Manual 37278B GCP-30 Series - Genset Control
Page 102/174 © Woodward
Phase/Vector Shift Monitoring dϕ/dt
A phase/vector shift is a sudden change in the voltage curve that is caused by a large generator load change. The
measuring circuit detects a change in a single sine wave. This sine wave is compared with a calculated mean val-
ue from previous measurements. Monitoring encompasses all three phases. The threshold value in degrees speci-
fies the difference in time between the mean and the measured value in reference to a full cycle. Monitoring can
be set in various manners. The phase/vector shift watchdog may be used as an additional means for decoupling
from the mains. The minimum voltage that the phase shift is activated is 70 % of the rated secondary voltage.
Function: "Voltage cycle duration not within the permissible range" - The voltage cycle duration exceeds the
configured limit value for the phase/vector shift. The result is the power circuit breaker that disconnects from the
mains is opened and an alarm message is displayed. The prerequisite for phase/vector shift monitoring is that the
generator is operating in a mains parallel operation (the MCB and GCB are both closed).
Parameter 216
Phase shift
monitoring ON
Phase/vector shift monitoring ON/OFF
ON ................ Monitoring of the mains frequency will be performed for
phase/vector shift. The subsequent parameters of this function are
displayed.
OFF .............. Monitoring is disabled, and the subsequent screens of this function
are not displayed.
Parameter 217
Monitoring
----------------
Phase/vector shift monitoring one-/threephase / only threephase
one-/threephase..During single-phase voltage phase/vector shift monitoring, trip-
ping occurs if the phase/vector shift exceeds the configured threshold
value (Parameter 218) in at least
one of the three phases. Note: If a
phase/vector shift occurs in one or two phases, the single-phase thre-
shold value (Parameter 218) is taken into consideration; if a
p
hase/vector shift occurs in all three phases, the three-phase thre-
shold value (Parameter 219) is taken into consideration. Single phase
m
onitoring is very sensitive and may lead to nuisance tripping if the
selected phase angle settings are too small.
only threephase..During three-phase voltage phase/vector shift monitoring, trip-
ping occurs only if the phase/vector shift exceeds the specified thres-
hold value (Parameter 219) in all three phases within 2 cycles.
Issuing of class F0 alarm
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