ABB REG316 4 Series Operating Instructions Manual page 308

ABB Switzerland Ltd REG 316*4 1MRB520049-Uen / Rev. F
Setting: TripAngle
Phi is evaluated in relation to 'TripAngle' when one of the zones
has reached its number of slips, i.e. n ³ n1 or n2.
For a setting of 'TripAngle' = 180°, the tripping command 'Trip1'
and the signals 'Trip1' and 'Trip2' are issued immediately.
For a setting of 'TripAngle' = 0°, these signals are only issued
when the slip detector has reset, i.e. when the generator is again
close to synchronism with the power system.
A setting of 'TripAngle' between 180° and 0° (typically 90°) de-
termines the rotor angle at which tripping takes place and the
signals are generated.
The setting at which tripping should take place is determined
according to an operating point that
· occurs shortly after the last permissible slip
· is favourable for the circuit-breaker (least stress due to
reignition)
Typical setting: 'TripAngle' = 90°.
Settings: n1, n2, t-Reset
The number of slips n1 or n2 that may be considered permissible
depends on the generator being protected and must be stated by
the manufacturer.
For settings of n1 and n2 £ 1, the reset time 't-Reset' can be set
to any low value.
For settings of n1 or n2 > 1, 't-Reset' must not be set lower than
the period 1/f of the lowest slip frequency f to be detected. Slip
S S
frequencies from 0.2 Hz upwards are reliably detected using the
typical setting of 5 seconds.
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