Woodward LS-5 v2 Series - Df;Dt (ROCOF)

The alarm must be acknowledged and
reset by manually pressing the
appropriate buttons or by activating
the LogicsManager output "External
acknowledgement" (via a discrete
input or via an interface).
3056 Monitoring lockable 2 Yes Monitoring for fault conditions is only
performed if "Lock Monitoring Status
24.40" is false.
[No] Monitoring for this fault condition is
continuously enabled regardless of
"Lock Monitoring Status 24.40".
4.3.1.4 df/dt (ROCOF)
General notes
df/dt (rate of change of frequency) monitoring measures the stability of the frequency.
The frequency of a source will vary due to changing loads and other e󰈠ects. The rate of
these frequency changes due to the load variances is relatively high compared to those of
a large network.
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 di󰈠erentiated from a phase shift. This results in a
minimum response time of approximately 100 ms (at 50 Hz).
The "df/dt (ROCOF)"
con󰈡guration parameters are located below the "SyA. decoupling"
function menu on the display.
ID Parameter CL Setting range
[Default]
Description
3104 Limit 2 0.1 to 9.9 Hz/s
[2.6 Hz/s]
(Hysteresis: 0.1 Hz/s)
(Reset Delay: 80 ms)
The df/dt threshold is de󰈡ned here. If
this value is reached or exceeded for
at least the delay time without
interruption, an alarm with the class
con󰈡gured in parameter
3101 is
initiated.
The decoupling procedure will open
the CBA.
3105 Delay 2 0.10 to 2.00 s
[0.10 s]
If the monitored rate of df/dt exceeds
the threshold value for the delay time
con󰈡gured here, an alarm will be
issued.
If the monitored df/dt exceeds the
threshold (plus the hysteresis) again
102 LS-5 v2 Series 37650
4 Con󰈡guration
4.3 Con󰈡gure Monitoring
Released