Patent ID: 9118181
Filing Date: 2015-08-25
Classification: H02H

Abstract:
1. A method of fault phase selection and fault type determination in electric power lines, comprising: connecting an analog/digital converter to the electric power lines to generate digitized current values, coupling a protection relay to current transformers associated with electric power lines to receive said digitized current values, first receiving said digitized current values in a buffer module maintained in said protection relay, said buffer module storing said digitized current values, making use of said protection relay having a fault phase selection and fault type determination module which receives and processes said digitized current values from said buffer module in a pre-filtering block, using in said fault phase selection and fault type determination module which receives and processes said digitized current values a fault inception detection and an estimation of fault phase current signals, pre-fault current signals and zero-sequence current in order to receive the absolute value of incremental current signals (I calculating the maximum of the value of all fault type indicators (F where the index flt is an integer number from 1 to 10 and means one specific type of all type faults, determining the fault type as one of the indicators (F flt=1 then there is a phase A to ground G fault, flt=2 then there is a phase B to ground G fault, flt=3 then there is a phase C to ground G fault, flt=4 then there is a phase A to phase B fault, flt=5 then there is a phase B to phase C fault, flt=6 then there is a phase C to phase A fault, flt=7 then there is a phase A to phase B and to ground G fault, flt=8 then there is a phase B to phase C and to ground G fault, flt=9 then there is a phase C to phase A and to ground G fault, flt=10 then there is a phase A to phase B to phase C fault; calculating in a calculating module linked to said buffer module and said fault phase selection and fault type determination module the fault type indicators (F calculating the sum of the minimum value of the combination of real value indicators (S which gives the first group of indicators (F calculating the minimum value of the combination of real value indicators (S which gives the second group indicators (F calculating the sum of the previously calculated indicator (F which gives the third group indicators (F calculating the minimum value of real value indicators (S presenting the real fault type indicator (F