Abstract: A system and method for estimating fault current using a sliding observation window that is shorter than one cycle. The method may also include providing a pickup level that defines a current threshold for opening a switch in response to detecting the fault current; estimating the fault current from current measurement signals; accumulating time from a reset zero position during the time that the estimation of the fault current is greater than the pickup level; subtracting time from the accumulated time during the time that the estimation of the fault current is less than the pickup level after time has been accumulated from when the estimation of the fault current is greater than the pickup level; detecting the fault current if the accumulated time reaches a predetermined accumulation time; and opening the switch if the fault current is detected.

Abstract: A method for isolating a fault in an underground power distribution network. The network includes a power line, a plurality of transformers electrically coupled to and positioned along the power line, a first end switch connected to one end of the power line and a second end switch connected to an opposite end of the power line, where each transformer includes an upstream switching device and a downstream switching device, and where source power is provided to both ends of the power line through the first and second end switches and one of the switching devices is a normally open switching device. The method includes detecting overcurrent in the network from the fault, opening certain ones of the switching devices in response thereto, detecting loss of voltage as a result of the open switching devices and opening or closing certain ones of the switching devices to isolate the fault.

Abstract: Methods and systems are provided for automatically coordinating protection settings for relays within an electrical power distribution network. A method includes using a graph traversal mechanism to analyze geographical-based equipment data that contains information about overcurrent relays within the electrical power distribution network. A customizable rule base is applied to protection guidelines. Protection settings are determined based upon the applied customizable rule base and the direction of fault current flow from each source. The determined protection settings are used for the overcurrent relays to control switches in the electrical power distribution network in response to a detected fault.

Abstract: Methods and systems are provided for automatically coordinating protection settings for relays within an electrical power distribution network. A method includes using a graph traversal mechanism to analyze geographical-based equipment data that contains information about overcurrent relays within the electrical power distribution network. A customizable rule base is applied to protection guidelines. Protection settings are determined based upon the applied customizable rule base and the direction of fault current flow from each source. The determined protection settings are used for the overcurrent relays to control switches in the electrical power distribution network in response to a detected fault.