Multi-objective optimization for the superconducting bias coil of a saturated iron core fault current limiter using the T-A formulation

Abstract

The short-circuit levels have increased considerably in transmission and distribution systems in the last years. Fault current limiter (FCL) devices are a potential solution to this problem. Among several FCL topologies, this group has good experience in the use of superconducting fault current limiters (SFCL) to reduce the electrical current during short-circuits. The literature also presents studies of the saturated iron core superconducting fault current limiter (SIC-SFCL) topology employing mathematical modeling and prototypes design. Some of them have shown promising results, including the construction of pilot prototypes in medium and high voltage substations. The SIC-SFCL simulation studies presented optimal topologies that reduce the amount of ferromagnetic material used in the core and represent well the behavior of this limiter. The finite element method and the finite element analysis are suitable to model the SIC-SFCL. However, a more detailed study focusing on the optimization of the DC bias superconducting coil of the SIC-SFCL has not been presented in the literature yet. In this context, this work proposes a multi-objective optimization method using the Nelder–Mead algorithm to find an optimal geometry for the superconducting coil. In this optimization, the objectives functions are: to maximize the critical current density in the high-temperature superconductor (HTS), minimize the voltage drop in the copper winding, minimize the current through the DC biased superconducting winding, and minimize the price of the HTS superconducting winding. Before implementing the multi-objective optimization algorithm, we have tested a non-superconducting saturated iron core prototype and used the results to validate the simulation models. After that, we have replaced the DC copper winding with an HTS coil in the simulations and initiate the optimization process. Results show that constructing the DC bias superconducting coil using the minimum possible fill factor might not be the best choice.

Roadmap on artificial intelligence and big data techniques for superconductivity

“…Multiobjective design methodologies and seamlessly integrated simulation toolboxes: metaheuristic and evolutionary strategies, such as GAs [105], have already been used to design SFCL devices by multiobjective optimisation addressing distinct design parameters while complying with technical and economic requirements [103,106]. One such methodology relies on representing the SFCL by a reluctance-like circuit, whose characteristics depend on several parameters of the limiter.…”

Essential Material Knowledge and Recent Model Developments for REBCO-Coated Conductors in Electric Power Systems

“…The coupling method proposed in [23] and applied in [6] provides a proper way to consider all the material non-linearities for both the superconductor and the ferromagnetic core (when present) while still allowing an easy coupling with electrical lumped-parameters systems in 2D and 3D. Through the FEM, the electrical parameters of the superconducting device are calculated and passed to the power grid model.…”

“…Electrical equipment using High-Temperature Superconducting (HTS) materials are reaching maturity after more than two decades of research and development. Nowadays, devices like Fault-Current Limiters (FCL) [1][2][3][4][5][6], power cables [7,8], and electric machines [9,10] have been built, and in some cases, installed in electric networks. The HTS materials with the most potential to address simultaneously cost and technical requirements are the second generation (2G) wire (or tape).…”

Analysis of Electromagnetic Characteristics of 6.5 MVA/25 kV HTS Traction Transformer Using T–A Formulation

“…This method couples T and A formulations and can effectively solve the analysis of large-scale HTS systems. With the further study of T-A formulation [15], the application field of T-A formulation has become more and more widely, including superconducting motor [16][17], superconducting fault current limiter [18], superconducting cable [19], superconducting flux pump [20]. However, the application of T-A formulation in superconducting transformer has not been involved.…”