Event Records - GE L90 Instruction Manual

RECORDS
where
R is the fault resistance in secondary ohms
F
Z is the line positive-sequence impedance
1
D is the distance to fault in per unit
pu
When the single-ended fault location method is applied, the fault loop impedance is calculated as per the following
equation.
The table defines the loop voltage and current.
Table 6-3: Quantities used to calculate fault loop impedances
Fault type V
loop
AG VA
BG VB
CG VC
AB, ABG VA – VB
BC, BCG VB – VC
CA, CAG VC – VA
ABC Average of AB, BC, CA loop impedances
Where VA, VB, VC are phase voltage phasors in secondary volts; IA, IB, IC are current phasors in secondary amps, I0 is the
zero sequence current phasors in secondary amps; and IG is the ground current from the parallel line scaled to the source
phase CT in secondary amps. Z0/Z1 is the zero sequence impedance to positive sequence impedance ratio, and Z0M/Z1 is
mutual zero sequence impedance to positive sequence impedance ratio.
VTs of the
FAULT REPORT 1 SOURCE
connected VT to display the loop impedance and fault resistance for single phase-to-ground faults.
For the application of partially parallel circuits and in the case of single phase-to-ground faults, the reported fault
6
resistance and fault loop impedance may not be accurate even the compensation method is applied.
Depending on the number of terminals and the location method applied, the fault resistance and loop impedance are
reported in the different ways as tabulated in the following table.
Table 6-4: Report mechanism for fault resistance and loop impedance
Method Number of terminals Fault resistance
Multi-ended 2
3
Single-ended 2
3

6.5.2 Event records

ACTUAL VALUES  RECORDS  EVENT RECORDS
 EVENT RECORDS

6-30
Z = V / I
loop loop loop
I
loop
IA + (Z0/Z1-1)*I0 + Z0M/Z1*IG/3
IB + (Z0/Z1-1)*I0 + Z0M/Z1*IG/3
IC + (Z0/Z1-1)*I0 + Z0M/Z1*IG/3
IA - IB
IB - IC
IC - IA
must be connected in Wye or
Report at two terminals, seen from the individual end
Only report at the line terminal of the faulted segment. At the other two terminals, results are
not applicable, set values to the maximum number 9999.99.
Not applicable, set to the maximum number
9999.99
Not applicable, set to the maximum number
9999.99
EVENT: XXX

XXX

EVENT: 3

POWER ON
must be set correctly for the Delta
VT SUBSTITUTION
Loop impedance
Report at two terminals, seen from the
individual end
Report at all terminals, but the value is only
accurate at the line terminal of the faulted
segment
Date and time stamps
EVENT 3
 
DATE: 2000/07/14
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 6: ACTUAL VALUES
Eq. 6-9