A quick-action leakage detection protection circuit with a regular self-checking function is provided. The quick-action leakage detection protection circuit may include a power input end, a power load end, a power user end, twin induction coils for detecting leakage current and low resistance failure, a control chip, a trip coil in which an iron core is disposed, a reset button, a self-checking chip, and a self-checking silicon controlled rectifier. The reset button may be linked with a main circuit switch, an analog path switch, and a normally-open self-checking path switch. The main circuit switch may include a pair of dynamic contact levers extended from the power load end, a first pair of static contact ends extended from the power input end passing through the twin induction coils, and a second pair of static contact ends extended from the power user end. In some embodiments, a first end of the trip coil may be connected to a live line end of the power input end and to the live line of the power load end via the first normally-closed switch. And, a second end of the trip coil may be connected to a neutral line end of the power load end via a second normally-closed switch.

A quick-action leakage detection protection circuit with a regular self-checking function is provided. The quick-action leakage detection protection circuit may include a power input end, a power load end, a power user end, twin induction coils for detecting leakage current and low resistance failure, a control chip, a trip coil in which an iron core is disposed, a reset button, a self-checking chip, and a self-checking silicon controlled rectifier. The reset button may be linked with a main circuit switch, an analog path switch, and a normally-open self-checking path switch. The main circuit switch may include a pair of dynamic contact levers extended from the power load end, a first pair of static contact ends extended from the power input end passing through the twin induction coils, and a second pair of static contact ends extended from the power user end. In some embodiments, a first end of the trip coil may be connected to a live line end of the power input end and to the live line of the power load end via the first normally-closed switch. And, a second end of the trip coil may be connected to a neutral line end of the power load end via a second normally-closed switch.

A temporary power delivery system includes a power source, a booth stringer, and a portable GFCI device. The GFCI device is receives current from the power source by a first terminal and delivers current to the booth stringer by a second terminal. An electronic processor of the GFCI device compares a combined magnitude of current flowing through first and second phase conductors of the GFCI device to a magnitude of current flowing through a neutral conductor of the GFCI. The electronic processor also compares a first voltage between the first phase conductor and neutral conductor to a second voltage between the second phase conductor and neutral conductor. A circuit breaker of the GFCI device is opened if a difference between the combined magnitude of phase conductor current and neutral conductor current exceeds a first threshold or a difference between the first voltage and second voltage exceeds a second threshold.

A power delivery system may include a first phase conductor. A power delivery system may include a second phase conductor. A power delivery system may include a neutral conductor. A power delivery system may include a protection circuit including a circuit breaker that opens when a difference between a combined magnitude of current flowing through the first and second phase conductors and a magnitude of current flowing through the neutral conductor exceeds a first threshold.

A device for monitoring and protecting equipment powered by at least one solid-state power controller (SSPC) including at least one current measurement circuit having a current measuring transformer receiving at a primary at least three phases of a three-phase power supply of the equipment, a measuring and testing module including a controller for measuring a current at a secondary I.sub.m, representative of a differential current I.sub.d at the primary, and a channel for injecting current into said transformer, the channel having a current I.sub.inj generator controlled by an output of the controller and connected to an injection winding on the transformer, the injection winding including a number of turns N.sub.in so that the current I.sub.inj produces in said measurement windings a test current I.sub.m of said secondary in the absence of current at the primary.

A device for monitoring and protecting equipment powered by at least one solid-state power controller (SSPC) including at least one current measurement circuit having a current measuring transformer receiving at a primary at least three phases of a three-phase power supply of the equipment, a measuring and testing module including a controller for measuring a current at a secondary I.sub.m, representative of a differential current I.sub.d at the primary, and a channel for injecting current into said transformer, the channel having a current I.sub.inj generator controlled by an output of the controller and connected to an injection winding on the transformer, the injection winding including a number of turns N.sub.in so that the current I.sub.inj produces in said measurement windings a test current I.sub.m of said secondary in the absence of current at the primary.

A circuit breaker for protecting a low-voltage electric circuit for an AC voltage, ascertains the level of an instantaneous differential current of conductors of the low-voltage circuit. If an instantaneous differential current quantity has been overshot, a prevention of current flux in the low-voltage circuit is initiated by a high-ohmic state of switching elements of an electronic interruption unit in the closed state of break contacts. A method for using a circuit-breaker for protecting a low-voltage electric circuit for an AC voltage, is also provided.

A circuit breaker for protecting a low-voltage electric circuit for an AC voltage, ascertains the level of an instantaneous differential current of conductors of the low-voltage circuit. If an instantaneous differential current quantity has been overshot, a prevention of current flux in the low-voltage circuit is initiated by a high-ohmic state of switching elements of an electronic interruption unit in the closed state of break contacts. A method for using a circuit-breaker for protecting a low-voltage electric circuit for an AC voltage, is also provided.