A method for monitoring the electric insulation status of a piece of equipment for a medium-voltage or high-voltage electric system, which includes the following steps: acquiring detection data indicative of the behaviour of said piece of equipment, said detection data including a time sequence of measured discharge values related to partial-discharge events observed at subsequent observation instants in time; basing on said detection data, calculating stochastic data indicative of the electric insulation status of said piece of equipment, said stochastic data including probability values related to the observed partial-discharge events and calculated as a function of one or more characteristic parameters related to said partial-discharge events; basing on said stochastic data, calculating estimated data indicative of said one or more characteristic parameters related to said subsequent observation instants.

The present disclosure includes: a signal generation unit for applying a pulse signal to an electric line; a signal measurement unit for measuring the voltage of an applied pulse signal from the ground, when the pulse signal is applied to the ground through insulation resistance; an average voltage calculation unit for calculating the average voltage of the voltages measured during a period depending on sampling intervals; and a control unit for calculating the sampling intervals on the basis of an initial sampling interval and a preset time multiple, calculating the average voltage during the sampling period according to the calculated sampling intervals, and, according to whether the difference between a calculated first average voltage and a second average voltage measured before the first average voltage is within a first error range, detecting the first average voltage as a normal voltage, or calculating the sampling intervals by applying different time multiples thereto.

A fault monitoring device may monitor and detect for faults corresponding to a high-side voltage rail, to low-side voltage rail, or internally within a voltage source connected to the high-side voltage rail and the low-side voltage rail. The fault monitoring device may determine sample voltage levels and/or sample resistance values to detect the faults. Also, in various embodiments, the fault monitoring device may perform one or more fault monitoring processes over multiple stages. The fault monitoring device may determine the sample voltage levels and/or the sample resistance values while switching a secondary resistance circuit in different states over the multiple stages.

A fault monitoring device may monitor and detect for faults corresponding to a high-side voltage rail, to low-side voltage rail, or internally within a voltage source connected to the high-side voltage rail and the low-side voltage rail. The fault monitoring device may determine sample voltage levels and/or sample resistance values to detect the faults. Also, in various embodiments, the fault monitoring device may perform one or more fault monitoring processes over multiple stages. The fault monitoring device may determine the sample voltage levels and/or the sample resistance values while switching a secondary resistance circuit in different states over the multiple stages.

Methods and apparatus for detecting and characterizing arc faults in an aerospace electric propulsion system and then coordinating the operation of various elements of the protection system to execute a fault-clearing sequence. In a current-based method, the arc is detected and characterized based on differential readouts from current sensors. The difference between currents measured at two ends of a protection zone are compared to a difference threshold. In a power-based method, the arc is detected and characterized based on differential readouts from voltage and current sensors. The differential voltage and current readouts are used to compute the respective powers at two ends of a protection zone. The difference between the respective powers is integrated over a period of time and then the integrated difference is compared to a difference threshold. A differential protection trip mode is invoked when the difference threshold is exceeded.

A fault-arc identification method, device and apparatus, and a storage medium. The method comprises: performing sampling on a target arc at a high frequency, and obtaining a high-frequency sampling signal (S11); preprocessing the high-frequency sampling signal, and obtaining a processed sampling signal (S12); performing feature extraction on the processed sampling signal, and obtaining a target arc feature (S13); and inputting the target arc feature to a neural network model, obtaining a target output result, and determining, according to the target output result, whether the target arc is a fault-arc (S14). Performing sampling on a target arc at a high frequency can obtain more arc features from the target arc. Moreover, since a neural network model has favorable data classification capability, using a neural network model to perform determination with respect to the target arc can improve the accuracy and reliability of a fault-arc detection result.

A method for evaluating partial discharge signals. Partial discharge signals are captured, at only one point or at a plurality of points, near insulation of the electrical outer conductors of a multi-phase alternating current. The multi-phase alternating current, flowing in respective outer conductors, has fixed phase shifts relative to each other. Partial discharge signals are superposed on each other. At least one characteristic variable of the partial discharge signals is defined. Each partial discharge signal is assigned a phase position. A characteristic variable value of each characteristic variable is determined. Each partial discharge signal is assigned a number tuple from each characteristic variable value of the partial discharge signal and from the phase position. Clusters of the partial discharge signals in a multi-dimensional space with points formed by the number tuples are determined. A partial discharge activity is determined for each outer conductor from the determined clusters.

An electric power conversion device has a function of detecting, at low cost and at an early stage, a sign of insulation failure of a transformer or a rotational machine. This electric power conversion device is provided with an inverter circuit and a PWM signal generation unit that makes a comparison between a carrier signal and a voltage command value and generates a PWM signal for driving the inverter circuit. The electric power conversion device feeds and receives electric power through connection to a transformer or a rotational machine provided with a winding wire. The electric power conversion device is provided with: a current sensor that detects a current to be fed to or received from the transformer or the rotational machine; and a diagnostic unit that diagnoses insulation degradation of the transformer or the rotational machine.

A controller (1) forms an insulation measurement path and turns on a third switch connected in parallel to a capacitor, (2) after a lapse of a first time period turns off the third switch, and (3) detects an insulation abnormality based on a voltage of the capacitor measured after a lapse of a second time period after the turning off of the third switch.

A method of connecting electrical substation wiring in an electrical substation provides pre-bundled yard cables configured to connect between field devices in the substation and a yard interface connection cabinet. The yard interface connection cabinet has an outside plug bulkhead plate that is accessible from outside of a control house that houses the yard interface connection cabinet. The outside plug bulkhead plate has a plurality of connectors configured to mate with the yard cables. The yard interface connection cabinet further has internal wires extending from an inside plug bulkhead plate and terminating at a terminal block. The connections and wires in the yard interface connection cabinet are tested with the yard cables before installation of the yard interface connection cabinet and yard cables in the substation. The yard cables are connected between the field devices and the outside plug bulkhead plate from outside of the control house.