A bushing for gas-insulated switchgear has an electrical conductor, which has a longitudinal axis and which is embedded in an insulating material, and a coated electrode that is arranged coaxially spaced apart from the conductor and that is formed from a plurality of segments.

Test measurements on a utility power device by a switch matrix apparatus and a common voltage source as separate devices is performed. Through the switch matrix apparatus, the common voltage source selectively sends a first high voltage signal via a first lead to a first terminal of the utility power device, measures a first corresponding signal returned via a second lead of the switch matrix apparatus from a second terminal of the utility power device. While the first lead and the second lead of the switch matrix apparatus remain electrically coupled to the first and the second terminal of the utility power device, a second high voltage signal is selectively sent via the second lead to the second terminal of the utility power device, and a second corresponding signal returned from the first terminal of the utility power device via the first lead of the switch matrix apparatus is measured.

A high speed controllable load uses a voltage waveform synthesizer and a driver circuit to dynamically control an electronically variable load to generate a current though an arc fault circuit interrupter (AFCI) device under test. Sensors may be used to monitor a source voltage and the output current to generate an arbitrary waveform have a range of voltage and current phase shifts. An optical isolation circuit allows separation of grounds between a control stage and the AFCI device under test.

This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.

A system includes a circuit interruption device, such as a circuit breaker, contactor or other switch of an automatic transfer switch (ATS) or a similar device providing power to an input of an ATS, and a monitoring circuit, such as a controller of the ATS, coupled to the circuit interruption device and configured to monitor voltages at inputs and outputs of the circuit interruption device, to monitor an auxiliary contact signal associated with auxiliary contacts of the circuit interruption device, and to determine a status of the auxiliary contacts responsive to the monitored voltages and auxiliary contact signal.

A portable diagnostic apparatus for performing diagnostic testing on a circuit breaker includes a number of sensor devices structured to generate a number of sensed parameter signals relating to operation of the circuit breaker during an operational sequence, a number of auxiliary input connectors structured to receive a number of auxiliary data signals from the circuit breaker, the number of auxiliary data signals relating to and being generated in response to the operation of the circuit breaker during the operational sequence, and control and diagnostic circuitry. The control and diagnostic circuitry is structured to control operation of the portable diagnostic apparatus, receive the number of sensed parameter signals and the number of auxiliary data signals, and generate a time signature based on the number of sensed parameter signals and the number of auxiliary data signals.

A contact wear indicator assembly for a circuit breaker assembly is provided. The contact wear indicator assembly includes an interface assembly, an indicator drive assembly, and a user display assembly. The user display assembly includes an output device. The output device is structured to produce a visual indication representative of a measurable contact characteristic. The indicator drive assembly is operatively coupled to the interface assembly, whereby the indicator drive assembly moves between a first position and a second position corresponding to an interface assembly first and second position. The indicator drive assembly is measurably coupled to the user display assembly. The user display assembly is structured to convert the position data of the indicator drive assembly into a quantified output such as, but not limited to, contact characteristics. The user display assembly is further structured to display the indicator drive assembly position data on the output device.

A component monitoring system structured to monitor circuit breaker assembly operating mechanism component characteristics is provided. The component monitoring system includes a record assembly, at least one sensor assembly and a comparison assembly. The record assembly includes selected nominal data for a selected circuit breaker component. The least one sensor assembly is structured to measure a number of actual component characteristics of a selected circuit breaker component and to transmit actual component characteristic output data. The comparison assembly is structured to compare the sensor assembly actual component characteristic output data to the selected nominal data and to provide an indication of whether the sensor assembly output data is acceptable when compared to the selected nominal data. The at least one sensor assembly is in electronic communication with the comparison assembly.

A failure prediction assembly is structured to monitor circuit breaker assembly sub-assemblies and their component's characteristics. The failure prediction assembly includes a sensor supported D-shaft and a sensor assembly including a housing and a number of sensors. The sensor assembly housing defines a D-shaft passage. A control unit is in electronic communication with the sensor assembly. The sensor assembly housing is coupled to the circuit breaker sidewalls with the sensor assembly housing D-shaft passage aligned with the circuit breaker sidewall D-shaft passages. The sensor supported D-shaft is rotatably coupled to the sensor assembly with the sensor supported D-shaft disposed through said sensor assembly housing D-shaft passage.

Test measurements on a utility power device by a switch matrix apparatus and a common voltage source as separate devices is performed. Through the switch matrix apparatus, the common voltage source selectively sends a first high voltage signal via a first lead to a first terminal of the utility power device, measures a first corresponding signal returned via a second lead of the switch matrix apparatus from a second terminal of the utility power device. While the first lead and the second lead of the switch matrix apparatus remain electrically coupled to the first and the second terminal of the utility power device, a second high voltage signal is selectively sent via the second lead to the second terminal of the utility power device, and a second corresponding signal returned from the first terminal of the utility power device via the first lead of the switch matrix apparatus is measured.