A power protection system includes a first DC power source, a first load, a first power bus connecting the first power source and the first load, and a first solid state circuit breaker circuit integrated in the first power bus. The first solid state circuit breaker circuit includes a first semiconductor switch, a first capacitor arranged between the high side voltage rail and the low side voltage rail closer to the power source or to the load than the semiconductor switch, and a first inductor located such that current generated by the first capacitor when unloading in case of a short circuit at the power source or at the load passes the first inductor. The controller is configured to measure a voltage change over the first inductor and trigger an actuation signal for the first semiconductor switch if a voltage change surpasses a predetermined threshold voltage.

A method may include receiving, via at least one processor, a first set of data indicative of a fault being present and send a first signal to a breaker based on the first set of data. The first signal may cause the breaker to open a plurality of poles of the breaker. The method may then involve receiving a second set of data indicative of the fault being cleared and sending a second signal to the breaker based on the second set of data. The second signal may cause the breaker to close a first pole of the plurality of poles at a first time and close a second pole of the plurality of poles at a second time different from the first time.

An interface supply system includes a switching power supply, a control chip, and a control circuit. The control circuit is coupled to the switching power supply and the control chip. The switching power supply is configured to supply power to an interface. The control circuit is configured to be switched on and output a detection signal to the control chip when the switching power supply and the control chip are shorted. The control chip is configured to not supply power to the interface after receiving the detection signal.

An electrical switching apparatus includes separable contacts, an operating mechanism structured to open and close the separable contacts, and a motor cooperating with the operating mechanism to open or close the separable contacts. The motor includes an input structured to input power. The electrical switching apparatus also includes an electronic circuit structured to condition the input power to the motor.

An electrical switching apparatus includes separable contacts, an operating mechanism structured to open and close the separable contacts, and a motor cooperating with the operating mechanism to open or close the separable contacts. The motor includes an input structured to input power. The electrical switching apparatus also includes an electronic circuit structured to condition the input power to the motor.

A fault protection system is configured to detect a fault in an electric power system. The fault protection system obtains a differential measurement signal. The differential measurement signal may, for example, indicate, as a function of time, the difference between currents or voltages measured at two or more terminals or boundaries of a fault protection zone of the electric power system. Regardless, the fault protection system generates a fault detection signal by cross-correlating the differential measurement signal with a reference signal. The reference signal may for instance be the differential measurement signal that is expected upon occurrence of a fault. The fault protection system performs fault detection, for detecting a fault internal to the fault protection zone, as a function of the fault detection signal.

A safety device for a DC grid includes a voltage measuring device between a potential line and a reference potential line, and a protective circuit for reducing an electric shock caused by Y-capacitors of the electric DC grid. The protective circuit includes a circuit breaker between the respective potential line and the reference potential line. A plurality of tripping criteria are predefined and the first circuit breaker and/or the second circuit breaker can be actuated so as to close exclusively in the event of all predefined tripping criteria being met as determined by the first voltage measuring device and/or by the second voltage measuring device.

A safety device for a DC grid includes a voltage measuring device between a potential line and a reference potential line, and a protective circuit for reducing an electric shock caused by Y-capacitors of the electric DC grid. The protective circuit includes a circuit breaker between the respective potential line and the reference potential line. A plurality of tripping criteria are predefined and the first circuit breaker and/or the second circuit breaker can be actuated so as to close exclusively in the event of all predefined tripping criteria being met as determined by the first voltage measuring device and/or by the second voltage measuring device.

According to one embodiment, an excitation inrush current suppression device for suppressing excitation inrush currents flowing through a breaker of the three-phase collective operation type for opening and closing connection is configured to measure a three-phase AC voltage of the power supply bus bar to calculate prospective magnetic fluxes of the transformer, and to measure a three-phase AC voltage on the transformer side to calculate residual magnetic fluxes of the transformer after shutoff, so as to set the breaker closed when polarities of the prospective magnetic fluxes respectively agree with polarities of the residual magnetic fluxes in all of the phases respectively.

The invention relates to a method of differential protection in the power distribution networks based on phase difference principles. The method comprises the following steps: collecting the current and voltage signals of each loading switch; calculating phase difference between the corresponding currents at two adjacent loading switches, wherein at least one of the two adjacent loading switches accords with I.sub.max>n.Math.I.sub.T+I.sub.dz; tripping the two adjacent loading switches if the phase difference corresponding to the two adjacent loading switches being greater than a threshold then a section between the two adjacent loading switches being determined as a fault section. The method only needs to calculate the phase difference between the corresponding currents at the two adjacent loading switches, and achieves the fault determination according to the phase difference being greater than the threshold. The method has low data synchronizing requirements, and processes the fault determination according to the collected signals. The time required for the entirely determining process is short, and a fast protecting response is achieved, thus the problem of slowly protecting response in the existing relay-protection method for the power distribution networks is solved.