EGCP-2 Engine Generator Control Package Manual 26086
86 Woodward
Point G
A step load decrease on the bus brings the system load down to approximately
35%. All three generators remain on line in isochronous load sharing.
Point H
A further step load decrease on the isolated bus brings the system load below
the Min Gen Load setpoint of 25% to approximately 10%. The master begins
timing for the Reduced Gen Dly time of 30 seconds.
Point J
Since the system load is still below 25%, and the master’s Reduced Gen Dly
timer has expired. The master unit issues a command to Unit 3 (network priority
3) to off load and open its gen breaker. Unit 3 begins to ramp off load. System
load begins increasing. The master begins its Max Stop Time delay of 15
seconds before checking to see system load is low enough to allow sequencing
of another unit off line.
Point K
Unit 3 reaches its unload trip point and opens its generator breaker. The system
load is still below the Min Gen Load setpoint of 25%. The Master’s Max Stop
Time delay has expired. The master begins timing for the next gen off delay time.
Point L
The system load remains below 25%, and the master issues a command to unit
#2 (network priority #2) to off load.
Point M
Unit 2 ramps off load and opens its generator breaker. This leaves the master
unit (network priority #1) on line supplying the load. When required the master
will sequence units on and off line as shown above and determined by the
sequencing setpoints in its Real Load Control tuning menu.
The Master unit in any multiple unit EGCP-2 system is always the unit with the
lowest Network Priority setting. All slave units are then sequenced on line in
ascending order of their Network Priority settings, and sequenced off line in
descending order of their Network Priority Settings. The Master is always
responsible for any automatic sequencing of the slave units on and off line.
In order to give the end user of the EGCP-2 the ability to control engine run time
levels in a multiple unit system, any EGCP-2 in the system can be used to
change the network priority of any of the EGCP-2 units actively on the same
network. For a unit to be active on the network, it must have its Auto discrete
input closed, be configured for Multiple Unit operation, have its Auto Sequencing
setpoint Enabled, and be physically connected to the RS-485 network between
units.
The ability to change the priority of any unit on the network has some
fundamental rules associated with making changes to the unit priority. These
rules have to do with assuming a new master, changing the sequence of on load
units, and permissive sequence change states.
To Next Page
Loading...
