A method and a device for detecting faults and for protection of electrical networks, the electrical networks being fed from a transformer station through a first three-phase switching device with circuit breaker, a distribution network and feeders. A second three-phase switching device with circuit breaker is connected before the feeders. The circuit breaker of the second switching device, has parallel-coupled damping impedances and is connected in series between the first three-phase switching device and the feeders when a short circuit current is detected. At least one of the damping impedances has deviating properties compared to the others, so as to create a negative sequence current detectable in the electrical networks. The damping impedances are bypassed by the circuit breaker of the second switching device after a predetermined period of time.

A circuit interrupter includes separable contacts; an operating mechanism; an electronic trip unit; and a current sensor assembly including: a harvester circuit having a primary conductor through which input current passes, a secondary winding and a harvester core structured to saturate at a first input current level, a Rogowski coil structured to measure voltage at an output of the Rogowski coil, the measured voltage indicative of output current of the Rogowski coil, where linearity of the output of Rogowski coil deviates more than a deviation tolerance based at least in part on saturation of the harvester core at the first input current level, and a compensation coil arranged at 180 degree opposite to the secondary winding of the harvester core, the compensation coil structured to delay saturation of the harvester core until the input current reaches a second input current level higher than the first input current level.

An electrical apparatus configured to electrically connect to a multi-phase alternating current (AC) electrical power distribution network includes: an input electrical network including: a plurality of input nodes, each configured to electrically connect to one phase of the multi-phase AC electrical power distribution network; at least one non-linear electronic component electrically connected to the input electrical network; an impedance network electrically connected between the input electrical network and ground; and a control system configured to: access a voltage signal that represents a voltage over time at the input electrical network; determine a frequency content of the voltage signal; determine a property of the frequency content; and determine whether an input current performance condition exists in the electrical apparatus based the property of the frequency content.

A system and method for interrupting power in a three-phase power system interrupts power in the faulted phase and the next sequential phase at high speeds, while interrupting power in the remaining phase at a normal operation speed. Limiting high-speed interruption to only two phases requires significantly less energy storage than implementing high-speed interruption in all three phases. When hybrid circuit interrupters are used, the need to wait for a zero-crossing in the current signal in order to initiate interruption operations is eliminated.

A meter collar adapter including a housing, a plurality of contacts to electrically connect the meter collar adapter to a meter socket and to a utility meter, a load management device within the housing to manage electrical load to an interface circuit with external, co-located electric equipment, and an overcurrent protection device electrically connected in series with an interface circuit. The load management device includes the interface circuit to electrically connect to either the line side or load side of an electrical service via the utility meter an external, co-located electric equipment. An interface contact to electrically connect the co-located electric equipment to the interface circuit, an adjustable electrical switch electrically configured to control electric load, and an energy management unit to control, monitor, and/or report a position of the adjustable electrical switch to manage the electrical loads.

An electrical apparatus configured to electrically connect to a multi-phase alternating current (AC) electrical power distribution network includes: an input electrical network including: a plurality of input nodes, each configured to electrically connect to one phase of the multi-phase AC electrical power distribution network; at least one non-linear electronic component electrically connected to the input electrical network; an impedance network electrically connected between the input electrical network and ground; and a control system configured to: access a voltage signal that represents a voltage over time at the input electrical network; determine a frequency content of the voltage signal; determine a property of the frequency content; and determine whether an input current performance condition exists in the electrical apparatus based the property of the frequency content.

A hybrid load protection apparatus (1) comprises a primary power supply path (1A) between input terminal and output terminals (2, 3) and a controllable mechanical switch (5A) connected in series with a primary coil (4A-1) coupled inductively to a secondary coil (4A-2) providing a voltage, U.sub.A, corresponding to a current rise speed of the electrical current flowing through the primary path (1A). The voltage, U.sub.A, is applied directly to a driver input (IN) of a first driver circuit (6A) to trigger automatically a switch-off of the mechanical switch (5A) within a first switch-off period (Δt1) to interrupt the primary power supply path (1A). A secondary power supply path (1B) is provided in parallel to the primary path (1A) and having a further coil (4B) connected in series with a semiconductor power switch (5B). wherein a second driver circuit (6B) associated with the secondary path (1B) detects an increasing electrical current, I, flowing through the secondary path (1B) caused by the interruption of the primary current path (1A) on the basis of a voltage drop (ΔU.sub.4) generated by the further coil (4B) and a non-linear voltage drop (ΔU.sub.5) along the semiconductor power switch (5B) applied as a sum voltage (U.sub.B) directly to a driver input (DESAT) at a high voltage side of the second analog driver circuit (6B) to trigger automatically a switch-off of the semiconductor power switch (5B) within a second switch-off period (Δt2) to interrupt the secondary power supply path (1B).

A system and method for interrupting power in a three-phase power system interrupts power in the faulted phase and the next sequential phase at high speeds, while interrupting power in the remaining phase at a normal operation speed. Limiting high-speed interruption to only two phases requires significantly less energy storage than implementing high-speed interruption in all three phases. When hybrid circuit interrupters are used, the need to wait for a zero-crossing in the current signal in order to initiate interruption operations is eliminated.

A method for processing an interphase short circuit is provided, including: when a two-phase or three-phase interphase short circuit occurs in a line, maintaining a fault phase of the line to be conducted and tripping off the remaining fault phases, and artificially grounding another fault phase connected to the fault phase or directly utilizing an existing grounding point; connecting a neutral point or a charged phase of a three-phase ineffectively grounded power supply system other than the fault phase to the ground, so as to form a closed loop with the fault phase and generate a current, and detecting a current duration by a controlled switch. When a certain controlled switch reaches a trigger condition and cuts off the line, a fault is cleared.

A method for identifying a fault event in an electric power distribution grid sector including one or more electric loads and having a coupling node with a main grid, at which a grid current adsorbed by said electric loads is detectable. The method allows determining whether a detected anomalous variation of the grid current, adsorbed at the electric coupling node, is due to the start of a characteristic transitional operating period of an electric load or is due to an electric fault.