Showing papers on "Fault current limiter published in 1988"
24 Oct 1988
1 citations
TL;DR: In this paper, the skin effect of conducting current in a ferromagnetic pipe was used to detect DC current and ground fault current on a three-phase power line system, and two detectors were proposed.
Abstract: New methods for detecting DC current and ground fault current in a three-phase power line system are described. Two detectors both utilize the skin effect of conducting current in a ferromagnetic pipe. The detectors have no windings. The DC current detector outputs almost sinusoidal voltage whose amplitude corresponds well to the DC current. The detector has a simplified circuit configuration and short response time. There are no contacts between the DC line and the sense circuit. The ground fault detector breaks down the three-phase power line within three drive-frequency cycles. This paper summarizes those results.
20 Mar 1988
TL;DR: In this article, general expressions for the fault currents and voltages for various types of ungrounded (isolated) faults are derived for any N-phase system, and actual calculations for six and twelve-phase systems are made, and the results are presented as normalized graphs.
Abstract: High-phase-order transmission is considered as a viable alternative for increasing the power transmission capability of a transmission line. Fault analysis is an important aspect of the determination of breaker and protection specifications. General expressions for the fault currents and voltages for various types of ungrounded (isolated) faults are derived for any N-phase system. Actual calculations for six- and twelve-phase systems are made, and the results are presented as normalized graphs. >
Patent•
26 Oct 1988TL;DR: In this paper, a Zener diode was used to stabilize the voltage of the voltage source producing the fault current in order to enhance the response process of the switch devices. But the effect of voltage fluctuation on the fault-current response process was not considered.
Abstract: Electromagnetically controlled fault current switch devices have the advantage that their response process is enhanced by the fault current. If the amplitude of the voltage source producing the fault current fluctuates in use, this also acts in an undesired manner on the fault current excitation. The special feature of the circuit arrangement according to the invention is that the fault current excitation of the electromagnetically controlled switch device is carried out by means of a voltage stabilised with the aid of a Zener diode. The switch devices whose response process has been enhanced in the abovementioned manner are used for controlling power supply systems in railway protection systems.