Provided is a light-emitting element drive device including a transistor control unit arranged to drive and control a transistor connected to a light-emitting element, an output ground fault detection unit arranged to output an output ground fault detection signal corresponding to the voltage level at a connection node between the light-emitting element and the transistor, a stop control unit arranged to stop driving the transistor when the output ground fault detection signal indicates an output ground fault, and a mask signal generation unit arranged to generate a mask signal that masks the output ground fault detection signal on device startup.

In one embodiment, an aircraft electronics system includes a hardware processor, a charge collection circuit to collect charge; a switching circuit controlled by the hardware processor to discharge the charge collected on the charge collection circuit through a bonding circuit formed from a chassis and a bonding surface; and a voltage measurement circuit to measure a voltage difference between measurement terminals across the chassis and the bonding surface.

An electrical link includes an electrical protection device. The electrical link, for linking an AC high-voltage generator to a user apparatus, includes an electrical conductor surrounded by a first inner insulating envelope. An electrical protection device includes a conductive sheath around the inner insulating envelope. A fixed DC current generator is connected to a current injection point of the conductive sheath. A circuit breaker that can be activated is on the electrical conductor and configured to break the electrical link when it is activated. A detection module is connected to a current tap-off point of the conductive sheath and to the circuit breaker, the detection module being configured to detect a break in the conductive sheath, a current leak out of the electrical conductor or a current leak out of the sheath and to activate the circuit breaker.

In a multi-phase power grid fed by a power source, earth fault (460) is located by means of a power supply source synchronized with the power grid, which is connected between a zero point of the grid and earth. In a fault current compensation mode (420), a control unit controls the alternating voltage source to compensate for any ground fault current in the power grid to a value below a threshold level. In a fault detecting mode (430), the control unit gradually adjusts the output voltage of the alternating voltage source with respect to amplitude and/or phase angle (440). A change of zero-sequence current and zero-sequence admittance between the alternating voltage source and a fault location is measured (450) by means of at least one detector. The at least one detector is communicatively connected to the control unit and reports recorded measured values representing zero-sequence current and/or zero-sequence admittance to the control unit. In the fault detecting mode, the control unit localizes a ground fault (460) based on at least one of said measurement values representing changes of the zero-sequence current and/or zero-sequence admittance, upon which an affected branch is disconnected (470) or the system switches to the fault compensation mode (420).

A smart sensor network for power grid health monitoring includes a plurality of spaced sensors that are magnetically coupled to the power transmission line to be monitored. The sensors include a signal injection unit and a signal sensing unit. As such, one of the sensors acts to inject, via its signal injection unit, a high frequency signal through the magnetic coupling into the power transmission line, while sensors on either side of the signal injecting sensor act to block the injected signal, which is then detected by the signal sensing unit of the injecting sensor, and is used to measure the impedance of the power transmission line segment being analyzed. Based on the difference between a pre-measured impedance of the power transmission line being monitored and the actual impedance value of the power transmission line being measured by the sensor, the health of the power line can be obtained.

An electric propulsion system is described that includes at least one branch for distributing electrical power, provided by a power source, to one or more loads. The at least one branch is partitioned into one or more zones and comprises a plurality of branch isolation devices that are configured to isolate the at least one branch from the power source in response to a fault current at the at least one branch. In addition, the at least one branch comprises a respective pair of zone isolation devices for each respective zone from the one or more zones. The respective pair of zone isolation devices for each respective zone is configured to isolate the respective zone from the at least one branch, during a test of the at least one branch for identifying which of the one or more zones is a source of the fault current.

The present disclosure relates to an electronic circuit for detecting the current winding temperature of phase windings and/or other characteristics of an electronically commutated electric motor, which is connected, or can be connected, to a frequency converter, comprising one or more capacitive two-terminal networks with a temperature-dependent impedance, each network being arranged parallel to two winding terminals (u, v, w) of the phase windings, as well as a detector for detecting the current responses in the motor feeds on the basis of steep-flanked voltage changes at the output of the frequency converter.

The present disclosure relates to calculating a fault location in an electric power transmission system based on traveling waves. In one embodiment, a system consistent with the present disclosure may be configured to detect a fault in an electric power transmission system. The system may include a traveling wave detection subsystem configured to detect and measure traveling waves on a transmission line and a fault location estimation subsystem. The fault location estimation subsystem may receive from the traveling wave detection subsystem a first plurality of traveling waves on the transmission line generated during a reference event. The fault location estimation subsystem may receive from the traveling wave detection subsystem a second plurality of traveling waves generated during an unplanned event. An unmatched traveling wave in the second plurality of waves may be detected and a location of the unplanned event based on the unmatched traveling wave.

A test signal is applied from a continuity test source to a photovoltaic (PV) panel string, to test electrical continuity in the PV panel string and between the PV panel string and an inverter that is coupled to the PV panel string. If the test signal is detected at a PV panel disconnect switch that is separate from the continuity test source and switchably couples one or more Direct Current (DC) PV panels in the PV panel string, then the PV panel disconnect switch is controlled to connect the one or more DC PV panels in the PV panel string. Otherwise, the PV panel disconnect switch is controlled to disconnect the one or more DC PV panels from the PV panel string. The test signal could be, for example, an Alternating Current (AC) signal tuned to a PV installation that includes the PV panel string and the inverter.

A LCDI power cord circuit is provided. The circuit includes energizing shielded wires and monitoring the energized shields for surges, e.g., arcing, and/or voltage drops, e.g., shield breaks detected by a Power Cord Fault Circuit (PCFC). In addition to shield breaks the PCFC also monitors the energized shields for shield degradation due to, for example, galvanic corrosion.