GE L60 Instruction Manual page 278

Line phase comparison system, ur series
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5.5 GROUPED ELEMENTS
PHS DIST Z1 XFMR VOL CONNECTION: The phase distance elements can be applied to look through a three-phase
delta-wye or wye-delta power transformer. In addition, VTs and CTs could be located independently from one another
at different windings of the transformer. If the potential source is located at the correct side of the transformer, this set-
ting shall be set to "None".
This setting specifies the location of the voltage source with respect to the involved power transformer in the direction
of the zone. The following figure illustrates the usage of this setting. In section (a), zone 1 is looking through a trans-
former from the delta into the wye winding. Therefore, the Z1 setting shall be set to "Dy11". In section (b), Zone 3 is
looking through a transformer from the wye into the delta winding. Therefore, the Z3 setting shall be set to "Yd1". The
zone is restricted by the potential point (location of the VTs) as illustrated in Figure (e).
PHS DIST Z1 XFMR CUR CONNECTION: This setting specifies the location of the current source with respect to the
involved power transformer in the direction of the zone. In section (a) of the following figure, zone 1 is looking through
a transformer from the delta into the wye winding. Therefore, the Z1 setting shall be set to "Dy11". In section (b), the
CTs are located at the same side as the read point. Therefore, the Z3 setting shall be set to "None".
See the Theory of operation chapter for more details, and the Application of settings chapter for information on calcu-
lating distance reach settings in applications involving power transformers.
5
Figure 5–62: APPLICATIONS OF THE
PHS DIST Z1 REACH: This setting defines the zone reach for the forward and reverse applications. In the non-direc-
tional applications, this setting defines the forward reach of the zone. The reverse reach impedance in non-directional
applications is set independently. The reach impedance is entered in secondary ohms. The reach impedance angle is
entered as the
PHS DIST Z1 RCA
To achieve specified operating speed of distance elements, the relay internally calculates source to line impedance
ratio (SIR) from fault phasors. In these calculations, line impedance is estimated based on the zone 1 reach setting.
Therefore, in order to calculate the SIR value properly and to maintain the optimal operating speed of the distance ele-
ments, you need to set zone 1 reach with a regular 80 to 85% of the line impedance reach setting, even when zone 1
is disabled.
5-140
(a)
delta
wye, 330
o
Z3
Z3 XFRM VOL CONNECTION = None
Z3 XFRM CUR CONNECTION = None
Z1
Z1 XFRM VOL CONNECTION = Dy11
Z1 XFRM CUR CONNECTION = Dy11
(c)
o
delta
wye, 330
Z3
Z3 XFRM VOL CONNECTION = None
Z3 XFRM CUR CONNECTION = Yd1
Z1
Z1 XFRM VOL CONNECTION = Dy11
Z1 XFRM CUR CONNECTION = None
setting.
L60 Line Phase Comparison System
(b)
lag
delta
Z3
Z3 XFRM VOL CONNECTION = Yd1
Z3 XFRM CUR CONNECTION = None
Z1 XFRM VOL CONNECTION = None
Z1 XFRM CUR CONNECTION = Dy11
(e)
lag
L
1
Zone 3
Z
L1
PH DIST XFMR VOL/CUR CONNECTION
5 SETTINGS
wye, 330
o
lag
Z1
L
2
Zone 1
Z
Z
T
L2
830717A1.CDR
SETTINGS
GE Multilin

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