Fault Protection System and Method for an Electrical Power Distribution System

Abstract

A fault protection system for an electrical power distribution system and a method of configuring and operating a fault protection system for an electrical power distribution system accepts device fault protection parameters, such as the time-current-characteristics (TCCs), of boundary devices, and selects and sets fault protection parameters for one or more fault protection devices, such as fault-interrupters, that thus coordinate with the boundary devices. Fault protection parameter selection for each fault protection device may occur automatically, and each device may reconfigure its fault protection parameters based upon changes in the electrical power distribution system, for example, as the result of fault isolation and/or service restoration.

1 . A fault protection system, comprising:
 a distribution line, the distribution line connecting a source via a first boundary protection device to a load via a second boundary protection device;   a fault protection device segmenting the line between the first boundary protection device and a second boundary protection device; the fault protection device being operable to isolate the source from a fault in the distribution line between the fault protection device and the load; the fault protection device including a controller, a memory coupled to the controller and a fault isolation operator coupling a source side of the distribution line to a load side of the distribution line, the fault isolation operator being responsive to the controller;   the controller being operable to receive fault operating characteristic data relating to the boundary protection devices and further being operable upon the fault operating characteristic data to determine a fault operating parameter for the fault protection device and to store the fault operating parameter in the memory; such that, in operation the fault isolation operator is operable responsive to the controller to provide fault isolation in the distribution line based upon the fault operating parameter.   
   
   
       2 . The fault protection system of  claim 1 , wherein the fault operating characteristic data comprises time-current-characteristic (TCC) data. 
   
   
       3 . The fault protection system of  claim 2 , wherein the time-current-characteristic data is expressed as a function of fault operating characteristic data of the boundary protection device. 
   
   
       4 . The fault protection system of  claim 2 , wherein the time-current-characteristic data is expressed as a data set defining a nominal response, minimum response, or maximum clear time-current-characteristic of the boundary protection device. 
   
   
       5 . The fault protection system of  claim 1 , the controller being operable to determine a validity of the fault operating parameter in relationship to the fault operating characteristic data of the boundary devices. 
   
   
       6 . The fault protection system of  claim 1 , comprising a second fault protection device segmenting the distribution line between the boundary protection devices; the controller being further operable to receive fault operating characteristic data relating to the second fault protection device. 
   
   
       7 . The fault protection system of  claim 6 , each of the fault protection device and the second fault protection device comprising respective communication devices, the communication devices being operable to communicate the fault operating characteristic data from the second fault protection device to the first fault protection device. 
   
   
       8 . The fault protection device of  claim 6 , a second fault operating parameter associated with the second fault protection device, the first fault operating parameter and the second fault operating parameter being determined to provide coordinated operation of the fault protection device and the second fault protection device. 
   
   
       9 . The fault protection device of  claim 8 , the fault protection device being operable to communicate a message to the second fault protection device upon operation of the fault protection device, the second fault protection device being operable to modify the second fault operating parameter responsive to the message such that the second fault protection device remains coordinated with the first fault protection device. 
   
   
       10 . The fault protection device of  claim 9 , wherein the message is a delay message and wherein in response to the delay message the second fault protection device time shifts its time-current-characteristic. 
   
   
       11 . The fault protection device of  claim 8 , wherein the fault protection device and the second fault protection device operate as a coordinated team. 
   
   
       12 . A method of providing coordinated fault protection for a distribution line coupling a source to a load, a boundary protection device being disposed on the distribution line between the source and the load and a fault protection device being disposed on the distribution line between the boundary protection device and the load; the method comprising:
 receiving fault operating characteristic data relating to the boundary protection device;   determining a load path from the source to the load, the load path including the boundary protection device and the fault protection device;   determining a fault operating parameter for the fault protection device based at least in part upon the fault operating characteristic date of the boundary protection device; and   activating a fault operating characteristic within the fault protection device based upon the determined fault operating parameter.   
   
   
       13 . The method of  claim 12 , the fault protection device comprising a plurality of fault protection devices being disposed within the load path, the method comprising:
 propagating fault operating characteristic data for each of the plurality of fault protection devices to each other of the plurality of fault protection devices;   generating a fault operating parameter for each of the plurality of fault protection devices based upon the fault operating characteristic data of the boundary device and the propagated fault operating characteristic data of the plurality of fault protection devices; and   activating a fault operating characteristic within each of the plurality of fault protection devices based upon the determined fault operating parameter for the respective fault protection device.   
   
   
       14 . The method of  claim 12 , comprising:
 wherein the fault operating parameter of each of the plurality of fault protection devices is determined to provide coordinated operation of the plurality of fault protection devices with respect to each other and the boundary device.   
   
   
       15 . The method of  claim 12 , comprising:
 determining a first fault protection device has an invalid fault protection parameter;   setting the fault protection parameter of the first fault protection device to be the same as the fault protection parameter of a second fault protection device, the fault protection parameter of the second fault protection device being determined to be valid.   
   
   
       16 . The method of  claim 15 ; comprising:
 coordinating the fault protection operation of the first fault protection device and the second fault protection device.   
   
   
       17 . The method of  claim 16 , wherein the coordinating comprises sending a message from the first fault protection device to the second fault protection device upon fault protection operation of the first fault protection device, the message affecting coordinated operation of the second fault protection device with respect to the first fault protection device. 
   
   
       18 . The method of  claim 17 , the message comprising a delay message; the second fault protection device delaying its fault protection characteristic responsive to the delay message. 
   
   
       19 . The method of  claim 17 , the message comprising a delay message propagated to each of the plurality of fault protection devices from the first fault protection device to the boundary device. 
   
   
       20 . The method of  claim 17 , the message comprising multiple delay messages, the number of delay messages corresponding to a number of fault protection devices sharing a fault protection characteristic. 
   
   
       21 . The method of  claim 16 , wherein coordinating comprises:
 determining a prior operation of the first fault protection device to a fault; and   delaying operation of the second fault protection device to the fault responsive to the operation of the first fault protection device.   
   
   
       22 . The method of  claim 16 , wherein coordinating comprises:
 determining substantially simultaneous operation of the first fault protection device and the second fault protection device to a fault; and   sequentially resetting the first fault protection device and the second fault protection device to restore service.   
   
   
       23 . The method of  claim 22 , wherein sequential resetting comprises first resetting the closest to the source of the first fault protection device and the second fault protection device. 
   
   
       24 . The method of  claim 22 , wherein sequential resetting comprises resetting one of the first fault protection device and the second fault protection device, and testing by the other of the first fault protection device and the second fault protection device a persistence of the fault. 
   
   
       25 . The method of  claim 24 , comprising modifying the fault operating parameter and hence the fault operating characteristic of the one of the first fault protection device and the second fault protection device during the testing to temporarily prevent its operation during the testing. 
   
   
       26 . The method of  claim 16 , wherein coordinating comprises:
 determining an operation of the first fault protection device to a first fault type;   determining a second fault type to exist at the second fault protection device, and operating the second fault protection device responsive to the second fault type; and   sequentially resetting the first fault protection device and the second fault protection device to restore service.   
   
   
       27 . In a fault protection system for an electrical power distribution system, a method of configuring the fault protection system comprising:
 obtaining an operating parameter of a non-configurable device;   determining a response characteristic of a fault protection device within a current path from a source to a load including the non-configurable device and the fault protection device;   determining a validity of the response characteristic;   setting the fault protection device to operate in accordance with the response characteristic.   
   
   
       28 . The method of  claim 27 , the non-configurable device comprising one of a source boundary device and load boundary device. 
   
   
       29 . The method of  claim 27 , wherein determining a response characteristic comprises determining a time-current-characteristic of the fault protection device relative to the operating parameter of the non-configurable device. 
   
   
       30 . The method of  claim 29 , wherein the time-current-characteristic is based upon a minimal clearance between a maximum total clearing time of a downstream device and a minimum pickup time of an upstream device, the downstream device and the upstream device being relative to the fault protection device. 
   
   
       31 . The method of  claim 27 , a plurality of fault protection devices being disposed in the current path, the method comprising providing a unique operating characteristic for each of the plurality of fault protection devices. 
   
   
       32 . The method of  claim 27 , a plurality of fault protection devices being disposed in the current path, the method comprising providing a unique operating characteristic for a first portion of the fault protection devices, providing a common operating characteristic to a second portion of the fault protection devices, and providing coordination of the operation for the second portion of the fault protection devices. 
   
   
       33 . The method of  claim 27 , wherein the common operating characteristic comprises a maximum protection characteristic selected from a group of characteristics determined for each fault protection device of the second portion of fault protection devices. 
   
   
       34 . The method of  claim 33 , wherein the coordination comprises sending a message from a first fault protection device of the second portion to a second fault protection device of the second portion upon fault protection operation of the first fault protection device, the message affecting coordinated operation of the second fault protection device with respect to the first fault protection device. 
   
   
       35 . The method of  claim 34 , the message comprising a delay message; the second fault protection device delaying its fault protection characteristic responsive to the delay message. 
   
   
       36 . The method of  claim 32 , wherein coordination comprises:
 determining a prior operation of a first fault protection device of the second portion to a fault; and   delaying operation of a second fault protection device of the second portion to the fault responsive to the operation of the first fault protection device.   
   
   
       37 . The method of  claim 32 , wherein coordination comprises:
 determining substantially simultaneous operation of a first fault protection device and a second fault protection device for the second portion to a fault; and   sequentially resetting the first fault protection device and the second fault protection device to restore service.   
   
   
       38 . The method of  claim 37 , wherein sequential resetting comprises first resetting the closest to the source of the first fault protection device and the second fault protection device. 
   
   
       39 . The method of  claim 37 , wherein sequential resetting comprises resetting one of the first fault protection device and the second fault protection device, and testing by the other of the first fault protection device and the second fault protection device a persistence of the fault. 
   
   
       40 . The method of  claim 39 , comprising modifying the fault operating parameter and hence the fault operating characteristic of the one of the first fault protection device and the second fault protection device during the testing to temporarily prevent its operation during the testing. 
   
   
       40 . The method of  claim 32 , wherein coordinating comprises:
 determining an operation of a first fault protection device of the second portion to a first fault type;   determining a second fault type to exist at a second fault protection device of the second portion, and operating the second fault protection device responsive to the second fault type; and   sequentially resetting the first fault protection device and the second fault protection device to restore service.   
   
   
       41 . The method of  claim 27 , wherein determining a response characteristic comprises determining a response characteristic for the fault protection device based upon each of plurality of operating configurations of the fault protection device. 
   
   
       42 . The method of  claim 41 , wherein setting the fault protection device to operate in accordance with the response characteristic comprises selecting a maximum response characteristic from each of the response characteristics for the fault protection device corresponding to the plurality of operating conditions. 
   
   
       43 . The method of  claim 42 , wherein the plurality of operating configurations comprise multiple load paths to a source. 
   
   
       44 . The method of  claim 42 , wherein the plurality of operating configurations comprise a load path to each of a plurality of sources. 
   
   
       45 . The method of  claim 42 , wherein the plurality of operating configurations comprise multiple current ranges. 
   
   
       46 . The method of  claim 42 , wherein the plurality of operating configurations comprise multiple terminal connections to the fault protection device.