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The transport alternating current (AC) losses of the three coils used in the fault current limiters (FCL) application are measured. The results have shown that two bifilar pancake coils have different AC loss characteristics.

The I-V characteristics and over-current behaviors of a 1-m single-layer test YBCO cable are examined. Numerical simulations are performed in order to clarify the over-current characteristics, hot-spot existence and effect of magnetic coupling.

The fault current limiting characteristics are examined according to the fault angle in the integrated three-phase flux-lock type superconducting fault current limiter (SFCL) in the fault type such as the single-line-to-ground fault, the double-line-to-ground fault and the triple-line-to-ground fault. The results have confirmed that the SFCL has a same current limiting rate irrespective of a fault angle in the same fault type.

The design and test results of a 6.6 kV-class superconducting fault current limiter (FCL) coil wound with YBCO tapes. The fault current limiting performance of the FCL is evaluated through over-current tests by using a capacitor bank.

A new topology of the active superconducting DC fault current limiter (DC-SFCL) applied in the hybrid AC.DC power supply systems is described. The simulation models of the DC-SFCL and the hybrid AC/DC power supply system are created by using MATLAB SIMULINK and the simulation tests are performed to evaluate the system performance.

Superconducting Fault Current Limiters (SCFCLs) have improved the reliability and stability of power systems, which consists of a transformer type inductive SCFCL with a ZnO device and a resistor in parallel. The contribution share of the voltage drop suppression and the acceleration energy consumption to the improvement of the power system stability are clarified with conditions like generator output and fault clearing time.

The current limiting properties of different kinds of Mg[B.sub.2] wires at 50 Hz in the temperature range of 20-30 K are examined. Findings reveal fast transition to the normal state during the first half of the first cycle and a limiting effect during the subsequent six cycles.

The performance of a short-circuit test on non-inductively wound solenoid type superconducting fault current limiter (SFCL) is discussed. Results suggest that a shorter difference between the outer and inner tape is essential for more elaborate simulation.

In order to determine the pressure rise due to fault arcs in electrical installations, the portion of energy heating the surrounding gas of the fault arc has to be known. The ratio of the portion of energy to the electrical energy, the thermal transfer coefficient, well known in literature as [k.sub.p]-factor, is adopted here. This paper presents a theoretical approach to calculate the thermal transfer coefficient [k.sub.p] and to determine the pressure rise in an electrical installation. It is based on the solution of the fundamental hydro- and thermodynamic conservation equations taking into account melting and evaporation of metals as well as chemical reactions with the surrounding gas of the fault arc. The results for closed arc chambers show that factors such as the kinds of insulating gas and of electrode material, the size of the test vessel, and the gas density considerably influence the thermal transfer coefficient and thus the pressure rise. Furthermore it is demonstrated, with an example of a short-circuit in a compact medium-voltage station with heavy metal evaporation, that the mathematical approach is a reliable tool to assess the development of pressure. Index Terms--Chemical reaction, electrical installation, energy balance, fault arc, hydro- and thermodynamics, melting and evaporation, pressure, relative purity, theoretical approach, thermal transfer coefficient.

In this paper, a fuzzy logic-based algorithm to identify the type of faults in radial, unbalanced distribution system has been developed. The proposed technique is able to accurately identify the phase(s) involved in all ten types of shunt faults that may occur in an electric power distribution system under different fault types, fault resistance, fault inception angle, system topology and loading levels. The proposed method needs only three line current measurements available at the substation and can perform the fault classification task in about half-cycle period. All the test results show that the proposed fault identifier is well suited for identifying fault types in radial, unbalanced distribution system. Index Terms--Distribution system, fault identification, fuzzy logic.