An electrical apparatus configured to electrically connect to a multi-phase alternating current (AC) electrical power distribution network includes: an input electrical network including: a plurality of input nodes, each configured to electrically connect to one phase of the multi-phase AC electrical power distribution network; at least one non-linear electronic component electrically connected to the input electrical network; an impedance network electrically connected between the input electrical network and ground; and a control system configured to: access a voltage signal that represents a voltage over time at the input electrical network; determine a frequency content of the voltage signal; determine a property of the frequency content; and determine whether an input current performance condition exists in the electrical apparatus based the property of the frequency content.

The present disclosure pertains to systems and methods to verify information received from a merging unit. In one embodiment, a system may include a merging unit interface comprising a port configured to communicate with the merging unit. The system may include a commissioning subsystem to receive a unique identifier (“UID”) associated with the merging unit using the port during a commissioning process, to store the UID associated with the merging unit, and to associate the UID with the port. In operation, a verification subsystem may receive a plurality of transmissions from the merging unit and verify that the plurality of transmissions originated from the merging unit based on matching the UID stored in the commissioning process with the UID in the plurality of transmissions, and confirming that the plurality of transmissions is received through the port associated with the UID.

A surge suppression circuit is used in a rotating electrical machine system including a switching circuit composed of a plurality of switching elements and a rotating electrical machine connected thereto via an electrically conducting path comprising a plurality of electrically conductive bodies. The surge suppression circuit suppresses surge voltage generated in a plurality of connecting lines connecting the plurality of electrically conductive bodies to windings of plural phases of the rotating electrical machine. The surge suppression circuit includes a plurality of upper diodes with anodes respectively connected to the plurality of connection lines, a plurality of lower diodes with cathodes respectively connected to the plurality of connection lines, an upper line connected to respective cathodes of the plurality of upper diodes, a lower line connected to respective anodes of the plurality of lower diodes, and a voltage holding circuit connected between the upper line and the lower line. The voltage holding circuit includes a charging unit to store electric charge by the surge voltage and a discharge unit to discharge the electric charge stored in the charging unit.

A control system and method for tie point fault interrupter and sectionalizing recloser devices in an electrical grid feeder. The technique enables automated sectionalizing reclosers equipped with three-phase current sensing and single- or three-phase voltage sensing, and able to detect pulse-closing operations, to isolate faults and restore load based on pulse count rather than requiring source re-energization and waiting for loss of voltage timers. The system includes a fault interrupter initiating a pulse-testing sequence upon detecting loss of voltage, where a number of preliminary pulses are used to distinguish transient faults from persistent faults, and pulses are counted by the sectionalizing reclosers to determine which of these devices should open. An alternate configuration is disclosed for reinitializing faults, including the fault interrupter closing if initial pulse testing indicates no fault, and subsequent cycles cause a sectionalizing recloser adjacent the fault to open, allowing the fault interrupter to close and hold.

A system and method using thyristors to protect a series-connected Flexible AC Transmission Systems (FACTS) device from surge currents are disclosed. According to some embodiments, the system includes a thyristor connected in shunt with the FACTS device to be protected. The system further includes control circuitry coupled to the thyristor to drive a gate of the thyristor with a direct current (DC) signal and turn on the thyristor in a time span on order of microseconds. The system and method can be used to protect any series-connected FACTS device that is in danger of being exposed to surge current such as a reclose after a deadline.

An apparatus can include an inverter to provide an output N-phase alternating-current to an external component. When N equals two, a phase of the N phases can include an upper gate and a lower gate. The apparatus can also include a current detector configured to detect a phase current magnitude of the output alternating current. The apparatus can also include a controller coupled to the current detector and to the inverter. The controller can generate a gate command for controlling a gate of the inverter. The controller can also determine a value for a current threshold less than a shutoff current threshold for the external component. The controller can provide a protection command to turn off the upper gate of a corresponding phase of the inverter responsive to detecting that the phase current magnitude is greater than the current threshold.

At least one example embodiment provides a low-voltage circuit breaker for interrupting a low-voltage circuit. The low-voltage circuit breaker includes at least one first current sensor configured to determine a magnitude of an electrical current of the low-voltage circuit, an interruption unit with contacts configured to interrupt the low-voltage circuit, an electronic trip unit connected to the first current sensor and the interruption unit and configured in such a way that an interruption of the low-voltage circuit is instigated upon current or/and current period limit values being exceeded, and a power supply unit configured to supply power to the electronic trip unit and to at least one additional component of the low-voltage circuit breaker, wherein a second current sensor is between the power supply unit and the at least one additional component, said second current sensor configured to determine the magnitude of the current of the additional component.

An example method may include generating an alternating current (AC) output at a power source within a borehole in a subterranean formation. An electrical component may receive a direct current (DC) output from a converter circuit coupled to the power source and the electrical component. One or more measurements corresponding to the power source, the converter circuit, the electrical component, or a protection circuit coupled to the converter circuit may be received. Blocking devices within the protection circuit may be selectively caused to block current flow in the converter circuit based, at least in part, on the one or more received measurements.

The semiconductor circuit breaker includes a semiconductor switch unit connected to an AC circuit, and a phase control unit that controls conduction and non-conduction of the semiconductor switch unit by the control signal. The phase control unit includes an accident detection unit to detect an accident based on a current detected from the AC circuit, a zero point detection unit to detect a current zero point based on the current detected from the AC circuit, and a control signal output unit to output the control signal for setting the semiconductor switch unit to be non-conductive when the accident detection unit detects the accident or when the zero point detection unit detects the current zero point in response to a command to cut off the current.

An electrical power supply disconnector for establishing or severing the connection between current conductors and a power supply circuit. The electrical power supply disconnector includes a housing including a central passage, the walls of which bear contact strips that are located facing one another along a contact axis, and a slider sliding through the central passage in the direction of a centre axis, and bearing at least a first electrically conductive bar, oriented along the contact axis, for electrically connecting at least one first low contact strip and one high contact strip when the slider is in a first position. A protection module including such a power supply disconnector.