Manual 37143A
MFR 15 - Protection Relay & Control
© Woodward
Page 61/119
Reactive Power Distribution (
Option O
)
In isolated operation in parallel with other gensets, the function ensures an even distribution of reactive power to
all machines operating in parallel with the busbar. Each controller involved in distribution control influences the
machine to which it is assigned in such a manner that the rated voltage (main control variable) which has been set
remains constant. All units are interlinked via terminal Psum (terminal 57), via which any deviation in reactive
power (generator power) can be determined for each machine. This secondary control variable is taken into con-
sideration on controlling the voltage. The weighting, with which the secondary and the main control variable
(= "reference variable") processed, can be set via a factor. In the adjusted state, the isolated system has the set
rated power, the total reactive power being divided in equal parts among the machines involved in the distribu-
tion control.
NOTE
This control does not perform active load sharing. This requires the speed controller to be set up for
parallel operations (i.e. droop mode).
Prerequisite
The following parameters
must
be configured identically for each unit that will participate in load sharing:
•
Voltage controller set point
•
Reactive power load sharing must be enabled
•
The discrete input "Isolated operation" is energized on all units participating in load sharing
Reactive power
Load share ON
Active power distribution
ON/OFF
ON
................ Reactive power is distributed to several generators operating in paral-
lel. The generator outputs are distributed depending on the set value.
The subsequent screens of this option are displayed.
OFF
.............. No distribution is carried out, and the subsequent screens of this op-
tion are not displayed.
React.load share
Voltage = 00%
Reactive-power distribution reference variable
10 to 99 %
Increasing the weighting factor increases the influence of the main control variable
(voltage) on the controlling. The smaller the factor which is set, the greater the in-
fluence of the secondary control variable (generator reactive power). The behavior
of voltage control (isolated operation) is determined by the main control variable,
that of reactive-power distribution by the secondary control variable.
