The invention relates to an insulation monitoring device for simultaneously monitoring an ungrounded power supply system comprising network sections that can be interconnected via coupling switches, comprising a signal generator for generating a measuring signal and a coupling circuit for coupling the measuring signal to the power supply system. According to the invention, the insulation monitoring device comprises a coupling circuit for each interconnectable network section to be monitored, a switchable electrical connecting element being arranged for connecting adjacent coupling circuits.

A system for locating a ground fault in an HRG power distribution system includes an HRG pulsing system having a ground fault sensor to detect a ground fault, a pulsing contactor to introduce a pulsing current into the power distribution system, and a controller to control the pulsing contactor to introduce the pulsing current into the power distribution system in response to a ground fault detection by the ground fault sensor. Current sensors in the power distribution system monitor three-phase current signals on conductors of the power distribution system, with the current sensors positioned on distribution networks in the power distribution system and at a protection device included on each respective distribution network. A processor associated with each protection device and operably connected to the current sensors thereat receives signals from the current sensors for identifying a location of a ground fault in the power distribution system.

The present invention is an in-vehicle charger for detecting ground faults originating in sections in which alternating current is flowing. This device is an in-vehicle charger (100) for charging a vehicle-mounted battery, wherein the device is provided with: a bridge rectifier (14) for converting alternating current supplied from a power source to direct current; a ground fault detecting circuit (21) for outputting a test voltage when a test current flows in a circuit in the in-vehicle charger (100) and, based on changes in the test current in response to the presence or absence of a ground fault resistor, for detecting a ground fault in the circuit of the in-vehicle charger (100); and a controller (23) for controlling the ground fault sensing circuit (21) so as to output a test voltage exceeding the forward voltage of a diode provided by the bridge rectifier (14).

The present invention is an in-vehicle charger for detecting ground faults originating in sections in which alternating current is flowing. This device is an in-vehicle charger (100) for charging a vehicle-mounted battery, wherein the device is provided with: a bridge rectifier (14) for converting alternating current supplied from a power source to direct current; a ground fault detecting circuit (21) for outputting a test voltage when a test current flows in a circuit in the in-vehicle charger (100) and, based on changes in the test current in response to the presence or absence of a ground fault resistor, for detecting a ground fault in the circuit of the in-vehicle charger (100); and a controller (23) for controlling the ground fault sensing circuit (21) so as to output a test voltage exceeding the forward voltage of a diode provided by the bridge rectifier (14).

A grounding wire fault circuit interrupter for an electrical machine includes a chassis ground wire, a sensor, and a logic circuit. The chassis ground wire is configured to be electronically connected to a structure of the electrical machine such that the structure of the electrical machine is further electrically connected to one or more power lines that provide electrical power to the electrical machine. The sensor is electronically connected to the chassis ground wire. The logic circuit is electronically connected to the sensor. The sensor is configured to detect current leaks within the electrical machine by sensing electrical power on the chassis ground wire, and the logic circuit is configured to interrupt the flow of electrical power to the electrical machine when the sensor detects a current leak.

The invention relates to a method and to devices for extended insulation-fault search in an IT power supply system using a multifunctional test current, wherein, selectively and depending on the application, the test current functions as a voltage compensation current so as to compensate a voltage increase in an active conductor of the IT power supply system, as a tripping current so as to trip a residual current protection device arranged in a subsystem of the IT power supply system and/or as a leakage-capacitance compensation current so as to compensate a capacitive leakage current. The test current can fulfil more than one of the cited functions simultaneously.

A monitoring system is applied to an electrical system, which includes a DC power source and an electrical apparatus that is connected to the DC power source by a pair of electric power leads incorporating respective switches. To detect leakage current from the DC power source, a low-frequency AC signal is applied via a large-capacitance capacitor to a specific connection position, between a first terminal of the DC power source and the corresponding switch, and the resultant voltage of that signal is measured. To detect a short-circuit failure of one or both of the switches, a high-frequency AC signal is applied via a low-capacitance capacitor to the specific connection position, and the resultant signal voltage is measured. Judgement as to occurrence of leakage current and/or short-circuit failure is based on the measured signal voltage values.

An apparatus and method for sensing a leakage current along a primary conductor are provided. A first fault detection module is deployed at a first location along the primary conductor and a second driver module is deployed at a second location along the conductor, where the conductor passes through current sensors at each of the modules. The modules are further linked by a safety cable, which also passes through the current sensors. The driver module drives a compensation current in the safety cable to drive the net current passing through the driver current sensor to zero. The fault sensing module senses the net current passing through its current sensor. When the sensed current deviates significantly from zero, the fault sensing module generates a leakage current indication signifying a potential ground fault between the two modules.

The present invention refers to a combined device for electrical protection against transient overvoltages and monitoring of an electrical installation, of those used in installations with alternating single-phase or multi-phase current, or direct current, of those formed by cartridges plugged in to a fixed base or formed by a monoblock, both types of devices comprising one or more components for overvoltage protection in each plug-in cartridge or in the monoblock, characterised in that it comprises monitoring means configured so that they continuously measure and process one or several parameters related to the state of the electrical installation and the protective device itself, and connected to said monitoring means a series of indication means configured to indicate one or a combination of output parameters are comprised.

A signal generation module injects a signal in a pilot conductor with a DC component and one or more AC components. Pilot conductor current is injected in a grounding conductor of power cables connecting power source to load. A current monitor module monitors current in the pilot conductor or ground return, a DC detection module determines DC current present in the monitored current, an AC detection module determines AC current corresponding to each frequency of the AC components in the monitored current, a DC minimum threshold module determines if the DC current is below a DC current minimum threshold, an AC threshold module determines if any of the AC currents is below an AC threshold, and a trip module opens a contact after determining that the DC current is below the DC current minimum threshold or that at least one of the AC currents is below an AC threshold.