An apparatus for testing insulated high voltage devices includes a first ground plane connected to a reference voltage potential having a first plurality of resiliently compressible conductive fibers extending therefrom and a second ground plane connected to the reference voltage potential having a second plurality of resiliently compressible conductive fibers extending therefrom. The first and second ground planes are arranged to receive an insulated high voltage device under test connected to a voltage potential greater or less than the reference voltage potential between them and configured such that at least a portion of the first and second pluralities of resiliently compressible conductive fibers are in compressive contact with the insulated high voltage device under test. A method of testing insulated high voltage devices is also presented herein.

A ground fault detection device includes: a detection capacitor; a switch group for switching between a first charging path connecting the battery and the detection capacitor, a second charging path connecting the battery, a negative side insulation resistance and the detection capacitor, a third charging path connecting the battery, a positive side insulation resistance and the detection capacitor, and a measurement path for measuring a charging voltage of the detection capacitor; and a controller configured to calculate the insulation resistance based on a charging voltage measured value of the detection capacitor which exists after charging each of the charging paths, wherein after measurement of the charging voltage of the second charging path, the controller is configured to cause the switch group to switch to the third charging path before switching to the first charging path.

A ground fault detection device includes: a detection capacitor; a switch group for switching between a first charging path connecting the battery and the detection capacitor, a second charging path connecting the battery, a negative side insulation resistance and the detection capacitor, a third charging path connecting the battery, a positive side insulation resistance and the detection capacitor, and a measurement path for measuring a charging voltage of the detection capacitor; and a controller configured to calculate the insulation resistance based on a charging voltage measured value of the detection capacitor which exists after charging each of the charging paths, wherein after measurement of the charging voltage of the second charging path, the controller is configured to cause the switch group to switch to the third charging path before switching to the first charging path.

An apparatus is disclosed to identify defects in a cable plant including a cable comprises a carriage and a roller attached to the carriage. The roller is configured to sit on a cable plant. A motor is attached to the carriage and is coupled to the roller to cause rotation of the roller in at least a first direction, to cause movement of the carriage across the cable plant. A transmitter is attached to the carriage and an antenna is coupled to the transmitter. The antenna is configured to emit an RF signal under the control of the transmitter. If there is a defect in the cable, the RF signal may enter the cable through a defect. Detection of the RF signal in the cable is indicative of the presence of a defect in the cable and the location of the defect. Methods and systems are also disclosed.

An apparatus for diagnosing an insulation condition between a battery pack and the ground includes a first resistor element electrically connected between a positive terminal of the battery pack and the ground, and a control circuit. The control circuit records a current flowing through the first test port as a first test current, while a high-level voltage is being applied between the positive terminal and the ground. The controller diagnoses the insulation condition between the battery pack and the ground, based on the first test current.

An inspection tool and associated methods for testing physical and electrical properties of a perforating gun and sending the perforating gun to a wellbore site with at least one of an electrical property and a dimension that has been previously verified. The perforating gun may be received in a perforating gun holder positioned between a first connecting portion and second connecting portion. The first connecting portion may be moved from a first position to a second position at which the at least one of the electrical property and the dimension is measured. Upon verification that the at least one of the electrical property and the dimension is within a predetermined specification, the perforating gun may be sent to the wellbore site.

A method for reducing and/or managing energy-related stress in an electrical system includes processing electrical measurement data from or derived from energy-related signals captured by at least one intelligent electronic device (IED) in the electrical system to identify and track at least one energy-related transient in the electrical system. An impact of the at least one energy-related transient on equipment in the electrical system is quantified, and one or more transient-related alarms are generated in response to the impact of the at least one energy-related transient being near, within or above a predetermined range of the stress tolerance of the equipment. The transient-related alarms are prioritized based in part on at least one of the stress tolerance of the equipment, the stress associated with one or more transient events, and accumulated energy-related stress on the equipment. One or more actions are taken in the electrical system in response to the transient-related alarms to reduce energy-related stress on the equipment in the electrical system.

A method for reducing and/or managing energy-related stress in an electrical system includes processing electrical measurement data from or derived from energy-related signals captured by at least one intelligent electronic device (IED) in the electrical system to identify and track at least one energy-related transient in the electrical system. An impact of the at least one energy-related transient on equipment in the electrical system is quantified, and one or more transient-related alarms are generated in response to the impact of the at least one energy-related transient being near, within or above a predetermined range of the stress tolerance of the equipment. The transient-related alarms are prioritized based in part on at least one of the stress tolerance of the equipment, the stress associated with one or more transient events, and accumulated energy-related stress on the equipment. One or more actions are taken in the electrical system in response to the transient-related alarms to reduce energy-related stress on the equipment in the electrical system.

An inverter system includes a converter, an inverter, a first switch SW1 that connects between the converter and an AC power source, a capacitor that smooths a DC power in a DC bus, a resistor Rr connected from a positive voltage side of the DC bus to ground, a second switch SW2 that connects between the resistor Rr and ground, and a controller that controls drive of the inverter system. The controller is configured to: after charging the capacitor, while the first switch SW1 is in an OFF state, turn on the second switch SW2 and obtain a first across voltage E.sub.R1 of the resistor Rx; turn on an element, among semiconductor elements of the inverter, that is connected to the negative voltage side of the DC bus, and then obtain a second across voltage E.sub.R2 of the resistor Rx; and inspect insulation resistance of a motor based on the across voltages E.sub.R1, E.sub.R2.

With a method and a device for detecting a partial discharge at a winding of an electrical machine, electromagnetic first measuring signals are detected in a partial discharge frequency range and electromagnetic second measuring signals are detected in an interference frequency range. A time window around a first measuring signal is predefined, and an identification criterion is defined for a partial discharge signal and an interference signal criterion is defined for a second measuring signal. A determination is made as to a partial discharge when a first measuring signal is detected that meets the identification criterion and when, in the time window around the first measuring signal, no second measuring signal that meets the interference signal criterion is detected. A quality of the detected partial discharge is assessed based on a characteristic value of the second measuring signal.