- 66 -
The start signal is the value of the maximum required
load step.
The stop signal is the value when the generator should
be stopped automatically.
Example: Installation with 3 gensets
G1 = 300 kW; G2 = 200 kW; G3 = 200 kW.
– Start signal is set at 90 kW (maximum load step <
90 kW).
Start signal if:
Total Power needed > (total available power of
running gensets -set point start signal).
• Only G1 is running; at 210 kW load (300 kW
- 90 kW) => G2 will be started.
• G1 & G2 are running; at 410 kW load (200 kW
+ 300 kW - 90 kW) => G3 will be started.
– Stop signal is set at 100 kW and priority is set as
(high) G1 > G2 > G3 (low).
Stop signal if:
Total Power needed < (Total available power of
running gensets - Power of generator with lowest
priority - set point stop signal).
• G1 & G2 & G3 are running; at 400 kW
(700 kW - 200 kW - 100 kW) => G3 will be
stopped.
• G1 & G2 are running; at 200 kW (500 kW -
200 kW - 100 kW) => G2 will be stopped.
The priority on starting & stopping the generators can
be chosen on priority settings or on the amount of
running hours. In manual mode the start & stop
sequence is determent by the chosen priority between
the generators. The generator with the lowest priority
will start as the latest genset and will stop as first. If
running hours are chosen as priority the start & stop
sequence will be defined based on the actual running
hours of the different generators. The lowest running
hours will get the highest priority.
Paralleling
Prior to starting parallel operation of two generators,
following connections need to be made:
– Connect the communication cable between the
generators (sockets X30 & X31).
Each dedicated generator or SAPE has two of
these connections, to enable paralleling more than
two generators.
– Connect the load with the generator.
Go via the site distribution panel (to be installed
by the customer) to connect the generator(s) and/
or the SAPE unit(s) with the load. Always connect
generator with the load, and never directly with
second generator.
When paralleling generators with
PMS, it is no longer necessary to use
the analogue load sharing lines. This
will be done through the PMS
communication lines. Use a screened
CAN communication cable with a
maximum total distance of 200
meters. Do not connect the cable
screen to the ground! Use a 120
Ohm resistor at both end controllers
of the PMS.
For more information on this
option, see User Manual Qc4002™.
When paralleling, make sure to
disable the Earth leakage relay by
putting switch S13 into off position.
QAS 1
QAS 2
Site distribution
panel
Load
CORRECT
QAS 1
QAS 2
Load
WRONG
Summary of Contents for QAS 500 Volvo S2A APP
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Page 114: ...Printed in Belgium 05 2009 2954 3870 00 www atlascopco com...
