Numerical models based on the finite-element method (FEM) are popular tools for investigating the macroscopic electromagnetic behavior of high-temperature superconductor (HTS) applications. This article explains how to use the T -A formulation for modeling HTS coils in 2D with different coupling scenarios between the turns. First we consider a racetrack coil wound from one piece of superconducting tape. Then we consider a coil obtained by winding a cable composed of different HTS tapes. In the latter case, the tape turns are either electrically connected along their entire length or just at the two ends of the coil: in the model, these two different types of electrical connection are implemented with the help of the electrical circuit module. The current density distributions and the AC losses of the coils in the different coupling scenarios are compared and discussed. The limits of applicability of the presented approach are pointed out. The model is developed for the straight section of racetrack coils, but can be easily adapted to axisymmetric geometries.
The increase in distribution power demand and distributed generation may lead to a rise in power substation fault current levels. One possible solution to this problem is the use of a Solid-State Fault Current Limiter (SS-FCL). In this context, this paper proposes the concept of a bridge-type solid-state device switching an air-core reactor as an SS-FCL topology. The overvoltage protection system details are presented, along with an explanation of the fault detection algorithm control's principle. An experimental setup is designed to evaluate various events in addition to the short circuit, such as load-steps, harmonic loads, motor startups and transformer’s inrush. Fault current is detected within one millisecond, with a total reduction of 42%. The overvoltage protection system clamped the peak voltage across the semiconductor switch and kept the dv/dt below the maximum stipulated. The load input tests showed a proper limiting operation, provided the device is within the parameterization range.
The increase in distribution power demand and distributed generation may lead to a rise in power substation fault current levels. One possible solution to this problem is the use of a Solid-State Fault Current Limiter (SS-FCL). In this context, this paper proposes the concept of a bridge-type solid-state device switching an air-core reactor as an SS-FCL topology. The overvoltage protection system details are presented, along with an explanation of the fault detection algorithm control's principle. An experimental setup is designed to evaluate various events in addition to the short circuit, such as load-steps, harmonic loads, motor startups and transformer's inrush. Fault current is detected within one millisecond, with a total reduction of 42%. The overvoltage protection system clamped the peak voltage across the semiconductor switch and kept the dv/dt below the maximum stipulated. The load input tests showed a proper limiting operation, provided the device is within the parameterization range.
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