In order to be able to perform a shutdown test on an inverter with little expenditure, a trigger signal is modulated to the AC current or the AC voltage at a first moment, and the inverter is used at a second moment, which occurs a defined duration after the start of the trigger signal at the first moment, to generate an AC current or an AC voltage with a fault signal that is detected by the inverter and which triggers a shutdown of the inverter, and the shutdown moment of the AC current or the AC voltage is determined. A shutdown duration of the inverter is determined from the difference between the shutdown moment and the second moment.

A detection circuit includes a tunable delay circuit that generates a delayed signal and that receives a supply voltage. The detection circuit includes a control circuit that adjusts a delay provided by the tunable delay circuit to the delayed signal. The detection circuit includes a time-to-digital converter circuit that converts the delay provided by the tunable delay circuit to the delayed signal to a digital code and adjusts the digital code based on changes in the supply voltage. The control circuit causes the tunable delay circuit to maintain the delay provided to the delayed signal constant in response to the digital code reaching an alignment value. The detection circuit may continuously monitor timing margin of a data signal relative to a clock signal and update the digital code in every clock cycle. The detection circuit may be a security sensor that detects changes in the supply voltage.

A circuit interrupting device including one or more line terminals for connecting to an external power supply, one or more load terminals for connecting to an external load, one or more contacts electrically connecting one or more line terminals to one or more load terminals, and an auto-monitoring circuit. The auto-monitoring circuit configured to monitor one or more signals to determine an operating state of said circuit interrupting device, output a first signal having a first voltage level based on the operating state, wherein the first voltage level is greater than zero volts, and output a second signal having a second voltage level based on the operating state, wherein the second voltage level is greater than the first voltage level.

An apparatus includes a plurality of surge protection devices (e.g., multiple metal oxide varistors connected in parallel) configured to be coupled to a power system, a plurality of mechanical actuators associated with respective ones of the surge protection devices and configured to indicate status of the associated surge protection devices, and a detector circuit configured to sense actuation of the actuators and responsively determine a protection status of the plurality of surge protection devices. The detector circuit may include a plurality of switches configured to be actuated by respective ones of the actuators. The detector circuit may further include a processor coupled to the plurality of switches and configured to determine states of switches and to determine the protection status based on the determined status of the switches. The processor may be configured to interpret the status of the switches based on a stored identifier.

Example devices and methods for compensating for monitoring a surge protection device are provided. In some embodiments, a device is configured to couple to a surge protection device. The device comprises a processor that is capable of sending a DC current signal. A serial data interface is electrically connected to the processor and includes at least one shift register. The device also comprises a multiplexer coupled to the serial data interface. The serial data interface is operable to direct the DC current through the multiplexer. The device also comprises an analog to digital converter (optionally embedded within the processor) that is operable to output a digital signal corresponding to a voltage induced by the DC current signal. Returned DC signals represent surge protection device’s health and a multitude of other surge module information.

A diagnostic test instrument for testing power system equipment may include a chassis having a number of bays capable of receiving test circuitry modules, which may be field inserted by a user desiring to perform a particular test. The instrument may include controller circuitry that may sense in each of the bays whether a respective test circuitry module is inserted therein, and then interrogate respective test circuitry modules in each respective bay to identify a type of the respective test circuitry module. Available testing capabilities may be identified according to the type of each of the respective test circuitry modules identified in respective bays. The controller circuitry may output configuration instructions to test circuitry modules, and respective test ports included in each of the respective test circuitry modules may be selectively illuminated as a configuration instruction to visually identify an assigned functionality of the respective test ports.

Example devices and methods for compensating for monitoring a surge protection device are provided. In some embodiments, a device is configured to couple to a surge protection device. The device comprises a processor that is capable of sending a DC current signal. A serial data interface is electrically connected to the processor and includes at least one shift register. The device also comprises a multiplexer coupled to the serial data interface. The serial data interface is operable to direct the DC current through the multiplexer. The device also comprises an analog to digital converter (optionally embedded within the processor) that is operable to output a digital signal corresponding to a voltage induced by the DC current signal. Returned DC signals represent surge protection device's health and a multitude of other surge module information.

The present disclosure provides a test system and method for a charging device. The test system for the charging device includes a load module, a test board and the charging device. A path is formed between the charging device and the load module through the test board. The test board is configured to report a test battery voltage to the charging device. The charging device is configured to receive the test battery voltage, to calculate a path impedance from the charging device to the load module according to the test battery voltage, to adjust an operating state of the charging device according to the calculated path impedance, and to determine whether the charging device needs to enter a protection state, for testing a path impedance protection function of the charging device.

Testing device for testing an overcurrent protector, and method of operating the same. First and second switches are provided for connecting the first and second terminals of the overcurrent protector to first and second capacitors, respectively. The first and second capacitors are pre-charged to first and second voltages, where the second voltage is lower than the first. A controller switches the first and second switches to their test positions, which establishes a current path from the first capacitor to the second capacitor through the overcurrent protector. The first and second voltages are selected so that the peak current that would be generated in the current path is greater than the overcurrent threshold of the overcurrent protector.

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.