An arc fault detection system senses current flow in a power source branch and in one or more load branches in an electrical system. Over a frequency range divided into a predetermined number of frequency bins, a controller records and tallies the branch having largest magnitude of power spectral density for each frequency bin. The branch having highest total tally is determined to be the branch in which the arc fault occurred and can then safely be isolated from the electrical system.

According to one embodiment, an insulation diagnostic system comprising: a peak-value acquisition circuit configured to acquire at least one peak value of a section corresponding to local discharge of a voltage signal acquired by at least one sensor that detects the voltage signal in a non-contact manner; a function acquisition circuit configured to acquire a calculation function for calculating charge amount related to the discharge based on at least two peak values acquired from the voltage signal that is detected by the sensor by applying a test voltage to a rotating electrical machine while the rotating electrical machine is stopped; and a charge-amount calculation circuit configured to calculate the charge amount related to partial discharge of the rotating electrical machine based on the calculation function and the peak value obtained from the voltage signal that is detected by the sensor during operation of the rotating electrical machine.

Provided are an insulation detection method and apparatus for a fuel cell vehicle, and a vehicle. The method comprises: determining whether a vehicle is started; when the vehicle is started, executing the following steps: controlling a battery management system to perform the first insulation detection; detecting whether a fuel cell is started; and when the fuel cell is not started, controlling a fuel cell control unit to perform second insulation detection, wherein an insulation detection module for performing insulation detection on the fuel cell is provided in the fuel cell control unit of the vehicle.

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.

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.

An earth fault detection apparatus includes a switch group configured to switch between a first measurement path including a battery and a capacitor, and a second and third measurement paths including the battery, a positive/negative-side insulation resistance, and the capacitor; a reference resistance and a test switch; and a control unit calculating a first reference value based on each charging voltage in a case where the test switch is opened and the capacitor is charged, and calculating the insulation resistance with reference to a conversion map created to correspond to an electrostatic capacitance between a power supply line and ground, wherein the control unit calculates a second reference value based on each charging voltage in a case where the test switch is closed and the capacitor is charged for a shorter time, and estimates the electrostatic capacitance with reference to a predetermined test conversion map.

The present description concerns a circuit (5) for monitoring the operation of a component (1) associated with equipment (3), comprising: at least one device (100) for measuring one or a plurality of physical quantities associated with the operation of the component; and a circuit for calculating a value representative of a remaining lifetime of a component, said monitoring circuit (5) being linked to the equipment.

In one example, an arc fault circuit interrupter (AFCI) is provided. The AFCI may include a plurality of current arc signature detection blocks configured to output a plurality of corresponding current arc signatures, and a processor. The processor may be configured to receive each of the plurality of current arc signature from each of plurality of current arc signature detection blocks, respectively, and generate a first trigger signal. The processor may be further configured to assess each of the current arc signatures, determine whether an arc fault exists based on the assessment, and generate the first trigger signal if an arc fault is determined to exist. A method for detecting an arc fault is also provided.

An arrangement for detecting arcs in a low-voltage circuit has at least one voltage sensor for periodically determining voltage values of the low-voltage circuit and at least one current sensor for periodically determining current values of the low-voltage circuit. A first control unit is connected to the voltage sensor and the current sensor, has a processor, and is configured in such a way that the presence of a switch arc is determined on the basis of the determined voltage values and current values. A switch arc detection signal is output if a switch arc is determined to be present.

A system for evaluating a high voltage asset (HV asset) comprises a PD detector disposed in the HV asset. The PD detector comprises an electrical coupler configured to couple electrical disturbances indicative of a partial discharge from a high voltage conductor of the HV asset to an electrical-to-optical converter. The electrical-to-optical converter comprises a light emitter, and is configured to convert the electrical disturbances to a light signal. An optical power receiver is disposed in the high voltage asset and coupled to the PD detector. The optical power receiver is configured to receive optical power from an external optical power source via a non-conducting optical fiber arrangement. The electrical-to-optical converter is configured to communicate the light signal indicative of the partial discharge to an electronic device external of high voltage asset via the non-conducting optical fiber arrangement.