ABB RELION 670 SERIES REG670 Applications Manual page 431

1MRK 502 071-UUS A
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Application manual
V
N
3
=
I
energisation + +
''
X X Z
d T network
ANSIEQUATION2398 V1 EN-US
Where
V is the rated voltage of the generator
N
X '' is the subtransient reactance for the generator (Ω)
d
X is the reactance of the step-up transformer (Ω)
T
Z is the short circuit source impedance of the connected network recalculated to the generator
network
voltage level (Ω)
The setting can be chosen:
I > to be less than 0 8 . ⋅ I
energisation
EQUATION2283 V2 EN-US
tOC: Time delay for trip in case of high current detection due to accidental energizing
of the generator. The default value 0.03s is recommended.
27_pick_up: Voltage level, given in % of VBase, for activation (arming) of the
accidental energizing protection function. This voltage shall be lower than the lowest
operation voltage. The default value 50% is recommended.
tArm: Time delay of voltage under the level Arm< for activation. The time delay shall
be longer than the longest fault time at short circuits or phase-ground faults in the
network. The default value 5s is recommended.
59_Drop_out: Voltage level, given in % of VBase, for deactivation (dearming) of the
accidental energizing protection function. This voltage shall be higher than the
27_pick_up level. This setting level shall also be lower than the lowest operation
voltage. The default value 80% is recommended.
tDisarm: Time delay of voltage over the level 59_Drop_out for deactivation. The time
delay shall be longer than tOC. The default value 0.5s is recommended.
Section 9
Current protection
(Equation 231)
(Equation 232)
425