tri-Axial HTS Cable

Abstract

Tri-axial cable has been rapidly developed recently because of the advantages such as more compact structure, small leakage field, and low heat and AC losses. One the other hand, it causes an inherent imbalanced three-phase currents distribution due to the different radii of concentric layers. In our previous research, it is demonstrated that a proposed tri-axial cable composed of two longitudinal sections with adjusted twist pitches can transmit balanced three-phase currents. However, before the cable can be installed in a real grid, the heat reliability of the cable in steady-state operation and fault condition should be ensured. The heat balance calculation of the tri-axial cable in steady state under the balanced current distribution allows us to estimate thermal parameters of the cable such as inlet and outlet temperatures, pressure drop and operation temperature. When a phase current suddenly changes under fault conditions, the remaining phase currents become large because of mutual inductances between fault and sound phases. Simulation of the typical fault suggests the copper stabilizer amount on the HTS tape for stability and safety. It is found that copper of 2 mm in thickness keeps the cable temperature under 110 K.Index Terms-Fault current, HTS power cable, stabilizer, triaxial cable.

High temperature superconducting cables and their performance against short circuit faults: current development, challenges, solutions, and future trends

“…In [153], an analytical model was presented for 66 kV/6 kA/ 5 km superconducting power cable, which fully describes the steady and fault conditions of the understudied HTS cable. The presented formulations in [153] have the advantage of simplicity in applying. This is due to converting the partial differential equation of heat transfer to an ordinary differential equation (ODE).…”

“…In addition, the effect of former thickness on the temperature variation was investigated. Figure 20 displays the temperature rise of the HTS cable with respect to different former thicknesses for a fault with a duration of 2 s [153]. During a fault, the temperature of the tapes in each phase rises and exceeds the critical temperature value of the cable.…”

Thermal-hydraulic models for the cooling of HTS power-transmission cables: status and needs

“…Very few zero-dimensional (0D) fully-lumped models have been adopted to describe the overall cable temperature evolution of HTS cable; among them, the model in [31] just solves a simple global heat balance for the coolant for a tri-phases co-axial cable in fault conditions, to compute the outlet and operating temperature.…”

Efficient Multiphysics Finite Element Simulation of a Transient Fault in a Bi-2223 HTS Power Cable

“…This problem is amplified in systems such as superconducting cables, where a certain part of the cable must be modelled along its entire length (longitudinal temperature flow in the cable coolant) but another part simply cannot be (electromagnetic phenomena in the cable in 3D for the entire length of a cable are practically impossible and 1D would be very inaccurate). Therefore the preferred means of simulation have been via analytical or other, simpler, numerical methods [2]- [17], for example the equivalent circuit model. While these are fast and often reliable, they are not capable of describing the multiphysics at every point within the cable.…”