A circuit for alternating current and direct current leakage detection. The circuit can achieve multiple functions such as direct current leakage detection, alternating current leakage detection, and leakage sampling link self-check. The circuit mainly comprises: an LDO module for converting an externally input power supply voltage into a voltage required for leakage detection; a frequency divider module for performing frequency division on a high-frequency clock signal; a logic control module for driving an MOS transistor and controlling the switching of different working modes; an MOS transistor driving module for driving an external leakage detection coil; a leakage detection coil for inducing alternating current and direct current leakage signals and a leakage self-check signal; a sampling resistor for converting the current signal flowing through the leakage detection coil into a voltage signal; a PGA module for amplifying a sampling signal; a gain control module for controlling a PGA amplification factor; an ADC module for performing digital-to-analog conversion of the signals; a DSP module for processing the alternating current and direct current leakage signals and the leakage self-check signal; and a current limiting module for limiting a loop current.

The invention relates to a method and a device for detecting fault currents in a regulated DC intermediate circuit having an active power factor correction.

A DC-component-based fault classification apparatus and method for a three-phase power distribution cable utilizes the reconstructed three-phase currents by measuring the magnetic field around the cable with an array of magnetic sensors arranged around the cable surface. A magnetic shield houses the magnetic sensors and blocks background magnetic fields. A data acquisition system acquires analog signals from the sensors and a processing system extracts DC components in the analog signals for the phases during the transient period after a fault. The potential DC components are extracted by mathematical morphology. These DC components arise in the faulted phases when a fault occurs since there is a large current change in the inductive power network.

The invention relates to a charging station for charging an electric energy storage means of an electric vehicle using alternating charging current, having a fault-current protective device and having a charging controller.

In a first embodiment, the fundamental idea is based on carrying out the fault-current protective device modularly. For this purpose, the modular fault-current protective device is divided into its functional units, a differential-current monitoring unit forming an integral structural unit in the form of a charging-current controller and monitoring device in conjunction with the charging controller according to the invention.

In an alternative embodiment, the fault-current protective device forms an integral structural unit in the form of a charging-current controller and protective device in conjunction with charging controller.

A residual current circuit breaker has a summation current transformer that has primary windings as well as a secondary and a tertiary winding, the secondary winding forming a circuit with an electronic trigger unit that is independent of the network voltage, and the tertiary winding forming a circuit with an electronic trigger unit that is dependent on the network voltage. The residual current circuit breaker may have an electronic control unit designed to actuate a switch upon predefinable actuation by the network voltage-dependent electronic trigger unit, and the switch, when in the actuated state, may interrupt contact of the secondary winding with the network voltage-independent electronic trigger unit and establishes contact of the tertiary winding with the network voltage-dependent electronic trigger unit.

Methods and systems for ensuring operation of one or more circuit breakers electrically connected on a phase of a multi-phase power line on a transformer electrically connected within a power grid at a substation are disclosed. The method includes detecting, at the transformer, a direct current component of a multi-phase power signal received at the transformer, the direct current component comprising a direct current received at a transformer neutral, the transformer neutral being electrically connected to a ground. The method further includes determining whether the direct current is above a predetermined threshold, the predetermined threshold being based on a determination that, above the predetermined threshold, at least one of the one or more circuit breakers is incapable of reliable operation. The method includes, in response to a determination that the direct current component is above the predetermined threshold, blocking the direct current between the transformer neutral and a ground.

A magnetic core is electromagnetically coupled to two conductors that allow an AC current to flow through. An exciter is configured to supply a winding with an excitation current that is an alternating current. A current detector is configured to detect a current flowing through the winding. A DC component detector is configured to detect a DC component level from the current detected with the current detector. Two contact elements are respectively disposed along the two conductors. A discrimination controller is configured to: turn the two contact elements on when the DC component level detected with the DC component detector is less than or equal to a threshold; turn the two contact elements off when the DC component level detected with the DC component detector is greater than the threshold; and turn the two contact elements off in de-energized condition.

A photovoltaic power generation system includes an inverter, a controller, and at least two direct current branch circuits. The leakage current detection apparatus is configured to: detect a leakage current of the direct current branch circuit on which the leakage current detection apparatus is located and send the leakage current to the controller. The controller is further configured to: when the photovoltaic power generation system runs and a value of a leakage current of the direct current branch circuit exceeds a preset range, determine that an insulation fault occurs on the direct current branch circuit. The system can determine the direct current branch circuit on which the insulation fault occurs in the photovoltaic power generation system, so that measures are taken in time for the direct current branch circuit on which the insulation fault occurs, to eliminate a potential safety hazard.

Control circuit includes a current sensor that is configured to detect alternating current transmitted through a power line. The alternating current includes an alternating current (AC) component and a direct current DC offset component. The control circuit also includes a filter sub-circuit that is configured to receive a sensor output from the current sensor that is representative of the AC component and the DC component. The AC component has a frequency higher than a frequency of the DC component. The filter sub-circuit is configured generate a DC output that is based on the DC component. The control circuit also includes an analysis sub-circuit that is configured to receive the DC output and determine that the DC output has passed a designated threshold. The analysis sub-circuit is configured to trip a relay or output a signal when the DC output passes the designated threshold.

A method is for checking the adequacy of the residual currents passing through a differential circuit breaker disposed at the head of an electrical installation. The method includes acquiring over a total acquisition duration, at a determined sampling frequency, residual current samples during successive acquisition periods; frequency-analyzing by FFT these residual current samples in predetermined frequency bands; determining for each frequency band and for each of the successive acquisition periods, a maximum effective current and, at the end of the total acquisition duration, recording the maximum value of the maximum effective currents; and disqualifying or not the differential circuit breaker depending on whether or not this maximum value of the maximum effective currents meets a predetermined compatibility condition and displaying this disqualification or non-disqualification in binary mode by a pictogram on the leakage current measuring clamp.