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2.3 PROTECTION FUNCTION SETTINGS
For the sample generator system,
motoring power
Set REV PWR to:
REV PWR = 0.5 × 87.3 (functions 32-1 and 32-2)
2
= 43.6 watts
Set TL1 to:
TL1 = 2 or 30 seconds, depending on Setting 803: SQ TR EN.
Set TL2 to:
TL2 = 30 seconds
Algorithm:
K
T
=
------------------------------------ -
⁄
I I
PU
---------------------- - 1
–
⁄
V V
NOM
where: T = Operating time.
K = time factor (Setting 1004: TIME FAC).
I / I
= current in multiple of I
PU
V
= Nominal Voltage (Setting 114: NOM VOLT)
NOM
×
V =
3
phase-to-ground voltage
phase-to-phase voltage for Delta connected VTs
1. Time T is computed individually for each phase.
2. See the table below for the restraint voltages corresponding to phase currents for different PHASE (Setting
109) and VT CONN (Setting 116) settings.
3. If the quantity V / V
4. If the quantity
---------------------- -
V V
5. Reset Time: Linear reset with maximum of 1.4 seconds.
Table 2–2: 51V RESTRAINT VOLTAGES
CURRENT
PHASE →
ABC
VT →
WYE
I
V
A
I
V
B
I
V
C
2-
22
×
22000 1000
=
------------------------------------------------------------- -
×
CT RATIO
VT RATIO
seconds
(Setting 1003: PICKUP).
PU
for Wye connected VTs (see note 2)
< 0.3, then 0.3 is used as its value in the equation.
NOM
⁄
I I
PU
<
0.3
, then 65.5 is used as its value in the equation.
⁄
NOM
RESTRAINT VOLTAGES
ABC
ACB
DELTA
WYE
V
V
A
AB
A
V
V
B
BC
B
V
V
C
CA
C
DGP Digital Generator Protection System
×
22000
1000
watts
=
----------------------------------- - watts
×
1600
157.5
2.3.7 OVERCURRENT WITH VOLTAGE RESTRAINT (51V)
ACB
DELTA
V
AC
V
BA
V
CB
2 CALCULATION OF SETTINGS
=
87.3 watts
GE Power Management
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