Siemens SGT-400 User manual

Turbine Package Operators Manual
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Chapter 1
Turbine Package System Overview
Engine Core Assembly...................................................................................................................5
General Description...................................................................................................................................5
Air Inlet Casing...........................................................................................................................................5
Compressor Inlet Bearing Housing Assembly........................................................................................5
Compressor Stator Casings......................................................................................................................5
Center Casing and Bearing Housing Assembly......................................................................................6
Combustion System..................................................................................................................................6
Compressor Turbine Outer Casing..........................................................................................................6
Compressor Turbine Nozzle Assembly Stage 1 and Duct .....................................................................6
Turbine Rotor Assemblies........................................................................................................................6
Power Turbine Outer Casing and Interduct Assembly...........................................................................7
Power Turbine Bearing Housing ..............................................................................................................7
Exhaust Diffuser ........................................................................................................................................7
Auxiliary Gearbox......................................................................................................................................7
Cooling and Sealing Air System...............................................................................................................7
Turbine Instrumentation............................................................................................................................8
Temperature Monitoring...........................................................................................................................................8
Speed monitoring.....................................................................................................................................................8
Vibration Monitoring.................................................................................................................................................8
Pressure Monitoring.................................................................................................................................................8
Turbine Core Auxiliary Equipment...........................................................................................................9
Variable Guide Vane (VGV) Actuator.......................................................................................................................9
Interstage Bleed Valve.............................................................................................................................................9
P2 Blow-off Valves...................................................................................................................................................9
Waterwash Nozzles..................................................................................................................................................9
Auxiliary Gearbox....................................................................................................................................10
Lubricating Oil System.................................................................................................................11
General Description.................................................................................................................................11
Lubricating Oil Tank...............................................................................................................................................11
Lubricating Oil Pumps............................................................................................................................................11
Temperature Control Valve.................................................................................................................................... 12
Pressure Control Valve..........................................................................................................................................12
Lubricating Oil Filters..............................................................................................................................................12
Oil Cooler Circuit....................................................................................................................................................12

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Oil Mist Eliminator..................................................................................................................................................12
Lubricating Oil Tank Breather System Flame Trap (if applicable)..........................................................................12
Secondary Breather Flame Traps (if applicable)....................................................................................................12
Instrumentation........................................................................................................................................12
Temperature Monitoring.........................................................................................................................................13
Pressure Monitoring...............................................................................................................................................13
Lubricating Oil Tank Level Monitoring....................................................................................................................13
Lubricating Oil System Requirements...................................................................................................13
Fuel System...................................................................................................................................15
General Description.................................................................................................................................15
Gas Fuel System Components...............................................................................................................15
Off-Skid Block and Vent Valve...............................................................................................................................15
Demister or Filter/Coalescer (if applicable)............................................................................................................16
Pipeline Trace Heating (if applicable).....................................................................................................................16
Fuel Strainer........................................................................................................................................................... 16
Block Valves...........................................................................................................................................................16
Vent Valve..............................................................................................................................................................16
Fuel Control Valve/Actuator Assemblies................................................................................................................16
Electronic Control Unit (ECU).................................................................................................................................17
Fuel Burners........................................................................................................................................................... 17
Igniter.....................................................................................................................................................................17
Instrumentation........................................................................................................................................17
Position Monitoring.................................................................................................................................................17
Pressure Monitoring...............................................................................................................................................17
Temperature Monitoring.........................................................................................................................................18
Burner Instrumentation........................................................................................................................................... 18
Fuel System Requirements.....................................................................................................................18
Air Distribution System................................................................................................................19
Air Distribution System Components....................................................................................................19
Instrument Air Manual Shut-Off Valve and Filter Assembly...................................................................................19
Gas Fuel Module....................................................................................................................................................19
Off-Skid Gas Fuel Block and Vent Valve Assembly...............................................................................................19
Lubricating Oil Module............................................................................................................................................19
P2 Blow-Off Valve Air Manifold..............................................................................................................................20
Engine Auxiliary Module.........................................................................................................................................20
Combustion Air Filter System.................................................................................................................................20
Ignition System .............................................................................................................................21
Introduction..............................................................................................................................................21
General Description.................................................................................................................................21
High Energy Spark Generator.................................................................................................................21
Starting System.............................................................................................................................23
General Description.................................................................................................................................23
AC Electric Drive Motor.......................................................................................................................................... 23
Hydraulic Pump Assembly.....................................................................................................................................23
Hydraulic Motor Assembly......................................................................................................................................23

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Hydraulic Pump Boost Flow Oil Filter.....................................................................................................................24
Starter Clutch.........................................................................................................................................................24
Turbine Underbase, Enclosure and Air Supply/Exhaust Systems............................................25
Introduction..............................................................................................................................................25
Underbase ................................................................................................................................................25
Turbine Acoustic Enclosure ...................................................................................................................25
Ventilation System...................................................................................................................................25
Dampers.................................................................................................................................................................26
Ventilation Inlet and Outlet Silencers.....................................................................................................................26
Ventilation Inlet Filter – Inertial Type (if applicable)................................................................................................26
Ventilation Inlet Filter – Marine Type (if applicable) ...............................................................................................26
Negative Pressure Ventilation Fan(s) (if applicable)..............................................................................................26
Positive Pressure Ventilation Fan(s) (if applicable)................................................................................................26
Instrumentation.......................................................................................................................................................26
Combustion Air System..........................................................................................................................27
Air Inlet Filter - Marine Type (if applicable)............................................................................................................27
Air Intake Filter - Pulse Type (if applicable)............................................................................................................27
Air Intake Silencer..................................................................................................................................................27
Acoustic Lagging....................................................................................................................................................28
Instrumentation.......................................................................................................................................................28
Exhaust System.......................................................................................................................................28
Exhaust Silencer....................................................................................................................................................28
Acoustic and Thermal Lagging...............................................................................................................................28
Instrumentation.......................................................................................................................................................28
Fire & Gas Protection System......................................................................................................29
General Description.................................................................................................................................29
System Control and Operation...............................................................................................................29
System Components...............................................................................................................................29
Heat Detectors.......................................................................................................................................................29
Infra Red (IR) Flame Detectors..............................................................................................................................30
Gas Detectors........................................................................................................................................................30
Ventilation Dampers...............................................................................................................................................31
Extinguishant Bottles..............................................................................................................................................31
Instrumentation........................................................................................................................................31
Pressure Monitoring...............................................................................................................................................31
Position Monitoring.................................................................................................................................................32
Gearbox and Generator................................................................................................................33
Gearbox....................................................................................................................................................33
Generator..................................................................................................................................................33
Cooling System......................................................................................................................................................33
Generator Bearing Lubrication............................................................................................................................... 33
Vibration Monitoring...............................................................................................................................................34
Generator Winding Temperature Monitoring..........................................................................................................34
Anti-condensation Heating.....................................................................................................................................34

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Electrical Operation.................................................................................................................................34
Generator Control System......................................................................................................................34
General Description................................................................................................................................................34
Operation................................................................................................................................................................34
Control Panels and Electrical Equipment Cabinets...................................................................35
Introduction..............................................................................................................................................35
Unit Control System ................................................................................................................................35
General Description................................................................................................................................................36
Human / Machine Interface (HMI)..........................................................................................................................36
Generator Monitoring & Control.............................................................................................................................37
Generator Control Panel (GCP) ..............................................................................................................37
Description.............................................................................................................................................................37
Batteries & Battery Charging System....................................................................................................38
Battery Charger & System Controller.....................................................................................................................38
24 Volt Batteries.....................................................................................................................................................38
24 Volt DC Battery Charger....................................................................................................................................38

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Engine CoreAssembly
The SGT-400 is a twin shaft, simple open cycle; non-regenerative industrial gas turbine designed
for both power generation and mechanical drive applications. The core engine consists of a
radial inlet casing through which air enters the eleven stage axial compressor for compression
prior to entry to the combustion system.
General Description
The combustion system employs reverse flow combustion chambers to mix, burn and expand the
air fuel mixture to drive the twin shaft turbine and exit through the exhaust diffuser.
The integrated compressor and compressor turbine assembly, and separate power turbine rotor
assembly, are supported and located by journal and thrust bearings in the inlet, compressor
turbine and power turbine bearing housings respectively.
An auxiliary gearbox provides ancillary drives for the main lubricating oil pump, the liquid fuel
pump (if fitted), and to provide drive to the turbine from the starting system.
Refer to the SECTIONAL ARRANGEMENT – SGT-400 (MW-1-1) located in this Manual
Volume.
Air Inlet Casing
The Air Inlet Casing is secured to the Inlet Bearing Housing both designed and shaped to provide
a smooth path for the incoming air to the compressor. An inlet screen and a flexible joint, which
accommodates relative movements due to thermal expansion, are fitted to the rectangular casing
entry point to which external ducting is connected.
Compressor Inlet Bearing Housing Assembly
The Compressor Inlet Bearing Housing Assembly, which is mounted on the turbine/auxiliary
gearbox support casing, provides support for the Air Inlet Casing and Low Pressure (LP)
Compressor Stator casing. Provision is made, at the bottom of the casing, for the attachment of
the front gas generator support assembly. A tilting pad journal and thrust bearing assembly
within the housing supports and locates the inlet end of the gas generator rotor.
Compressor Stator Casings
The Compressor Stator Casings consist of an LP Compressor Stator casing and a High Pressure
(HP) Compressor Stator casing.
The LP Compressor Stator casing is split along its centerline, bolted at its forward face to the
Compressor Inlet Bearing Housing assembly, and has a spigot bolted to the center casing at the
rear end. Boroscope access holes are provided in the top half casing to enable examination of
the compressor stator and rotor blades.
Variable geometry inlet guide vanes form the first row of stator vanes, with the subsequent four
rows being variable geometry compressor stator blades, which assist starting and prevention of
compressor surge. An externally mounted operating mechanism controls the movement of the
vanes. The remaining LP stator blades are retained by dovetail grooves in the casing.

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The HP compressor stator casing is in the form of an insert split along its horizontal centerline
and located in the pressure casing back plate. The HP compressor stator blades being retained by
dovetail grooves in the insert.
Center Casing and Bearing Housing Assembly
The Center Casing and Bearing Housing Assembly provide support for the hot end of the gas
generator assembly, including the combustion system and the Compressor Turbine (CT) Outer
Casing. A tilting pad journal bearing provides support for the exit end of the gas generator rotor.
Combustion System
The Combustion System comprises six tubular combustion chambers symmetrically positioned on
the forward face of the Center Casing and Bearing Housing Assembly.
The system is of axial reverse flow design; air leaving the compressor exit nozzle is reversed and
enters the head of the combustion chambers via a swirler plate, which imparts a rapid swirling
motion to the flow to ensure complete mixing of fuel and air.
Compressor Turbine Outer Casing
The CT Outer Casing provides the interface between the Center Casing and Bearing Housing
Assembly and the Power Turbine (PT) Outer Casing and Interduct Assembly. Provisions are
made, at the bottom of the casing, for the attachment of the rear gas generator support
assemblies. Boroscope access holes are provided in the top of the casing to enable examination
of the CT stator and rotor blades.
Compressor Turbine Nozzle Assembly Stage 1 and Duct
Within the Compressor Turbine Nozzle Assembly Stage 1 and Duct are housed the CT1 nozzle
segments, the combustion chamber transition ducts and the CT 2 nozzle assembly. Also, with the
CT2 nozzle segments is the CT 2 retaining shroud, which carries a seal ring between the CT
Nozzle Assembly Stage 1 and Duct and the PT Outer Casing and Interduct Assembly.
Turbine Rotor Assemblies
The turbine rotor assemblies are comprised of two separate assemblies, the CT Rotor Assembly,
and the PT Rotor Assembly.
The Compressor Rotor is a single spool 11 stage axial design made up of a series of discs
carrying dovetail rooted compressor blades, located together with Hirth couplings at the outside
diameter and held together with a single central tension stud bolt. Overhung from the
Compressor rotor and secured to it with a central tension stud bolt is the CT, which is of a two-
stage design. It consists of two rotor discs located on the Compressor spool by means of a
central tension stud and Hirth couplings and carrying fir tree rooted turbine blades.
The Power Turbine is of two-stage axial design, consisting of two-rotor disc located with Hirth
couplings and carrying fir tree rooted turbine blades. The PT rotor is bolted to a solid output
shaft by means of a tension bolt.

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Power Turbine Outer Casing and Interduct Assembly
The Power Turbine Outer Casing and Interduct Assembly are attached to the CT Center Casing
and Bearing Housing and the Spoke Frame Assembly. It provides the mounting for the PT1
Stator assemblies with the Exhaust Diffuser bolted to the Spoke Frame Assembly/PT Support
Assembly.
Power Turbine Bearing Housing
The exhaust diffuser and support assembly from the outer casing rigidly support the Power
Turbine Bearing Housing. The power turbine exit rotor shaft is supported in two tilting pad
journal bearings and provided with main and reverse thrust bearings.
Exhaust Diffuser
The lagged Exhaust Diffuser, mounted from the turbine pressure casing provides diffusion of the
exhaust gases for the exhaust ducting system.
Auxiliary Gearbox
The auxiliary Gearbox is mounted via an adapter ring directly off the gas generator inlet bearing
housing and driven from the gas generator shaft. It contains the necessary auxiliary drives for
the hydraulic starter motor and its associated clutch, and the main lubricating oil pump.
Cooling and Sealing Air System
Compressor air is used for sealing at labyrinth seals and cooling of high temperature
components. Refer to the COOLING AND SEALING AIR SYSTEM DIAGRAM – SGT-400
(MW-2-1) located in this Manual Volume. Medium pressure air, taken from the bleed band at
the seventh stage of the compressor, is used to:
•Pressurize the inlet labyrinth seal.
•Pressurize the labyrinth seals located either side of the compressor turbine journal
bearing to prevent stage ten high-pressure air entering the bearing housing.
•Pressurize the labyrinth seals of the PT and cool the turbine discs.
Stage ten high-pressure bleed air taken from before the compressor exit guide vane is used to:
•Balance the medium pressure air used to pressurize the labyrinth seals at the compressor
journal bearing.
•Cool the turbine rotor discs and the interstage diaphragm.
Compressor exit air is used to:
•Cool the CT1 and CT2 nozzle assemblies via holes in the nozzle inner and outer carrier
rings into the cooling tube of each nozzle followed by discharge into the gas stream by
trailing edge slots.
•Cool the CT1 and CT2 rotor blades via their triple pass convection system prior to being
ejected into the gas stream.
Used medium pressure air is vented to atmosphere through the secondary breather system.
Used stage ten high-pressure air is vented into the exhaust system through the primary breather
system.

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Turbine Instrumentation
Instrumentation is provided to monitor the turbine parameters and provide warning and trip
control functions.
Refer to the Turbine Instrumentation schematic diagram located in this Manual Volume.
Temperature Monitoring
Temperature detectors (RTD1 and RTD48) mounted in the air inlet casing, and thermocouples
(TC1 to TC13 inclusive), mounted in the gas generator exhaust outlet, monitor compressor
turbine operating temperature and temperature deviation. Additionally the output thermocouples
monitor combustion condition and will shut the turbine down in the event of flame out in one of
the combustion chambers. A further two thermocouples (TC101 and TC102) are mounted in the
exhaust ducting, downstream of the exhaust diffuser, as part of the turbine gas path
instrumentation for turbine control.
Thermocouples (TC17 and TC18), mounted in the Center Casing and Bearing Housing Assembly,
measure the compressor exit temperature.
Thermocouples (TC21 to TC28, and TC91, TC92, TC96 and TC227) positioned in the appropriate
bearings, measure journal and thrust bearing temperatures.
Speed monitoring
Speed probes (SD20 to SD23) are used for speed detection and overspeed protection in the gas
generator, and speed probes (SD24 to SD27) are used for speed control indication and
overspeed protection in the power turbine. Probes monitor from the gas generator rotor shaft
and power turbine rotor shaft.
Vibration Monitoring
X-Y non–contacting vibration probes (UD10X1 UD10Y1, UD11X1, UD11Y1, UD12X1, UD12Y1 and
UD13X1 UD13Y1) are provided adjacent to each rotor journal bearings, within the gas generator
and power turbine, to monitor radial vibration. Probes (UD10X2 UD10Y2, UD11X2 UD11Y2,
UD12X2 UD12Y2, UD13X2 and UD13Y2) are fitted as non–active spares.
Axial vibration detection probes (ZD10T1 and ZD10T2) are provided at the gas generator input
end thrust bearings.
Keyphasors (ND10K1 and ND12K1) are provided at the gas generator input end bearing and
power turbine output end bearing respectively, (ND10K2 and ND12K2) are fitted as non-active
spares.
Pressure Monitoring
Pressure transmitters are provided to facilitate engine control as follows:
•Air inlet pressure (PT7).
•Turbine compressor discharge pressure (PT8).
•Interduct static pressure (PT258).

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Turbine Core Auxiliary Equipment
Variable Guide Vane (VGV) Actuator
The purpose of the variable guide vane (VGV) system is to vary the flow through the gas
generator to optimize starting and running conditions. This is achieved by altering the angles at
which the inlet guide vanes and the first three stages of compressor blades are presented to the
airflow. The position of the blades is altered by the operation of the mechanically linked VGV
actuator.
The electrical VGV actuator (ZZ8) consists of an actuator and servo positioner assembly. The
assembly is mounted on the turbine to vary the position of the inlet guide vanes and the first,
second, third and fourth stages of compressor stator blades.
The actuator position is controlled by the servo positioner, which reacts to drive signals (ZC4)
from the unit control panel. The unit control panel monitors the position of the VGS blades/inlet
guide vanes using a proportional feedback signal (ZT9) from the VGS actuator.
Interstage Bleed Valve
To prevent gas generator surge during starting, it is necessary to reduce the compressor delivery
air pressure. This is achieved by the use of the interstage bleed valve, mounted on the upper
low-pressure compressor stator casing.
During the turbine starting sequence, as the compressor speed increases, control air is bled from
the delivery stage of the compressor and routed through a pilot valve (XV60) onto the piston of
the interstage bleed valve (XV59). As the air pressure increases, the piston is pushed to its full
extent of travel, thus closing off the air being vented to atmosphere.
Operation of the pilot valve is achieved by instrument air controlled by a solenoid mounted in the
instrument air pipeline.
P2 Blow-off Valves
Blow-off valves (XV267 and XV268) are mounted on the port and starboard sides of the turbine
to modulate engine compressor air during starting and to enable a rapid discharge of air during
engine over-speed conditions.
This is achieved by bypassing engine air from upstream of the power turbine through the blow-
off valves into the exhaust diffuser.
The blow-off valves are operated by solenoid valves (port - SOL625, SOL627 and starboard -
SOL626, SOL628). The solenoids direct P2 air to either side of the valve actuators (XV267 and
XV268). The solenoid valves are operated by a drive signal (ZC43, ZC44) from the unit control
panel. The unit control panel monitors the position of the P2 blow-off valves using a proportional
feedback signal (ZT141, ZT142) from the P2 blow-off valve butterfly spindles.
Waterwash Nozzles
Waterwash nozzles are mounted in the engine air inlet to facilitate the supply of wash and rinse
fluids into the turbine during engine hot and cold wash operations. A last chance filter (XF27)
ensures filtration of the wash/rinse fluids.

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Auxiliary Gearbox
The auxiliary gearbox is mounted via an adaptor ring directly off the gas generator inlet bearing
housing and driven from the gas generator shaft. It contains the necessary auxiliary drives for
the hydraulic starter motor and its associated clutch, and the main lubricating oil pump.

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Lubricating Oil System
Mineral lubricating oil is used to lubricate and cool the turbine journal and thrust bearings, the
generator bearings and the gearbox bearings, gears and splines. The oil is also used as a
hydraulic oil to operate the hydraulic starting system when starting the turbine.
General Description
The oil is delivered from an on-skid lubricating oil tank and circulated throughout the lubricating
system under normal running conditions by a main oil pump. The system includes a temperature
control valve, pressure control valve, filter, instrumentation and associated piping to provide the
correct delivery conditions.
The used oil is returned to the tank by gravity drainage to create a continuously circulating
system.
Heat is removed from the oil by an oil cooler circuit, which is controlled by the temperature
control valve.
A lubricating oil tank breather system is provided to vent to atmosphere oil fumes that are
generated whilst the turbine is running.
A schematic diagram of the lubricating oil system is located in this Manual Volume.
Lubricating Oil Tank
The lubricating oil tank is integrated into the underbase fabrication and is provided with internal
baffles to aid circulation and maximize removal of entrapped air. Covers are provided to facilitate
cleaning of the interior if contamination occurs.
The tank is fitted with immersion heater(s) to maintain the correct pre-start oil temperature.
Integral thermal protection is provided.
Flip lid filler point(s) with integral strainers are provided for filling and replenishment.
Level gauge(s) provide visual indication of the oil level within the oil tank.
Lubricating Oil Pumps
Three lubricating oil pumps are provided:
•The main pump (XP1) which is mounted on, and driven by the auxiliary gearbox,
provides lubrication during normal running.
•The auxiliary pump (XP2), which is submerged in the lubricating oil tank and driven by an
AC motor, provides lubrication during turbine start, run up and post shutdown.
•The emergency pump (XP3) which is submerged in the lubricating oil tank and driven by
a DC motor, provides essential lubrication to the turbine hot bearing in the event of the
auxiliary pump or AC power failure, during or after shutdown.
Circulation between the three pumps is controlled by non-return valves, located in each pump
delivery system.
Each pump is provided with a pressure relief valve to guard against over-pressurization.
A strainer is provided at each pump suction inlet.

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Temperature Control Valve
A temperature control valve (XV428) operates at a set value to divert lubricating oil through the
oil cooler (TH1) as necessary to maintain the temperature of the oil at the optimum level.
Pressure Control Valve
Pressure control valve (PCV1) maintains a constant oil pressure to the bearings during turbine
running. The excess oil is spilled back through the valve to the lubricating oil tank.
Lubricating Oil Filters
Two filters are provided:
•The main filter(s) (XF2 and XF3), which are installed downstream of the pressure control
valve, filters the main line flow of lubricating oil from the main and auxiliary pumps.
•The lubricating oil flow from the DC motor driven emergency pump, which is separate
from the main line flow, is filtered by an emergency filter (XF4).
Oil Cooler Circuit
An oil cooler circuit incorporating an air blast oil cooler (TH1) is used to dissipate heat from the
lubricating oil prior to its entry into the main supply line. Flow to the cooler circuit is controlled
by the temperature control valve (XV428).
Non-return valves (XV26 and XV27) are fitted in the supply and return lines to prevent the
lubricating oil draining back to the tank when the turbine is shutdown.
Oil Mist Eliminator
An oil mist eliminator (XF7) is provided in the lubricating oil tank breather system to reduce the
amount of oil mist being exhausted to atmosphere.
Lubricating Oil Tank Breather System Flame Trap (if applicable)
The breather system contains a flame trap to prevent the ignition of any oil mist, which may
cause a subsequent explosion in the lubricating oil tank.
Secondary Breather Flame Traps (if applicable)
Flame traps are fitted in the compressor turbine and power turbine secondary breather systems
to prevent the ignition of any oil mist which may cause a subsequent explosion in the breather
passages.
Instrumentation
Instrumentation is provided to monitor the lubricating oil system parameters, provide warning
and trip control functions.
Refer to the Lubricating Oil System schematic diagram located in this Manual Volume.

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Temperature Monitoring
A resistance temperature detector (TT7) mounted in the lubricating oil supply tank monitors the
tank oil temperature and provides a permissive signal for tank immersion heater(s) control. The
information is also used to inhibit a start until the tank oil temperature is above a set value.
The temperature of the lubricating oil is measured by instrumentation mounted in the manifold
block by resistance temperature detectors (TT66A and TT66B) provide high oil temperature
warning and shutdown.
Pressure Monitoring
A pressure transmitters (PT6A, PT6B and PT6C (if fitted)) are mounted in the compressor
turbine supply line to provide lubricating oil pressure low/high warning and emergency lubricating
oil pump control signals.
The pressure drop across the main lubricating oil filter assembly is monitored by a pressure
differential transmitter (PDT8) to provide a warning of deteriorating element condition.
Each main lubricating oil filter housing (XF2, XF3) and the emergency oil filter housing (XF4) is
fitted with a pop up indicator button to provide a visual indication of filter blockage.
Lubricating Oil Tank Level Monitoring
A level transmitter (LT1) is used to monitor the level of the oil in the lubricating oil tank. The
information provided is used to inhibit starts if the oil level is below a set value during the gas
turbine starting process and to annunciate a warning or shutdown if the oil level falls below a set
value during normal gas turbine operation.
The level switch is also used to inhibit the operation of the immersion heater(s) if the level of the
oil in the tank is below a pre-determined level.
Lubricating Oil System Requirements
In normal conditions, the turbine is designed to run on mineral oil to ISO/VG46 in accordance
with company Fluids Specification 65/0027, which is located in this Manual Volume. Where, due
to prevailing ambient conditions or driven machinery requirements, it is necessary to use a
heavier or lighter viscosity grade of oil, ISO/VG68 or ISO/VG32 may be used respectively.
However, the company must be consulted before the use of these alternative oils.
aCaution: It is important to use the correct type of lubricating oil. The use of oil
with insufficient or incorrect additives will cause oil performance to deteriorate.

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Fuel System
The fuel system is designed to deliver fuel to the combustion system at the correct pressure and
flow required for the applicable power demand.
General Description
The schematic diagrams of the Fuel System can be found in this Manual Volume.
The fuel system comprises:
Off-skid Components
•block and vent valve assembly (XV30, XV31)
•demister (if applicable)
•filter/coalescer (if applicable)
On-skid components
•gas fuel supply strainer (XF94)
•two block valves (XV6, XV7)
•vent valve (XV212)
•main fuel control valve/actuator assembly (XV150, XM26)
•pilot fuel control valve/actuator assembly (XV149, XM27)
•electronic control unit
•system monitoring and control instrumentation
•pipeline trace heating (if applicable).
Gas Fuel System Components
Off-Skid Block and Vent Valve
The block and vent valve assembly is located in the customers gas supply line. The assembly
comprises of a block valve (XV30) and a vent valve (XV31). Both valves are controlled by
pneumatically operated rotary actuators. Air is directed to the actuators by solenoid valves
(SOL12 and SOL11) respectively. When the situation demands, the block valve closes to prevent
gas entering the on-skid fuel system and the vent valve opens to vent the interconnecting
pipework.
The block valve is spring loaded to fail in the ‘closed’ position. The vent valve is spring loaded to
fail in the ‘open’ position.

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Demister or Filter/Coalescer (if applicable)
The off-skid demister or filter/coalescer is used to remove liquids and particulates from the gas
fuel.
The gas enters the filter/colaescer at the inlet pipe and passes through a special filter element
into the top chamber, from where it leaves the filter/colaescer in a clean dry condition via the
outlet pipe.
Pipeline Trace Heating (if applicable)
The gas fuel pipelines are trace heated to prevent the formation of condensation in the gas
system.
Fuel Strainer
A 76-micron fuel strainer (XF94) is located in the fuel pipework downstream of the skid edge to
protect the burner orifices from blockage and contamination.
Block Valves
The primary (XV7) and secondary (XV6) block valves provide isolation of the on–skid fuel system
from the gas supply. They are controlled by integral actuators, which are operated by instrument
air and spring pressure. The instrument air supply to the actuators is controlled by pilot solenoids
(SOL5 and SOL110).
The block valves are designed to fail in the closed position.
Vent Valve
The vent valve (XV212) provides for venting of the gas fuel pipework between the two block
valves on turbine shutdown. The valve is controlled by an integral actuator operated by
instrument air and spring pressure. The instrument air supply to the actuator is controlled by a
pilot solenoid (SOL470).
The vent valve is designed to fail in the open position.
Fuel Control Valve/Actuator Assemblies
The main and pilot fuel control valves (XV150 and XV149) are of the rotary ball valve type and
operated through a zero backlash coupling by electrically operated rotary actuators (XM26 and
XM27). Each valve/actuator assembly is firmly mounted and connected into the fuel system. The
valves are calibrated and set up to meter the fuel flow to the burners under the control of an
electronic control unit. Integral position transmitters (ZT12 and ZT103) monitor the position of
the control valve actuators.

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Electronic Control Unit (ECU)
The ECU is an integral part of the fuel system and interfaces with the fuel control valve actuator
and the turbine governor to provide accurate fuel control, utilizing a high-speed microprocessor
at its heart.
The ECU constantly receives fuel condition input signals, and uses this information to calculate
the correct position of the fuel valve according to the flow rates demanded by the turbine
governor. The ECU also provides feedback of valve position and fault conditions to the turbine
control system.
Fuel Burners
The burners incorporate main and pilot gas ports to introduce the correct proportion of fuel for
the combustion process during starting and turbine operation.
Igniter
An igniter (IG1 to IG6) is incorporated in each burner to provide a heat source to the fuel during
engine starting. The units are connected by high-tension leads to a high-energy spark generator.
Instrumentation
Instrumentation is provided to monitor the fuel system parameters and provide warning and
protective control functions if unsafe or damaging conditions are detected.
Position Monitoring
Position switches (ZS12 and ZS45) monitors the open/closed position of the off-skid block valve
and switches (ZS44 and ZS11) monitor the open/closed position of the off-skid vent valve.
Position switches (ZS178 and ZS5) monitor the open/closed position of the primary on-skid block
valve, switches (ZS207 and ZS208) monitor the open/closed position of the secondary on-skid
block valve and switches (ZS742 and ZS743) monitor the open/closed position of the vent valve.
The switches initiate a start inhibit signal if the any of the valves are wrongly positioned prior to
start.
Pressure Monitoring
Pressure transmitters (PT2 and PT181) monitor the gas supply pressure at the input and the
demand pressure at the output of the main gas fuel control valve respectively. The pressure
differential across the valve is used in conjunction with the valve feedback position to calculate
the approximate percentage fuel flow through the valve.
Pressure transmitters (PT220 and PT182) monitor the gas supply pressure at the input and the
demand pressure at the output of the pilot gas fuel control valve respectively. The pressure
differential across the valve is used in conjunction with the valve feedback position to calculate
the approximate percentage fuel flow through the valve.
Dynamic air pressure through the center casing is monitored by a pressure transmitter (PT200).

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Turbine Package System Overview
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Temperature Monitoring
A temperature transmitter (TT6) monitors the gas fuel supply temperature upstream of the gas
fuel control valve(s). The transmitter relays temperature information to the ECU and
programmable controller and provides low and high temperature shutdown signals.
Burner Instrumentation
Six temperature sensors (TC255–TC260) mounted in each of the burner assemblies continuously
monitor burner operation and provide operational data to the turbine control system.
Fuel System Requirements
Refer to the SIEMENS Fluids Specification 65/0027, which is located in this Manual Volume,
for more specific information on fuel requirements.

Turbine Package Operators Manual
Chapter 1
Turbine Package System Overview
1-19
Air Distribution System
Instrument air is supplied to the package to assist in the operation and control of the gas fuel
module valves, the off-skid gas fuel block and vent valves, the lubricating oil module valves, the
P2 blow-off valves during starting and stopping, the interstage bleed valve, the combustion air
filter pulse cleaning system, the enclosure vent dampers, the auto drain system and the turbine
seals. P2 air from the turbine core is used to operate and control the P2 blow-off valves during
normal turbine operation.
The air distribution system delivers the air through a system of pipework and manifolds to the
various components.
Refer to the SIEMENS Fluid Specification 65/0027, which is located in this Manual Volume,
for specific information on the instrument air quality requirements.
Instrumentation
The pressure transmitter (PT185) monitors the instrument air supply pressure. The pressure
transmitter initiates high and low pressure warning and shutdown signals.
Air Distribution System Components
Instrument Air Manual Shut-Off Valve and Filter Assembly
A manual shut-off valve (HV220) and filter (XF102) assembly is located in the instrument air
supply pipework. The shut-off valve facilitates manually isolation of the system for maintenance
purposes. The filter provides filtration of the instrument air supply to remove particles above
5 microns.
Gas Fuel Module
Instrument air is supplied to the gas fuel module to provide actuation for the primary and
secondary block valves (XV7, XV6), and for the vent valve (XV212). The air is directed by the
valve solenoids (SOL5, SOL110, SOL470) to the actuators, which position the valves as required
for engine operation.
Off-Skid Gas Fuel Block and Vent Valve Assembly
Instrument air is supplied to the block valve (XV30) solenoid (SOL12) and the vent valve (XV31)
solenoid (SOL11) of the off-skid gas fuel block and vent valve. The air is directed by the
solenoids to actuators, which position the valves as required for engine operation.
Lubricating Oil Module
Instrument air is supplied to the lubricating oil module to provide control air for the lubricating oil
supply pressure control valve (PCV1) and the temperature control valve (XV428) position
indication.

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Turbine Package System Overview
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P2 Blow-Off Valve Air Manifold
Instrument air is supplied to the P2 blow-off valves via the air manifold during engine start and
shutdown. The P2 blow-off valve system is protected from excessive pressure by a pressure relief
valve (PSV159).
P2 air for the P2 blow-off valves is supplied from the engine through a filter (XV187) and
pressure control valve (PCV150) during normal engine operation.
A non-return valve (XV430) prevents P2 air from entering the main instrument air system during
normal engine operation.
Engine Auxiliary Module
Instrument air is supplied via process airlines to the engine auxiliary module for pressurization of
the engine seals and to the instrument air manifold.
Combustion Air Filter System
Instrument air is supplied as required to the combustion air filter for operation of the pulse clean
system (if applicable).