A symptom of malfunction regarding operating characteristics of a switch should be detected exactly. A switch operating characteristic monitoring device is comprised of a current sensor that measures a close command current of a switch, an auxiliary switch that outputs signals from at least two or more auxiliary contacts with reference to positions of a contactor, a measurement unit that measures signals from the current sensor and the auxiliary switch, a diagnosis unit that judges whether or not a malfunction occurs, and a display unit that displays a malfunction when a malfunction has been determined. A threshold is obtained in advance from multiple results of an opening/closing test performed beforehand. A calculation is made for characteristic times which are obtained from the close command current and signals from the auxiliary switch during actual operation of a circuit breaker. If a deviation is found by comparison with a threshold, a malfunction is determined.

A symptom of malfunction regarding operating characteristics of a switch should be detected exactly. A switch operating characteristic monitoring device is comprised of a current sensor that measures a close command current of a switch, an auxiliary switch that outputs signals from at least two or more auxiliary contacts with reference to positions of a contactor, a measurement unit that measures signals from the current sensor and the auxiliary switch, a diagnosis unit that judges whether or not a malfunction occurs, and a display unit that displays a malfunction when a malfunction has been determined. A threshold is obtained in advance from multiple results of an opening/closing test performed beforehand. A calculation is made for characteristic times which are obtained from the close command current and signals from the auxiliary switch during actual operation of a circuit breaker. If a deviation is found by comparison with a threshold, a malfunction is determined.

A system and method for detecting and isolating an electromagnetic pulse (EMP) along first phase, second phase, and third phase electrical lines electrically connected to a monitored infrastructure so as to protect the monitored infrastructure, the method for detecting and isolating includes a phase unit receiving electric signal data from a sensor electrically connected individually to each of the first phase, second phase, and third phase electrical lines, respectively, upstream of and associated with the monitored infrastructure. The method includes determining if the received electric signal data associated with the respective electrical line is indicative of an E1 component of an EMP and, if so, actuating an isolation subsystem in less than 300 nanoseconds to electrically isolate the respective electrical line against electrical communication with the monitored infrastructure.

A system and method for detecting and isolating an electromagnetic pulse (EMP) along first phase, second phase, and third phase electrical lines electrically connected to a monitored infrastructure so as to protect the monitored infrastructure, the method for detecting and isolating includes a phase unit receiving electric signal data from a sensor electrically connected individually to each of the first phase, second phase, and third phase electrical lines, respectively, upstream of and associated with the monitored infrastructure. The method includes determining if the received electric signal data associated with the respective electrical line is indicative of an E1 component of an EMP and, if so, actuating an isolation subsystem in less than 300 nanoseconds to electrically isolate the respective electrical line against electrical communication with the monitored infrastructure.

An apparatus for mitigating GIC (geomagnetically induced current) effects through a fuzzy logic controlled variable resistor. Under GIC conditions (or any unbalanced fault current condition), the GIC or unbalanced fault current flows through the neutral of a power transformer. It is detected by the fuzzy logic controller, which sends a signal to a switch to open. The resistor is in the circuit and impedes the flow of current through the neutral, thereby protecting the transformer from getting overheated.

A subsea-replaceable fuse assembly has at least one fuse and a wet-mateable fuse connector element. The connector element is arranged to connect the fuse assembly to a subsea electrical load requiring protection of the fuse. The fuse connector element has conductor elements that are electrically connected to the fuse. A corresponding method of protecting a subsea electrical load includes connecting a fuse to the load underwater in a wet-mating operation effected between connector elements that are electrically connected, respectively, to the fuse and to the load.

A system and method for suppressing EMP-induced electrical system voltage surges due to detonation of a nuclear weapon, the EMP comprising E1, E2, and E3 component pulses. A plurality of shunting assemblies, each including MOVs, gas discharge tubes, other mechanical, electrical and ionization discharge devices and combinations thereof, detect and react to the overvoltage according to timing parameters associated with each of the E1, E2, and E3 components and shunt the overvoltage to decrease to under a predetermined allowable level.

A system and method for suppressing EMP-induced electrical system voltage surges due to detonation of a nuclear weapon, the EMP comprising E1, E2, and E3 component pulses. A plurality of shunting assemblies, each including MOVs, gas discharge tubes, other mechanical, electrical and ionization discharge devices and combinations thereof, detect and react to the overvoltage according to timing parameters associated with each of the E1, E2, and E3 components and shunt the overvoltage to decrease to under a predetermined allowable level.

Electrical faults pose a significant risk to people and property. A system is described that deploys instrument devices with sensors to detect faults within an alternating current (AC) electrical distribution system. These sensors may detect electrical, optical, thermal, acoustic, radio frequency, and other phenomena associated with a fault. Data from different sensors may also be used to distinguish fault and non-fault status. Users are notified if a fault status is detected. Mitigating actions may be automatically taken, such as de-energizing a branch circuit associated with the fault status. Information about non-fault status may also be used to mitigate nuisance circuit breaker interruptions. In some situations, a nuisance interruption of a breaker may be automatically reset if all instrument devices connected to the breaker reported non-fault status before the interruption.

Electrical faults pose a significant risk to people and property. A system is described that deploys instrument devices with sensors to detect faults within an alternating current (AC) electrical distribution system. These sensors may detect electrical, optical, thermal, acoustic, radio frequency, and other phenomena associated with a fault. Data from different sensors may also be used to distinguish fault and non-fault status. Users are notified if a fault status is detected. Mitigating actions may be automatically taken, such as de-energizing a branch circuit associated with the fault status. Information about non-fault status may also be used to mitigate nuisance circuit breaker interruptions. In some situations, a nuisance interruption of a breaker may be automatically reset if all instrument devices connected to the breaker reported non-fault status before the interruption.