Abstract: A system and method for providing fault protection and coordination between fault interrupting devices in a power distribution network. The method includes assigning a coordination number to each device depending on where the device is in the network and what other fault interrupting devices are downstream of the device, where the assigned coordination number to the device is equal to the largest coordination number of any downstream device plus one. The method further includes calculating a TCC curve for the devices having the lowest coordination number based on a TCC curve of a fuse-like device downstream of the device and tolerances of the device. The method then sequentially calculates a TCC curve for the devices having the next lowest coordination number based on the TCC curves of the devices having a lower coordination number and tolerances of the device until all of the devices have a TCC curve.

Abstract: A system and method for adaptive impedance protection in a power network. The method includes determining a measured impedance in an upstream interrupting device, determining an impedance set point in the upstream interrupting device, and identifying a predetermined percentage of the impedance set point. The method also includes determining if the measured impedance falls below the predetermined percentage, determining whether a change in a measured current value on the power line is less than a threshold change value in a downstream interrupting device, and sending the determination of whether the change in the measured current value is less than the threshold change value from the downstream interrupting device to the upstream interrupting device. The upstream interrupting device is opened if the measured impedance falls below the predetermined percentage of the impedance set point and the change in the measured current value is less than the threshold change value.