An example method for detecting and mitigating attacks on electric power substations comprises detecting a command to open or close a circuit breaker in the electric power substation. A modified extended substation model for the electric power substation is generated, based on the detected command and based on measurements in substation, where the modified extended substation model is a power flow model for the substation and for one or more directly connected neighboring substations. A power flow analysis is performed, using the modified extended substation model, to generate a predicted voltage for each of a plurality of nodes in the substation and in the one or more directly connected neighboring substations. Each predicted voltage is compared to a corresponding allowable voltage range, and execution of the command is blocked in response to determining that one or more of the voltages is outside the corresponding allowable voltage range.

The present disclosure provides a protection assistance device of multiple circuit breakers in a low-voltage system, in which protection assistance in both directions from the upper side to the lower side or from the lower side to the upper side is possible, and the number of wires for protection assistance between multiple upper/lower circuit breakers can be minimized. The protection assistance device includes at least one upper low-voltage circuit breaker; at least one middle low-voltage circuit breaker; at least one lower low-voltage circuit breaker; and a communication line which makes a communication connection between the low-voltage circuit breakers, wherein the low-voltage circuit breakers comprise a control unit for, when a trip operation of automatically breaking a circuit is performed, transmitting a communication packet for reporting a trip operation state to at least one predetermined circuit breaker among the circuit breakers through the communication line.

A load center comprises a common instantaneous tripping unit that works on a principle of solid state switching. The load center further comprises a plurality of branches of branch circuit breakers each of which is coupled to the common instantaneous tripping unit via a corresponding high power connection and a corresponding low power connection such that the common instantaneous tripping unit feeds the plurality of branches at the same time. The common instantaneous tripping unit interrupts a short circuit fault in an interruption time which is significantly reduced thus reducing or eliminating chances for a personal injury during the short circuit fault.

A load center comprises a common instantaneous tripping unit that works on a principle of solid state switching. The load center further comprises a plurality of branches of branch circuit breakers each of which is coupled to the common instantaneous tripping unit via a corresponding high power connection and a corresponding low power connection such that the common instantaneous tripping unit feeds the plurality of branches at the same time. The common instantaneous tripping unit interrupts a short circuit fault in an interruption time which is significantly reduced thus reducing or eliminating chances for a personal injury during the short circuit fault.

A method includes detecting an initial fault in a system and opening a contactor to isolate a load bus from the system for a window of time. During the window of time, the method includes detecting whether current flows from a generator of the system. If current flows from the generator of the system during the window of time, the method includes isolating the load bus from the generator. If current does not flow from the generator to the system during the window of time, the method includes isolating the load bus from all sources including the generator.

A system includes a first circuit breaker comprising a first solid state switch, first mechanical contacts, and a current sensor structured to sense current flowing through the first circuit breaker, and a second circuit breaker electrically coupled to the first circuit breaker and being structured to interrupt current flowing to the first circuit breaker, wherein the first circuit breaker is structured to transmit, to the second circuit breaker, a request upon detecting a failure mode, and wherein the second circuit breaker is structured to interrupt current flowing to the first circuit breaker in response to receiving the request, and the first circuit breaker is further structured to open the first mechanical contacts when the current flowing through the first circuit breaker drops to a predetermined level.

Systems and methods to isolate faults and restore power are described herein. For example, an intelligent electronic device (IED) may receive a blocking signal indicating a fault is detected on a power line. The IED may obtain one or more current measurements of the power line. The IED may determine that a fault is not present on the power line at the IED based on the one or more current measurements. The IED may trip a first current interruption device of the IED The IED may send a close permissive signal to another IED indicating that the other IED is permitted to permitted to close an open current interruption device of the other IED to restore power to one or more loads.

A control system and method for a feeder, or portion of the distribution grid, which enables fault location, isolation and service restoration without communications between the feeder switches. The method uses definite time coordination between feeder switches and local measurements to determine which switches should open or close in order to isolate the fault and restore service downstream of a faulted section. Time-current characteristics and feeder topology are shared with all switches in the feeder prior to a fault event. When a disturbance occurs, a timer is started at each switch. When a switch measures voltage loss in all three phases, it stops its timer. Each switch evaluates the timer values and, when a particular switch determines based on the time-current characteristics that the immediate upstream switch opened to isolate the fault, that particular switch also opens. Power upstream of the particular switch is then provided by an alternative source.

A power restoration system for restoring power to feeder segments in response to a fault. The system includes a reclosing device having a switch and one or more sensors for measuring current and/or voltage on the feeder, where the reclosing device performs a pulse testing process to determine circuit fault conditions. The system also includes a plurality of switching devices electrically coupled along the feeder, where each switching device includes a section switch and one or more sensors for measuring current and/or voltage on the at least one feeder. In one embodiment, each switching device recognizes predetermined pulse codes having a sequence of pulses, where the reclosing device uses the pulse testing process to generate and selectively transmit defined pulse codes on the feeder that selectively cause the section switches to change states between an open state and a closed state depending on the code.

Systems and methods to isolate faults and restore power are described herein. For example, an intelligent electronic device (IED) may receive a blocking signal indicating a fault is detected on a power line. The IED may obtain one or more current measurements of the power line. The IED may determine that a fault is not present on the power line at the IED based on the one or more current measurements. The IED may trip a first current interruption device of the IED The IED may send a close permissive signal to another IED indicating that the other IED is permitted to permitted to close an open current interruption device of the other IED to restore power to one or more loads.