SYSTEM CONFIGURATION
when the OPR MODE SELECT switch is in the
AUTO position. The indicator portion is
The electrical system is designed so that two
illuminated when that condition exists. When one
generators can supply all electrical loads. The
of the switches is depressed, it will cause the
third SSGTGS can be put on standby. Then it can
indicated generators to be paralleled.
automatically be started and synchronized to the
bus if one or both of the on-line generators should
fail. Automatic failure detection and recovery is
available only when the EPCC is in control and
in automatic mode. Also, the electric plant must
be in a standard parallel plant or standard split-
plant configuration. The different types of
configurations are the standard parallel-plant
configurations, the standard split-plant con-
figurations, the nonstandard plant configurations,
TURBINE OVERLOAD
and the emergency configurations.
PROTECTION SYSTEM
Standard Parallel-Plant Configurations
The TOPS is an automatic protection system
to prevent an overload/overtemperature condition
A standard parallel-plant configuration
from developing on the remaining SSGTG should
consists of two generators online and paralleled,
one of the paralleled generators fail. Primary
with all BTBs closed, connecting the three main
power is 120 volts ac and is converted into the
SWBDs in a loop system. Configuration status
required dc voltages needed for operation. The
logic at the EPCC identifies the on-line generators
system has an internal battery to provide a backup
for auto recovery control.
source on power failure.
The TOPS control unit receives analog inputs
from the PAMISE, such as SSGTGS inlet
temperature, rpm, and kilowatt. The control unit
also receives digital inputs from the EPCC, such
as GB, BTB, and shore power circuit breaker
status. The control unit will process the signals
and provide a listing, or menu, to the display unit.
The display unit is essentially a video display
terminal with a pressure-sensitive surface. The
operator touches the surface to select the menu
Standard Split-Plant Configurations
to be displayed.
Another series of output signals from the
A standard split-plant configuration consists
control unit go directly to the SSGTGS, SWBD,
of two generators online, but not paralleled. The
and the load shed relay. Based upon the results
off-line generator SWBD is energized through the
of the analysis of the data, the control unit will
bus tie connection to one of the on-line generator
issue the commands to close the bleed air valves,
SWBDs. The remaining bus ties are not energized.
open GBs, and/or initiate load shed. This is done
The configuration status logic at the EPCC can
individually or in combination. The control unit
identify any of these configurations by monitoring
will initiate whatever action is needed to
the open and closed status of the GBs and BTBs.
maintain the vital electrical load.
LOAD CENTERS
The load centers are very similar to the
distribution section of a main SWBD. They are
sometimes referred to as load center SWBDs.
Nonstandard Plant Configurations
They are located at remote locations from the
A nonstandard plant configuration is an open
main SWBDs. The load center uses the same type
loop configuration which energizes all three
of breakers as the main SWBDs to feed the loads.
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