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.

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 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.

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.

A cable condition monitoring sensor device includes a TMR magnetic field sensor module, a high-pass filtering module, and a signal-amplifying module which are sequentially connected. The TMR magnetic field sensor module measures a magnetic field change signal of a cable, converts the same into a voltage signal, and outputs the voltage signal to the high-pass filtering module. The high-pass filtering module filters out DC bias of the voltage signal, and transmits the filtered voltage signal to the signal-amplifying module. The signal-amplifying module amplifies the filtered voltage signal to obtain an output voltage signal and outputs the output voltage signal. In the present invention, a common mode current to be measured in the cable is extracted by placing the magnetic shielding ring made of ferromagnetic material outside the cable to filter out a differential mode load current in the cable, and the magnitude of the common mode current is determined.

The disclosure discloses a method and device for monitoring partial discharge. The monitoring method including: step a, connecting a monitoring circuit in parallel to both ends of a tested product, disposing a ground wire between the monitoring circuit and ground, disposing a first sensor in the monitoring circuit, and disposing a ground wire sensor on the ground wire; step b, applying an excitation signal to the tested product, acquiring a first signal through the first sensor and acquiring a ground wire signal through the ground wire sensor within a monitoring cycle; and step c, determining whether the tested product has partial discharge through the first signal and the ground wire signal. The disclosure can avoid the partial discharge monitoring device from wrongly determining an interference signal to be a partial discharge signal, enhance anti-interference capability of the partial discharge monitoring device, and improve monitoring accuracy.

Method for monitoring for partial discharges in an electrical installation comprising at least one electrical cubicle, the electrical cubicle comprising at least one item of medium-voltage or high-voltage electrical equipment.

Disclosed herein are methods for determining resistance in an electric circuit, including the steps of: applying a voltage pulse to a test point of said electric circuit, said voltage pulse having a predetermined pulse duration; measuring an electric observable at a response point of said electric circuit during at least a part of said pulse duration; estimating during said pulse duration an expectation value from said measured observable; and determining said resistance from said expectation value. Also disclosed herein are devices for determining resistance in an electric circuit.

A method for automatically creating installation-specific measuring profiles for an insulation monitoring system, includes: assisting in a computer-controlled manner by means of an assist system via guided instructions for acquiring installation data; and executing the instructions by means of one more sensor devices. The method further includes pre-selecting, assisting, recording, evaluating, detecting, and optimizing steps.

Techniques, systems and articles are described for monitoring electrical equipment of a power grid and predicting likelihood failure events of such electrical equipment. In one example, a sensing device is configured to couple to an electrical power cable. The sensing device includes a plurality of concentric layers and a monitoring device. The plurality of concentric layers include a first layer, second layer, and third layer. The first layer is configured to concentrically surround a central conductor of the electrical cable and includes an insulating material. The second layer includes a conducting material. The third layer includes a resistive material configured to resist electrical flow between the second layer and a ground conductor exterior to the third layer. The monitoring device includes a sensor and communication unit configured to output data indicative of the sensor data.