A system and method of protecting the input components of a power supply. An input overcurrent protection module is provided, which may be implemented in firmware, which monitors the input current through an input interface of the power supply. When the input current exceeds a threshold current (i.e., a current above the maximum rating of an input component, such as an input cable), the input current protection module determines whether an input overcurrent event is occurring. When it is determined that an input overcurrent event has occurred, the input current protection module disables the output circuitry of the power supply and triggers a few timers. The input overcurrent protection module continues to monitor the input and, if the input current continues to exceed the threshold current, is configured to shut down the power supply. In this way, input components may be protected from overcurrent issues in high-power systems.

A system and method of protecting the input components of a power supply. An input overcurrent protection module is provided, which may be implemented in firmware, which monitors the input current through an input interface of the power supply. When the input current exceeds a threshold current (i.e., a current above the maximum rating of an input component, such as an input cable), the input current protection module determines whether an input overcurrent event is occurring. When it is determined that an input overcurrent event has occurred, the input current protection module disables the output circuitry of the power supply and triggers a few timers, The input overcurrent protection module continues to monitor the input and, if the input current continues to exceed the threshold current, is configured to shut down the power supply. In this way, input components may be protected from overcurrent issues in high-power systems.

A system and method of protecting the input components of a power supply. An input overcurrent protection module is provided, which may be implemented in firmware, which monitors the input current through an input interface of the power supply. When the input current exceeds a threshold current (i.e., a current above the maximum rating of an input component, such as an input cable), the input current protection module determines whether an input overcurrent event is occurring. When it is determined that an input overcurrent event has occurred, the input current protection module disables the output circuitry of the power supply and triggers a few timers. The input overcurrent protection module continues to monitor the input and, if the input current continues to exceed the threshold current, is configured to shut down the power supply. In this way, input components may be protected from overcurrent issues in high-power systems.

The invention discloses an adaptive fault clearing scheme for an MMC VSC-HVDC grid based on source-grid coordination. A grid-side circuit breaker topology is disposed at each end of each DC line of the MMC VSC-HVDC grid to coordinate with a source-side control strategy when a fault occurs to the DC line so as to isolate the fault together. When a system runs stably, the voltage regulation controller does not actuate, after the fault occurs, the voltage regulation controller is started, and the output voltage regulation coefficient decreases, so that voltage at outlets of the converters drops accordingly, and coordinates with voltage of the pre-charging capacitor of the grid-side circuit breaker topology to realize fault isolation based on source-grid coordination. The adaptive fault clearing scheme provided by the invention greatly improves the speed of fault isolation.

The invention discloses an adaptive fault clearing scheme for an MMC VSC-HVDC grid based on source-grid coordination. A grid-side circuit breaker topology is disposed at each end of each DC line of the MMC VSC-HVDC grid to coordinate with a source-side control strategy when a fault occurs to the DC line so as to isolate the fault together. When a system runs stably, the voltage regulation controller does not actuate, after the fault occurs, the voltage regulation controller is started, and the output voltage regulation coefficient decreases, so that voltage at outlets of the converters drops accordingly, and coordinates with voltage of the pre-charging capacitor of the grid-side circuit breaker topology to realize fault isolation based on source-grid coordination. The adaptive fault clearing scheme provided by the invention greatly improves the speed of fault isolation.

A fault detection system that includes a recloser configured to perform a reclosing operation in response to detecting overcurrent, where the recloser includes a communications device for receiving communications signals. The system also includes a transformer having an outer can, a sensor mounted to the can and extending into the can for measuring pressure therein, where the sensor includes a mechanical indicator that extends when overpressure is detected. The transformer further includes a radio mounted to the can and coupled to the sensor, where the radio includes a switch coupled to the mechanical indicator and a transmitter. When the mechanical indicator extends in response to detecting overpressure in the can it causes the switch to close which causes the transmitter to send a signal that is received by the communications device, which prevents the recloser from reclosing.

An abnormal-voltage protection apparatus includes a switch unit, a voltage detection unit, and a delay time control unit. The switch unit is coupled to a power supplying path formed between an AC power source and a load. The voltage detection unit detects the AC power source and provides a detection signal. The delay time control unit is coupled to the voltage detection unit and the switch unit, and receives the detection signal and provides a control signal to the switch unit according to the detection signal. When the voltage detection unit detects that the AC power source changes from an abnormal voltage to a normal voltage, the delay time control unit turns on the switch unit by the control signal after a delay time so that the AC power source supplies power to the load through the power supplying path.

A method for operating an electronic switch is described hereinafter. According to one exemplary embodiment, the method (for an electronic switch in the switched on state) comprises detecting whether there is an undervoltage condition at a supply voltage node and providing an undervoltage signal which indicates an undervoltage condition. The method further comprises switching off the electronic switch if the undervoltage signal indicates an undervoltage condition and switching (back) on the electronic switch if the undervoltage signal no longer indicates an undervoltage condition. If the undervoltage signal indicates an undervoltage condition during a switch-on process of the electronic switch, the electronic switch is switched off again and switching back on is prevented for a defined period of time, irrespective of the undervoltage signal. Moreover, a corresponding circuit is described.

A single-phase electric meter having a phase conductor intended to be connected to a phase of an electric line located upstream of the single-phase electric meter and to a phase of an electric installation located downstream of the single-phase electric meter, the single-phase electric meter further including a breaking unit mounted on the phase conductor, an upstream voltage sensor arranged to periodically measure an upstream voltage upstream of the breaking unit, and a processing device arranged to acquire upstream voltage measurements and to open the breaking unit when the upstream voltage drops below a first predetermined threshold voltage.

A time-current coordination (TCC) curve for a programmable low-set instantaneous overcurrent (IOC) relay for at least one station breaker in an electrical distribution feeder with a fuse-saving scheme and a method of coordinating at least one recloser with the station breaker in the said feeder, for the reduction of frequency of power interruptions encountered by at least one load on the feeder and wherein the method includes the steps of: (a) feasible selection of a range for a time delay of a station breaker's programmable low-set IOC relay; (b) choosing a time delay based on a fuse-saving relation; and optionally (c) locating the recloser on the feeder.