The present disclosure discloses a self-check chip of a leakage protector. The self-check chip includes a power-on reset circuit, used for resetting the self-check chip after being powered-on; a reference voltage module, used for providing a reference voltage for a comparator module; a bias circuit, used for providing direct-current bias for the reference voltage module, the comparator module and a ring oscillator; the comparator module, used for monitoring an open-circuit condition of a trip coil and the change of a thyristor anode voltage and generating a power frequency clock; the ring oscillator, used for providing a clock for a counting module and a digital processing module; the counting module, used for generating a self-check signal, a leakage trigger signal, a PHASE pin detection signal and a reset signal of the counting module and the digital processing module; a trip enabling signal generation module; and the digital processing module.

A detector is provided that generates a leakage signal corresponding to a current imbalance between a line conductor and a neutral conductor for a load, and selectively injects a test signal into the neutral conductor. A frequency of the test signal substantially corresponds to a utility frequency. The detector measures a first value of the leakage signal, determines if the first value is less than first threshold value, and begins injection of the test signal into the neutral conductor in response to determining that the that first value is less than the first threshold value. In response to injecting the test signal, the detector measures a second value of the signal, determines if the second value is greater than a second threshold value, and disconnects the line conductor from the load in response to determining that the second value is greater than the second threshold value.

A ground fault circuit interrupter is provided, including a main control chip, a tripping unit and a self-test detection unit, wherein the tripping unit is connected with the self-test detection unit at a detection point and coupled with a load circuit; the self-test detection unit is coupled with the main control chip, and configured to detect a signal at the detection point and output the signal to the main control chip; the main control chip is coupled with the self-test detection unit, and configured to in a self-test state, simulate a circuit fault, perform self-test, and determine whether the circuit fault could be detected and an alarm signal response to the circuit fault is generated, based on the signal. A self-test function and alarm function response to a circuit fault in a ground fault circuit interrupter can be tested during a final test of production.

An arc detection device includes: a current detector that includes a magnetic core penetrated by first and second paths and each connecting a DC power source and a device, and detects a current flowing through each of the first and second paths and in accordance with a magnetic field generated at the magnetic core; a low impedance circuit having a lower impedance than the DC power source and the device, the low impedance circuit being connected to the first path and the second path to cause a high frequency component to bypass one of the first path or the second path; and an arc determiner that determines an occurrence of an arc based on a current detected by the current detector. In the magnetic core, a direct current flows through the first path in a direction opposite to a direction in which a direct current flows through the second path.

A circuit interrupting device including a fault detection circuit and an auto-monitoring circuit. The fault detection circuit is configured to output a pre-trigger signal, wherein the pre-trigger signal is configured to not place the circuit interrupting device in a tripped condition. The auto-monitoring circuit is configured to monitor an auto-monitoring input signal, wherein the value of the auto-monitoring signal is at least partially determined by a value of a pre-trigger signal generated.

A method for processing a direct current electric arc and an apparatus, includes: obtaining a first current which is a direct current input current of a direct current cable of a photovoltaic cell system; obtaining a second current, where the second current is a direct current common mode current of a direct current cable or an alternating current common mode current of an alternating current cable; calculating a correlation coefficient between a frequency domain component of the first current and a frequency domain component of the second current; and when determining that the first current meets an electric arc occurrence condition and the correlation coefficient is greater than or equal to a preset coefficient threshold, skipping sending a direct current electric arc fault alarm. The correlation coefficient is used to reflect a proportion of common mode noise generated by the second current, and the preset coefficient threshold is set.

A method for processing a direct current electric arc and an apparatus, includes: obtaining a first current which is a direct current input current of a direct current cable of a photovoltaic cell system; obtaining a second current, where the second current is a direct current common mode current of a direct current cable or an alternating current common mode current of an alternating current cable; calculating a correlation coefficient between a frequency domain component of the first current and a frequency domain component of the second current; and when determining that the first current meets an electric arc occurrence condition and the correlation coefficient is greater than or equal to a preset coefficient threshold, skipping sending a direct current electric arc fault alarm. The correlation coefficient is used to reflect a proportion of common mode noise generated by the second current, and the preset coefficient threshold is set.

A leakage current protection device with an illumination function, including a shell, a movement assembly in the shell, power input and output assemblies coupled to the movement assembly, and an illumination assembly disposed inside the shell, which includes: an illumination control board electrically coupled to the power input or output assembly; a sensing unit coupled to the illumination control board and configured to sense an ambient condition outside the shell to generate a sensing output signal; a light emitting unit coupled to the control board, and controlled by the control board to turn on or off in response to the sensing output signal; and a light guide unit, formed by an operating element partially protruding out of the shell and disposed adjacent the light emitting unit, configured to guide the illumination light emitted by the light emitting unit out of the shell. The device is convenient to use and compact.

A fault protection arrangement may include a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, coupled to the neutral grounding resistor, where the neutral grounding resistance monitor assembly includes a sense circuit, coupled to the ground end of the neutral grounding resistor; and an injection signal generator, arranged to generate a frequency of 240 Hz or greater.

A device, system, and method is disclosed for improving safety of a power system. For example, a differential current may be detected using at least one sensor by temporarily enabling sampling of current flowing through one or more conductors. Additionally, current flow may be temporarily altered in order to sample current in a system. The measurements may be handled locally and/or remotely and appropriate actions may be taken to enhance the overall safety of the system.