Fault detection in electric power delivery systems using underreach, directional, and traveling wave elements

Abstract

The present disclosure pertains to systems and methods for detecting faults in an electric power delivery system. In one embodiment, system may include a data acquisition subsystem configured to receive a plurality of representations of electrical conditions. The system may also include an incremental quantities subsystem configured to calculate an incremental current quantity and an incremental voltage quantity based on the plurality of representations. A fault detection subsystem may be configured to determine a fault type based on the incremental current quantity and the incremental voltage quantity, to select an applicable loop quantity, and to declare a fault based on the applicable loop quantity, the incremental voltage quantity, and the incremental current quantity. A protective action subsystem may implement a protective action based on the declaration of the fault.

What is claimed is: 
     
         1 . A system configured to detect a fault in a multiple-phase electric power delivery system, comprising:
 a data acquisition subsystem configured to receive a plurality of representations of electrical conditions of each phase associated with at least a portion of the multiple-phase electric power delivery system;   an incremental quantities subsystem configured to calculate incremental quantities for each phase based on the plurality of representations of electrical conditions associated with the at least a portion of the multiple-phase electric power delivery system;   a fault detection subsystem configured to:
 obtain the incremental quantities for each phase from the incremental quantities subsystem; 
 compare the incremental quantities for each phase from the incremental quantities subsystem; 
 determine a fault type based on the comparison of the incremental quantities; 
 determine a faulted phase based on the determined fault type; 
 calculate a fault condition for the faulted phase using the plurality of representations of electrical conditions; and, 
 declare a fault condition based on the calculated fault condition; and 
   a protective action subsystem configured to implement a protective action based on the declaration of the fault.   
     
     
         2 . The system of  claim 1 , further comprising a directional subsystem configured to determine a direction to the fault. 
     
     
         3 . The system of  claim 2 , wherein the direction to the fault is determined based on an operating signal determined based on the product of an incremental voltage quantity, and an incremental current quantity calculated using the plurality of representations of electrical conditions. 
     
     
         4 . The system of  claim 1 , wherein the fault type comprises a phase-to-ground fault. 
     
     
         5 . The system of  claim 4 , wherein the faulted phase comprises a phase from the multiple-phase electric power delivery system associated with an incremental quantity greater than the incremental quantities associated with remaining phases of the multiple-phase electric power delivery system. 
     
     
         6 . The system of  claim 1 , wherein the fault type comprises a phase-to-phase fault. 
     
     
         7 . The system of  claim 6 , wherein the comparing of the incremental quantities comprises comparing of differences between incremental quantities of a first set of two phases with differences between incremental quantities of a second set of two phases. 
     
     
         8 . The system of  claim 7 , wherein the faulted phases comprise the set of two phases associated with the greater difference. 
     
     
         9 . The system of  claim 1 , wherein the comparing of incremental quantities comprises comparing operating quantities. 
     
     
         10 . The system of  claim 1 , wherein the incremental quantities comprise incremental voltage quantities. 
     
     
         11 . The system of  claim 1 , wherein the incremental quantities comprise incremental current quantities. 
     
     
         12 . A method for detecting a fault in a multiple-phase electric power delivery system, comprising:
 receiving a plurality of representations of electrical conditions of each phase associated with at least a portion of the multiple-phase electric power delivery system;   calculating a plurality of incremental quantities for each phase of the multiple-phase electric power delivery system based on the plurality of representations of electrical conditions associated with the at least a portion of the multiple-phase electric power delivery system;   comparing the incremental quantities for each phase of the multiple-phase electric power delivery system;   determining a fault type based on comparison of the incremental quantities;   determine a faulted phase based on the determined fault type;   calculating a fault condition for the faulted phase using the plurality of representations of electrical conditions; and,   declaring a fault condition based on the calculated fault condition; and,   implementing a protective action based on the declaration of the fault.   
     
     
         13 . The method of  claim 12 , further comprising determining a direction to the fault. 
     
     
         14 . The method of  claim 13 , wherein determining the direction to the fault comprises determining an operating signal based on the product of an incremental voltage quantity, and an incremental current quantity calculated using the plurality of representations of electrical conditions. 
     
     
         15 . The method of  claim 12 , wherein the incremental quantities comprise incremental voltage quantities. 
     
     
         16 . The method of  claim 12 , wherein the incremental quantities comprise incremental current quantities. 
     
     
         17 . The method of  claim 12 , wherein the fault type comprises a phase-to-ground fault. 
     
     
         18 . The method of  claim 17 , wherein the faulted phase comprises a phase from the multiple-phase electric power delivery system associated with an incremental quantity greater than the incremental quantities associated with remaining phases of the multiple-phase electric power delivery system. 
     
     
         19 . The method of  claim 12 , wherein the fault type comprises a phase-to-phase fault. 
     
     
         20 . The method of  claim 19 , wherein:
 the comparing of the incremental quantities comprises comparing of differences between incremental quantities of a first set of two phases with differences between incremental quantities of a second set of two phases; and,   the faulted phases comprise the set of two phases associated with the greater difference.