Passive monitoring the integrity of current sensing devices and associated circuitry in GFCI and AFCI protective devices is provided. A protection circuit interrupter employs a capacitively coupled noise signal obtained by an arrangement of one or both of the line side arms relative to a Rogowski coil. The noise signal is monitored while the line and load sides of a protective circuit interrupter are disconnected, and the connection of the line and load sides disabled if the noise signal fails to correlate sufficiently to a reference noise cycle. When the line and load sides are connected, the RMS value of the observed current signal is monitored such that the line and load sides are disconnected if the observed current signal fails to meet an RMS threshold. The observed current signal is compensated by subtracting the reference noise cycle prior to monitoring for the fault condition applicable to the protective device.

An electrical operating device includes measuring equipment for an electrical measured variable, and preprocessing equipment for digital measured values. The preprocessing equipment has an integrated circuit and an electronic memory component for configuring a logic circuit. A processor evaluates preprocessed measurement data and, on the basis of the evaluation, transmits data telegrams to other electrical operating devices. The preprocessing equipment calculates a respective checksum for a digital measured value, and the processor recognizes a malfunction from the measured value and the checksum of the measured value, and suppresses the evaluation and/or the transmission of the data telegrams in the event of a malfunction. There is also described a method for recognizing malfunctions.

Disclosed is a power control system for preemptive detection and prevention of electric disasters including a feed end that supplies power, a receiver end that receives the power from the feed end through a line, a power control device that calculates at least one of a loss power value, a leakage current value, a voltage drop value, and an impedance value based on a voltage value and a current value, which are measured at each of the feed end and the receiver end, detects whether the line is abnormal, by comparing the calculated at least one value with a corresponding predetermined threshold and identifying a change in electrical properties, and controls the power supplied to the receiver end when it is detected that the line is abnormal.

There is provided mechanisms for differential protection of a transmission line (20) of a transmission system (25). A method comprises obtaining a restraining current and a differential current from the transmission line (S102). The method comprises determining a compensation current for the differential current (S104). The method comprises providing the differential current as compensated for by the compensation current and the restraining current to a differential protection arrangement for making a trip decision (S106). The method comprises detecting an internal fault for the transmission system (S108). The method comprises, as a result thereof, providing the differential current without being compensated for by the compensation current and the restraining current to the differential protection arrangement for making the trip decision (S110).

The present disclosure provides a protection assistance device of multiple circuit breakers in a low-voltage system, in which protection assistance in both directions from the upper side to the lower side or from the lower side to the upper side is possible, and the number of wires for protection assistance between multiple upper/lower circuit breakers can be minimized. The protection assistance device includes at least one upper low-voltage circuit breaker; at least one middle low-voltage circuit breaker; at least one lower low-voltage circuit breaker; and a communication line which makes a communication connection between the low-voltage circuit breakers, wherein the low-voltage circuit breakers comprise a control unit for, when a trip operation of automatically breaking a circuit is performed, transmitting a communication packet for reporting a trip operation state to at least one predetermined circuit breaker among the circuit breakers through the communication line.

The present disclosure provides a protection assistance device of multiple circuit breakers in a low-voltage system, in which protection assistance in both directions from the upper side to the lower side or from the lower side to the upper side is possible, and the number of wires for protection assistance between multiple upper/lower circuit breakers can be minimized. The protection assistance device includes at least one upper low-voltage circuit breaker; at least one middle low-voltage circuit breaker; at least one lower low-voltage circuit breaker; and a communication line which makes a communication connection between the low-voltage circuit breakers, wherein the low-voltage circuit breakers comprise a control unit for, when a trip operation of automatically breaking a circuit is performed, transmitting a communication packet for reporting a trip operation state to at least one predetermined circuit breaker among the circuit breakers through the communication line.

A system and method for differential protection is provided. Aspects includes determining a first current value associated with a first current transformer coupled to a first location in a differential protection zone, the first current transformer having a first transformer ratio, determining a second current value associated with a second current transformer coupled to a second location in the differential protection zone, the second current transformer having a second transformer ratio, and determining, by a controller, a type of fault associated with the differential protection zone based on the first current value and the second current value.

In a control device, control circuit units are connected to separate circuit power sources and to separate grounds. Ground monitor circuits respectively have a first resistor with one end connected to a voltage source, a second resistor with one end connected to an input terminal of a corresponding control circuit unit, and a capacitor. Among the one end of the first resistor, an other end of the first resistor, and the other end of the second resistor, at least one is connected to the subject system, and at least one is connected to an other system, and the control circuit unit monitors a ground abnormality of the other system based on a terminal voltage of the input terminal to which the second resistor is connected.

In a control device, control circuit units are connected to separate circuit power sources and to separate grounds. Ground monitor circuits respectively have a first resistor with one end connected to a voltage source, a second resistor with one end connected to an input terminal of a corresponding control circuit unit, and a capacitor. Among the one end of the first resistor, an other end of the first resistor, and the other end of the second resistor, at least one is connected to the subject system, and at least one is connected to an other system, and the control circuit unit monitors a ground abnormality of the other system based on a terminal voltage of the input terminal to which the second resistor is connected.

Systems and methods to disconnect a faulted region of a power grid are described. For example, a control system may obtain a set of regions of a power grid. The control system may obtain a current magnitude and a voltage magnitude of the power grid. The control system may detect a fault in the power grid based at least in part on the current magnitude. The control system may, from the set of regions, determine a faulted region that the fault is located within based on a voltage magnitude of one or more buses in the power grid, a net change in power with respect to time of one or more regions in the set of regions, or both. The control system may send one or more signals to electrically disconnect the faulted region from the power grid.