Woodward easYgen-2000 Series User Manual page 152

Configuration
Configure Monitoring > Mains > Change Of Frequency
Fig. 82: Phase shift
df/dt (ROCOF)
ID Parameter
3058 Change of fre‐
quency
3053 Phase shift:
Monitoring
152
A vector/phase shift as shown in Fig. 82 causes a premature or
delayed zero passage. The determined cycle duration difference
corresponds with the occurring phase shift angle.
The monitoring may be carried out three-phased or one/three-
phased. Different limits may be configured for one-phase and
three-phase monitoring. The vector/phase shift monitor can also be
used as an additional method to decouple from the mains. Vector/
phase shift monitoring is only enabled after the monitored voltage
exceeds 50 % of the PT secondary rated voltage.
df/dt (rate of change of frequency) monitoring measures the sta‐
bility of the frequency. The frequency of a source will vary due to
changing loads and other effects. The rate of these frequency
changes due to the load variances is relatively high compared to
those of a large network.
CL Setting range Description
[Default]
2 [Phase shift] Phase shift monitoring is carried out according to the parameters described in
Ä "Phase shift" on page 151 .
df/dt
df/dt monitoring is carried out according to the parameters described in
dt (ROCOF)" on page 152 .
Off Monitoring is disabled.
2 [1- and 3 During single-phase voltage phase/vector shift monitoring, tripping occurs if
phase] the phase/vector shift exceeds the configured threshold value (param‐
eter
3 phase During three-phase voltage phase/vector shift monitoring, tripping occurs only
if the phase/vector shift exceeds the specified threshold value (param‐
eter
easYgen-2200/2500 | Genset Control
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, that the
power circuit breaker that disconnects from the mains,
is opened, the message "Mains phase shift" is dis‐
played, and the logical command variable "07.14" is
enabled.
The prerequisite for phase/vector shift monitoring is
that the generator is operating in a mains parallel oper‐
ation (the MCB and GCB are both closed).
Function "Rate of change of frequency not within
permissible limits"
The control unit calculates the unit of measure per unit
of time. The df/dt is measured over 4 sine waves to
ensure that it is differentiated from a phase shift. This
results in a minimum response time of approximately
100ms (at 50 Hz).
3054 Ä p. 153) in at least one of the three phases.
3055 Ä p. 153) in all three phases within 2 cycles.
Ä "df/
37535B