A method for operating an electronic circuit arrangement is provided for electrical current limiting in a potentially explosive area, which comprises at least one electrical consumer which is supplied with electrical energy via an electrical supply line from an electrical voltage source, typically from a rechargeable battery which provides an electrical supply voltage, according to which at least one of at least two semiconductor switches present in the electrical supply line is switched into an open state so that the electrical supply line is interrupted when the total electrical voltage present at the semiconductor switches exceeds a predefined voltage threshold value, and according to which the at least one semiconductor switch is switched from the open into the closed state again when an external electrical voltage is applied to the electrical consumer.

Provided is a method for determination of a location of a short circuit fault in a generator arrangement, wherein the generator arrangement includes an electrical machine and at least one channel, wherein the or each channel includes a breaker, a converter unit and a set of stator windings of the electrical machine connected to the converter unit via the breaker, wherein upon an occurrence of a short circuit in a channel, the connection between the set of stator windings and the converter unit interrupted by opening the breaker, wherein depending on at least one measured signal of a measurand, wherein the measured signal is measured by at least one sensor of the electric machine and wherein the measurand describes a torque ripple of the electrical machine, either the electrical machine or the converter unit of the channel is determined as location of the short circuit fault.

Techniques for identifying faulty sections in power transmission lines are described. A first positive sequence voltage and first positive sequence current at a first terminal of a power transmission line are computed based on a first voltage and first current at the first terminal. A second positive sequence voltage and second positive sequence current at a second terminal are computed based on a second voltage and second current. Based on the first positive sequence voltage and the first positive sequence current, a first junction voltage and first junction current from the first terminal at a junction are computed. Based on the second positive sequence voltage and the second positive sequence current, a second junction voltage and second junction current from the second terminal are computed. A ratio of a junction voltage parameter to a junction current parameter is computed. Using the ratio, the faulty section is identified.

A method is disclosed for locating an earth fault in a DC network, to which multiple load zones are connectable. Each load zone has two symmetrically earthed load zone lines. In an embodiment of the method, for each load zone line, a line voltage is continuously measured between a line potential, at which the load zone line lies, and an earth potential. In the event that an earth fault is detected at a main line of the DC network, the main lines are separated from both load zone lines of a load zone and the earth fault is assigned to this load zone, if a magnitude difference between the magnitudes of the line voltages of the two load zone lines of this load zone are not significantly reduced after separating the main lines from the load zone lines.

A method identifies a location of a fault on a faulty line of an electrical power supply network having a plurality of lines, a plurality of inner nodes, and at least three outer nodes. The outer nodes each bound a line and are provided with measurement devices which are used to measure high-frequency current and/or voltage signals. To locate faults, one of the outer nodes is selected as the starting node for the search for the fault location. Starting from the starting node, paths to the other outer nodes are determined, and that those paths on which the fault location could be located are selected. A line on which the fault location could be located, in principle, is identified for each of the selected paths using the respective times at which the traveling waves arrive, and a potential fault location is determined for the respectively identified line.

A transformer assembly including a transformer that is part of an underground residential power distribution circuit and that provides fault isolation and restoration. The transformer assembly includes an enclosure enclosing a primary winding and a secondary winding. The transformer assembly also includes first and second switching devices mounted to a panel of the enclosure, where each switching device includes an outer housing, a transformer interface electrically coupled to the primary winding, a connector interface electrically coupled to a first connector and a vacuum interrupter having a fixed contact and a movable contact. The fixed contact is electrically coupled to the connector interface or the transformer interface and the movable terminal is electrically coupled to the other connector interface or the transformer interface.

Disclosed is a method for determining the distance to a fault location of a power line to be protected in an electric power system, the method including: configuring the power line to be protected into a plurality of segments, obtaining a plurality of line settings separately for each of the plurality of segments configured, and using the line settings obtained to determine a fault location of the power line to be protected, wherein the line settings include at least one of impedance, resistance, reactance, length, compensation factor, angle. Also disclosed is an intelligent electronic device.

A switching device that is part of a transformer in an underground residential power distribution circuit and provides fault isolation and restoration. The switching device includes a transformer interface for coupling the device to the transformer and a connector interface for coupling the device to a connector. The device also includes a vacuum interrupter having a fixed terminal and a movable terminal, where the fixed terminal is electrically coupled to the connector interface and the movable terminal is electrically coupled to the transformer interface. A control rod is coupled to the movable terminal, an actuator assembly is coupled to the control rod and is operable to move the control rod to open and close the vacuum interrupter. A capacitor is electrically coupled to the fixed terminal, and provides an interface for power line communications signals, voltage sensing, help determine power flow direction and help determine the distance to a fault.

A switch assembly that is part of a transformer in an underground residential power distribution circuit and that provides fault isolation and restoration. The switch assembly includes first and second switching devices each having an outer housing, a transformer interface electrically coupled to the transformer, a connector interface electrically coupled to a first connector and a first vacuum interrupter having a fixed contact and a movable contact, where the fixed contact is electrically coupled to the connector interface and the movable contact is electrically coupled to the transformer interface. A control board controls the first and second switching devices, where the control board is responsive to voltage signals from capacitors in the first and second switching devices.

A method for isolating a fault in an underground power distribution network. The network includes a power line, a plurality of transformers electrically coupled to and positioned along the power line, a first recloser connected to one end of the power line and a second recloser connected to an opposite end of the power line, where each transformer includes an upstream switching device and a downstream switching device, and where power is provided to both ends of the power line through the first and second reclosers and one of the switching devices is a normally open switching device. The method includes detecting overcurrent by some of the switching devices, detecting loss of voltage by some of the switching devices and sending clear to close messages to some of the switching devices to open and close certain ones of the switching devices to isolate the fault.