Abstract: Voltage samples are collected for a source and loads connected thereto by an electrical network. Respective negative sequence voltage difference values are generated for respective source/load pairs from the voltage sample. A connection (e.g., a loose connection) in the electrical network is identified based on the generated negative sequence voltage difference values. The identified connection is reported to a user. Identifying a connection in the electrical network may include identifying at least one source/load pair having an associated negative sequence voltage difference value that meets a predetermined criterion and identifying the connection based on the identified at least one source/load pair. Identifying the connection may include identifying at least one source/load pair having an associated negative sequence voltage difference value with a magnitude falling outside of at least one range associated with the at least one source/load pair.

Abstract: A control system includes: a controller configured to: access an estimated torque and estimated speed of a motor mechanically coupled to an impeller of a centrifugal machine; access at least one set of pre-determined performance data values associated with a known speed of the impeller, where each set of pre-determined performance data values includes: a plurality of flowrate values and a plurality of performance metric values; determine an operating point of the centrifugal machine based on the estimated torque, the estimated speed, and the at least one set of pre-determined performance data values; compare the determined operating point to a best efficiency point (BEP) associated with the centrifugal machine; and determine whether to change the speed of the motor based on the comparison.

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 improved bus bar apparatus is usable in high temperature electrical terminations and is configured to provide sufficient heat dissipation such that when connected at one end with a 90° C. wire, the bus bar apparatus is at most only at 75° C. at another end thereof, which end can be connected with a lower temperature electrical component such as a circuit interrupter. The bus bars apparatus may include bus bars that extend directly between the high temperature wires and the low temperature electrical component, or the bus bar apparatus may additionally include wires that are electrically interposed between the low temperature region of the bus bars and the electrical component. Additional cooling could be provided by employing oversized wires. The bus bars may additionally include fins, fans, or supplementary heat sinks to enhance thermal convection of the bus bar. The bus bar apparatus additionally can be provided with its own enclosure to be usable in a retrofit situation.

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 improved bus bar apparatus is usable in high temperature electrical terminations and is configured to provide sufficient heat dissipation such that when connected at one end with a 90° C. wire, the bus bar apparatus is at most only at 75° C. at another end thereof, which end can be connected with a lower temperature electrical component such as a circuit interrupter. The bus bars apparatus may include bus bars that extend directly between the high temperature wires and the low temperature electrical component, or the bus bar apparatus may additionally include wires that are electrically interposed between the low temperature region of the bus bars and the electrical component. Additional cooling could be provided by employing oversized wires. The bus bars may additionally include fins, fans, or supplementary heat sinks to enhance thermal convection of the bus bar. The bus bar apparatus additionally can be provided with its own enclosure to be usable in a retrofit situation.

Abstract: An improved bus bar apparatus is usable in high temperature electrical terminations and is configured to provide sufficient heat dissipation such that when connected at one end with a 90° C. wire, the bus bar apparatus is at most only at 75° C. at another end thereof, which end can be connected with a lower temperature electrical component such as a circuit interrupter. The bus bars apparatus may include bus bars that extend directly between the high temperature wires and the low temperature electrical component, or the bus bar apparatus may additionally include wires that are electrically interposed between the low temperature region of the bus bars and the electrical component. Additional cooling could be provided by employing oversized wires. The bus bars may additionally include fins, fans, or supplementary heat sinks to enhance thermal convection of the bus bar. The bus bar apparatus additionally can be provided with its own enclosure to be usable in a retrofit situation.

Abstract: An improved bus bar apparatus is usable in high temperature electrical terminations and is configured to provide sufficient heat dissipation such that when connected at one end with a 90° C. wire, the bus bar apparatus is at most only at 75° C. at another end thereof, which end can be connected with a lower temperature electrical component such as a circuit interrupter. The bus bars apparatus may include bus bars that extend directly between the high temperature wires and the low temperature electrical component, or the bus bar apparatus may additionally include wires that are electrically interposed between the low temperature region of the bus bars and the electrical component. Additional cooling could be provided by employing oversized wires. The bus bars may additionally include fins, fans, or supplementary heat sinks to enhance thermal convection of the bus bar. The bus bar apparatus additionally can be provided with its own enclosure to be usable in a retrofit situation.

Abstract: A system for locating a ground fault in a high resistance grounded (HRG) power distribution system includes a pulsing circuit configured to introduce a pulse current into the distribution system and current sensors adapted to monitor three-phase current signals present on conductors of the distribution system, with the current sensors positioned on a number of distribution networks included in the HRG power distribution system and at a protective device included on each respective distribution network. A processor associated with each protective device receives signals from the current sensors for identifying a location of the ground fault in the HRG power distribution system, with the processor associated with each protective device receiving measurements of the three-phase current signals from the current sensors over a plurality of cycles and identifying a pattern of interest in the three-phase current signals across the plurality of cycles in order to detect a ground fault.

Abstract: Changes in equipment cooling performance may be detected by indirectly measuring cooling performance by way of a cooling efficiency indicator. An operating cooling efficiency indicator is calculated as a ratio between equipment electrical power consumption and a temperature differential between the equipment and an ambient temperature. The operating cooling efficiency indicator is compared to a baseline cooling efficiency indicator to detect changes in cooling performance.

Abstract: Changes in equipment cooling performance may be detected by indirectly measuring cooling performance by way of a cooling efficiency indicator. An operating cooling efficiency indicator is calculated as a ratio between equipment electrical power consumption and a temperature differential between the equipment and an ambient temperature. The operating cooling efficiency indicator is compared to a baseline cooling efficiency indicator to detect changes in cooling performance.

Abstract: A power generation system includes a generator configured to be connected to a bus. The system also includes a timing reference signal generator circuit configured to detect a timing variation of a voltage on the bus and to generate a timing reference signal from a timing reference other than the voltage on the bus in response to detection of the variation. The system further includes a generator control circuit configured to synchronize operation of the generator to the timing reference signal.

Abstract: A power system includes a load bus configured to be connected to a power source, a generator and an uninterruptible power supply (UPS). The generator is operated as an induction generator to provide power to the load bus while providing reactive power to the load bus from the UPS. In some embodiments, prior to operating the generator as an induction generator, the generator is operated as an induction motor while the load bus is receiving power from the power source. Responsive to loss of the power source, the UPS may be used to maintain operation of the generator as an induction motor while the prime mover accelerates up to a speed sufficient to drive the generator as an induction generator.

Abstract: A power system includes a load bus configured to be connected to a power source, a generator and an uninterruptible power supply (UPS). The generator is operated as an induction generator to provide power to the load bus while providing reactive power to the load bus from the UPS. In some embodiments, prior to operating the generator as an induction generator, the generator is operated as an induction motor while the load bus is receiving power from the power source. Responsive to loss of the power source, the UPS may be used to maintain operation of the generator as an induction motor while the prime mover accelerates up to a speed sufficient to drive the generator as an induction generator.

Abstract: A power generation system includes a generator configured to be connected to a bus. The system also includes a timing reference signal generator circuit configured to detect a timing variation of a voltage on the bus and to generate a timing reference signal from a timing reference other than the voltage on the bus in response to detection of the variation. The system further includes a generator control circuit configured to synchronize operation of the generator to the timing reference signal.