Bank Phase Current Unbalance Settings - GE UR Series C70 Instruction Manual

10.4 SETTING EXAMPLE
Figure 10–13: VOLTAGE DIFFERENTIAL BLOCKING DURING VT FUSE FAILURE
The 87V-2 and 87V-3 differential elements for the strings against tap voltage are created in a similar manner. In these
cases, the K factor will be different, reflecting the voltage division of K = 463.8194 between the string and tap capacitor volt-
ages.
Two phase current unbalance (ANSI 60P) stages are used to provide trip and alarm levels during capacitor unit failures in
each differential element.
The pickup setting for the stage 1 phase current unbalance alarm element is programmed for one element failure.
10
10-18
SRC2 VT FUSE FAIL OP
OR(2)
SRC3 VT FUSE FAIL OP
OR(2)
= VTFF 87V-1 (VO1)
SRC1 VT FUSE FAIL OP
OR(2)
SRC2 VT FUSE FAIL OP
OR(2)
= VTFF 87V-2 (VO2)
SRC1 VT FUSE FAIL OP
OR(2)
SRC3 VT FUSE FAIL OP
OR(2)
= VTFF 87-3 (VO3)
60P alarm 0.9I
=
( )
unbal f1_max
C70 Capacitor Bank Protection and Control System
10 APPLICATION OF SETTINGS
= VTFF 87V-1 (VO1)
= VTFF 87V-2 (VO2)
= VTFF 87V-3 (VO3)
843765A1.CDR

10.4.6 BANK PHASE CURRENT UNBALANCE SETTINGS

×
0.9 0.0209 pu 0.019 pu
= = (EQ 10.24)
GE Multilin