7/7/2015Control System Overview – Fuel SystemAcceleration Sequence Following light-off, the starter continues to crank the engine. The control system increases the fuel flow to gradually elevate T5 temperature and engine speed (Ngp). At approximately 60-70 percent Ngp, the start system is deenergized. As the Engine continues to accelerate, the inlet variable vanes move toward maximum open position, while the compressor bleed valve closes, further increasing T5 temperature. The control system increases the rate of fuel supply until Ngp reaches 90 percent. The engine is now ready for load. During load transients (fluctuation of engine load), the control system Continuously adjusts fuel flow, inlet variable vanes and compressor bleed valve positions, to maintain T5 temperature and Ngp.© 2013 Chevron 101Control System Overview – Bleed Air and Variable VaneSystem© 2013 Chevron 102 51
7/7/2015Control System Overview – Bleed Air and Variable VaneSystemAir System The engine air system, in addition to its main function of supporting combustion, also pressurizes oil seals, cool turbine rotor disks, assists in obtaining smooth engine operation by preventing surge conditions at critical speeds, and supply control air for operation of the fuel control system. Air system supply is compressor discharge air pressure, symbolized as “Pcd”. The air system starts to function with the rotation of the engine compressor rotor which draws in ambient air. The air is compressed and directed through the diffuser to the combustion chamber where fuel is injected and the combustible mixture is burned. This action transforms the air into the hot gas which expands through the turbine, creating mechanical energy. The gas is then expelled to the atmosphere through the exhaust collector.© 2013 Chevron 103Control System Overview – Bleed Air and Variable VaneSystem© 2013 Chevron 104 52
7/7/2015Control System Overview – Bleed Air and Variable VaneSystemBleed Air System The bleed valve control system keeps the gas turbine out of compressor surge during acceleration and low speed operation and maintains T5 average within ±5° F at partial loads. The bleed valve is electrically controlled and activated. A pre-established T5 set point value controls the bleed valve position. When the bleed valve is open, compressor airflow bypasses the turbine through the exhaust collector.© 2013 Chevron 105Control System Overview – Bleed Air and Variable VaneSystemBleed Air System The bleed air system is designed to prevent engine surge by reducing backpressure imposed on the engine compressor during acceleration and low-speed operation. Compressed air (bleed air) is bled from the combustor housing by venting to the turbine exhaust diffuser and bellows assembly. To control compressor surge during acceleration and low-speed operation, the bleed valve will open in response to commands from the microprocessor control in a manner that satisfies an anti-surge schedule of corrected engine speed. Gas turbine speed, corrected to T1, is used to compensate for the effects of engine air inlet temperature. A proportional system is used to control the opening and closing of the bleed valve. Surge Control – Compressor surge is controlled during acceleration and low-speed operation by a microprocessor-based controller that contains an anti-surge program. The controller sends commands that open the bleed valve the amount needed to prevent surge.© 2013 Chevron 106 53
7/7/2015Control System Overview – Bleed Air and Variable VaneSystemBleed Air Actuator The bleed valve assembly is mounted to a flange located at the two o'clock position on the compressor diffuser/combustor assembly. The bleed valve assembly consists of a valve actuator, butterfly valve, actuator bracket, and explosion proof motor junction box. The bleed valve actuator is an Exlar, 24 Vdc, linear-drive device that replaces electro- hydraulic actuators on older packages that use 24 Vdc battery/charger power distribution systems. The bleed valve actuator is an electric motor-driven, roller-screw actuator that has position feedback. The actuator provides the feedback necessary to accurately put the bleed valve in the correct position. The actuator moves in response to a 4-20 mA positioning signal from an analog output module in the control system. The bleed valve actuator is supported by the valve actuator bracket. The bleed valve actuator assembly consists of two major components: the linear actuator drive and the associated EP controller box. The linear actuator drive houses the roller-screw assembly, drive motor, resolver, and EP motor junction box. The wires from the EP controller box are connected to the actuator at the EP motor junction box.© 2013 Chevron 107Control System Overview – Bleed Air and Variable VaneSystem© 2013 Chevron 108 54
7/7/2015Control System Overview – Bleed Air and Variable VaneSystemVariable Vane System The variable vane system is provided to avoid compressor surge and to maintain maximum engine performance over the entire turbine engine operating range. The variable vane system consists of a single row of variable Inlet Guide Vanes (IGVs) and up to five rows of Variable Stator Vanes (VSVs) depending on the engine model. The variable vane system prevents engine compressor surge by aerodynamically matching the low-pressure and high-pressure stages of the engine compressor. This change of vane position varies the effective volume of air that enters the compressor rotor. The blade angle determines the compression characteristics for any particular compression stage. By changing the position of the vanes, the critical low pressure stages are realigned to maintain a balanced airflow.© 2013 Chevron 109Control System Overview – Bleed Air and Variable VaneSystemVariable Vane System The variable vane system uses a motor-driven linear actuator with position feedback. The variable vane actuator position, which is a function of corrected gas turbine speed, is controlled by a 4-20 mA input signal. Upon loss of the electrical signal, the variable vanes return to the closed position (minimum variable vane angle).© 2013 Chevron 110 55
7/7/2015Control System Overview – Bleed Air and Variable VaneSystemVariable Vane Actuator The variable vane actuator is an Exlar, 24 Vdc, linear-drive device that replaces electro-hydraulic actuators on older packages that use 24 Vdc battery/charger power distribution systems. The variable vane actuator is an electric motor-driven, roller-screw actuator that has position feedback. The actuator provides the feedback necessary to accurately put the variable vanes in the correct position. The actuator moves in response to a 4-20 mA positioning signal from an analog output module in the control system. When the actuator is given a test stroke during the engine start sequence, the actuator supplies a 4-20 mA motor-current feedback-signal to the control system, so the control system can check the motor's current. The control system also uses the motor- current feedback-signal when the operator initiates a test stroke while the engine is not in operation (guide vane cycle test).The electrical stops for the variable vane opening schedule are set to 0.5 mA to prevent damage to the mechanical stops on the engine. The variable vane actuator consists of two major components: the linear actuator drive and the associated explosion proof (EP) controller box. The linear actuator drive house the roller-screw assembly, drive motor, resolver, and EP motor junction box. The wires from the EP controller box are connected to the actuator at the EP motor junction box.© 2013 Chevron 111Control System Overview – Lube Oil System© 2013 Chevron 112 56
7/7/2015Control System Overview – Lube Oil System The lube oil system supplies filtered lubricating oil to turbine engine bearings and various package components within operating pressure and temperature limits. The lube oil system is monitored by the package control system and incorporates a lube oil reservoir, oil cooling system, pumps, filters, pressure control devices, and temperature control valves. The lube oil system is comprised of three interrelated systems. 1. Pre/Post Lube Oil System 2. Main Lube Oil System 3. Backup Post lube System© 2013 Chevron 113Control System Overview – Lube Oil SystemAC Pre/Post Lube Oil System The pre/post lube oil system supplies lube oil to the engine bearings and driven equipment before engine start up and after engine shutdown. The pre/post lube oil system operates independent of the main lube oil pump. The pre/post lube oil system can be activated by the control system to provide temporary lube oil in the event of failure of the main lube oil pump.© 2013 Chevron 114 57
7/7/2015Control System Overview – Lube Oil SystemMain Lube Oil System The main lube oil system provides lube oil to the engine bearing while the Engine is running. The system is comprised of a reservoir pump or pumps, pressure and temperature control valves, filters, lube oil cooling system, supply manifolds and return lines.DC Backup Post lube System The backup post lube system supplies lube oil to the engine bearings if the pre/post system fails.© 2013 Chevron 115Control System Overview – Lube Oil SystemPre-lube Lube Oil Pump Check When a cold engine start or test crank is initiated, the control system tests the Backup post-lube oil pump (DC) and the Pre/Post lube oil pump (AC). The control system energizes the backup post-lube oil pump. Once the backup post- lube oil pump has achieved the minimum pressure setpoint, the pump is de-energized. If the backup post-lube oil pump fails to achieve the minimum pressure setpoint, a backup post-lube oil pump failure shutdown is annunciated and the control system aborts the pre-lube lube oil pump check. If lube oil pressure fails to drop after the backup post-lube oil pump is de-energized, a shutdown is annunciated and the control system aborts the pre-lube lube oil pump check.© 2013 Chevron 116 58
7/7/2015Control System Overview – Lube Oil SystemPre-lube Lube Oil Pump Check After the lube oil pressure drops, the control system energizes the pre/post lube Oil pump. If the pre/post lube oil pump discharge pressure reaches the Minimum pressure setpoint, the pre-lube lube oil pump check is complete. The pre/post lube oil pump remains energized for the duration of the package Pre-lube. If the pre/post lube oil pump fails to reach the minimum pressure set point and/or the pressure signal is lost, a pre/post lube oil pump failure shutdown is annunciated. The control system aborts the pre-lube lube oil pump check© 2013 Chevron 117 Control System Overview – Lube Oil System Pre-lube Lube Oil Pump Check© 2013 Chevron 118 59
7/7/2015Control System Overview – Lube Oil SystemPre-lube Lube Upon completion of the pre-lube lube oil pump check, the control system starts The pre- lube oil timer. During pre-lube, lube oil header pressure must remain above the minimum pressure setpoint for 30 seconds. After 30 seconds of Pre-lube, the control system permits start motor operation.© 2013 Chevron 119Control System Overview – Lube Oil SystemEngine Operation During the start cycle the pre/post lube oil pump is de-energized when the engine speed (Ngp) is greater than the starter dropout setpoint and the engine-driven lube oil pump is providing sufficient pressure. Once engine speed is greater than 5% Ngp and light off temperature is achieved, the backup relay system is enabled. The backup relay system conducts post-lube if the programmable logic controller (PLC) fails. If the engine-driven lube oil pump fails to provide sufficient pressure after Starter dropout, a low lube oil pressure alarm is annunciated and the pre/post lube oil pump is energized. If the minimum pressure is not reached and/or the pressure continues to drop, a low lube oil pressure shutdown is annunciated, fuel is shut off to the engine, the backup post lube oil pump is energized. The backup post lube oil pump remains energized for 30 seconds minimum to prevent pump cycling as the lube oil header pressure fluctuates.© 2013 Chevron 120 60
7/7/2015Control System Overview – Lube Oil SystemPost Lube After engine operation, a post-lube is required to cool the engine bearings and Driven equipment bearings. The pre/post lube oil pump is energized during rundown and continues to operate for the duration of the post-lube timer. If the pre/post lube oil pump fails to maintain the minimum pressure set point during Post-lube, the backup post-lube oil pump is energized.© 2013 Chevron 121Control System Overview – Back Up Relay System Backup Relay System© 2013 Chevron 122 61
7/7/2015Control System Overview – Back Up Relay SystemBackup Control Relays© 2013 Chevron 123Control System Overview – Back Up Relay System Backup control relays are maintained in a fail-safe (energized) condition by a series of relay and switch contacts from the backup over speed monitor, local and remote manual fast stop switches, and microprocessor fail relay. When any one of these contacts in the series circuit open, the relays are De-energized and the backup shutdown sequence is initiated. The shutdown sequence de-energizes fuel valve solenoids to cut off the engine Fuel supply, activates driven equipment unloading devices, and operates Post-lube system to protect engine and driven equipment. During shutdown sequence, the backup system active indicator illuminates. Backup control locks out main control system until backup control system is reset. Resetting the backup control system rearms backup control circuits, extinguishes backup system active indicator, and (providing that the engine has decelerated to a safe speed) resets backup over speed monitor contacts.© 2013 Chevron 124 62
7/7/2015Control System Overview – Back Up Relay SystemConditions to activate backup relay system - Turbine over speed - Emergency stop manual switch activation - Controller failure - Fire indication© 2013 Chevron 125Control System Overview – Back Up Relay SystemPost Lube Cycle after Emergency Stop Shutdown. After the fuel is shut off, the control system starts the post-lube timer. Total Post Lube Timer is 4 hrs. Pre/Post lube pump will continue running in the first hrs. After 1 hrs. timer is completed, Pre/Post lube pump will stop 9.5 min and then start 2.5 min. until reach 15 cycles. (3 hrs.) If fire case detect, Pre/Post lube pump will stop 9.5 min. before resume and continue the cycle. If the post-lube is stopped for an extended period, The control system prevents the start motor from energizing until the engine lockout timer expires or the post-lube is resumed and completed© 2013 Chevron 126 63
7/7/2015Control System Overview – Vibration System Software Configure AB PLC Standard I/O Cnet NetworkRemote I/O Adapter Vibration Card Vibration Sensor© 2013 Chevron 127Control System Overview – Vibration System A vibration monitor system uses proximitor probes, accelerometers and velocity transducers to monitor vibration and acceleration. Proximity probe transducer is used in measuring the static and dynamic distance between the target and the probe it uses to measure shaft vibration, differential expansion, plus radial and axial shaft position. It can also be used for machinery diagnostic system. Velocity transducers A transducer whose output is directly proportional to the velocity of the measured unit. A velocity transducer consists of a magnet suspended on a coil, surrounded by a conductive coil. Movement of the transducer induces movement in the suspended magnet.© 2013 Chevron 128 64
7/7/2015Control System Overview – Vibration System Accelerometers transducers is used to measure an intertia of velocity and Position. It also represent as a vibration or impact (shock) sensor Accelerometers is implement capacitive sensing output a voltage dependent on the distance between two planar surfaces. One or both of these “plates” are charged with an electrical current. Changing the gap between the plates changes the electrical capacity of the system, which can be measured as a voltage output.© 2013 Chevron 129Control System Overview – Vibration System The vibration monitor system is a subsystem of the controller. The vibration monitor system uses probes to measure displacement. From these measurements, radial and thrust vibration data are developed. The probes are energized and measure gap dc voltage between probe and a moving surface. Probes measure high frequency displacement. The vibration system uses seismic sensors to measure velocity or acceleration. Seismic devices, also called accelerometers, measure lower frequency displacements. Seismic measurements are based on elastic deformation of a piezo- electric element mounted to a relatively high inertia mass.© 2013 Chevron 130 65
7/7/2015Control System Overview – Vibration System© 2013 Chevron 131 Control System Overview – Vibration System© 2013 Chevron 132 66
7/7/2015Control System Overview – Speed and Backup OverSpeed NGP Speed Sensor Backup Over Speed© 2013 Chevron 133Control System Overview – Speed and Backup OverSpeed Gas producer and power turbine speed is sensed with magnetic pickups. Magnetic pickups are mounted in the forward gas producer and power turbine bearing housings. Pickups extend into the interconnect shaft cover cavity and sense the splines on the interconnect shaft hub. Electrical leads are brought out to a conduit connection. Magnetic pickups provide an ac signal (5 to 70 volts) with a frequency that Directly relates to shaft speed. Magnetic pickups have a coil of fine copper wire wrapped around a magnetic Core in the tip. The magnetic tip is located very close (0.05 inch/1.27 mm) to the ferrous metal splines on the shaft hub. When the hub rotates, splines pass by the magnetic tip causing a change in the flux field. The change in flux field causes a current to flow in the coil of wire and develops a voltage between connection leads.© 2013 Chevron 134 67
7/7/2015Control System Overview – Speed and Backup OverSpeed Voltage amplitude varies almost proportionally to the speed and inversely to the magnetic tip gap. The signal is essentially a sine wave with one cycle being Produced by each spline.© 2013 Chevron 135Control System Overview – Fire and Gas System© 2013 Chevron 136 68
7/7/2015Control System Overview – Fire and Gas System A typical fire system consists of an operator control panel, fire warning system, power distribution module, fire system controller, enhanced digital input/output (EDIO) modules, flame detectors, gas detectors, thermal detectors, and fire suppression system. The fire system controller monitors fire detection components through enhanced digital input/output (EDIO) modules and by a two-wire, digital communication supervisory circuit, referred to as the local operating network (LON). The fire system controller communicates fire and gas system fault summaries to the unit's Turbotronic™ control system via ControlNet.© 2013 Chevron 137Control System Overview – Fire and Gas SystemFire Detection System If fire is detected by flame detectors or excessive heat is sensed by the thermal detectors, The control system shuts down the unit, the following events occur at the same time: • Gas-turbine engine shuts down (fast stop lockout shutdown). • Enclosure ventilation fan(s) stop. • Fire extinguishing agent releases. • Fire damper(s) close. After the gas-turbine engine comes to a complete stop, the control system interrupts the operation of the lube oil pump motor(s). Ten minutes after the fire was detected, the post lube pump motors are reenergized to complete the post lube cycle.© 2013 Chevron 138 69
7/7/2015Control System Overview – Fire and Gas SystemDisabling the CO2 Extinguishing Agent Before inspecting the interior of the enclosure or entering it, personnel must use the appropriate method to disable the CO2 extinguishing agent: If personnel are inspecting the interior of the package enclosure but will not be entering it, the FIRE SYSTEM AUTO/INHIBIT Key switch must be placed in the INHIBIT position If personnel are entering the package enclosure for any reason, the main-release system control-head solenoid valve and the reserve system control-head solenoid valve, if applicable, must be removed and the FIRE SYSTEM AUTO/INHIBIT Keyswitch must be placed in the INHIBIT position.© 2013 Chevron 139Control System Overview – Fire and Gas System1. A fire system AUTO/INHIBIT Key switch, on the turbine control junction box, de- energizes automatic features of the fire system for servicing. When the switch is in the INHIBIT position, it interrupts automatic operation of the fire suppression system. When armed, with the Key switch in the AUTO position, normal activation is controlled by the controller.2. If 1 from 6 fire detector (MIR) detect flame inside the enclosure or 1 from 2 thermal detector activated, it will send output to activated strobe/horn and CO2 discharge solenoid.3. If 1 from 6 gas detector (IR LON) detect excessive gas inside the package (Alarm 10, Shutdown 25) , For alarm level it will activate alarm function but if it reach shutdown level. It will initiate fast stop lock out command.4. No have any voting function for both of Fire and Gas detector.5. The RELEASE push button provides emergency engine shutdown and release of the fire extinguishing agent.© 2013 Chevron 140 70
7/7/2015Control System Overview – Fire and Gas SystemC5690 – Train#1, Train#2 and Train3 CO2 Discharge Line PSHSV SV SV Pressure Release Confirmed Switch Enclosure SkidMain Reserve Extended Fire & Gas I/O Manual Release PB on Skid JB Main Res.Selector Switch on UCP Fire Suppression© 2013 Chevron 141Control System Overview – Fire and Gas SystemC5690 – Train#1, Train#2 and Train31. Operator can have an option to select operation of fire suppression system from the UCP. The selection can be Main CO2 system or Reserve CO2 system.2. Every time when fire detected, there will be 2 CO2 cylinder dumped. Main or Reserve cylinder and extended cylinder. Main or reserve cylinder (depend on position of selector switch on the UCP) will be dumped immediately after fire detected. Extended cylinder will be dumped together at the same time with main or reserve3. Manual release PB will be used to manual dump CO2 cylinder. Main or reserve cylinder (depend on position of selector switch on the UCP) will be dumped together with extended cylinder.4. Inhibit switch will ignore operation of solenoid valve both of auto and manual mode.© 2013 Chevron 142 71
7/7/2015Control System Overview – Fire and Gas SystemC5691 – Train#4© 2013 Chevron 143Control System Overview – Fire and Gas SystemC5691 – Train#41. Operator can have an option to select operation of fire suppression system from the UCP. The selection can be Main CO2 system or Reserve CO2 system.2. Each CO2 system is combined from 2 CO2 cylinders but it has only one solenoid to activate, remaining cylinder will be activated by high pressure from the first one.3. Every time when fire detected, there will be 4 CO2 cylinder dumped. Main or Reserve system (2 cylinders per each system) and extended main or extended reserve system (2 cylinders per each system). Main or reserve system (depend on position of selector switch on the UCP) – 2 cylinders per each system will be dumped immediately after fire detected. Extended main or extended reserve system will be dumped (depend on position of selector switch on the UCP) together at the same time with main or reserve4. Manual release PB will be used to manual dump CO2 system (4 Cylinders at a time). Main or reserve system and extended main or extended reserve system (depend on position of selector switch on the UCP) will be dumped together.5. Inhibit switch will ignore operation of solenoid valve both of auto and manual mode.© 2013 Chevron 144 72
7/7/2015 HMI Screen and Function© 2013 Chevron 145Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 146 73
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 147Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 148 74
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 149Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 150 75
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 151Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 152 76
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 153Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 154 77
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 155Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 156 78
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 157Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 158 79
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 159Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 160 80
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 161Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 162 81
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 163Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 164 82
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 165Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 166 83
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 167Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 168 84
7/7/2015Erawan ECP Compressor Control Upgrade - O&MTraining : HMI Screen© 2013 Chevron 169 Starting Sequence© 2013 Chevron 170 85
7/7/2015Starting Sequence – Package start up check listsPackage start up check lists. Ensure power supply circuit breaker from battery charger to UCP is turned on (At battery charge CB-504) Check for any tripped circuit breaker, blow fuse inside the UCP reset and replace (Local Start – Inside Control Room) Verify OFF/LOCAL/AUXILIARY Switch in LOCAL position. Verify LOCAL light is illuminated. (Auxiliary Start – Package JB) Verify OFF/LOCAL/AUXILIARY Switch in Auxiliary position. Verify AUX light is illuminated. Check for any fault existed on Fire and Gas Controller, Clear all alarms and shutdown conditions to allow package start up Check for any existed of alarm and shutdown message on the HMI (UCP HMI or Package JB HMI). Clear all alarms and shutdown conditions. Verify that READY light is illuminated. Check backup system active indicator. Reset back up system if required.© 2013 Chevron 171Starting Sequence – Start Up SequenceStart Up Sequence1. Before push start turbine compressor package, seal oil system must be manual started to build up pressure and ensure seal oil sequence check will be completed when perform seal oil system checking during start up sequence2. Press the system START pushbutton switch momentarily. Seal Oil Manual Sequence will automatic transfer to Automatic mode.3. The STARTING indicator light begins flashing, the enclosure fan is commanded to start The Pre Start Pre Crank will be activated and start enclosure purge timer for 30 sec. At the same time, lube oil sequence check is activated, pre/post lube pump starts and pre- lubrication begins, pre-lube timing will be completed in 15 sec.4. Upon completion of Pre Start Pre Crank timer, the system will wait to fully fill seal oil run down tank. When seal oil tank level high activate, it will move to compressor pressure pressurize sequence.© 2013 Chevron 172 86
7/7/2015Starting Sequence – Start Up SequenceStart Up Sequence5. Compressor pressurizes will start by the opening of suction loading valve and still keep opening vent valve for 30 sec. During this compressor purge sequence, anti- surge valve will be closed to keep purging path via compressor. Anti-surge valve will return to open position again when vent valve return to close position.6. Upon completion of compressor purge (30 Sec.) Compressor will be pressurized until differential pressure across suction valve decrease to 50 psid. Suction valve will start opening. Loading Valve will start closing. Pressure inside compressor will build up until differential pressure across discharge valve decrease to 50 psid. Then discharge valve will be commanded to open. The compressor pressurizes sequence need to be completed within 360 sec. before timeout shutdown command is initiated.7. Upon completion of yard valve sequence, Inlet Guide Vane will activate sequence check© 2013 Chevron 173Starting Sequence – Start Up SequenceStart Up Sequence8. When loading valve, vent valve is fully closed, suction valve and discharge valve is fully open, the startup sequence will move to test crank step. During exhaust purge crank step, pneumatic starting motor will be activated to bring up gas producer to crank speed (24 %NGP to 28 %NGP). Fuel valve sequence check also start by opening primary shutoff valve, secondary shutoff valve and EGF fuel gas valve. Upon completion of fuel valve sequence check, exhaust purge crank will start count down timer for 90 sec.9. After exhaust purge crank sequence complete, gas fuel is admitted to the igniter torch by the opening of primary shutoff and secondary shutoff valve then torch will start pre- ignite. Three second later, EGF fuel valve will step opening to allow fuel gas going into fuel manifold before pass to fuel injectors. The mixture is ignited in the presence of combustion air. Light off need to be occurred within 10 sec. by detecting of T5 temperature at 400°F© 2013 Chevron 174 87
7/7/2015Starting Sequence – Start Up SequenceStart Up Sequence10. At 400 °F T5 Temperature, the fuel torch and ignition are shutoff. EGF Fuel Valve will open more based on fuel schedule during accelerate. The engine continues to accelerate until starter droop out speed at 60 %NGP11. When engine speed reaches 60% NGP, the engine-driven main lube oil pump pressure increases, AC pre/post lube pump will be commanded to stop. Gas starter solenoid will be de-energized. The starter begins cool down cycle, starter clutch over-runs then dropped out. The hour meter begins to log engine-operating hours12. Engine will continue accelerate until ready to load speed at 71% NGP, the STARTING indicator is extinguished and READY TO LAOD light© 2013 Chevron 175Starting Sequence – Start Up SequenceStart Up Sequence13. Bleed valve will start closing at 60 %NGP from 55% opening and fully close at 80 %NGP. Inlet Guide Vanes will start opening from fully close at 75% NGP to maximum opening position at 90% NGP.14. At ready to load speed, The start counter registers a successful start and the engine still continues accelerate until reach minimum Power Turbine speed at 50% NPT (Engine Idle speed).15. The control system monitors engine speed, turbine inlet temperature, lube and seal gas and air pressure, lube oil temperature and tank level, gas fuel pressure, engine and gas compressor vibration, dc control voltage, gas compressor suction and discharge pressures, and gas compressor discharge temperature. The control system provides minimum error control (T5 Control, NPG Control, NPT Control and Fuel DP Control) in the event that the error of one from all control mode nearly to reach set point. It also provides the appropriate malfunction alarm on the HMI both of UCP HMI and package JB HMI, and provides automatic control of shutdown sequencing and post lubrication of engine and compressor bearing© 2013 Chevron 176 88
7/7/2015Starting Sequence – Enclosure Purge Sequence After start command is initiated, The turbine enclosure vent fan will command to start Enclosure purge timer will start count for 30 sec. to complete enclosure purge sequence Air flow inside turbine enclosure must greater than 1 InH2O before initiated alarm within 20 sec, then 30 sec later will initiate vent fan fail FL command. If F&G System is active, after command start vent fan for 20 sec. if turbine enclosure pressure lower than 0.15 psi then 30 sec later will initiate vent fan fail FL command If F&G System is inhibited, after command start vent fan for 20 sec. if turbine enclosure pressure lower than 0.15 psi initiate alarm only© 2013 Chevron 177Starting Sequence – Lube Oil Sequence Check After start, Check lube oil header pressure must less than 3 psi and all pressure switch deactivate ( Lube Header PSH, S322_3, S322_5) If lube oil header pressure is between 3-6 PSI then FN activated Turn on back up post lube pump, check confirm header pressure greater than 4 psi and back up lube oil pump discharge pressure increasing to 12 psi for 1 sec then turn off back up pump. Waiting for header pressure decreasing to 3 psi and Backup pump discharge pressure lower than 9 psi (S322-5 De-activated) After turn off back up pump, if header pressure is not less than 3 psi and Backup pump discharge pressure is still greater than 9 psi then FN Activated Turn on pre/post lube pump, check confirm header pressure greater than 4 psi, lube oil header pressure switch increasing to 6 psi and Pre/Post lube pump discharge pressure increasing to 6 psi. then complete pre-lube check sequence and continue running pre/post lube pump.© 2013 Chevron 178 89
7/7/2015Starting Sequence – Yard Valve Sequence Check After compressor seal system and lube oil system OK, command loading valve to OPEN, Vent Valve still keep OPEN and Anti-Surge Valve command to CLOSE. Once loading valve fully open, start Compressor purge timer 30 Sec. After compressor purge complete, command vent valve to CLOSE. And command Anti- Surge Valve to OPEN Wait until differentials pressure across suction valve lower than 50 psi, then command suction valve to OPEN. And close loading valve Pressure-up compressor loop. (Pressure equal suction header) And Wait until differentials pressure across discharge valve lower than 50 psi, then command discharge valve to open. Yard valve sequence need to be completed within 360 sec. time out.© 2013 Chevron 179Starting Sequence – Purge Crank Sequence When loading valve, vent valve is fully closed, suction valve and discharge valve is fully open, the startup sequence will move to test crank step. During exhaust purge crank step, pneumatic starting motor will be activated to bring up gas producer to crank speed (24 %NGP to 28 %NGP) Crank failed time out will initiate if NGP cannot ramp to crank speed at 20 %NGP with in 80 sec.© 2013 Chevron 180 90
7/7/2015Starting Sequence – Fuel Valve Sequence Check After speed reach 15 %NGP, delay 2 sec. then check fuel gas supply pressure greater than 12 psi. If gas fuel valve pressure (TP342_1) greater than Pcd pressure more than 10, require gas fuel venting and must be decreased within 60 sec. Delay 10 sec. before start primary valve pressure check Fuel gas pressure 12-35 Psi – maintain DP 20 sec. greater than12 psi. Fuel gas pressure 35-65 Psi – maintain DP 10 sec. greater than12 psi. Fuel gas pressure greater than65 Psi – maintain DP 5 sec. greater than 20 psi During check DP, Difference between gas valve pressure and initial value must less than 10 psi. Open primary valve 4 sec. then waiting 20 sec. before start sec. valve pressure check Fuel gas pressure 12-35 Psi – maintain DP 20 sec. greater than12 psi. Fuel gas pressure 35-65 Psi – maintain DP 10 sec. greater than12 psi. Fuel gas pressure greater than 65 Psi – maintain DP 5 sec. greater than20 psi During check DP, Difference between gas valve pressure and initial value must less than 10 psi.© 2013 Chevron 181Starting Sequence – Purge Crank, Ignition and Accelerate Upon completion of fuel valve sequence check, sequence will move to purge crank Exhaust purge crank will continue for 90 sec After exhaust purge crank sequence complete, primary shutoff and secondary shutoff command to OPEN Torch will start pre-ignite 3 sec. before EGF Fuel Valve Step Open EGF fuel valve will step opening to allow fuel gas going into fuel manifold before pass to fuel injectors Engine temp greater than 400F in 10 Sec At 400 °F T5 Temperature, the fuel torch and ignition are shutoff After light off, EGF Fuel Valve will open more based on fuel schedule during accelerate. The engine continues to accelerate until starter droop out speed at 60 %NGP Engine speed need to reach 60% NGP within 180 sec before time out.© 2013 Chevron 182 91
7/7/2015Starting Sequence – Purge Crank, Ignition and Accelerate The engine-driven main lube oil pump pressure increases, AC pre/post lube pump will be commanded to stop. Gas starter solenoid will be de-energized. The starter begins cool down cycle, starter clutch over-runs then dropped out. The hour meter begins to log engine-operating hours Deactivate Starter Engine will continue accelerate until ready to load speed at 71% NGP, the STARTING indicator is extinguished and READY TO LAOD light is illuminated At ready to load speed, The start counter registers a successful start. Engine still continues accelerate until speed reach minimum Power Turbine speed at 50% NPT (Engine Idle speed) Bleed valve will start closing at 60 %NGP from 55% opening and fully close at 80 %NGP Inlet Guide Vanes will start opening from fully close at 75% NGP to maximum opening position at 90% NGP© 2013 Chevron 183 Stop Sequence© 2013 Chevron 184 92
7/7/2015Stop Sequence Gas-turbine engine and driven equipment have four types of shutdown Normal stop Emergency stop Control system stop Cool down stop non lockout Cool down stop lockout Fast stop non lockout Fast stop lock out External Command to Stop unit by SIS/FGS© 2013 Chevron 185Stop Sequence Normal Stop A normal stop shutdown sequence includes a cool down period, which allows the gas- turbine engine and driven equipment to run with no load for a preset period before the gas-turbine engine is stopped Gas-turbine engine slows to idle speed and continues to run for a preset cool down cycle After preset cool down cycle, fuel system valves close, combustion ceases, and gas- turbine engine begins to decelerate. When gas-turbine engine speed decreases below 25%. It will activate Slow Roll function After preset slow roll cycle, start motor is de-energized and coasts to a stop© 2013 Chevron 186 93
7/7/2015Stop Sequence Normal Stop© 2013 Chevron 187Stop Sequence Emergency Stop An emergency stop does not include a cool down period, which allows the gas-turbine engine and driven equipment to run with no load for a preset period before the gas- turbine engine is stopped. The emergency stop shutdown should only be used when plant conditions require an immediate shutdown. An emergency stop prevents gas-turbine engine operation until the emergency stop shutdown is acknowledged and reset Gas-turbine engine shuts down immediately with no cool down cycle. Slow roll cycle is bypassed© 2013 Chevron 188 94
7/7/2015Stop Sequence Emergency Stop© 2013 Chevron 189Stop Sequence Control System Stop There are two types of control system stops; cool down stop and fast stop. If an Unsafe operating condition is detected by the control system, the control system initiates a shutdown. Depending upon the severity of the shutdown, the control system initiates either a cool down stop or a fast stop. If the control system stop was initiated due to a condition that is self-correcting, the gas-turbine engine can be restarted after the condition returns to normal. If the control system stop was initiated due to a condition that is not self-correcting, contact maintenance personnel to perform corrective actions.© 2013 Chevron 190 95
7/7/2015Stop Sequence Control System Stop : Cool down Stop Cool down Non-lockout (CN) – Cool down non-lockout shutdowns reduce gas- turbine engine speed to idle for a preset cool down period before initiating a shutdown. Cool down non-lockout shutdowns include operator initiated normal stops, operating conditions that reached a shutdown limit because Maintenance was not performed, a momentary disruption that causes an out-of-limits condition, and operating conditions that exceed alarm levels but are not serious enough to cause any immediate damage. Cool down non-lockout shutdowns can be reset after corrective action has been taken or operating conditions revert to normal using either the local or remote ACKNOWLEDGE and RESET Switches© 2013 Chevron 191Stop Sequence Control System Stop : Cool down Stop Cool down Lockout (CL) – Cool down lockout shutdowns reduce gas-turbine engine speed to idle for a preset cool down period before initiating a shutdown. Cool down lockout shutdowns typically result from a component failure and not because operating conditions have exceeded alarm or shutdown levels. Cool down lockout shutdowns may not present immediate danger, but Corrective action must be taken to avoid damage resulting from a component failure. Cool down lockout shutdowns prevent gas-turbine engine operation until the shutdown is acknowledged and reset using the local ACKNOWLEDGE and RESET Switches.© 2013 Chevron 192 96
7/7/2015Stop Sequence Control System Stop : Fast Stop Fast Stop Non-lockout (FN) - Fast stop non-lockout shutdowns initiate an immediate shutdown of the gas-turbine engine. Fast stop non-lockout Shutdowns typically result from a disruption in operation due to abnormal Operating conditions and may not require corrective action. Fast stop Non-lockout shutdowns can be reset when operating conditions revert to normal using either the local or remote ACKNOWLEDGE and RESET Switches© 2013 Chevron 193Stop Sequence Control System Stop : Fast Stop Fast Stop Lockout (FL) - Fast stop lockout shutdowns initiate an immediate shutdown of the gas-turbine engine. Fast stop lockout shutdowns prevent gas-turbine engine operation until the shutdown is acknowledged and reset using the local ACKNOWLEDGE and RESET Switches. In addition to using the local ACKNOWLEDGE and RESET Switches, fast stop lockout shutdowns initiated due to a microprocessor failure, fire detection, backup over speed, or pressing of EMERGENCY STOP Switch will require the backup relay system to be reset. Fast stop lockout shutdowns are the most severe shutdown types and require corrective action before the gas-turbine engine can be restarted.© 2013 Chevron 194 97
7/7/2015Anti-Surge Control, Process Control and Load Sharing System© 2013 Chevron 195 Q&A 98
Search
