Systems and method for automated self-testing of a protective device for a transformer are disclosed. One system includes a protection circuit electrically connected to a transformer neutral, the transformer electrically connected to a power grid, the protection circuit may include a DC blocking component, a switch assembly, and a spark gap assembly each positioned in parallel between the transformer neutral and ground, a switch assembly. The system may further include various testing circuits configured within the protection circuit and switches which when actuated inject a signal to test various components in the protective device.

Circuit interrupters with opto-electronic and/or acoustic systems that can measure displacement over time, optionally along with interrupt current measurements, during an opening and closing event with signal data collected when triggered by a “breaker open” or “breaker close” event.

A system for diagnosing switching element selectively connecting Y-capacitors to ground is provided. The state of a switching device in a power conversion circuit is adjusted such that voltages of different levels are applied to the Y-capacitors, respectively. Therefore, a Y-capacitor disconnect switch which connects a plurality of Y-capacitors connected in common to a DC link to chassis ground is diagnosed.

A solid-state circuit breaker (SSCB) with self-diagnostic, self-maintenance, and self-protection capabilities includes: a power semiconductor device; an air gap disconnect unit connected in series with the power semiconductor device; a sense and drive circuit that switches the power semiconductor device OFF upon detecting a short circuit or overload of unacceptably long duration; and a microcontroller unit (MCU) that triggers the air gap disconnect unit to form an air gap and galvanically isolate an attached load, after the sense and drive circuit switches the power semiconductor device OFF. The MCU is further configured to monitor the operability of the air gap disconnect unit, the power semiconductor device, and other critical components of the SSCB and, when applicable, take corrective actions to prevent the SSCB and the connected load from being damaged or destroyed and/or to protect persons and the environment from being exposed to hazardous electrical conditions.

An electrical protection apparatus includes at least one first or main electrical protection function able to be carried out by a microcontroller and a button termed a test button intended to be actuated by a user to give rise to the implementation of the testing of at least one second electrical function, this implementation of the test being intended to give rise to the tripping of the protection apparatus D. The electrical protection apparatus includes a device for pooling the actuation of this test button with at least one action intended to carry out a third function, as a function of various types of action exerted on the test button, these actions being detected by the microcontroller, the aim being for the latter to give the order to carry out one of the third functions or else the testing of one of the second functions.

A system for diagnosing switching element selectively connecting Y-capacitors to ground is provided. The state of a switching device in a power conversion circuit is adjusted such that voltages of different levels are applied to the Y-capacitors, respectively. Therefore, a Y-capacitor disconnect switch which connects a plurality of Y-capacitors connected in common to a DC link to chassis ground is diagnosed.

A lockout subassembly of an electronic circuit breaker. The lockout subassembly includes a rotatable latch bar having an engagement portion configured to engage with and prevent movement of an operating handle to an ON position, the rotatable latch bar including a lock portion, and a latch device configured to be receivable in the lock portion, wherein rotation of the rotatable latch bar is limited between a first and second rotational position in response to the latch device being received in the lock portion. The lockout of the operating handle can be removed upon passing at least one test so that the operating handle can be moved to the ON position. Circuit breakers including the lockout subassembly and methods of operating the circuit breaker are provided, as are other aspects.

A circuit interrupter including a line conductor, a neutral conductor, separable contacts, an operating mechanism structured to trip open the separable contacts, a magnetic trip actuator structured to cause the operating mechanism to trip open the separable contacts in response to a short-circuit between the line and neutral conductors, a protection circuit including a self-test circuit structured to perform a self-test and to output a signal in response to failing the self-test, and an electrical component electrically connected between the line and neutral conductors and having an open state and a closed state. The electrical component is structured to switch from the open state to the closed state and cause a short-circuit between the line and neutral conductors in response to receiving the signal from the self-test circuit.

A method monitors a circuit breaker in an electrical power supply network, in which one section of the electrical power supply network is monitored in respect of the occurrence of a fault. Upon detection of a fault in the monitored section, a trigger signal is output to a circuit breaker bordering the section, and a switch-fault signal indicating a fault upon opening the circuit breaker is generated if a continuous current flow through the circuit breaker is detected after the trigger signal is output. In order to provide for a preferably rapid and reliable detection of a continuous current flow or an interruption of the current flow during the monitoring of a circuit breaker, it is provided that a curve shape of the time curve of the instantaneous current flowing through the circuit breaker is investigated in order to detect a continuous current flow.

According to an embodiment of the present disclosure, an apparatus of preventing a malfunction of a circuit breaker may include a circuit breaker and a variable resistor installed on a distributing board, the variable resistor being disposed outside the circuit breaker separately from the circuit breaker, wherein the variable resistor is connected in parallel to an anti-pumping auxiliary relay R.sub.W, and total resistance of the anti-pumping auxiliary relay R.sub.W and the variable resistor connected in parallel to each other is less than resistance of the anti-pumping auxiliary relay R.sub.W.