A method for leakage current compensation in a photovoltaic system includes determining a reference current flowing from at least one current-carrying line under voltage via a capacitor to earth, and generating a compensation current, having a phase and a frequency of the reference current, and having an amplitude adjusted by a negative scaling factor based on the reference current. The method further includes determining a current sum using a differential current sensor for at least a portion thereof, wherein the addends of the current sum are the currents through a complete set of current-carrying lines and the compensation current, minimizing the determined current sum by adjusting the scaling factor, and routing the compensation current through at least one other differential current sensor, such that the compensation current compensates a leakage current component of a differential current monitored by the other differential current sensor. A related device and system is also disclosed.

A mining machine including a motor, an adjustable speed drive providing a voltage to the motor, the voltage having an excitation component comprising a magnitude and a frequency for operating the motor at a desired speed and including an additional voltage component for use in detecting a ground fault condition, and a ground fault relay for detecting a ground fault current when the ground fault current exceeds a predetermined threshold.

A mining machine including a motor, an adjustable speed drive providing a voltage to the motor, the voltage having an excitation component comprising a magnitude and a frequency for operating the motor at a desired speed and including an additional voltage component for use in detecting a ground fault condition, and a ground fault relay for detecting a ground fault current when the ground fault current exceeds a predetermined threshold.

A main electrical cabling is subject to variations in ambient temperature over its length. A detection system for detecting a fault in the main electrical cabling able to cause a serial arc, or heating within a connection, includes a monitor electrical cabling placed alongside the main electrical cabling and a controllable current generator injecting, at the input of the monitor electrical cable, a current proportional to the current flowing through the main electrical cabling. The main and monitor sets of electrical cabling being joined at the output, an electronic circuitry measures the difference between the electrical potential at the input of the main electrical cabling and that at the input of the monitor electrical cabling and detects a fault in the main electrical cabling when the difference of the electrical potentials exceeds a predefined threshold. A fault in the main electrical cabling is detected despite the variations in temperature.

In electrical fault detection device that is mounted on a vehicle and includes: energy storage unit to be mounted in a state of being insulated from a chassis ground of the vehicle; first switch inserted into positive wire; and second switch inserted into negative wire, in order to suppress a total cost by not using an expensive component while securing detection accuracy, electrical fault detection device further includes coupling capacitor, AC output unit, first voltage measurement unit, first determination unit, voltage dividing circuit, second voltage measurement unit, and second determination unit. Voltage dividing circuit is connected between positive wire between first switch and one end of load and negative wire between second switch and the other end of load.

In first coupling capacitor, a first terminal is connected to a first connection point on a current path of power storage in a state of being insulated from a ground. Second coupling capacitor has a second terminal connected to a second connection point that is on a current path of power storage and is lower in potential than the first connection point, and second coupling capacitor has a first terminal connected to a second terminal of first coupling capacitor. AC output unit applies a predetermined AC voltage via impedance element to third connection point between the second terminal of first coupling capacitor and the first terminal of second coupling capacitor. Voltage measurement unit measures a voltage at third connection point. Determination unit determines the presence or absence of an electrical fault on the basis of the voltage measured by voltage measurement unit.

A ground fault detection circuit can include a band-pass filter that can have a first node and a second node that can be coupled to an earth ground. The first node can be coupled to a local ground of an automatic test equipment (ATE) system for an electrical device that can be coupled via at least one wire to the ATE. The band-pass filter can be configured to pass and amplify a test current signal established at the first node in response to a coupling of one of a conductor of the at least one wire carrying the test current signal to the local ground, and a conductive element of the electrical device carrying the test current signal to the local ground. A fault alert signal can be provided to provide an indication of ground fault based on a comparison of the amplified test current signal.

In one example, a ground fault circuit interrupter is provided. It may include a current imbalance detection circuit configured to provide a leakage signal and a main processing circuit including a processor. The leakage signal may correspond to a current imbalance between a supply path and a return path. The processor may be configured to receive the leakage signal, analyze a time pattern of the leakage signal, determine whether a ground fault exists based on analysis of the time pattern, and generate a first trigger signal if the ground fault is determined to exist. The ground fault circuit interrupter may further include a back-EMF detection circuit configured to provide a back-EMF detection signal. Methods for detecting and responding to a ground fault are also provided.

In one example, a ground fault circuit interrupter is provided. It may include a current imbalance detection circuit configured to provide a leakage signal and a main processing circuit including a processor. The leakage signal may correspond to a current imbalance between a supply path and a return path. The processor may be configured to receive the leakage signal, analyze a time pattern of the leakage signal, determine whether a ground fault exists based on analysis of the time pattern, and generate a first trigger signal if the ground fault is determined to exist. The ground fault circuit interrupter may further include a back-EMF detection circuit configured to provide a back-EMF detection signal. Methods for detecting and responding to a ground fault are also provided.

A network protector includes a resettable switching apparatus configured to electrically connect to a low-voltage feeder of a secondary distribution network; a switch control configured to control a state of the resettable switching apparatus to thereby determine whether electrical current flows through the switching apparatus; and a controller configured to: determine whether a fault condition exists; and if a fault condition does not exist, allow electrical power to flow through the resettable switching apparatus in any direction.