Power distribution systems and methods are described. In one example, a method of determining by a first circuit protection device in a zone selective interlocking (ZSI) system whether to output a blocking signal to a second circuit protection device in the ZSI system is described. The method includes detecting, by a current rate of change sensor, a rate of change of a current flowing through the first circuit protection device. A trip unit receives a current rate of change signal from the current rate of change sensor. The current rate of change signal is proportional to the detected rate of change of the current flowing through the first circuit protection device. The trip unit determines whether to output the blocking signal to the second circuit protection device based, at least in part, on the current rate of change signal.

Power distribution systems and methods are described. In one example, a method of determining by a first circuit protection device in a zone selective interlocking (ZSI) system whether to output a blocking signal to a second circuit protection device in the ZSI system is described. The method includes detecting, by a current rate of change sensor, a rate of change of a current flowing through the first circuit protection device. A trip unit receives a current rate of change signal from the current rate of change sensor. The current rate of change signal is proportional to the detected rate of change of the current flowing through the first circuit protection device. The trip unit determines whether to output the blocking signal to the second circuit protection device based, at least in part, on the current rate of change signal.

A method for controlling a power distribution network includes receiving, by an electronic processor, a fault indication associated with a fault in the power distribution network from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset of the plurality of phases not associated with the fault indication. The first and second subsets each include at least one member. The processor identifies an upstream isolation device upstream of the fault. The processor identifies a downstream isolation device downstream of the fault. The processor sends an open command to the downstream isolation device for each phase in the first subset. Responsive to the first isolation device not being the upstream isolation device, the processor sends a close command to the first isolation device for each phase in the first subset.

A method for controlling a power distribution network includes receiving, by an electronic processor, a fault indication associated with a fault in the power distribution network from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset of the plurality of phases not associated with the fault indication. The first and second subsets each include at least one member. The processor identifies an upstream isolation device upstream of the fault. The processor identifies a downstream isolation device downstream of the fault. The processor sends an open command to the downstream isolation device for each phase in the first subset. Responsive to the first isolation device not being the upstream isolation device, the processor sends a close command to the first isolation device for each phase in the first subset.

A fault type determination method and device of a terminal unit for automation used in a power distribution network are disclosed. The method includes: for each line of incoming lines and outgoing lines of a distribution device, recording the number of faults occurring on the line; after a fault occurs, determining, according to the current and/or voltage on each line, whether automated reclosing is executed, and recording the number of executed automated reclosings; in a fault type determination period, for each line, if the number of faults occurring on the line is greater than the maximum number of automated reclosings allowed by the transformer substation side, or the fault is a repeat fault, then identifying the fault on the line as a permanent fault.

A control system and method for sectionalizing switches and pulse-testing interrupter/reclosers in a distribution grid feeder which enables fault location, isolation and service restoration without requiring an external communications infrastructure to pass information between the switches. The method includes switches entering an armed state when they experience a high fault current during an initial fault event. Then, when the interrupter/recloser runs its test pulse sequence, any armed switch counts all test pulses as fault pulses, while non-armed switches count the test pulses as load pulses. Switches open to isolate the fault based on threshold values of fault pulse count and load pulse count. When an initially active interrupter/recloser completes its test pulse sequence, another interrupter/recloser begins its sequence, and all switches reconfigure their threshold values based on the new interrupter/recloser. Interrupter/reclosers after the initial device use a fast close-open event if necessary to arm some switches for proper fault-count opening.

Measuring data are provided for monitoring a current-supply network, based on one or a plurality of measured electrical quantities of the current-supply network. A time signal is assigned to the measuring data. The measuring data are inspected for the occurrence of one a plurality of predetermined events. Based on determining the occurrence of predetermined event or events, corresponding event data based on the measuring data are generated. A time stamp is conferred to the event data, where the time stamp is based on a link of a synchronized clock time provided by a clock and the time signal assigned to the measuring data. User data are generated from the event data comprising the time stamp, and transmitted via a communication network.

In an electrical distribution system including a solid-state circuit breaker (SSCB) and one or more downstream mechanical circuit breakers (CBs), a solid-state switching device in the SSCB is repeatedly switched ON and OFF during a short circuit event, to reduce a root-mean-square (RMS) value of the short circuit current. The resulting pulsed short circuit current is regulated in a hysteresis control loop, to limit the RMS to a value low enough to prevent the SSCB from tripping prematurely but high enough to allow one of the downstream mechanical CBs to trip and isolate the short circuit. Pulsing is allowed to continue for a maximum short circuit pulsing time. Only if none of the downstream mechanical CBs is able to trip to isolate the short circuit within the maximum short circuit pulsing time is the SSCB allowed to trip.

A power restoration system comprising a feeder, a plurality of power sources available to provide power to the feeder, a plurality of normally closed reclosing devices electrically coupled along the feeder, at least one normally open recloser electrically coupled to the feeder, and a plurality of normally closed switches electrically coupled along the feeder between each adjacent pairs of normally closed reclosing devices. Each switch is assigned a position code having a value for each of the plurality of power sources that determines when the switch will open in response to the fault current and which power source the switch is currently receiving power from, where timing control between the reclosing devices and the switches allows the switch to be selectively opened to isolate the fault within a single feeder section between each pair of adjacent switches or between each switch and a reclosing device.

A circuit breaker distribution system is configured to provide selective coordination. The system comprises a solid-state switch disposed as a main or upstream breaker and a switch with an over current protection disposed as a branch or downstream breaker. The solid-state switch comprises a microcontroller including a processor and a memory, and computer-readable logic code stored in the memory which, when executed by the processor, causes the microcontroller to: allow repeated pulses of current through to the branch or downstream breaker in an event of an overload or short circuit, and choose a maximum current limit for the solid-state switch as a “chop level” such that the chop level is chosen higher than a rated current of the solid-state circuit breaker but low enough that the solid-state switch is not damaged from repeated pulses over a period of time needed to switch OFF the branch or downstream breaker.