ABB REG316 4 Series - Page 653

Numerical generator protection
ABB Switzerland Ltd
Utility Automation
REG316*4
1MRK502004-Ben
Page 25
Table 35: Dead machine protection (51, 27)
Features:
· Quick separation from network at accidental energization of generator (e.g. at stand-still or on turning
gear)
· Instant overcurrent measurement
· Voltage-controlled overcurrent function e.g. blocked at voltage values >0.85 U
N
This function does not exist in the library, it must be combined from the voltage, current and time function
Settings:
Voltage 0.01 to 2 U
N
in steps of 0.002 U
N
Reset delay 0 to 60 s in steps of 0.01 s
Current 0.02 to 20 I
N
in steps of 0.02 I
N
Delay 0.02 to 60 s in steps of 0.01 s
Table 36: 100% Stator earth fault protection (64S)
Features:
· Protection of the entire stator winding, including star points, even at standstill. Works also for most of
the operating conditions.
· Also suitable when 2 earthings (groundings) are in the protection zone
· Permanent supervision of the alsostate of the insulation
· Based on the earth (ground) voltage displacement principle and calculation of the earth (ground) fault
resistance
· Alarm and tripping values are entered, resp. measured and displayed in kW
Type of earthings (groundings):
· Star point earthing with resistors (requires REX011)
· Star point earthing with grounding transformer (requires REX011-1)
· Earthing transformers on generator terminals (requires REX011-2)
Settings:
Alarm stage 100 W to 20 kW in steps of 0.1kW
Delay 0.2 s to 60 s in steps of 0.1 s
Tripping stage 100 W to 20 kW in steps of 0.1kW
Delay 0.2 s to 60 s in steps of 0.1 s
R
ES
400 W to 5 kW in steps of 0.01kW
Number of star points 2
R
ES
-2. starpoint 900 W to 30 kW in steps of 0.01kW
Reset ratio 110% for setting values of £10 kW
Accuracy 0.1 kW to 10 kW: <±10%
Starting time 1.5 s
Functional requirements:
- max.earthing current I
0
<20A (recommended I
0
= 5A)
- stator earthing capacity 0.5 mF to 6 mF
- stator earthing resistance R
PS
130 W to 500 W
- stator earthing resistance R
ES
700 W to 5 k W (³4.5 x R
PS
)
(All values are based on the starpoint side)
The actual earthing resistances R
ES +
R
PS
have to be calculated in accordance with the User’s Guide:
The 100% stator earth fault protection function always requires an injection unit type REX010, an injection
transformer block type REX011 and a 95% stator earth fault protection function.