A method for identifying a malfunctioning current sensor in an electrical apparatus, in which an electrical power supply of the electrical apparatus is at least partly supplied by a switched-mode electrical power supply circuit connected to at least one current sensor which samples an electrical current in a phase conductor of an electrical installation, the power supply circuit delivering a regulated electrical voltage, the method including: determining a switching duty cycle of a power switch of the switched-mode electrical power supply; analysing the determined switching duty cycle; and identifying a failure condition if the behaviour of the switching duty cycle is representative of a malfunctioning of at least one of the current sensors.

A distribution transformer system includes a distribution transformer and a distribution transformer monitoring (DTM) device secured to the transformer. The DTM device includes multiple sensors, a controller, and a communication interface. The sensors are configured to monitor physical properties of the distribution transformer. Each of the sensors outputs respective sensor data representative of at least one monitored physical property of the distribution transformer. The controller is configured to receive the respective sensor data from each sensor to produce received sensor data. The communications interface is in communication with the controller and configured to communicate the received sensor data to a remote system for use in determining operational parameters of the distribution transformer. In one embodiment, the distribution transformer system further includes a surge arrester associated with the distribution transformer and the DTM device includes a surge arrester sensor configured to monitor the surge arrester and output surge arrester sensor data.

In accordance with at least one aspect of this disclosure, a controller for an aircraft electrical system includes, a software safe module. In embodiments, the software safe module can be configured to determine whether there was a sudden power failure upon controller initialization, and cause operation of the controller in a software safe mode if there was a sudden power failure such that manual intervention is required to leave the software safe mode to prevent repetitive power failure of the controller.

A method and a device for impedance monitoring for a single-phase or multiphase, ungrounded power supply system. The method comprising the following steps: measuring a complex impedance against ground simultaneously for each active conductor using a measuring device; calculating a complex touch current for each active conductor; testing in the computing unit whether the corresponding complex touch current exceeds a settable body-current threshold value; generating a switch signal in the computing unit upon the body-current threshold value being exceeded; and controlling a switch element using the switch signal for shutting off or isolating the power source.

The invention relates to a circuit arrangement (12) for monitoring and triggering an igniter (5) of an active electrical fuse (6). The arrangement comprises: a control and evaluation unit (1), an alternating current generating unit (2) activated by the control and evaluation unit (1), an alternating current transmission unit arranged between the igniter (5) and the alternating current generating unit (2), the control and evaluation unit (1) being designed and programmed, in a first operational state, to determine the electrical resistance of the igniter (5) from a current detected on the primary side and a voltage detected on the primary side, the value of the resistance being a measure for tripping of the igniter (5), and, in a second operational state, to trigger the igniter (5) by means of the alternating current generating unit (2). The invention further relates to an associated method, to a computer program product which carries out the method and a computer-readable medium, and to a converter and to an aircraft having such a circuit arrangement.

Disclosed are an apparatus and a method for sensing opening of a current interrupt device (CID) of a battery unit. An apparatus for sensing opening of a current interrupt device of a battery unit according to the present invention is configured to include: a setting unit setting a predetermined voltage section when discharge of one or more battery units starts; a measuring unit measuring a voltage section pass time which is the time when the one or more battery units pass through the predetermined voltage section for each battery unit; and a detecting unit detecting a battery unit in which the current interrupt device (CID) is opened among the one or more battery units and detecting the number of battery cells in which the CID is opened among one or more battery cells included in the battery unit in which the CID is opened based on the voltage section pass time for each battery unit.

Implementations of ground fault circuit interrupter (GFCI) self-test circuits may include: a current transformer coupled to a controller, a silicon controlled rectifier (SCR) test loop coupled to the controller, a ground fault test loop coupled to the controller, and a solenoid coupled to the controller. The SCR test loop may be configured to conduct an SCR self-test during a first half wave portion of a phase and the ground fault test loop may be configured to conduct a ground fault self-test during a second half wave portion of a phase. An SCR may be configured to activate the solenoid to deny power to a load upon one of the SCR self-test or the ground fault self-test being identified as failing.

An example method for monitoring the operation of a metal-oxide varistor (MOV) may involve monitoring an operating value of at least one parameter of the MOV using at least one sensor. Further, the method may involve determining, using one or more processors, that a difference between the operating value and a reference value corresponding to the at least one parameter satisfies a predetermined threshold condition corresponding to the at least one parameter. And the method may involve responsive to determining that the difference between the operating value and the reference value satisfies the predetermined threshold condition, transmitting a notification indicative of a potential failure of the MOV to at least one device.

The object of the invention is an overvoltage protection apparatus with monitoring function having a parallel circuit of two branch circuits, wherein the first branch circuit has a first overvoltage protection device and a second overvoltage protection device that are connected in series, wherein the second branch circuit has a third device and a fourth device that are connected in series, wherein the first overvoltage device and the third device have a first shared voltage potential during operation, and wherein the second overvoltage device and the fourth device have a second shared voltage potential during operation, wherein a first measuring tap is provided between the first overvoltage protection device and the second overvoltage protection device and wherein a second measuring tap is provided between the third device and the fourth device, with a signal being derived from the voltage between the first measuring tap and the second measuring tap that provides state information in relation to the first overvoltage protection device and the second overvoltage protection device.

Disclosed is a ground-wall insulation aging monitoring and locating method for a converter transformer. A neutral lead of three-phase windings on a valve side of a converter transformer is adjusted, an insulation leakage current of a certain phase winding on the valve side before aging is measured, a common-mode component and a differential-mode component in the insulation leakage current before aging are extracted, and a common-mode equivalent capacitance and a differential-mode equivalent capacitance before aging are calculated; a common-mode equivalent capacitance and a differential-mode equivalent capacitance after aging are calculated in the same way.