ECON-4 1.4.0 Global Guide
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Transition to parallel from zero local load.
When engine is running without load, speed request from controller is in bias position and engine has a throttle in
Idle position. So if those values are properly set in to ECON4 setpoints while going to parallel, engine startso to
run in SGO Bias and Idle Fuel point on Speed/Fuel line. When request for load is increased in controller, Speed
request is increased and throttle is opened and vice versa.
Transition to parallel from non-zero local load.
There could be situation in SPtm for example, when just GCB is closed and generator supply a local load. So
MCB is opened and GCB is closed and PID with Load parameters is used to control speed and Throttle position.
It is clear than Throttle is not in Idle position but on higher position. Now after synchronization, MCB is closed,
throttle stays in the same position because no Higher Power is generated just after synchronization and Actual
speed request is in Bias position because no power control has been done in previous stage. So there is
difference between actual speed request and speed request corresponding to actual throttle position. This
difference is called Speed request offset and we keep it to make transition burpless. When controller increase
aped request to provide more power to Mains, we move throttle to higher position on the Speed/fuel line and it
works fine. But we can not keep speed request offset all time, because when controller decrease speed request
throttle would go to zero position and even to negative value (theoretically). So we keep Speed request offset
just for one minute from breaker closing and then starts to decrease this offset. This will move throttle down, but
controller will notify decreasing of power and increase speed request. After a while, using this mechanism
Speed request offset oi zero and actual throttle position respects speed request and Speed/fuel line.
Speed request offset is decreased according ramp, which is set in setpoint SGOoffsetRamp. Time in this
setpoint is time needed to change Speed request offset from 10V to 0V.
