Section
10 Control, monitoring, alert and safety systems
10.1 General
10.1.2 The
control system is to ensure safe and effective operation of the gas
turbine package through the monitoring and control of critical parameters,
such as engine speed, temperatures and pressures.
10.1.3 Each
gas turbine is to be configured for the specified performance and
is to satisfy the relevant requirements for mechanical drive or electrical
generator applications.
10.1.4 The
arrangements for control, monitoring, alert and safety systems are
to be provided with a suitable back-up power supply to ensure that
the gas turbine package can be shut down in a safe and controlled
fashion upon loss of its primary and, where applicable, secondary
electrical power supplies.
10.1.5 Interlocks
are to be provided to prevent any operation of the gas turbine unit
under conditions that could be hazardous to the machinery and/or personnel.
The interlock system is to be arranged to be ‘fail safe’.
The characteristics of the ‘fail safe’ operation are to
be evaluated on the basis of the complete installation.
10.2 Overspeed protection and shutdown system
10.2.1 The
gas turbine is to be protected against overspeed by the provision
of a suitable device(s) and software functions capable of shutting
down the gas turbine safely before a hazardous overspeed condition
occurs.
10.3 Speed governors
10.3.1 For
each gas turbine that provides mechanical drive to propulsion device(s),
a speed governor independent of the overspeed protective device is
to be fitted. The speed governor’s set limits are to be adjusted
so that the speed does not exceed the limits which bring the overspeed
protective device into action, see
Vol 2, Pt 2, Ch 2, 10.2 Overspeed protection and shutdown system 10.2.1.
10.3.2 For
each gas turbine intended for driving an electric generator, a speed
governor, independent of the overspeed protective device is to be
fitted. The speed governor’s fixed settings are to control the
gas turbine speed within the design limits of the electrical system
requirements, as defined in the electrical System Operational Concept
document.
10.4 Power turbine inlet over-temperature control
10.4.1 The
power turbine is to be protected against over-temperature by the provision
of a suitable device(s) capable of controlling the temperature within
acceptable limits or shutting down the gas turbine safely to prevent
damage.
10.5 Flame out
10.6 Lubricating oil system
10.6.1 Means
are to be provided to determine accurately the pressure or flow of
the lubricating oil supply to the various parts of the gas generator
and power turbine, and scavenge oil and return systems, to ensure
safe operation.
10.6.2 Means
are to be provided to determine accurately the temperature of the
lubricating oil supply to the various parts of the gas generator and
power turbine, and scavenge oil and return systems, to ensure safe
operation.
10.6.3 Means
are to be provided to ensure that the temperature of the lubrication
oil supply is controlled automatically to maintain steady-state conditions
throughout the normal operating range of the gas turbine.
10.6.4 Where
the lubrication oil supply to the power turbine is fed from a separate
supply system, similar arrangements to those detailed above are to
be provided.
10.7 Stopping of gas turbines
10.7.1 Means
are to be provided, at both the local and remote control/operating
positions, to initiate manually the shutdown of the gas turbine in
an emergency.
10.8 Indication of temperature
10.8.1 Means
are to be provided for indicating the temperature of power turbine
exhaust gases.
10.9 Automatic and remote controls
10.9.1 Where
gas turbines are fitted with automatic or remote controls so that
under normal operating conditions they do not require manual intervention
by the Operators, they are required to be provided with alarm and
safety arrangements required by Vol 2, Pt 2, Ch 2, 10.9 Automatic and remote controls 10.9.2 and Table 2.10.1 Gas turbine machinery: Alarms and
shutdowns, as appropriate. Alternative
arrangements which provide an equivalent level of safety will be considered.
Table 2.10.1 Gas turbine machinery: Alarms and
shutdowns
| Item
|
Alarm
|
Note
|
| Overspeed
|
High
|
Automatic shutdown,
see also
Vol 2, Pt 2, Ch 2, 10.2 Overspeed protection and shutdown system
|
| Power
turbine inlet temperature
|
1st
stage high
|
Automatic
power reduction
|
| See Note 4
|
2nd stage high
|
Automatic shutdown, see also
Vol 2, Pt 2, Ch 2, 10.4 Power turbine inlet over-temperature control
|
| Flame
failure
|
Failure
|
Automatic shutdown, see also
Vol 2, Pt 2, Ch 2, 10.5 Flame out
|
| Failure to ignite
|
Failure
|
Automatic shutdown, see also
Vol 2, Pt 2, Ch 2, 10.5 Flame out
|
| Turbine
vibration
|
1st stage
high
|
–
|
| 2nd stage high
|
Automatic shutdown
|
| Uptake
temperature
|
High
|
To monitor for soot
fires
See Notes 5 and 6
|
Note
3 Where there are separate lubricating
oil systems for gas generator and power turbine/gearing sections, each
system is to be monitored.
Note
4 Where there is more than one combustion
chamber, the temperature of each chamber is to be monitored.
Note
5 Alarm only required when suitable for
operation on residual fuel grades and an exhaust gas
economiser/boiler/thermal oil heater is fitted.
Note
6 Alternatively, details (including
location) of an appropriate fire detection system are to be submitted
for consideration.
Note
7 The Table contains the minimum list of
alerts and shutdowns for a gas turbine; additional alerts and
shutdowns may be necessary as determined through risk-mitigating
activities in response to the completed Risk-Based Analysis (e.g.
FMECA) for the gas turbine.
Note
8 If certain alarms and shutdowns are not
applicable for the gas turbine, sufficient evidence shall be produced
to support the claim (e.g. Risk-Based Analysis such as FMECA).
|
10.9.3 Where
a first stage alarm together with a second stage alarm and automatic
shutdown of machinery are required in Table 2.10.1 Gas turbine machinery: Alarms and
shutdowns, the sensors and circuits utilised for the second stage
alarm and automatic shutdown are to be functionally independent of
those required for the first stage alarm, in that failure in one cannot
affect the functionality of the other.
10.10 Sensors
10.10.1 Sensors
are to be selected with regard to their accuracy and integrity. For
measurements required for safety functions, an engineering assessment
is to be presented justifying the sensor configuration adopted. This
assessment is to address any self-testing by the control system that
is used to monitor the health of those sensors.
10.10.2 Where
multiple sensor arrays are used to provide the necessary levels of
reliability and integrity, the control system is to use the value
that provides the greatest margin of safety.
10.11 Control engineering systems
10.11.1 The
engine control, monitoring, alert and safety systems are to be configured
to comply with the relevant requirements (e.g. operating profile,
alarms, shutdowns, etc.) of this Chapter and Vol 2, Pt 9, Ch 7 Control, Alerts and Safety Systems for an engine for main or auxiliary power purposes.
Details of the engine configuration are to be submitted for consideration
identifying:
-
Local and remote
means to carry out system configuration.
-
Engine packager
or system integrator procedures for undertaking configuring.
-
Roles and responsibilities
for configuration (e.g. Enginebuilder, engine packager, system integrator
or other nominated party) with accompanying schedule.
-
Configurable
settings and parameters (including those not to be modified from a
default value).
-
Configuration
for propulsion or auxiliary engine application.
Configuration records are to be maintained and are to be made
available to the Surveyor at testing and trials and on request, in
accordance with Vol 2, Pt 9, Ch 7 Control, Alerts and Safety Systems.
10.12 Software
|