Methods and devices are provided for determining whether a phase is faulted or one or more phases are open in capacitor bank system. Detecting open and faulted phases may include determining a neutral current of the capacitor bank system. An open-phase event and a fault event may be distinguished based on a magnitude of a neutral current within a first or a second predetermined range. According to one embodiment, an IED may calculate an aggregate power phasor for the phases of the capacitor bank system with respect to each rotation. According to another detection method, in response to the magnitude of the neutral current being greater than a threshold value, an IED may calculate an individual power phasor for each of the phases of the capacitor bank system with respect to each rotation. Based on the angles of the power phases, the IED may determine which phases may be faulted.

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 open circuit diagnosis apparatus, and method for open circuit diagnosis, for a motor drive circuit with a Miller plateau detection unit that detects whether there is a Miller plateau region in a gate voltage applied to a switching element of a motor drive circuit when the switching element is turned on; a body diode activation detection unit which detects whether the body diode of the switching element has been activated which depends on the on/off state of the switching element; and a control unit which determines whether the motor drive circuit is in the open circuit state on the basis of whether the body diode activation unit has been activated and whether there is a Miller plateau region in a gate voltage.

A power stage includes a control device and a power transistor, the control device comprising a primary circuit comprising: a control module able to generate a control current, a primary circuit malfunction detector able to detect a malfunction, a pulse transformer comprising a primary winding connected to the primary circuit, comprising a secondary winding connected to the secondary circuit, magnetically coupled to the primary winding and able to generate, from the control current, an induced pulse current making it possible to drive the power transistor, a secondary circuit comprising: a power and fault detection controller able to detect a malfunction of the secondary circuit or of the power transistor, the power and fault detection controller being able to communicate the malfunction of the secondary circuit or of the power transistor to the primary circuit malfunction detector.

A detection device, an inverter, and a detection method are disclosed. The detection device is configured to detect a leakage current flowing through a conductor. The detection device includes a magnetic core, a detection winding and a calibration winding both wound on the magnetic core, a detection circuit, and a calibration circuit. The detection circuit is coupled to the detection winding, and configured to sample a detection signal of the detection winding to obtain a leakage current detection value. The calibration circuit is coupled to the calibration winding, and configured to provide a calibration signal to the calibration winding.

A fault managed power system (FMPS) and method monitors and detects fault currents in PoE, PFC, and other cables that indicate likely human contact with cable conductors. The level of current detected through the human body combined with a fast response time limits the energy to prevent a person from experiencing ventricular fibrillation, resulting in a so-called touch-safe level. For overload and short-circuit fault protection, the system automatically and immediately removes power from the cables. This limits the amount of energy provided into the fault, thereby maintaining touch-safe operation and also preventing electrical fires and system component protection. The system/method can accomplish this even at voltage levels considerably higher than existing touch-safe standards, for example, Class 2 (below 50 Vac) power supplies. Such a system/method allows the amount of power in applications like PoE and PFC to be safely increased to levels much greater than the current maximum (100 W).

A metering and control subsystem for a photovoltaic solar system is configured for metering the photovoltaic solar system using current measurement devices and individually controlling relays to selectively energize photovoltaic branch circuits. In some examples, the metering and control subsystem includes photovoltaic branch connectors, a relay matrix, current measurement devices, and a metering and relay control circuit. The metering and control circuit is configured for metering the photovoltaic solar system using current measurement data from the current measurement devices and individually controlling the relays to selectively energize each photovoltaic branch circuit.

An overcurrent detector with an electric line and a sensor for monitoring an electric current in the line and outputting a measurement signal, and an integral-unit adapted to integrate an interval of consecutive values of the measurement signal and outputting an integrator-signal, the detector comprises a comparator unit for comparing a value of the integrator-signal with a threshold level and outputting a trigger signal, with the detector further comprises a threshold level determination unit, an input being connected to the sensor for receiving an actual measurement signal, and with an output being connected to the comparator unit, proving the comparator unit with the threshold level, and that the threshold level determination unit is adapted to determine the threshold level in dependence on the value of the actual measurement signal.

An AC/DC leakage detection method, which supports the detection of DC leakage and AC leakage. A DC leakage current and a low-frequency leakage current are measured by means of magnetic modulation technology, an AC signal is measured in the form of pure induction, and two detection modes are performed in a time-sharing manner. A collected leakage signal is converted into a digital signal through an AD converter. By means of the method of the present invention, the processing of a leakage signal is divided into three channels for respectively processing DC leakage, low-frequency AC leakage, and high-frequency AC leakage. The overall effective value of residual current is calculated by integrating results of DC detection and AC detection. The method of the present invention supports the detection of a suddenly increased current; and when there is a suddenly increased current, detection mode switching is performed by detecting the current sudden change of the current.

A facility plan evaluation device includes a proposed plan receiving unit receiving input of a facility plan including capacities and locations of charging and discharging facilities to be newly arranged in a power system, a prediction unit predicting charge and discharge amounts of the charging and discharging facilities, and demands and power generation amounts of existing facilities, which are facilities already connected in the power system, a power flow calculating unit estimating voltage and current in the power system based on a prediction result of the prediction unit, a determination unit determining whether at least one of deviation of voltage from a proper range and overcurrent occurs based on an estimation result of the power flow calculating unit, and determining whether the facility plan needs to be modified based on a determination result, and a result presenting unit presenting a determination result of the determination unit.