Abstract: 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.

Abstract: An autonomous thermal event control and monitoring system includes a processor component having an enclosure, a processor within the enclosure, a routine, a number of inputs from the processor, and a plurality of inputs to and a plurality of outputs from the processor for each of a plurality of feeders. The system also includes a human machine interface communicating with the processor. The inputs include for each of the feeders, a first input for a thermal sensor and a second input for a status of a network protector, a plurality of third inputs for statuses of a medium voltage interrupter, and a fourth input for a sudden pressure sensor of a network transformer. The outputs include for each of the feeders, a first output for a command to the network protector, and a plurality of second outputs for commands to the medium voltage interrupter.

Abstract: 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.

Abstract: An autonomous thermal event control and monitoring system includes a processor component having an enclosure, a processor within the enclosure, a routine, a number of inputs from the processor, and a plurality of inputs to and a plurality of outputs from the processor for each of a plurality of feeders. The system also includes a human machine interface communicating with the processor. The inputs include for each of the feeders, a first input for a thermal sensor and a second input for a status of a network protector, a plurality of third inputs for statuses of a medium voltage interrupter, and a fourth input for a sudden pressure sensor of a network transformer. The outputs include for each of the feeders, a first output for a command to the network protector, and a plurality of second outputs for commands to the medium voltage interrupter.

Abstract: An electric power system relay includes a simulator that substitutes test values of current and voltage for sensed values for use by relay logic to perform specified relay functions, but without loss of the relay protection functions. The sensed values of current at least are monitored even while the test values are being used by the relay logic. If the monitored sensed values exceed a threshold value, a data switch operates to return to use of the sensed current and voltage values by the relay logic. In addition, the sensed values of current and voltage replace the test values, if a time interval longer than that required to perform the specified relay functions using the test values has expired.

Abstract: An electric power system relay includes a simulator that substitutes test values of current and voltage for sensed values for use by relay logic to perform specified relay functions, but without loss of the relay protection functions. The sensed values of current at least are monitored even while the test values are being used by the relay logic. If the monitored sensed values exceed a threshold value, a data switch operates to return to use of the sensed current and voltage values by the relay logic. In addition, the sensed values of current and voltage replace the test values, if a time interval longer than that required to perform the specified relay functions using the test values has expired.

Abstract: The protective relay is primarily energized by a voltage transformer tap on the power circuit. The current transformers that provide the monitoring current to the protective relay also provide an auxiliary power input to the power supply circuit. A switching circuit monitors the input voltage and switches to the current feed to generate the relay supply voltage when the input voltage drops below a predetermined level. In one embodiment the fault tolerant power supply is provided as an optional, modular, add on unit. In a second embodiment, the power supply is an integral part of the protective relay where the current shares a common input between the monitoring and power circuit and the voltage input is common to both the power supply and any metering circuits contained within the protective relay.