An electrical stress protection circuit includes a detection circuit including a first transistor connected to a driving voltage rail and turned on when electrical stress is provided, and a bypass transistor turned on in response to a signal output when the first transistor is turned on and configured to provide electrical stress to a reference voltage rail. An electronic device configured to perform a predetermined function, includes a detection circuit including a first transistor connected to a driving voltage rail and turned on when electrical stress is provided, and an electrical stress protection circuit including a bypass transistor turned on in response to a signal output when the first transistor is turned on and configured to provide electrical stress to a reference voltage rail.

Electrical circuit arrangement for an energy storage system comprising a first electrochemical energy storage device and a second electrochemical energy storage device.

Improvements in the functioning of a line-mounted device to calculate a direction to a fault during current transformer (CT) saturation are disclosed herein. The line-mounted device may determine a load direction using voltage and current zero-crossings and a power system frequency before the fault condition. The line-mounted device may determine a fault direction in relation to the direction to the load after calculating and removing direct current (DC) components of a sampled current signal using valid sample pairs obtained during unsaturated regions of peaks of the sampled current signal. The line-mounted device may indicate the direction to the fault. A system of line-mounted devices may be used to determine a faulted section of a power system using indications of fault direction.

Methods and systems include identifying an abnormal condition in a PFC circuit comprising an input configured to be coupled to a 3-phase power source and to receive input 3-phase power from the 3-phase power source, a bus having a plurality of bus lines, each bus line configured to be coupled to the input and to carry one phase of the input 3-phase power, a PFC leg including a contactor configured to selectively couple a capacitor bank included in the PFC leg to the bus. In response to identifying the abnormal condition, the contactor is controlled to decouple the capacitor bank from the bus, and after a reset button has been activated, the contactor is recoupled to the capacitor bank to resume operating the PFC leg to provide power factor correction to the input 3-phase power.

A smart earth leakage circuit breaker is installed on a distribution line through which an electric current flows. The breaker measures, by means of a CT, a leakage current flowing through the distribution line, and if the measured current exceeds a preset rated sensitivity current, cuts off electricity by means of trip operation. The smart earth leakage circuit breaker further comprises: a measurement unit tracking and measuring, based on measurement information of the CT, a value of the leakage current exceeding an alarm current value; the MPU setting conditionality and the alarm current value less than the rated sensitivity current and when the conditionality is satisfied based on information measured by the measurement unit, issuing a warning by means of an alarm unit; and the alarm unit operated and controlled by the MPU and warning of an abnormal symptom of the distribution line.

A method of protecting a supercapacitor module of a vehicle contains steps of: A) installing; B) judging; C) executing a protection mode; and D) executing an operating mode. In the step A), an open circuit remains between the rechargeable battery and the supercapacitor module, and a voltage value of the supercapacitor module is 0. In the step B) the supercapacitor module is judged whether being satisfied with a protection condition, an external voltage is V1, a fully charging voltage of the supercapacitor module is V2, an ambient temperature value of the supercapacitor module is T1, and a safe temperature value of a respective supercapacitor is T2. In the step C), when the supercapacitor module is satisfied with the protection condition, the protection mode is executed. In the step D), when a connection circuit between the supercapacitor module and the rechargeable battery occurs, the supercapacitor module is rechargeable and dischargeable electrically.

A power detection circuit is provided. The power detection circuit includes a comparator circuit operative to generate an output signal in response to an input signal. The output signal is configured to change from a first value to a second value in response to the input signal attaining a first threshold value. The output signal is configured to change from the second value to the first value in response to the input signal subsequently attaining a second threshold value. A current limiting circuit is connected to the comparator circuit and operative to limit a leakage current of the comparator circuit.

A system and method that identify a location and/or magnitude of a ground fault in a circuit having a bus that connects battery strings with loads and a ground reference between the loads are provided. Potential of the bus is shifted relative to a ground reference in a first direction. A first impedance in the bus between the battery strings and the ground reference is determined, and the bus is shifted relative to the ground reference in a second direction. A second impedance in the bus between the battery strings and the ground reference is determined. A location and/or severity of a ground fault is determined based on a relationship between the first impedance and the second impedance.

Systems and methods to estimate trapped charge for a controlled automatic reclose are described herein. For example, an intelligent electronic device (IED) may calculate an analog amount of trapped charge of each phase of a power line based on voltage measurements of the power line. The IED may close a switching device of each phase at a time corresponding to a point-on-wave associated with the analog amount of trapped charge of the respective phase.

A leakage voltage detection system can be easily mounted on a ground structure such as an existing street light or a traffic light and can detect a leakage voltage of an electric structure in real time. The leakage voltage detection system includes a sensor node mounted on a ground structure, and an equipment management server that determines a risk of a leakage voltage in the ground structure based on detection voltage information from the sensor node. The sensor node includes an electric field probe that measures a potential difference caused by an electric field detected by electrodes, and a sensor box that detects the potential difference between the electrodes of the electric field probe and transmits the potential difference to the equipment management server as a detection voltage. The equipment management server determines the risk of the leakage voltage where the sensor node is mounted based on the received detection voltage from the sensor node, and outputs information on determination of the risk of the leakage voltage.