GE SPEEDTRONIC Mark VI Turbine Control System

GE SPEEDTRONIC Mark VI Turbine Control System

Description 

The SPEEDTRONIC™ Mark VI turbine control is the current state-of-the-art control for GE turbines that have a heritage of more than 30 years of successful operation. It is designed as a complete integrated control, protection, and monitoring system for generator and mechanical drive applications of gas and steam turbines. It is also an ideal platform for integrating all power island and balance-of-plant controls. Hardware and software are designed with close coordination between GE’s turbine design engineering and controls engineering to insure that your control system provides the optimum turbine performance and you receive a true “system” solution. With Mark VI, you receive the benefits of GE’s unmatched experience with an advanced turbine control platform.

The heart of the control system is the Control Module, which is available in either a 13- or 21- slot standard VME card rack. Inputs are received by the Control Module through termination boards with either barrier or box-type terminal blocks and passive signal conditioning. Each I/O card contains a TMS320C32 DSP processor to digitally filter the data before conversion to 32 bit IEEE-854 floating point format. The data is then placed in dual port memory that is accessible by the on-board C32 DSP on one side and the VME bus on the other. In addition to the I/O cards, the Control Module contains an “internal” communication card, a main processor card, and sometimes a flash disk card. Each card takes one slot except for the main processor that takes two slots. Cards are manufactured with surface-mounted technology and conformal coated per IPC-CC830.

I/O data is transmitted on the VME backplane between the I/O cards and the VCMI card located in slot 1. The VCMI is used for “internal” communications between:

■ I/O cards that are contained within its card rack
■ I/O cards that may be contained in expansion I/O racks called Interface Modules
■ I/O in backup <P> Protection Modules
■ I/O in other Control Modules used in triple redundant control configurations
■ The main processor card

The main processor card executes the bulk of the application software at 10, 20, or 40 ms depending on the requirements of the application. Since most applications require that specific parts of the control run at faster rates (i.e. servo loops, pyrometers, etc.), the distributed processor system between the main processor and the dedicated I/O processors is very important for optimum system performance. A QNX operating system is used for real-time applications with multi-tasking, priority-driven preemptive scheduling, and fast-context switching.

Communication of data between the Control Module and other modules within the Mark VI control system is performed on IONet. The VCMI card in the Control Module is the IONet bus master communicating on an Ethernet 10Base2 network to slave stations. A unique poling type protocol (Asynchronous Drives Language) is used to make the IONet more deterministic than traditional Ethernet LANs. An optional Genius Bus™ interface can be provided on the main processor card in Mark VI Simplex controls for communication with the GE Fanuc family of remote I/O blocks. These blocks can be selected with the same software configuration tools that select Mark VI I/O cards, and the data is resident in the same database.

The Control Module is used for control, protection, and monitoring functions, but some applications require backup protection. For example, backup emergency overspeed protection is always provided for turbines that do not have a mechanical overspeed bolt, and backup synch check protection is commonly provided for generator drives. In these applications, the IONet is extended to a Backup Protection Module that is available in Simplex and triple redundant forms. The triple redundant version contains three independent sections (power supply, processor, I/O) that can be replaced while the turbine is running. IONet is used to access diagnostic data or for cross-tripping between the Control Module and the Protection Module, but it is not required for tripping.

Control Functions

Turning Gear Control – The Mark VI can interface with the turning gear system in either a manual or an automatic mode. In manual mode, the operator engages the turning gear through the operator interface. In automatic mode, the turning gear is automatically engaged when the turbine speed is below a safe engaging speed.

Speed Control – The speed control system controls the turbine’s speed and load by operating in response to its actual speed signal and called-for speed reference. Passive magnetic type probes are used in conjunction with a multi-toothed wheel on the steam turbine shaft to sense rotational speed. Speed control prior to generator synchronization is Proportional Plus Integral (PPI). After synchronization the control is proportional only. The speed regulation is normally 5%.

Isochronous Control – In some applications, a unit is required either to operate under isolated conditions continuously or occasionally to maintain plant frequency. Once placed in service, usually from a tie line status contact, the isochronous speed control function resets speed to its setpoint following load variations by automatically manipulating on the load setpoint. Therefore, it maintains a constant steady-state speed and eliminates the operator continuously changing the load setpoint to match the load being carried.

Speed Wobulator – During startup, some units may require a speed wobulator incorporated in the speed control to slowly vary turbine speed above and below the speed setpoint. The wobulator prevents the turbine from running at a constant speed near critical bucket resonances.

Speed /Frequency Matching – The speed-matching function sets the steam turbine at synchronous speed at the completion of the start-up routine.

Synchronization – Automatic and manual synchronization are available in the Mark VI. Synchronization check protection may also be provided for backup protection.

Automatic Synchronization is performed with phase-slip windows in the control modules. The control system matches speed and voltage, and issues a command to close the breaker based on a calculated breaker closure time. Diagnostics monitor the actual breaker closure time and self-correct each time the breaker closes. A monitor mode allows automatic speed and voltage matching, but inhibits closing the breaker for the operator’s inspection.

Manual Synchronization can be initiated by operating a RAISE/LOWER load setpoint command either on the generator control panel or from the turbine control synchronization screen located on the operator interface.

Synchronization Check Protection provides backup to the automatic and manual synchronization systems. This function is performed in the protection

module.

Load Control – The load setpoint is an open loop command that is an opening reference to the control valves. The name implies that it is load control; however, it can only contribute to the demand for steam flow.

Valve Control – Valve interface is implemented with LVDT/R and servo loops or 4-20 mA valve interface. Each interface includes an auto-calibrate display for the valves and hardware diagnostics.

Main Stop Valve(s) are solenoid-operated and allow the turbine control valve(s) to be isolated from the high-pressure steam. It also provides, in conjunction with the control valve(s), redundant protection against overspeed through two independent lines of defense.

Inlet Control Valve(s) regulates the high-pressure steam flow into the turbine and respond to speed/load control commands.

Extraction Control Valve(s) regulate the steam flow into or out of the turbine down stream of the inlet control valve by responding to the pressure and speed/load control commands.

Automatic Extraction – The extraction control algorithm balances the turbine under various conditions. Unlike older systems, the Mark VI control allows the operator to bumpless transfer between operating modes. For example, to transfer from speed/load and extraction to inlet pressure and extraction control, the operator selected the desired mode. The Mark VI calculates the inlet pressure setpoint required to maintain the current inlet valve position in order to provide a bumpless transfer.Single automatic extraction units are normally used to control speed/load and one process pressure simultaneously. Both the inlet and the extraction control valves respond to speed/load control commands to change the steam flow to each section equally to control speed/load without affecting extraction flow, such as pressure. The inlet and extraction control valves respond to control commands to control extraction pressure without affecting speed/load. This is accomplished by moving the valves in opposite directions in such proportions that the change in load in the inlet section is balanced by an opposite change in load in the exhaust section. The difference between the inlet and exhaust steam flow is the extraction steam.

Extraction Flow control – Under certain plant conditions, it is desirable to operate the turbine extraction at a fixed flow rather than controlling the extraction pressure. In this mode of operation, the extraction pressure setpoint is changed to a level higher than the stage pressure and the flow control setpoint is reduced to fix the extraction flow reference signal. Extraction flow remains constant in this operating mode, providing extraction header pressure is maintained by another plant control system. It is important to remember that this method of control will allow the control valves to reduce flow if the stage pressure goes above the turbine maximum design.

Double Automatic Extraction – These units are used to control speed/load and two extraction process pressures simultaneously. In some cases, such units are used to control three process pressures, two extractions, and either inlet or exhaust pressure such as for non-condensing.

Inlet Pressure Control – This control mode allows the steam turbine to control inlet header pressure. The standard controller is a proportional + lag with a 5% regulation. The inlet pressure controller can be placed in service at any time after the generator breaker is closed and when there is approximately 20% load on the unit. The controller calculates a pressure setpoint that allows a bumpless transfer from load to inlet pressure control. Most applications allow a pressure control setpoint to be adjustable from 40% to 105% of design. The controller has a lower control valve position limit equal to approximately 3% load to ensure that the control action does not allow the turbine to come offline due to reverse power.

Sliding Pressure – Sliding pressure control manipulates the pressure setpoint to maintain the control valve position between 89% and 95% providing the least amount of pressure drop across the control valves. At minimum roll off inlet pressure, this function allows the control valves to slowly open and eventually maintain a fully open position as the pressure and setpoint increases to rated conditions.

Inlet Pressure Limiting – This can be performed as a function of a fixed level or a decreasing rate. Both provide closed loop control on inlet pressure, reducing inlet flow for abnormal decreases in inlet pressure.

Fixed Limiting control is implemented only with a proportional plus lag (droop control) algorithm. The inlet pressure limiter (IPL) setpoint is subtracted from the inlet pressure signal and the net error is multiplied by the appropriate gain, a function of regulation (normally 10%) and the pressure control range, to produce the control signal. The setpoint is usually adjusted below the header pressure and is always in a standby mode ready to control pressure if the header pressure decays to that level. The newer design of Inlet Pressure Control with a bumpless transfer is sometimes more desirable to use inlet pressure control with logic to place it in service when the header pressure drops a certain amount below header pressure.

Rate Limiting is recommended to protect the turbine against mechanical damage from water induction caused by carryover on turbines operating from unit boilers, or on header systems where rapid decay of inlet pressure is possible. This subsystem also decreases the rate at which the inlet pressure decreases and increases the chance of recovering before a boiler/turbine trip is necessary. The rate sensitive IPL is a control subsystem set up to remain in standby (even during a startup), ready to respond when the rate of decrease in the inlet pressure exceeds a preset value. It operates by placing an upper limit on the inlet control valve position, or speed/load signal. This limiting action increases, and the control valves eventually close to the floor limit if the rate of decrease in inlet pressure exceeds the preset value. The time required for this to occur depends on the amount that the rate exceeds the preset value. The floor limit prevents closing of the inlet control valves below the position necessary to pass minimum flow. The main requirement needed is the rate of decay in pressure (psig/min) the boiler can withstand without causing a high water level.

Exhaust Pressure Control – This is a closed loop proportional control function with adjustable regulation. For extraction units, it acts on a set of extraction or admission valves to maintain the pressure near the setpoint. If there is no extraction requirement, it will act on the inlet control. The required interaction between the extraction or admission valve and the inlet valve is included. Exhaust pressure control must be enabled by the operator. The standard regulation is 5%. Placing the control function in service does not require the operator to adjust the setpoint prior to the exhaust pressure control selection. The control system calculates the correct setpoint based on maintaining the control valve position at the time of transfer.

Megawatt Control – A megawatt setpoint is compared against a megawatt feedback value. The output of the deadband controller block produces adjustments to the load setpoint (raise/lower), depending on the error. The Mark VI can directly control generator MW or net MW if the MW input is from the tieline. A second controller block can be added to select control for either one. In single/double auto applications, one of the selected modes must be power. Bumpless transfer into MW control is accomplished by presetting the megawatt setpoint to the present running MW level. This preset is done as single shot upon selecting MW control.

Power Factor Control – A power factor setpoint is compared against a feedback from a transducer or the watts/VARs calculation. The error is used to energize raise/ lower relays feeding the exciter regulator. Pulsing is provided for slow, fine correction of small errors. This relay interface is the same as required for the voltage matching option. In addition, power factor is calculated from watts and VARs.

VAR Control – A VAR setpoint is compared against a scaled 4-20 mA VAR feedback from a transducer. The error is used to energize raise/lower relays feeding the exciter regulator.

Auxiliary Systems – The Mark VI can control some auxiliary systems, in addition to its primary function of controlling and protecting the steam turbine. These include condenser level control, lube oil temperature control, steam seal pressure control, water spray valve, and turbine auxiliary motors.

Stock part list:

“IS200AEADH1A
IS200AEADH1ACA”
IS200AEBMG1AFB
IS200AEGIH1BBR2
“IS200AEPAH1A
IS200AEPAH1AFD”
IS200ATBAG1BAA1
IS200BAIAH1BEE
“IS200BICIH1A
IS200BICIH1ACA”
IS200BICIH1ADB
“IS200BICLH1A
IS200BICLH1AFD”
IS200BICLH1AFF
IS200BICLH1BAA
IS200BICLH1BBA
IS200BPIAG1AEB
IS200BPIBG1AEB
IS200BPIIH1AAA
IS200BPVDG1BR1A
IS200CABPG1BAA
IS200DAMAG1BBB
IS200DAMAG1BCB
IS200DAMBG1ACB
IS200DAMDG1A
IS200DAMDG2AAA
IS200DAMEG1ABA
IS200DRLYH1B
IS200DRLYH1BBB
“IS210DRTDH1A
(IS200DRTDH1A)”
IS200DSFCG1AEB
IS200DSPXH1BBD
IS200DSPXH1CAA
IS200DSPXH1D
IS200DSPXH1DBC
IS200DSPXH1DBD
IS200DSPXH2CAA
IS200DSPXH2DBD
IS200DTCIH1ABB
IS210DTAIH1A (IS200DTAIH1A)
IS210DTCIH1A (IS200DTCIH1A)
IS210DTTCH1A (IS200DTTCH1A)
IS210DTURH1A (IS200DTURH1A)
IS200EACFG2ABB
IS200EBKPG1CAA
IS200ECTBG1ADA
IS200ECTBG1ADE
IS200EDCFG1BAA
IS200EDCFG1A
IS200EDCFG1ADC
IS200EDEXG1ADA
IS200EDEXG1AFA
IS200EGDMH1A
IS200EGDMH1AAB
IS200EGDMH1ADE
IS200EGDMH1AGG
IS200EGDMH1AFG
IS200EHPAG1AAA
IS200EHPAG1ABA
IS200EHPAG1ABB
IS200EHPAG1ACB
IS200EHPAG1DCB
IS200EISBH1A
IS200EISBH1AAA
IS200EISBH1AAB
IS200EMIOH1A
IS200EMIOH1ACA
IS200EMCSG1AAB
IS200EPCTG1AAA
IS200EPDMG1ABA
IS200EPDMG1BAA
IS200EPSMG1AEC
IS200EPSMG1AED
IS200ERSCG1AAA
IS200ERBPG1ACA
IS200ERBPG1A
IS200ERDDH1ABA
IS200ERIOH1AAA
IS200EROCH1ABB
IS200ESELH2A
IS200ESELH1AAA
IS200ESELH2AAA
IS200EXAMG1AAB
IS200EXHSG3AEC
IS200FHVBG1ABA
IS200GGXDG1ABB
IS200GGXIG1AFE
IS200HFPAG1ADC
IS200HFPAG2ADC
IS200IGPAG2AED
IS200ISBBG1AAB
IS200ISBDG1AAA
IS200ISBEH1ABB
IS200ISBEH1ABC
IS200ISBEH2ABC
IS200JPDHG1AAA
IS200JPDSG1ACB
IS200NATCH1CPR3
IS200RAPAG1BBA
IS200RAPAG1BCA
IS200RCSAG1ABB
IS200RCSBG1BAA
IS200SCNVG1ADC
IS200SPIDG1ABA
IS200SRLYH2AAA
IS200SSCAH2AGD
IS200STCIH2AED
IS200STAIH2A
IS200STAIH2ABA
IS200STAIH2ACB
IS200STCIH2A
IS200STURH2AEC
IS200TAMBH1ACB
IS200TBAIH1C
IS200TBAIH1CCC
IS200TBAIH1CDC
IS200TBAOH1CCB
IS200TBCIH1BBC
IS200TBCIH1B
IS200TBTCH1CBB
IS200TBTCH1C
IS200TDBTH6A
IS200TDBTH6ACD
IS200TDBSH2A
IS200TDBSH2AAA
IS200TDBSH6ABC
IS200TDBTH2ACD
IS200TDBTH6ABC
IS200TREGH1BDC
IS230TDBTH6A(IS200TDBTH6ABC)
IS200TRLYH1B
IS200TRTDH1C IS200TRTDH1CCC
IS210TREGH1B
IS210TRPGH1B (IS200TRPGH1BDE)
IS215UCVHM06A
IS200TRTDH1C IS200TRTDH1CCC
IS200TSVOH1BBB
IS200TTURH1BCC
IS200TTURH1BEC
IS200TVIBH2BBB
IS200VAICH1C
IS200VAICH1D
IS200TPROH1BBB
IS200TREGH1BDB
IS200TRLYH1BED
IS200TRLYH1BFD
IS200TRLYH1BGF
IS200TRPGH1BCC
IS200VAICH1DAA
IS200VCMIH2B
IS200VCRCH1B
IS200VCRCH1BBB
IS200VRTDH1D
IS200VRTDH1DAB
IS200VSVOH1B
IS200VSVOH1BDC
IS200VTCCH1C
IS200VTCCH1CBB
IS200VTURH1BAA
IS200VTURH1BAB
IS200VTURH2B
IS200VVIBH1C
IS200VVIBH1CAB
IS200WETBH1BAA
IS200WETCH1AAA
IS200WROBH1AAA
IS210DRTDH1A (IS200DRTDH1A)
IS215VAMBH1A (IS200VSPAH1ACC)
IS215VCMIH1B (IS200VCMIH1B)
IS215VCMIH2BB (IS200VCMIH2BCC)
IS215VCMIH2BC (IS200VCMIH2BCC)
IS215WETAH1BB (IS200WETAH1AEC+IS210BPPBH2CAA)
IS210MACCH1AKH (IS200WEMDH1ABA)
DS200DSPCH1ADA (DS200ADMAH1AAB)
IS215UCVDH7AM
IS200BPVCG1BR1 / 259B2460BTG2
IS200BPVCG1BR1
151X1207CK02SA02 IS200EDEXG1BAA
IS215ACLEH1A (IS200ACLEH1ABA)
IS215PMVPH1AA
IS215REBFH1A
IS215REBFH1BA
IS215UCVDH5A
IS215UCVDH5AN
IS215UCVDH7AM (DS200UCVAH1ABC)
IS215UCVEH2A
IS215UCVEH2AE
IS215UCVEM06A
IS215UCVGM06A IS215UCVGH1A
IS215VCMIH2C
IS215VCMIH2CC
IS215VPROH2B IS215VPWRH2AC
IS215VPROH2BC
IS215VPROH2BD
IS215WEPAH1AB
IS215WEPAH2AB
IS215WETAH1BA
IS215UCCCM04A
IS200TPROH1C
IS200EXAMG1BAA
IS230TNSVH3A (IS200TSVCH1A)
HE700GEN200
IS230SNTCH2A (IS200STTCH2ABA)
IS230SNIDH1A (IS200SDIIH1ADB)
IS230PCAAH1B
IS400TCASH1AGD
IS400JPGPA1ACD
IS215ACLEH1B
IS215ACLEH1C IS215ACLEH1CA
IS200TRPGH1BDE
IS200DAMCG1A
IS400TDBTH6AEF
IS200JPDCG1ACB
IS200TREGH1BEC
IS215UCCAM03A
IS200TPROS1CBB
IS210WSVOH1A
IS215VAMBH1A
IS210WSVOH1A IS200WSVOH1A
IS230TNRLH1B (IS200TRLYH1BHH)
IS415UCVHH1A
IS215UCVHM06A IS415UCVHH1A
IS200AEPAH1ABB
IS200EPSMG2ADC
IS200EPSDG1AAA
IS215VCMIH2B
IS200EPSMG1A
IS200TRPAH2AHE+IS230TNPAH2A
IS200EHPAG1DAB
IS200TPROH1CAA
IS230TNSVH3A(IS200TSVCH1AJE)
IS200JPDCG1ACB-W01
IS200SSCAH2AEC
IS210WSVOH1AE（IS200WSVOH1ACD）
IS200JPDSG1AEC
IS400JGPAG1ACD
IS200EPSMG2A
IS215VPROH1B
IS215VPROH1BD
259B2460APG1
IS200PMC1H1ABA
IS200PMC1H1ACC
IS200EDEXG1BAA
IS200ESELH3AAA
IS215ACLEH1BB
IS200PMCIH1A
IS200PMCIH1ACC
IS200EAUXH1A
IS200EAUXH1ACC
EX2100R 151X1213BA01SA01
CM400RGICH1ADC
IS200AEPDH1B IS200AEPDH1BAA
IS200AEPEH1CAA
IS200EBRGH2A
IS200HSLAH2A
IS200ESYSH3ABB
IS200JPDDG1AAA
IS200JPDFG1ADD
IS200JPDMG1ADC
IS200JPDPG1AAA
IS200TBAIH1CDD
IS200TPIMG1AAB
IS200TTURH1CED
IS200TVBAH2ABC
IS215ACLEH1AB
IS200ESYSH1A IS200ESYSH1AAA
IS200TCASH1ACB
IS200TRPGH1BDD
IS215UCVEM01A
IS200SHRAH2A
IS200SHRAH2AED
IS200EXIBG1A IS200EXIBG1ADB
IS200EXIBG1A IS200EXIBG1ACA
IS200GGXIG1A IS200GGXIG1AED
DS200GDPAG1A DS200GDPAG1AKF
IS200RPPAG1B IS200RPPAG1BCA
IS215ACLEH1A IS215ACLEH1AM
IS400TCATH1A IS400TCATH1ADC
IS215ACLAH1AM
IS215UCCCM04AB
IS200SRTDH2ABA
IS200SSCAH2ACB
IS200WNPSH1A IS200WNPSH1AAA
IS200JPDLG1A IS200JPDLG1AAC
IS200SRTDH2ABB
IS200TVBAH2A IS200TVBAH2ABB
IS200TVBAH2AAA