Alarms on the EPCC are of two types: hardwired
incorporates a variety of control and monitoring
a n d processor generated. Hardwired alarms come
d e v i c e s . These devices include: alarm and status
directly to the alarm display unit, causing an alarm to
indicators, generator status, mimic and distribution
sound and an indicator lamp to illuminate. The operator
control, and plant system control.
c a n cancel the sound by depressing the ALARM
In this section, we will briefly discuss the following
ACKNOWLEDGE push button. There are two levels of
control systems that are operated from the EPCC:
audible alarms at EPCC. The first level is a horn that
1. Diesel control and monitoring
signifies a problem that requires immediate operator
action to prevent damage or loss of power. The second
2. Generator monitoring and control
level is a bell for a problem that needs correction as soon
3. Switchboard and distribution monitoring and
as practical.
control
The EPCC controls the diesel for both start-up and
4. Shore power monitoring and control
shutdown. The SSDG can be shut down under normal
conditions or in an emergency. Under emergency
5. Engine fuel oil service system
conditions, some diesel functions must be reset. Once
6. Auxiliary fuel oil service system
the generator set is running, the EPCC controls what
type of voltage regulation will be used and how the
7. Jacket water system
governor will control SSDG speed and load. The
8. Supervisory control system (SCS)
processor in the EPCC can control the operation of the
SSDG when the AUTO mode is selected.
We will provide only a brief discussion of these systems.
Again, refer to the EOSS, the EOP, and appropriate
The EPCC operator can start the generator set if the
technical manuals for a more detailed description of the
L O C A L / R E M O T E switch is ON and all safety
operation of these systems.
conditions are met. Starting from the EPCC can be either
automatic or manual. As engine speed builds up, a fuel
Diesel Control and Monitoring
oil pressure switch opens and de-energizes a pilot
Each SSDG has sensors to provide remote
speed starts to pickup, the governor will maintain SSDG
monitoring of the diesel engine and generator. The
speed. Initially the speed is controlled by the mechanical
sensor information can be viewed either on meters or
governor until the limit setting is reached. Then as
the DDI. Sensor signals are of two types: analog and
generator voltage builds up, the electrical governor
discrete. Analog signals represent parameters, such as
takes over control. A 115-volt ac power supply is
fuel levels, temperature, pressure, or rpm. Discrete
required for the automatic start sequence, although the
signals indicate the occurrence of an event, such as a
start can be accomplished manually.
breaker open, breaker closed, motor running, or motor
Under normal conditions, the engine is stopped, by
not running. Commands are control outputs from the
the operator by pushing the engine STOP push button
EPCC, and some action is expected in response to this
on the local panel or depressing the remote PRIME
signal.
MOVER STOP push button on the EPCC. During this
The EPCC monitors several conditions of the SSDG
stop sequence, the governor actuator is disconnected
and displays them in several ways. The EPCC monitors
from the governor control circuit. Dropping resistors
the diesel for the following conditions:
apply a fixed voltage into the governor actuator, causing
it to go to the shutdown mode. As the engine loses speed,
Engine fuel tank level, fuel pressure, and return
t h e fuel pressure drops and opens a switch that
temperature
deactivates the shutdown condition.
SSDG manifold pressure
An emergency stop can be initiated by the operator
at the EPCC by depressing the EMERGENCY STOP
Diesel fuel temperature
push button. This is the same sequence as the normal
Turbocharger air pressure
shutdown except the air intake system is closed off by
activating the engine air box relay. After an emergency
SSDG lube oil discharge pressure, temperature,
stop, the air intake solenoid must be manually reset.
and sump level
Until it is reset, an engine-mounted shutdown lockout
Engine speed and exhaust temperature
switch will inhibit the engine from being started.
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