The threshold curve results from seven configurable points and a linear interpolation
between these points.
shows an example of a Low-Voltage-Ride-Through
(LVRT) curve for time-dependent voltage monitoring. The curve is configured by default
according to a typical grid code requirement.
Rules for configuration
The time points should always have an ascending order. The fallback threshold
(parameter
) should always be configured to a value higher/lower than the
initial threshold (parameter
The monitoring on undervoltage over the undervoltage curve (or overvoltage or
overvoltage curve) is always active, if the »Monitoring« (parameter
) is enabled.
A mains decoupling is only executed, if the generator runs parallel to mains.
The monitor behaves according to the configured »AND characteristic« (parameter 4960).
When the AND characteristic is configured to "On", all 3 phases are taken into account.
Only if all phases are below/above the configurable curve, the monitor will trip. When the
AND characteristic is configured to "Off", the single phases are taken into account. Even if
only one phase runs below/above the configurable curve, the monitor will trip.
The monitoring starts with passing the initial threshold. The tripping time is determined
by the voltage deviation and its according curve location. The monitoring is disabled, if
the voltage value (values) have crossed the fallback threshold. The monitor trips the
LogicsManager command variable 10877 "07.28 Time-dep. voltage 1".
FRT Monitoring Characteristic
The monitoring type influences the FRT:
Parameter "Mains voltage monitoring"
determines, if the Ph-Ph, Ph-N, or all
measurements are used.
If type "All" is available and configured, and 3Ph4W is configured, "Time dependent
Voltage Monitoring" is calculated with phase-phase and phase-neutral voltages. If All and
1Ph3W is configured, only PH-N values are used.
The mains time-dependent monitoring works with configurable FRT characteristics. In
conjunction with mains voltage measuring (ID1853) and mains voltage monitoring (see
section before) different monitoring procedures take place.
Bloking ROCOF Monitor During Dynamic Mains Stabilization
Due the higher prioritization of the Dynamic Mains Stabilization (FRT) as the ROCOF
monitor, the ROCOF monitor must be disabled for longest 5 seconds when any FRT curve
was initiated. Therefore each FRT (=Time-dependent voltage monitoring) function
provides a flag. The flag is set, if the particular initiation threshold is passed. The flag is
reset if all monitored voltages are back in band (parameter
).
The 3 flags are OR’ed and results in one “FRT initiated” flag. This flag will be kept TRUE
for maximal 5 seconds. Finally this ROCOF blocking flag will be inverted and entered as
LM Command Variable “07.34 FRT ROCOF enable”.
512
easYgen-3000XT Series
B37574
4 Configuration
4.5.3.10.1 Time Dependent Mains Voltage Monitor 1
Released