A system includes a dry contact with a first pair of switchable electrodes, a wet contact with a second pair of switchable electrodes, an arc suppressor, and a controller circuit operatively coupled to the arc suppressor and the first and second pairs of switchable electrodes. The controller circuit is configured to detect a failure of the wet contact and determine a stick duration associated with the first pair of switchable electrodes. The stick duration is based on a duration between an instance when a coil of the dry contact is deactivated and an instance of separation of the first pair of switchable electrodes during deactivation of the coil. The controller circuit generates, in-situ and in real-time, health assessment for the first pair of switchable electrodes based on a comparison of the determined stick duration with an average stick duration associated with a window of observation.

According to an aspect of this disclosure, an intrinsically safe circuit includes a voltage source, a Zener diode, a transistor, a switching element, one or more resistors, and a current limiting stage. According to this aspect, the intrinsically safe circuit may be configured such that an over-voltage threshold is determined by a voltage across the Zener diode, a base-emitter voltage of the transistor, and a voltage across the one or more resistors.

A power distribution monitoring system (100) is provided that can include a number of features. The system can include a plurality of monitoring devices configured to attach to conductor(s) on a power grid distribution network. In some embodiments, a monitoring device is disposed on each conductor of a three-phase network and utilizes a complex platform of software and hardware to detect faults and disturbances that can be analyzed to determine or predict the risk of wildfires.

The present disclosure provides an electrostatic discharge (ESD) protection circuit for a chip, including: a monitoring unit, configured to generate a trigger signal when there is an ESD pulse on a power supply pad; a plurality of controllable drive units, connected to the monitoring unit, and each of the controllable drive units being configured to switch an operating state under a control of a control signal, wherein the operating state includes an output state, and the output state refers to generating a drive signal according to the trigger signal; and a discharge transistor, connected to the plurality of controllable drive units, and configured to be turned on under a drive of the drive signal so as to discharge an electrostatic charge to the ground pad.

A negative sequence voltage (NSV) protection system is provided that can be added to existing equipment or included as a standalone device for detecting GFOV in electrical configurations connecting distributed energy resources to utility grids. The NSV protection system can be implemented at the low side of a distribution transformer of a typical distribution circuit or in a control system of inverter-based energy resources connected to a distribution feeder. The NSV protection system includes a passive monitoring system that outputs a trip signal when a potential GFOV is detected to occur. The trip signal can then be relayed to open the circuit breakers of a distribution circuit or to cause an inverter-based energy resource to trip offline.

A semiconductor device includes a switching element, a control circuit, and a first and second temperature detectors. The control circuit controls the switching element and have an overcurrent detection circuit for the switching element. The first temperature detector detects the temperature of the switching element and the second temperature detector detects the temperature of the control circuit. The control circuit includes a reference correction circuit for correcting an overcurrent reference value of the overcurrent detection circuit on the basis of a first detection value and a second detection value detected by the first and second temperature detectors and outputting a corrected overcurrent reference value.

A safety switching device for fail-safely disconnecting an electrical load has an input part for receiving a safety-relevant input signal, a logic part for processing the at least one safety-relevant input signal, and an output part. The output part has a relay coil and four relay contacts. The first and second relay contacts are arranged electrically in series with one another. The third and fourth relay contacts are also arranged electrically in series with one another. The first and the third relay contacts are mechanically coupled to each other and form a first group of positively driven relay contacts. The second and the fourth relay contacts are mechanically coupled to each other and form a second group of positively driven relay contacts. The logic part redundantly controls the first and the second groups of positively driven relay contacts to selectively allow, or to interrupt in a fail-safe manner, a current flow to the electrical load, depending on the safety-relevant input signal. The relay coil is electromagnetically coupled to the first and second groups of positively driven relay contacts so that the logic part can control the relay contacts together via a single relay coil.

Provided is an apparatus and method for protecting against unsafe electric current conditions. A protections circuit may be used in a device, as an electric grill, that has one or more electric loads, such as heating elements. The protection circuit may protect against various failure scenarios, including, without limitation, instances of ground fault, over current, driver failure, and failure of a microprocessor. In response to a failure, the protection circuit may trip a latch relay or disable a triac driver to stop current from flowing.

The invention relates to a method for ascertaining an earth fault and the earth-fault direction in a three-phase network which is operated in a compensated manner or in an insulated manner. Value pairs of a zero voltage and a zero current are measured, the active or reactive energy is calculated, and a voltage flag and a current flag are combined by a Boolean link, wherein the presence of a earth fault is ascertained depending on the result, and a decision is made as to whether the earth-fault direction is signalled as “forward” or “reverse” at least on the basis of the sign of the active or reactive energy.

Provided herein is a power distribution system comprising a main power bus, sub-buses coupled to the main power bus, and a controller. The sub-buses provide power to electrical components of a vehicle. Each of the sub-buses includes an electrically programmable fuse in series with a relay. The controller is configured to detect a fault in a sub-bus of the sub-buses, determine a fault type associated with the fault, and in response to determining the fault type, generate a command to cause the relay to change a relay state.