Using of high temperature superconductive in secondary winding of two types of transformers: fault current limiter and current injection transformer

Abstract

The Types of applications in which superconductivity has the potential to be effective in an electric power system can be separated into two general classes. The first type includes those technologies in which superconductivity is simply a replacement of existing resistive materials, for example, cable, motor, generators, and transformer. The second type includes technologies that will be enabled by superconductivity and that have little or, at most, limited capability if conventional resistive or other materials are used. Examples are superconducting magnetic energy storage (SMES) and large fault current limiter (FCL) [1]. Superconductivity brings a variety of features that provide new functionality to the electric power system. For example, today, the ability to limit the maximum current in a system, one is SMES, the other is the advanced flywheel, which spins at a very fast rate and is supported and constrained by magnetic bearings that use superconductors. The July 1997 issue of IEEE Spectrum was dedicated to recent developments in the applications of high temperature superconductivity (HTS) to electric power systems. FCLs are used to limit the fault current to the level that is within the interrupting capabilities of the existing circuit breakers. They are expected to improve reliability and flexibility of power system. Various types of them have been proposed and studied [2-3]. The HTS provide the advantage of a higher temperature operation and they are applied to FCL. The FCLs based on HTS materials have been developed for many years now [4-6]. Prototypes have been manufactured and tested in existing power system [6-7]. In the other hand, current injection transformer (CIT) are within the major group of the standard type test equipments in electrical industry, their performance are very important, one of the critical problem in this type of transformer is thermal characteristics: hot-spot temperatures, warm and cooling periods, and aging [8]. Using superconductive solves above mentioned problems, but trade off between economical purposes and technical problems is a major discussion. The purpose of this work is to study two types of transformers “FCL” and “CIT” using HTS coil. Simulations of Transient Characteristics and performances are considered for each type.