Test of 1.2 MVA high- superconducting fault current limiter

Abstract

A three-phase superconducting fault current limiter with a rated power of 1.2 MVA has been built, tested and installed in a power plant. The device is based on the `shielded iron core concept'. The superconducting part consists of a stack of rings made of Bi-2212 ceramic. They were fabricated by a special partial melt process and have a diameter of 38 cm, a height of 8 cm and a thickness of 1.8 mm. The current - voltage characteristic obeys a power law with . The critical current density defined by the criterion is about . The nominal current and voltage of the device are 70 A and 10.5 kV, respectively. In three-phase short-circuit tests with a prospective fault current of 60 kA the current was limited to about 700 A in the first half-wave. After 50 ms the limited current was below 250 A. The test results are in excellent agreement with detailed simulations of both the normal operation and the behaviour under fault conditions. The current limiter has been installed in the auxiliary line of a hydropower plant for a 1 year endurance test. It is the first superconducting device tested in a power plant under actual operating conditions.

HIGH DENSITY MgB2 OBTAINED BY REACTIVE LIQUID Mg INFILTRATION

“…As bulk magnets, the main area of applications concern the passive levitated bearings [13], the shielding of alternate and low magnetic fields[14}, the electrical motor either linear or rotating [15]. As conductors or variable resistors or inductors, the main application concern the current lead of cryogenic apparatus and the fault current limiter for the electrical grids, either inductive [16] or resistive [17].…”

Resistive fault current limiters with YBCO films 100 kVA functional model

“…Several types of FCL concepts based on 100 superconducting materials have been proposed so far, an overview is given in [l]. A 1.2 MVA prototype of the inductive "shielded iron core" type has been built and tested by ABB [2]. The so-called resistive FCL relies on the switchlike onset of resistivity during a quenching process caused by exceeding the superconductor's critical current.…”

Reverse engineering of inductive fault current limiters

“…Inductive fault current limiters (FCL) using high temperature superconducting materials (HTS) have been suggested almost two decades ago [1] and tested with success [2,3]. It consists in a primary coil magnetically linked with a superconducting cylinder, and its principle of operation was extensively described elsewhere [4][5][6].…”

“…[2,[8][9][10][11]. Nevertheless, some assumptions made with these models limit its application and they are seldom really used.…”