A method for determining phase locking of critical arc light includes: step 1: monitoring and collecting light radiation intensity of an arc inside a switch cabinet in real time, and converting the collected light radiation intensity into an electrical signal; step 2: extracting a power-frequency fundamental wave of the electrical signal, comparing an amplitude of the power-frequency fundamental wave of the electrical signal with a first threshold, and generating a pre-warning signal based on a comparison result of the first threshold; step 3: comparing the amplitude of the power-frequency fundamental wave of the electrical signal with a second threshold voltage, and generating a control signal based on a comparison result of the second threshold voltage and a protection time threshold; and step 4: protecting the switch cabinet under the critical arc light environment based on the pre-warning signal and the control signal.

An apparatus includes a current sense resistor configured to receive a supply current for one or more devices. The apparatus also includes a current sense amplifier configured to amplify a voltage across the current sense resistor. The apparatus further includes a comparator configured to compare the amplified voltage from the current sense amplifier to a reference voltage. In addition, the apparatus includes an octal driver configured to receive the supply current from the current sense resistor and to control one or more device outputs associated with the one or more devices. The apparatus may also include an optocoupler configured to receive an output from the comparator and, based on the output, control an output enable pin of the octal driver. There could be multiple resistors, amplifiers, comparators, drivers, and optocouplers arranged in multiple circuit branches, which could be configured to control multiple device outputs associated with different groups of devices.

In one example, a ground fault circuit interrupter is provided. It may include a current imbalance detection circuit configured to provide a leakage signal and a main processing circuit including a processor. The leakage signal may correspond to a current imbalance between a supply path and a return path. The processor may be configured to receive the leakage signal, analyze a time pattern of the leakage signal, determine whether a ground fault exists based on analysis of the time pattern, and generate a first trigger signal if the ground fault is determined to exist. The ground fault circuit interrupter may further include a back-EMF detection circuit configured to provide a back-EMF detection signal. Methods for detecting and responding to a ground fault are also provided.

A device (100) for monitoring the status of breakers (20) within a consumer unit (10). The device (100) uses a non-contact, optical sensor (104), such as an IR break-beam sensor (106, 108), or an optical time-of-flight sensor (106, 108) to monitor the positions of the toggle switches (22) on the breakers (20). In the event that one or more of the switches moves to an “off” position (22), an alarm is triggered, such as by sending an SMS message to a user, to alert them of the fact. The device (100) also monitors the consumer unit's power status (1020) and can warn in the event of a power outage of a master isolator or RCD trip. A UPS (1030, 1032, 1034) is suitably provided to enable the device to continue working during a mains power failure.

The present disclosure relates to a directional over-current ground relay (DOCGR) for performing a protective relay of the power source system such as a micro-grid system using communications between an SV-remote terminal unit (SV-RTU) and the DOCGR, wherein the SV-RTU is configured for measuring voltage and current of the distributed power source system and thus generating a sampled value (SV) signal. Further, the present disclosure relates to a method for operating the DOCGR.

Systems and methods for displaying electric power system metering information in a panel may use digitized signals from primary protection relays. The system may include multiple panel meters. One or more of the panel meters may receive the digitized signals using an electrically non-conductive communication media. In various embodiments, the panel may be electrically isolated from the primary protection relay. The panel may be hot swappable and may be connected to a primary protection relay while the relay is in continuous operation.

Systems and methods for displaying electric power system metering information in a panel may use digitized signals from primary protection relays. The system may include multiple panel meters. One or more of the panel meters may receive the digitized signals using an electrically non-conductive communication media. In various embodiments, the panel may be electrically isolated from the primary protection relay. The panel may be hot swappable and may be connected to a primary protection relay while the relay is in continuous operation.

A method of protection can be used in response to a fault in a multi-terminal power transmission system that includes a first transmission line section connecting a first terminal to a transmission line junction, a second transmission line section connecting a second terminal to the transmission line junction and a third transmission line section connecting a third terminal to the transmission line junction. The fault being located in one of the first, second or third transmission line sections. The section having the fault can be determined based on a number of calculations and other factors and a switching device can be controlled according to the identification of the section having the fault.

A controller for a secondary side of a switched mode power supply. A thermistor and an LED of an optocoupler are connected in parallel with each other between a voltage-supply-pin and a STOP pin of the controller. A reference-source provides a reference-signal between the STOP pin and the voltage-supply-pin. The STOP pin receives a temperature-measurement-signal from the thermistor, wherein the temperature-measurement-signal is representative of the resistance of the thermistor. The controller also includes an OTP-comparator that compares: (i) the temperature-measurement-signal; with (ii) a threshold-level, and provides an OTP-signal that is representative of whether or not the temperature-measurement-signal at the STOP pin crosses the threshold-level; and a switchable-current-source that selectively provides a bias-current to the STOP pin based on the OTP-signal, wherein the bias-current causes the LED to emit a light-signal that is representative of a fault to an associated photo-detector.

A wearable device designed to operate sets of instructions for protecting individuals from electric shocks. The wearable device comprises a sensor designed to convey a flow of electric charge sensed on a human body. The wearable device also comprises at least one wire configured to accept the flow of electric charge received from the sensor and convey the flow of electric charge to at least one bipolar junction transistor set, wherein the at least one bipolar junction transistor set is connected a power circuit comprising an illumination source connected to a power source, wherein the at least one bipolar junction transistor set is functioning as a switch designed to close the power circuit upon receiving a current of at least 0.1 microampere conveyed from the sensor, and wherein the power source is designed to illuminate the illumination source upon closing the power circuit by the at least one bipolar junction transistor set.