ABB MDAR, Инструкция по эксплуатации

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I.L. 40-385.5
6-4
Blinder Line Polarizing Operating
Left -j (V
X
G + I
X
R
C
∠
PANG-90
°
) I
X
∠
PANG-90
°
Right j (V
X
G - I
X
R
C
∠
PANG-90
°
) I
X
∠
PANG-90
°
where V
XG
= Phase to ground voltage, V
AG
or V
BG
.
I
X
= Phase current in ØA or ØB.
R
C
= Setting of the unit. R
T
for inner blinder
(21BI), R
U
for outer blinder (21BO).
PANG = the positive sequence line impedance angle.
FaultType Impedance Calculation
AG ZAG = VAG / [IA + Ko(Io)]
BG ZBG = VBG / [IB + Ko(Io)]
CG ZCG = VCG / [IC + Ko(Io)]
AB/ABG ZAB = VAB / IAB
BC/BCG ZBC = VBC / IBC
CA/CAG ZCA = VCA / ICA
ABC ZABC = VAG / IA
The distance to the fault is computed by multiplying the imaginary part of the fault
impedance times (VTR/CTR) and dividing by the distance multiplier setting (XPUD).
Distance = imag(Z) x (VTR/CTR) / XPUD
Operation occurs if the operating voltage leads the
polarizing voltage. The characteristic curves are
shown in Figure 11.
Both inner and outer blinders are included in phases
A and B for OS detection on SPT operation. Inner
and outer blinder reaches are determined by the set-
ting of R
T
and R
U
, respectively.
6.8 FAULT LOCATOR
The fault locator feature in MDAR (REL-300) com-
putes the magnitude and phase angle of the fault
impedance and the distance to the fault in both miles
and kilometers. The fault impedance is calculated
from the voltage and current phasors of the faulted
phase(s). Thus proper faulted phase selection is
essential for good fault locator results.
The impedance calculations for the various faults are
as shown below: