Superconducting technology for overcurrent limiting in a 25 kA current injection system

Abstract

Current injection transformer (CIT) systems are within the major group of the standard type test of high current equipment in the electrical industry, so their performance becomes very important. When designing high current systems, there are many factors to be considered from which their overcurrent protection must be ensured. The output of a CIT is wholly dependent on the impedance of the equipment under test (EUT). Therefore current flow beyond the allowable limit can occur. The present state of the art provides an important guide to developing current limiters not only for the grid application but also in industrial equipment. This paper reports the state of the art in the technology available that could be developed into an application of superconductivity for high current equipment (CIT) protection with no test disruption. This will result in a greater market choice and lower costs for equipment protection solutions, reduced costs and improved system reliability. The paper will also push the state of the art by using two distinctive circuits, closed-core and open-core, for overcurrent protection of a 25 kA CIT system, based on a flux-lock-type superconducting fault current limiter (SFCL) and magnetic properties of high temperature superconducting (HTS) elements. An appropriate location of the HTS element will enhance the rate of limitation with the help of the magnetic field generated by the CIT output busbars. The calculation of the HTS parameters for overcurrent limiting is also performed to suit the required current levels of the CIT.

Elimination of chaotic ferroresonance in power transformer by ISFCL

“…Among several types of SFCLs, like for example normal resistive [42,43], flux flow resistive [48], inductive [49], flux-lock [50,51] and saturated core [52,45], inductive type SFCL (ISFCL) has some superior properties like: automatic detection of fault current, flexibility in turn ratio, grandiosity of impedance in fault duration, isolation of device and power system from view point of current flowing, very low resistance and consequently low heat loss and finally self-recovering [45,[53][54][55].…”

Heuristic mathematical formulations and comprehensive algorithm for optimal decision making for power system cabling

“…These tests are performed using high-current, low-voltage test equipments, such as CIS, by means of controlling the current values, as well as the operating time of the Equipment Under Test (EUT) [9][10][11]. Due to high current passing through secondary windings, a considerable amount of interference magnetic field is dispersed within the system tank, giving rise to malfunction or damage to the control tools [10,13].…”

“…Therefore, an algorithm for an optimal cabling route based on AHP is presented. The proposed scheme is applied to a high voltage substation [1][2][3] and a 25 kA current injection system (CIS), which mainly incorporates a 25 kA-125 kVA transformer delivering an output secondary current (25 kA), as closely proportioned to the primary current as possible, at relatively low voltages (1-5 V) [9][10][11][12]. Results suggest a generic hierarchy algorithm for cabling routes to prioritize critical factors and to formulate strategies for implementation in various types of power system over a wide range of conditions.…”

Convolutional Codes Acting as Emi Virtual Shields in Current Injection Systems

“…To accomplish the proposed coding algorithm, a 25 kA, CIS which is considered here as a case study was, as mainly incorporating a 25 kA-125 kVA transformer delivering an output secondary current (25 kA), as closely as possible proportioned to the primary current at relative low voltages (1 to 5 Volts) [15,16].…”

“…The optimal route is selected, based upon various criteria such as monetary cost minimization, voltage drop, and quality (EMC) parameters. Based upon the aforementioned criteria, by using analytical hierarchy process (AHP), the intelligent choice of optimal cabling routes can be achieved [16].…”