A contact monitoring device for monitoring an electrical contact having a first contact state and a second contact state includes: an oscillator circuit for generating an excitation signal; a coupler including a signal input and a signal output, the oscillator circuit being connected upstream of the signal input in order to apply the excitation signal to the coupler, the coupler converting the excitation signal into a contact monitoring signal and outputting the contact monitoring signal at the signal output in order to act on the electrical contact; and a detector for detecting a version of the excitation signal in order to monitor the electrical contact. A first impedance value is set with the electrical contact in the first contact state on the oscillator circuit, and a second impedance value is set with the electrical contact in the second contact state on the oscillator circuit.

A method for monitoring a circuit breaker includes measuring at least two operating condition related parameters of the circuit breaker during operation of the circuit breaker; obtaining first data representing a vector having at least two components respectively representing the at least two measurements of the at least two parameters; judging location of the vector represented by the obtained data with respect to a vector space having an envelope separating healthy and unhealthy status of the circuit breaker, where the envelope has at least one portion of curvature; and generating a signal indicating the health status of the circuit breaker in consideration of the location of the vector if it is outside of the envelope.

A detection system for detecting an electrical discharge in an electrical apparatus includes a first sensing device that senses an acoustic wave and an electromagnetic wave and generates a first combined signal. A signal processing device processes the first combined signal and determines the occurrence and properties of an electrical discharge.

A method for performing a low energy pulse testing in a power distribution network that causes contacts to close and then open in about one fundamental frequency cycle of current flow time and close on a voltage waveform that produces symmetrical fault current. The method includes energizing a magnetic actuator to move the actuator against the bias of a spring to move a movable contact towards a fixed contact. The method also includes de-energizing the actuator when the movable contact makes contact with the fixed contact so as to allow the spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts is about one fundamental frequency cycle of the current, where energizing the magnetic actuator occurs when an applied voltage on the switch assembly is at a peak of the voltage wave so that the current is symmetric.

Systems and methods for testing a protection relay, such as a primary bus protection relay, may include a testing device for providing current signals imitating current on both sides of a bus to the primary bus protection relay. The signals may be provided using signals corresponding with a signal format from merging units or other monitoring devices. The testing device may be configured to receive communications from the primary bus protection relay for evaluation of the operation of the primary bus protection relay.

A method for performing a low energy pulse testing in a power distribution network that causes contacts to close and then open in about one fundamental frequency cycle of current flow time and close on a voltage waveform that produces symmetrical fault current. The method includes energizing a magnetic actuator to move the actuator against the bias of a spring to move a movable contact towards a fixed contact. The method also includes de-energizing the actuator when the movable contact makes contact with the fixed contact so as to allow the spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts is about one fundamental frequency cycle of the current, where energizing the magnetic actuator occurs when an applied voltage on the switch assembly is at a peak of the voltage wave so that the current is symmetric.

Systems and methods for testing a protection relay, such as a primary bus protection relay, may include a testing device for providing current signals imitating current on both sides of a bus to the primary bus protection relay. The signals may be provided using signals corresponding with a signal format from merging units or other monitoring devices. The testing device may be configured to receive communications from the primary bus protection relay for evaluation of the operation of the primary bus protection relay.

An apparatus having a conducting probe configured to couple with an electrical conductor of an electrical terminal. The apparatus has a sensor in contact with the conducting probe. The apparatus has a controller electrically coupled to the sensor, where the controller is configured to monitor the sensor values, and when the sensor values comply with a monitoring rule associated with a hazardous condition, the controller is configured to initiate an action to mitigate the hazardous condition.

Circuits and methods for testing power electronics devices. In some examples, a reconfigurable load tester includes a power conversion circuit configured to couple to a device under test (DUT). The power conversion circuit includes a number of arms, and each arm includes submodules. Each submodule includes one or more electronically-controlled switches. The reconfigurable load tester includes a controller configured for controlling the electronically-controlled switches of the submodules. The controller is configured for emulating, by controlling the electronically-controlled switches of the submodules, a plurality of electrical load levels/types on the DUT.

A method for monitoring a circuit breaker, a system and an internet of things using the same are disclosed. The method includes measuring at least two operating condition related parameters of the circuit breaker during operation of the circuit breaker; obtaining first data representing a vector having at least two components respectively representing the at least two measurements of the at least two parameters; judging location of the vector represented by the obtained data with respect to a vector space having an envelope separating healthy and unhealthy status of the circuit breaker, where the envelope has at least one portion of curvature; and generating a signal indicating the health status of the circuit breaker in consideration of the location of the vector if it is outside of the envelope.