The invention relates to a method for operating a motor vehicle (2) which has an electric high-voltage network (3) and an electric low-voltage network (4), wherein the high-voltage network (3) has at least one traction battery (5) and at least one electric drive machine (6), the low-voltage network (4) has a vehicle electrical system battery (9), and the high-voltage network (3) is monitored for an electrical short-circuit and, upon detection of a short-circuit, the traction battery (5) is disconnected from the high-voltage network (3). According to the invention, in order to check the plausibility of the detected short-circuit before the traction battery (5) is reconnected to the high-voltage network (3), a boost current (I.sub.HV) is applied to the high-voltage network (3) through the low-voltage network (4) by means of a DC/DC converter (11), and a boost voltage (U.sub.HV) measured in the high-voltage network (3) is compared with an expected boost voltage (U.sub.HV,soll).

A fire detection system may include isolation circuit having an isolation switch coupled with a system line of the fire detection system and configured to isolate a first side of the system line from a second side of the system line. The isolation circuit may also include a controller coupled with the isolation switch. The controller may be configured to detect repetitive, intermittent short circuit activity on the system line and control the isolation switch based on this activity.

A fault-preventing circuit recloser includes a ballast impedance, power line current and voltage monitors, and controller that operates the switch based on measurements obtained from the current and voltage monitors. The controller aborts the closing (i.e., reopens the switch) when the controller detects that the switch has closed into faulted line. The circuit recloser temporarily introduces the ballast impedance into the circuit during the closing operation to limit the current spike and voltage dip caused by initially closing the switch into the faulted line. The circuit recloser also temporarily introduces the ballast impedance into the circuit during the opening operation to limit the voltage transient that can be caused by initially opening a load-carrying power line. Different ballast resistor insertion times are applied depending on the type of recloser operation (opening or closing) and whether a fault is detected.

In a power converter having a regulator and charge pump, both of which operate in plural modes, a controller receives information indicative of the power converter's operation and, based at least in part on said information, causes transitions between regulator modes and transitions between charge-pump modes.

A power system comprises a power source, a transmission line coupled to the power source through a circuit breaker, a shunt reactor coupled to the transmission line, and a current transformer connected in series with the shunt reactor. A method for controlling the circuit breaker of the power system comprises processing an output signal of the current transformer to obtain the voltage on the transmission line by determining a time derivative of a current sensed by the current transformer. The method further comprises performing, by at least one control or protection device, a control or protection operation (e.g., auto-reclosing) based on the determined time derivative of the current sensed by the current transformer.

A power restoration system for restoring power to feeder segments in response to a fault. The system includes a reclosing device having a switch and one or more sensors for measuring current and/or voltage on the feeder, where the reclosing device performs a pulse testing process to determine circuit fault conditions. The system also includes a plurality of switching devices electrically coupled along the feeder, where each switching device includes a section switch and one or more sensors for measuring current and/or voltage on the at least one feeder. In one embodiment, each switching device recognizes predetermined pulse codes having a sequence of pulses, where the reclosing device uses the pulse testing process to generate and selectively transmit defined pulse codes on the feeder that selectively cause the section switches to change states between an open state and a closed state depending on the code.

A method for operating an electronic switch is described hereinafter. According to one exemplary embodiment, the method (for an electronic switch in the switched on state) comprises detecting whether there is an undervoltage condition at a supply voltage node and providing an undervoltage signal which indicates an undervoltage condition. The method further comprises switching off the electronic switch if the undervoltage signal indicates an undervoltage condition and switching (back) on the electronic switch if the undervoltage signal no longer indicates an undervoltage condition. If the undervoltage signal indicates an undervoltage condition during a switch-on process of the electronic switch, the electronic switch is switched off again and switching back on is prevented for a defined period of time, irrespective of the undervoltage signal. Moreover, a corresponding circuit is described.

A fault detection system that includes a recloser configured to perform a reclosing operation in response to detecting overcurrent, where the recloser includes a communications device for receiving communications signals. The system also includes a transformer having an outer can, a sensor mounted to the can and extending into the can for measuring pressure therein, where the sensor includes a mechanical indicator that extends when overpressure is detected. The transformer further includes a radio mounted to the can and coupled to the sensor, where the radio includes a switch coupled to the mechanical indicator and a transmitter. When the mechanical indicator extends in response to detecting overpressure in the can it causes the switch to close which causes the transmitter to send a signal that is received by the communications device, which prevents the recloser from reclosing.

Presented herein are techniques for power fault management that operates without power-source-side switching. A power transmitter is configured to provide power to a current loop, and a power receiver is configured to receive the power from the current loop. The power receiver is configured to, on a periodic basis, disconnect from the current loop to stop pulling power from current loop for a period of time to enable a safety check to be performed by the power transmitter. The power transmitter is configured to monitor current on the current loop, determine whether the current level on the current loop passes the safety check within a predetermined time interval since a determination that the current level was not within a safe range, and control connectivity of the power to the current loop based on whether the safety check has or has not passed within the predetermined time interval.

A power restoration system comprising a feeder, a plurality of power sources available to provide power to the feeder, a plurality of normally closed reclosing devices electrically coupled along the feeder, at least one normally open recloser electrically coupled to the feeder, and a plurality of normally closed switches electrically coupled along the feeder between each adjacent pairs of normally closed reclosing devices. Each switch is assigned a position code having a value for each of the plurality of power sources that determines when the switch will open in response to the fault current and which power source the switch is currently receiving power from, where timing control between the reclosing devices and the switches allows the switch to be selectively opened to isolate the fault within a single feeder section between each pair of adjacent switches or between each switch and a reclosing device.