The invention provides an over-current protection system. The over-current protection system includes a sensing device, a comparator, a first transistor, and a second transistor. The sensing device is adapted to sense a current flowing to an electrical device. The comparator is adapted to compare a signal received from the sensing device and a reference signal to generate any one of a high signal and a low signal, wherein the output of the comparator is connected to a control device. The first transistor is connected to the output signal of the comparator to control the first transistor, wherein the first transistor is in a conductive state when the output signal of the comparator is a high signal. The second transistor is connected to and controlled by the first transistor, wherein the second transistor is in a conductive state when the first transistor is in the conductive state.

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 resettable electronic fuse for a high-power device such as a power tool, a battery pack for the power tool, or a battery pack charger. The resettable electronic fuse is connected in a current path of the device and is operable or configured to selectively interrupt current through the resettable electronic fuse based on a detected condition of the device (e.g., a detected fault condition of the device). The resettable electronic fuse is also configured to be reset after a detected fault condition has ended. In some embodiments, the resettable electronic fuse is configured to reset itself. In other embodiments, the resettable electronic fuse is configured to receive a signal (e.g., from a device controller) to reset.

A fault detection system that that prevents a recloser from reclosing if a fault is determined to be internal to a transformer, where the recloser is configured to perform a reclosing operation in response to detecting overcurrent. The recloser includes a sensor, such as a light sensor, directed towards the transformer and detecting a fault event. If the recloser detects overcurrent, but the sensor does not detect the fault event, it is assumed that the fault is internal to the transformer and the recloser is prevented from reclosing.

A controller protection circuit for a voltage power optimiser. The circuit having: a first terminal for connecting to a first end of a winding in the voltage power optimiser; a second terminal for connecting to a second end of the winding in the voltage power optimiser; and a thyristor. The controller protection circuit also includes a thyristor gate control circuit. The thyristor gate control circuit is configured to: set the gate control signal such that the thyristor is configured to conduct in response to a potential difference between the anode terminal and the cathode terminal of the thyristor; and set the gate control signal such that the thyristor is configured not to conduct in response to a signal received from a voltage controller. The thyristor gate control circuit includes a normally-on switch having a conduction channel and a control terminal, and a photovoltaic isolator configured to set the gate control signal such that the thyristor is configured not to conduct in response to a signal received from a voltage controller.

Methods and systems for self-healing fault recovery in an electrical power distribution network, particularly distribution networks employing a mesh configuration. When a power source circuit breaker is tripped one or more virtual paths is traced throughout the mesh network, each virtual path originating at the power source that is offline, terminating at an alternate power source, and containing one or two open load switches. A restoration path is chosen from the virtual paths. Power can be transferred to other segments of the mesh network by isolating the fault and closing the open load switch in the chosen restoration path. Some or all of the method and system can be automated.

The invention relates to an energy supply module (1) comprising an input gate (2) for connection to a power source (4) and an output gate (3) as an interruption-free power supply, wherein the input gate (2) and the output gate (3) are through-connected separably via an electrical separating device (6), and an auxiliary energy source (10) is connected or can be connected in parallel with the input gate (2) and the output gate (3), wherein the separating device (6) is positioned between the auxiliary energy source (10) and the input gate (2), and the separating device (6) comprises a circuit arrangement having two transistors (15) and two diodes (16), wherein the transistors (15) are connected reversely in series, and a diode (16) is connected to each transistor (15), inversely to the current direction of said diode.

A power supply switching device and switch board checks whether or not a primary-side voltage of a remote shutoff breaker and a secondary-side voltage thereof become a rated voltage after a commercial power system is recovered from a blackout. Next, when both primary-side voltage and secondary-side voltage become the rated voltage, a contactor is actuated to interconnect a home power system with the commercial power system. Hence, charging of the home power system without causing a user to notice such a charging upon recovery of the commercial power system from a blackout can be prevented. As a result, the safety for the user can be ensured.

An autonomous breaker can apply a current through a high impedance source to a bus coupled to either end of a breaker in order to measure an impedance of the bus. The status of the bus can be determined from the measurement. Based on the determined status, a fault detection procedure can be selected and implemented to determine if a fault exists on the bus. When the fault detection procedure has been implemented and no fault has been detected, the breaker can close, and thus couple the bus to another bus.

Disclosed is a motor protection device (1). The motor protection device (1) includes an interrupter unit (11, Q1, Q2) for electrically connecting a power supply (Vcc) and an electric motor (M) in an operation mode and electrically disconnecting the power supply (Vcc) and the electric motor in an alternative overload mode. The motor protection device further includes an overload detection unit (12). The overload detection unit (12) is configured to monitor a motor current and to control the interrupter unit (11, Q1, Q2) to switch from the operation mode into the overload mode if the motor current indicates an overload condition of the electric motor (M) in the operation mode. The motor protection device (1) further includes a recovery detection unit (13). The recovery detection unit (13) is configured to monitor a motor temperature and to control the interrupter unit (11, Q1, Q2) to switch from the overload mode back into the operation mode if the motor temperature indicates a recovery from the overload condition.