System Backup Overcurrent - GE Multilin g60 Instruction Manual
Ur series generator protection system
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Also See for Multilin g60:
- Instruction manual (780 pages) ,
- Communications manual (532 pages) ,
- Instruction manual (696 pages)
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10 APPLICATION OF SETTINGS
To prevent maloperation for power swings the element is typically time delayed by 20 to 30 seconds. For sequential tripping
applications the time delay will be 2 to 3 seconds. The element may be blocked when the generator is offline. The line
source will be used for this application. Make the following changes in EnerVista UR Setup or through the
GROUPED ELEMENTS
SETTING GROUP 1
Sequential tripping logic can be implemented in FlexLogic™ as follows:
54
55
56
57
System backup protection is implemented using a phase time overcurrent element with voltage restraint enabled. The
NEUTRL source will be chosen for this element. The pickup of this element should be set at a safe margin above the max-
imum load expected on the machine.
PICKUP
The selection of all standard curves (and FlexCurves™) is allowed for easy coordination with system relaying. For the
example system, an IEEE extremely inverse curve will be used and a setting will be chosen such that the operate time for a
three phase fault on the high side of the transformer is 0.75 seconds. For simplicity, the power system contribution is not
considered.
Transformer Impedance
Fault Voltage
=
Pickup Reduction
The equation for an IEEE extremely inverse curve is as follows:
GE Multilin
SENSITIVE DIRECTIONAL POWER
DIR POWER 1 STG2 OP
INLET VALVE OFF(H8A)
AND(2)
= SEQ TRIP (VO9)
Figure 10–2: SEQUENTIAL TRIPPING FLEXLOGIC™
Generator Nominal Current
----------------------------------------------------------------------- -
1.5
=
CT Primary
211.765
-------------------- -
0.10
=
200
Impedance to Fault
0.216
=
1
V
-------------- -
Fault Current
--- -
=
=
0.322
X
Transformer Impedance
--------------------------------------------------------------- -
Nominal Voltage
Total Impedance
Fault Voltage
----------------------------------------------------------------------- -
=
Generator Nominal Voltage
-------------------------------------------------------------------------------------- -
I
T
TDM
=
-------------------------------------------------------------------- -
I
Pickup Reduction
pickup
G60 Generator Protection System
DIRECTIONAL POWER 1
AND(2)
= SEQ TRIP (VO9)
830731A1.CDR
10.1.9 SYSTEM BACKUP OVERCURRENT
6800
------------ -
1.5
1.275 pu
=
=
8000
0.106 pu on machine base
=
0.106
0.322 pu
+
=
6800
------------ -
2.64 pu
=
8000
10.6
---------- -
18 kV
=
32.2
5.93 kV
------------------- -
0.329
=
=
18 kV
A
B
+
p
1
–
10.1 SETTING EXAMPLE
SETTINGS
menu:
(EQ 10.16)
(EQ 10.17)
(EQ 10.18)
(EQ 10.19)
5.93 kV
(EQ 10.20)
=
(EQ 10.21)
(EQ 10.22)
10-5
10
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