Calculating General Settings - ABB REL650 Applications Manual

Section 3
REL650 setting examples
3.1.3.1
46

Calculating general settings

1. Set GlobalBaseSel to 1
2. Set LineAng to 81.9º
The positive sequence impedance line angle for the protected line is calculated as
=
LineAng arctan
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3. Set CharPGZx and CharPPZx to Mho, Quadrilateral and Combined as per the
application for each zone.
4. Set KN-factors
4.1. Set KNMag1 to 0.62
for Zone 1
4.2. Set KNAng1 to -0.6º
for Zone 1
4.3. Set KNMag2 to 0.62
For Zones 2, 3, 4, 5
4.4. Set KNAng2 to -0.6º
for Zones 2,3,4 and 5
the KN-factor is calculated for correct reach for phase-to-ground faults . The
definition of the KN-factor is:
-
Z Z
= , 0 line , 1 line
KN
3× Z
, 1 line
GUID-201DAAE3-7D9E-48B9-9CCA-33B5C2E51103 V1 EN
For phase-to-ground fault loops the apparent impedance is defined as:
V
= ph Ln ,
Z
-
ph ea
+ × ×
I KN 3
ph Ln ,
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The magnitude and phase angle are set separately as KN is a complex value. The
KN-factor can be set separately for zone 1 and for the other zones. This is mainly for
application for double circuit lines where zone 1 should be set to assure underreach
and the other zones should be set to assure overreach. For a single circuit line it is
recommended to set the KN-factors to the same values.
Let Z = 2.5 + j17.5 and Z
1,line
æ ö
æ ö
X 17 5 .
ç ç ÷ ÷
=
ç ÷
line arctan
R 2 5 .
è ø
è ø
line
I
0
= 7.5 + j17.5, then KN is calculated as:
0,line
1MRK 506 334-UUS A
= °
81 9 .
Application manual
(Equation 1)
(Equation 2)
(Equation 3)