the generator from service. A settable time delay tAlarm is provided for the alarm
function to avoid false alarms during short-time unbalanced conditions.
9.13 Accidental energizing protection for synchronous
generator AEGPVOC
(50AE)
GUID-B8AED221-36B4-45C3-8FD9-713DAAB4A365 v2
9.13.1 Identification
GUID-E8C9B9EB-A74D-49DE-A656-4B56772017E2 v2
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Accidental energizing protection for
synchronous generator
AEGPVOC U<I> 50AE
9.13.2 Application
GUID-1B7CD464-5995-48D0-AA3D-8430AF20EB1A v5
Operating error, breaker head flashovers, control circuit malfunctions or a combination
of these causes results in the generator being accidentally energized while of
fline.
Three-phase energizing of a generator that is at standstill or on turning gears causes it
to behave and accelerate similarly to an induction motor. The generator, at this point,
essentially represent sub-transient reactance to the system and it can draw one to four
per unit current depending upon the equivalent system impedance. This high current
may thermally damage the generator in a few seconds.
Accidental energizing protection for synchronous generator AEGPVOC (50AE)
monitors maximum phase current and maximum phase-to-phase voltage of the
generator. In its basis it is “voltage supervised over current protection”. When
generator voltage fails below preset level for longer than preset time delay an
overcurrent protection stage is enabled. This overcurrent stage is intended to trip
generator in case of an accidental energizing. When the generator voltage is high again
this overcurrent stage is automatically disabled.
9.13.3 Setting guidelines
GUID-0BFF0648-AA6A-40D1-B935-82CB891E4B16 v5
IPickup: Level of current trip level when the function is armed, that is, at generator
standstill, given in % of IBase. This setting should be based on evaluation of the largest
current that can occur during the accidental energizing: I
energisation
. This current can be
calculated as:
Section 9 1MRK 502 071-UUS A
Current protection
424 Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Application manual
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