Miscellaneous Functions - MarelliMotori D-Vo Light Manuel D'utilisation

5.7.

MISCELLANEOUS FUNCTIONS

FUNCTION
Droop Compensation
Soft start
9638571A0_C
When the limiter exits the active state, the limitation, the relevant alarm and the
associated relay, if any, shall be automatically reset.
The function can be enabled/disabled.
DESCRIPTION
This function is used to obtain the desired sharing of the reactive load between
two or more generators operating in parallel.
When the function is enabled, D-Vo calculates the reactive part of the generator
load, starting from the measurements of the phase-to-phase voltage of the
generator and of the currents, and accordingly modifies the generator voltage
setpoint.
•
If the power factor of the load is equal to one, the voltage setpoint will not be
modified.
•
An inductive (lagging) power factor results in a reduction of the generator
output voltage.
•
A capacitive (leading) power factor results in an increase of the generator
output voltage.
Droop can be set within a -20% (max compensation) to 20% (max droop) range.
The function is enabled by the closing of the PAR digital input (C5 contact by
default).
Droop can only be activated in AVR mode.
When Droop is active (PAR digital contact closed), the setpoint cannot be
changed, unless the function Enable voltage setpoint adjustment is enabled in the
Droop compensation tab di D-Vo Dashboard (Paragraph 7.3.4).
The underexcitation limiter (UEL) can also be optionally activated in Droop.
D-Vo provides a Soft Start function allowing to linearly bring the generator voltage
from a settable minimum value V
time, with minimum overshoot, starting from the instant D-Vo receives the
enablement from the START contact.
The chart shown in the following figure refers to the ideal curve the board
processor causes the voltage setpoint to follow to reach 100% of the preset value.
Under actual operating conditions, and at full rpm, the generator voltage may not
start from V , but from a voltage value equal to the residual machine voltage
MIN
when the START command is issued.
D-Vo Light – Marelli Motori
Droop
leading
lagging
reactive load
to the V setpoint value, in a settable T
MIN NOM
20%
20%
1 pu
R
EN 34