A method for determining direction of an earth fault (EF) in a feeder of a high impedance grounded power system can be performed by an Intelligent Electronic Device (IED). The method includes obtaining a measure of a first order harmonic active current component derived from residual voltage and current of the feeder when the EF occurred in the feeder, obtaining a measure of a higher order harmonic reactive current component derived from the residual voltage and current of the feeder when the EF occurred in the feeder, and determining the direction of the EF in the feeder based on a combination of the first order harmonic active current component and the higher order harmonic reactive current component.

A temporary power delivery system includes a power source, a booth stringer, and a portable GFCI device. The GFCI device is receives current from the power source by a first terminal and delivers current to the booth stringer by a second terminal. An electronic processor of the GFCI device compares a combined magnitude of current flowing through first and second phase conductors of the GFCI device to a magnitude of current flowing through a neutral conductor of the GFCI. The electronic processor also compares a first voltage between the first phase conductor and neutral conductor to a second voltage between the second phase conductor and neutral conductor. A circuit breaker of the GFCI device is opened if a difference between the combined magnitude of phase conductor current and neutral conductor current exceeds a first threshold or a difference between the first voltage and second voltage exceeds a second threshold.

Existing AC power distribution infrastructure in a building is leveraged for the DC power distribution, where one or more DC powers are delivered over an existing power distribution circuit and existing AC power sockets. A DC power attachment is coupled to an existing AC power socket to provide various DC voltages, including a high DC voltage for high power DC devices and a low DC voltage for low power DC devices. Transition from the AC centric environment to a DC environment is thus simplified thereby improving energy usage efficiency and making DC power readily available.

The present disclosure relates to an earth leakage circuit breaker and a method for controlling the same. The earth leakage breaker includes a zero-phase current detection unit for detecting a zero-phase current generated in a zero current transformer formed in three-phase electrical lines; a voltage detection unit for detecting a voltage from each of the two electrical lines; a trip unit for tripping contact points between the two electrical lines and a single-phase load when a trip signal is inputted; and a control unit which, when the zero-phase current is detected by the zero-phase current detection unit, detects an electrical line in which the voltage has dropped by a predetermined level or more, and generates and outputs the trip signal to the trip unit when the electrical line in which the voltage has dropped by a predetermined level or more exists.

A fault detection system for a system having a single DC input and a plurality of A/C loads such as an electric or hybrid electric vehicle. A plurality of inverters convert DC to 3-phase A/C and supply A/C power to a corresponding individual A/C load. Each inverter includes a common mode current transformer and a controller. An individual corresponding common mode current transformer is coupled to the 3-phase A/C output of the inverter. An individual corresponding controller is coupled to the output of an individual corresponding common mode current transformer and is coupled to an individual corresponding A/C load. Each controller is configured to detect a fault at the individual corresponding A/C load and in the case of detection of a fault at an individual corresponding A/C load, the corresponding controller disables the A/C load.

A power supply includes an I/O module configured to receive a high voltage DC input and output a high voltage DC, a plurality of DC converter modules configured to receive the high voltage DC output from the I/O module and output a low voltage DC output, and a plurality of AC inverter modules configured to receive the high voltage DC output from the I/O module and output a high voltage AC output. Each of the plurality of DC converter modules, each of the plurality of AC inverter modules and the I/O module may be mounted in a corresponding individual chassis. Each of the individual chassis may be configured to be stackable together into a single line replaceable unit (LRU). Each of the individual chassis may have an identically shaped outer frame.

A power supply includes an I/O module configured to receive a high voltage DC input and output a high voltage DC, a plurality of DC converter modules configured to receive the high voltage DC output from the I/O module and output a low voltage DC output, and a plurality of AC inverter modules configured to receive the high voltage DC output from the I/O module and output a high voltage AC output. Each of the plurality of DC converter modules, each of the plurality of AC inverter modules and the I/O module may be mounted in a corresponding individual chassis. Each of the individual chassis may be configured to be stackable together into a single line replaceable unit (LRU). Each of the individual chassis may have an identically shaped outer frame.

A temporary power delivery system includes a power source, a booth stringer, and a portable GFCI device. The GFCI device is receives current from the power source by a first terminal and delivers current to the booth stringer by a second terminal. An electronic processor of the GFCI device compares a combined magnitude of current flowing through first and second phase conductors of the GFCI device to a magnitude of current flowing through a neutral conductor of the GFCI. The electronic processor also compares a first voltage between the first phase conductor and neutral conductor to a second voltage between the second phase conductor and neutral conductor. A circuit breaker of the GFCI device is opened if a difference between the combined magnitude of phase conductor current and neutral conductor current exceeds a first threshold or a difference between the first voltage and second voltage exceeds a second threshold.

An electric circuit device and method is for recognizing a closed switch contact as well as a protective ground conductor interruption in a one- or multiphase electric supply line. A control of a residual current monitoring device (RCMB control) includes one fault current control unit for generating a control signal pattern including a series of switching-on impulses forwarded to a first electronic switch unit to activate a possible artificial passive fault current on one or more active conductors and the protective ground conductor (as a return conductor), this fault current actually flowing, being recognized, and evaluated in a closed circuit in a closed switch contact to be tested and an intact protective conductor. Owing to control signal patterns varying during monitoring, a reliable detection of the artificial passive fault current is ensured even in large dynamic disturbance levels while the electric installation (supply line) to be monitored is in operation.

An electric circuit device and method is for recognizing a closed switch contact as well as a protective ground conductor interruption in a one- or multiphase electric supply line. A control of a residual current monitoring device (RCMB control) includes one fault current control unit for generating a control signal pattern including a series of switching-on impulses forwarded to a first electronic switch unit to activate a possible artificial passive fault current on one or more active conductors and the protective ground conductor (as a return conductor), this fault current actually flowing, being recognized, and evaluated in a closed circuit in a closed switch contact to be tested and an intact protective conductor. Owing to control signal patterns varying during monitoring, a reliable detection of the artificial passive fault current is ensured even in large dynamic disturbance levels while the electric installation (supply line) to be monitored is in operation.