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- 1. Power Plant ApplicationsPowerPlant Applications Nigam SharmaNigam Sharma Sr. Regional Manager, Asia PacificSr. Regional Manager, Asia Pacific
- 2. AgendaAgenda Power PlantsOver View Main Components of a Power Plant Typical Controls Applications
- 3. Types of PlantsTypesof Plants Thermal Power Plants Coal Fired Utility Oil and Gas Fired Plants Bio-fuel Plants Gas Turbine Plants Gas and Oil Fired Simple Cycle Gas Turbine Plants Combined Cycle HRSG and Steam Turbine Plants (CCP) Cogeneration Plants (Industrial or District Heating) Oil & Gas Fired CCP Bio-Fuel CFB plants Nuclear Plants √√ √√ √√ XX
- 4. Thermal Plant OverviewThermalPlant Overview 1. Cooling Tower 2. Cooling Water Pump 3. 3-phase Transmission Line 4. Unit Transformer 5. 3-phase Electric Generator 6. Low Pressure Turbine 7. Boiler Feed Pump 8. Condensor 9. Intermediate Pressure Turbine 10. Steam governor valve 11. High Pressure Turbine 12. Deaerator 13. Feed Water Heater 14. Coal Conveyor 15. Coal Hopper 16. Pulverised Fuel Mill 17. Boiler Drum 18. Ash Hopper 19. Superheater 20. Forced Draught Fan 21. Reheater 22. Air Intake 23. Economiser 24. Air Preheater 25. Electrostatic Precipitator 26. Induced Draught Fan 27. Chimney Stack
- 5. Boilers orSteam Generators Generate steam at desired rate, pressure and temperature by burning fuel in its furnace. The boiler is that part of the steam generator where phase change (or boiling) occurs from liquid (water) to vapour (steam), essentially at constant pressure and temperature. Steam Turbine Steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful kinetic (rotational) energy which rotates the steam turbine. Most steam turbines rotate at 3000 rpm or 3600 rpm. Electric Generator Electrical generator is a device that converts kinetic energy to electrical energy, generally using electromagnetic induction. Electric Generators are rotated by Steam Turbines at 3000 rpm or 3600 rpm Major ComponentsMajor Components
- 6. Bottom Ash System Economizer Hoppers F D FanGeneral Water Sump BOTTOM ASH HOPPER Settling Pond WATER TREATMENT Coal Bunker Conveyors Pulverizers Load Gen.HP IPL P Turbine Econ- omizer Re- Heat Super Heater DRUM Condenser P A Fan ID Fans HP FW Htr LP FW Htr Ash Transfer Water Clean-up Precipitators Stack Gas Scrubber Emissions Monitor Flyash Cond. Pump BFP Deaerator Cooling Water Feeder Downcomers Risers Air Heater Power Plant Process MapPower Plant Process Map Water Vapor & Scrubbed Gases
- 7. Basic Boiler TypesBasicBoiler Types Up to an operating pressure of around 190Kg Bar in the evaporator part of the boiler, the cycle is Sub-Critical. In this case a drum-type boiler is used because the steam needs to be separated from water in the drum of the boiler before it is superheated and led into the turbine. Above an operating pressure of 220Kg Bar in the evaporator part of the Boiler, the cycle is Supercritical. The cycle medium is a single phase fluid with homogeneous properties and there is no need to separate steam from water in a drum. Drumless or Once- through boilers are therefore used in supercritical cycles. Advanced Steel types must be used in Supercritical boilers for components such as the boiler and the live steam and hot reheat steam piping that are in direct contact with steam under elevated conditions Sub-critical Boilers: Steam conditions up to 220Kg bas/ 540°C are achieved Supercritical Boilers: Steam conditions up to 300 Kg Bar/600°C/620°C are achieved using steels with 12 % chromium content.
- 8. Supercritical Once ThroughPower PlantSupercritical Once Through Power Plant Power Generation Cycle Efficiency primarily depends on the temperature difference across steam turbine. Higher boiler outlet temperature results in higher difference. Higher steam temperatures is also linked to increased pressures to keep the steam volume within manageable limits. At pressures in excess of 220Kg bar, the fluid is termed supercritical. The increased pressure also increases cycle efficiency and, although this increase is a second-order effect compared with the effect of temperature, but it can still make an important contribution to increasing overall plant efficiency. “SupercriticalSupercritical" is a thermodynamic expression describing the state of a substance where there is no clear distinction between the liquid and the gaseous phase (i.e. they are a homogenous fluid). Water reaches this state at a pressure above around 220 Kg Bar.
- 9. Supercritical Once ThroughPower PlantSupercritical Once Through Power Plant Supercritical coal fired power plants have higher efficiencies of almost 45% Supercritical Power plants have lower emissions than sub- critical plants at any given power output.
- 10. Various Boiler TypesVariousBoiler Types
- 11. HP FW HTR LP FW HTR HP L PSecondary Super Heater PowerPlant ProcessPower Plant Process MapMap Once-Thru Boiler BFP Water Vapor & Scrubbed Gases Load Gen. Turbine Econ- omizer Re- Heat Condenser ID Fan Precipitators Stack Gas Scrubber Emissions Monitor Flyash Deaerator Cooling Water Bottom Ash System Economizer Hoppers F D Fan Settling Pond Ash Transfer Water Clean-up Cond. Pump General Water Sump Coal Bunker Conveyors Pulverizers P A Fan Feeder Primary Super Heater IP Air Heater BOTTOM ASH HOPPER
- 12. Circulating Fluidized BedBoilersCirculating Fluidized Bed Boilers A bed of sand, ash and fuel particles is fluidized by the combustion air, which is blown into the bed through the bottom. Due to high air/flue gas velocity the fuel is carried over in the combustion gases. The solid material is then separated in a cyclone and recycled to the lower section of the bed. CFB combustion process is ideally suited to burning low-quality fuels, fuels with a high moisture content 'waste-type' fuels. All coals, lignite, petroleum coke, biomass, waste coal, refuse-derived fuels, agricultural and pulping waste, and municipal solid waste
- 14. Typical Large SteamTurbineTypical Large Steam Turbine Steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful kinetic (rotational) energy by expansion. The expansion takes place through a series of fixed blades (nozzles) and moving blades. The moving blades rotate on the turbine rotor and the fixed blades are concentrically arranged within the circular turbine casing which is substantially designed to withstand the steam pressure. Most steam turbines rotate at 3000 rpm or 3600 rpm.
- 15. Basic Steam TurbinesBasicSteam Turbines The Turbine designs for a Supercritical plant are similar to the sub-critical except that special materials required for the casings and walls for withstanding high Temperatures and pressures in Supercritical Steam Turbines. High Pressure (HP) Turbine: In order to cater for the higher steam parameters in supercritical cycles, materials with an elevated chromium content which yield higher material strength are selected. Intermediate Pressure (IP) Turbine Section: In supercritical cycles there is a trend to increase the temperature of the reheat steam that enters the IP turbine section in order to raise the cycle efficiency. As long as the reheat temperature is kept at 560 DEGC there is not much difference in the IP section of Sub critical and Super Critical plants. Low Pressure (LP) Turbine Section: The LP turbine sections in supercritical plants are not different from those in subcritical plants.
- 16. Combined Cycle PlantsCombinedCycle Plants Term Combined Cycle is used to describe process that uses combination of more than one thermodynamic cycles. Combined Cycle Power Plant (CCPP) means a combination of gas turbine generator (Brayton cycle) with turbine exhaust waste heat boiler and steam turbine generator (Rankine cycle) for the production of electric power. CCPP Common Combinations One CT and One Steam Turbine (1 on 1) Two CTs and One Steam Turbine (2 on 1) X CTs and Y STs (X on Y) CTs always paired with a HRSG 2 on 1 common - all generators work out to be comparable size
- 17. Simple Cycle Combustion(Gas) TurbineSimple Cycle Combustion (Gas) Turbine Thermal Efficiency = 35-40% 35-40% Electricity Generator 3% Aux. Power + Losses Air 100% Fuel Combuster Stack 57-62% Compressor Turbine
- 18. Combined Cycle PowerGenerationCombined Cycle Power Generation Thermal Efficiency = 45-55% 35-40% Electricity Generator 6% Aux. Power + Losses Air 100% Fuel Combuster Stack 20% Compressor Turbine 28%Steam Condenser HRSG Steam Supplementary Fuel (Optional) Exhaust Gas Steam TurbineGenerator 12-15% Electricity Lake
- 19. Typical Combined CyclePlantTypical Combined Cycle Plant Gas Supply Station Gas Supply Gas Turbine Stack Heat Recovery Steam Generator HRSG Stack Generator Transformer Transmission Deaerator Boiler Feed Pump Cooling Towers Condensate Extraction Pump Generator Transformer Transmission Gas Turbine IP LP Generator Cooling Water Switch Yard Demineralization Plant Raw Water FW FW Switch Yard Air Intake Condenser Bypass Damper
- 20. Most Common CombinedCycleMost Common Combined Cycle – 2 on 1 Process– 2 on 1 Process Air Air GT GT HRSG HRSG ST Gen Gen Gen Steam Steam Stack Gas Stack Gas Legend GT – Gas Turbine Gen - Generator ST – Steam Turbine HRSG – Heat Recovery Steam Generator
- 21. Common Cogeneration PlantsCommonCogeneration Plants Cogeneration is the simultaneous production of power/electricity, hot water, and/or steam from one fuel. Cogeneration plants can reach system efficiencies exceeding 80% Industrial Plants Multi utility plants; Electricity, Process Steam, Heating Steam, Hot water, Chillers etc. District Heating Plants Extraction steam for residential heating Oil or Gas fired Combined Cycle Cogen Conventional Boilers Cogen Circulating Fluidized Bed Boilers Low Calorific Value, high moisture, low Sulphur fuels Bagasse, Rice husk, Rice Straw, Wood Chips etc
- 22. Industrial Co-GenerationIndustrial Co-Generation Bagasse RiceHusk Rice Straw Wood Chips Etc. Thermal Efficiency = 80%
- 23. District HeatingDistrict Heating 15% Steam Stack Air 15%Electricity Boiler Steam Turbine Generator 5% Aux. Power + Losses Heat Exchanger 55% Steam Condenser 10% Losses Feedwater Loop Thermal Efficiency = 70%
- 24. Power Plants ControlsPowerPlants Controls CapabilityCapability
- 25. Typical Boiler PlantControl FunctionsTypical Boiler Plant Control Functions Fuel Management Fuel control Mill control Burner Safety & control Air Management Fans Control Steam temperature Management SH Steam Temp Control RH Steam Tem Control Feed Water Management Boiler Drum Level Control Deaerator Level Control Soot Blower Controls Emission Management
- 26. Typical Steam TurbineControl FunctionsTypical Steam Turbine Control Functions Speed loop Control MW loop Control Speed or MW demand and rate selections Initial MW pickup 1st stage pressure loop Load limiting Inlet pressure limiting (adjustable) Fail safe turbine trip design Valve testing & Valve calibration Individual valve curves Critical Overspeed detection & protection Hotwell Level & Condensate extraction Controls HP & LP Bypass Controls HP & LP Heater level Cascade Controls Gland steam Press control Turbine Stress Calculations Turning Gear Controls Main Oil, Safety Oil Pumps Control Seal Oil Pumps Extraction controls
- 27. Typical CCPP ControlFunctionsTypical CCPP Control Functions HRSG (Heat Recovery Steam Generator) Boiler Controls Un-fired HRSG Bypass Damper Control Feedwater - Drum Level Control Live Steam Temperature Control Turbine Bypass Control Deaerator Level Control Hotwell Level Control Advanced Controls Fired HRSG (additional controls) Fuel Controls Air Control Burner Management Temperature Control Gas Turbine Controls In most cases GT controls are supplied by OEM
- 28. Typical Balance ofPlant ControlsTypical Balance of Plant Controls Balance of Plant Controls (Miscellaneous Controls) Water Treatment Plant Controls Circulating Water System Raw Water system Turbine Cooling Oil Temperature Controls Generator Cooling Oil Temperature Controls Ash Handling System Controls Fuel Handling Systems Fuel Skid Controls (CCPP) Coal Handling System Controls Environmental Controls Flue Gas De-Sulphurization Controls Scrubber Controls Motor Controls Electrical Controls & Monitoring
- 29. Basic level: Singledrive control with electrical protections, auto/manual modes Single loop control with protection of actuators, auto/manual modes Interlocks between the control loops and drives Control of technological groups for Boiler and Turbine: Coordinated loops control (common setpoint, interactions) Cross interlock feedbacks and priorities Sequences Turbine start-up, roll-off, and other turbine coordinated controls Burner Management System Coordinated Unit Control: LDC - Load Demand Computer - selection of boiler / turbine modes Unit remote control from Dispatch Center Main unit control sequences Run-backs & Run-ups Concept of a Unit ControlConcept of a Unit Control
- 30. Binary Control Drive ControlStandards for: low voltage motors high voltage motors open/close valves or dampers electrical actuators Sequential Control Features of a sequence: consists of a sequence head and sequence steps sets time relations between performed steps allows start, stop and resume by operator incorporates emergency logic and procedures incorporates interaction logic and operator’s permissives Concept of a Unit ControlConcept of a Unit Control
- 31. Modulating Control ControlStructures: Basic level - single loop executing a direct control of actuator Cascade level calculating setpoint for basic level loop Coordinating level responsible for unit load and cross feedbacks between parts of the unit Supervisory optimization structure, which calculates corrections for other control loops, based on feed-forward and Smith prediction philosophy Control Algorithms: Mathematical algorithms Universal PID type (PID, PIDFF) Dedicated for power applications: Smith predictor, drum level correction, steam table, PID with variable parameters Value tracking for bumpless transfer during auto / manual switch Advanced algorithms Concept of a Unit ControlConcept of a Unit Control
- 32. Coordinated Unit ControlsCoordinatedUnit Controls
- 33. Coordinated Unit ControlsCoordinatedUnit Controls ADS Interface Unit Master Boiler Master Fuel Master Air Steam Temp Feedwater Boiler Turbine Turbine Master Mill 1 Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand
- 34. Front End Front EndSystemFront End System ADS Interface Unit Master Boiler Master Fuel Master Air Steam Temp Feedwater Boiler Turbine Turbine Master Mill 1 Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand
- 35. ADS Interface Fuel Master Air Steam Temp Feedwater Boiler Turbine Front End Mill 1Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand Load Demand Computer (LDC) Load Demand ComputerLoad Demand Computer
- 36. Invented byWestinghouse for coordinated unit control Allows to control a unit in different modes of operation: Turbine Follow Mode: Turbine control with throttle pressure – The turbine follows the boiler load, LDC tracks the actual unit load and calculates setpoint for the boiler (MW loop is not in use) Boiler Follow Mode: Boiler control with live steam pressure – The boiler adapts the steam generation to the consumption required by the turbine, LDC tracks the actual unit load and calculates the setpoint for turbine valve position (MW loop is not in use) Coordinated Control Mode: Either turbine or boiler controls live steam pressure and boiler or turbine respectively (MW loop is in use for turbine or boiler) Load Demand ComputerLoad Demand Computer
- 37. LDC isa software model of the process, which calculates on-line all required control setpoints using “feed-forward” Operator sets the required load or MW demand LDC calculates the main setpoints separately for the boiler and the turbine control structures The structure for boiler recalculates setpoints for loops controlling air and fuel Tunable function generator algorithms calculate setpoints for loops controlling the actuators LDC allows to keep unit in automatic control also during runbacks or trips Load Demand ComputerLoad Demand Computer
- 38. Four Modes Coordinated Turbine Follow Boiler Follow Manual (separated) Bumpless transfer between all modes Interlocks prevent Unit Master from controlling unless either Boiler or Turbine Master in Auto Rate limiting on ramped signals Load Demand ComputerLoad Demand Computer
- 40. Turbine Master(Fixed Pressure) regulates turbine to satisfy megawatt demand Recognizes boiler’s response capabilities Turbine MasterTurbine Master
- 41. Turbine Master(Variable or Sliding Pressure) Alternative to fixed pressure mode Throttle pressure varied with load while turbine valves remain in fixed position Valves allowed to move on load changes for fast response Throttle pressure allowed to vary to maintain proper valve position Not suitable for all boilers Turbine MasterTurbine Master
- 42. Boiler Master Sets boiler firing rate Interlocked to lower control loops Dynamic control to improve responsiveness Runbacks and rundowns based on boiler capabilities Boiler MasterBoiler Master
- 43. ADS Interface LDC Boiler Master Fuel Master Air Steam Temp Feedwater Boiler Turbine Turbine Master Mill 1Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand Fuel MasterFuel Master
- 44. FuelFuel MasterMaster Fuel Master Develops base control signal for coal mills Performs fuel/air cross limiting Incorporates a mill model to improve coal flow measurement Uses boiler as calorimeter
- 45. FuelFuel MasterMaster Mill Controls Regulates coal flow Regulates primary air flow Regulates coal/air temperature leaving mill Feeder overrides on high mill amps and/or mill differential pressure Primary air flow takes priority over coal/air temp. Includes interlocks to air dampers for safety and interface to BMS
- 46. ADS Interface LDC Boiler Master Fuel Master Air Steam Temp Feedwater Boiler Turbine Turbine Master Mill 1Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand
- 47. Air FlowAir Flow ControlControl FD Fan Control Controls combustion air flow Firing rate sets air flow requirement Includes damper interlocks Interlocked to ID fans for auto mode Includes fuel/air cross limiting (O2 trimming)
- 48. Air FlowAir Flow ControlControl Furnace Draft Control Regulates ID fans to provide proper exhausting force for gas flow through boiler Uses FD fan demand as feedforward Utilizes three furnace pressure transmitters (middle-of-three) for control Fully meets NFPA requirements for: Rapid closing of ID inlet dampers on MFT Directional blocking on low furnace pressure Includes damper interlocks for starting/stopping
- 49. ADS Interface LDC Boiler Master Fuel Master Air Steam Temp Feedwater Boiler Turbine Turbine Master Mill 1Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand
- 50. FeedwaterFeedwater ControlControl Feedwater Control Regulates feedwater flow and controls drum level Two modes of operation Single element for use during startup Three element for normal operation Drum level signals are density compensated
- 51.
- 52. ADS Interface LDC Boiler Master Fuel Master Air Steam Temp Feedwater Boiler Turbine Turbine Master Mill 1Mill n ID Fans FD Fans Furnace Draft S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand
- 53. SteamSteam TemperatureTemperature Superheat TemperatureControl Regulates main steam temperature Standard consists of two stage attemperation Includes integral windup protection Includes interlocks for spray and block valves
- 54. SteamSteam TemperatureTemperature Reheat TemperatureControl Regulates reheat steam temperature thru the use of sprays & burner tilting arrangement System tracks until spray valve open Interlocks for both spray and block valves included
- 55. Furnace 2 nd S.H. PID PID PID PID X FiringRate Boiler Master Desired Spray (20%) WW Outlet Temp LDC Out Econo mizer Fuel/Air 4th S.H. 3rd S.H. PID FW Flow Control FW/FR ratio DMC Algorithm SUM RH Tilts/Damper Setpoints 2nd , 3rd and 4th SH 1st S.H. APC Steam Temperature ControlAPC Steam Temperature Control SchemeScheme
- 56. A SafetySystem Permits safe start-up, operation, and shutdown of the boiler Supervises Fuel insertion/withdrawal from boiler conforming to established safety standards Monitors and controls igniters and burners Separate Flame Scanners used to detect igniter and main flames Three type of flame scanners Ultraviolet, typically used for natural gas and light oils Infrared, typically used for medium to heavy oils and pulverized coal All Fuels, typically used with gas igniters & coal as main fuel Other Field Devices Safety shut-off valves Pressure, temperature, flow & valve position limit switches Blowers to cool scanners or provide combustion air for igniters Burner Management SystemBurner Management System DefinitionDefinition
- 57. Critical safetysignals are wired as redundant I/O for maximum boiler safety. An automatic start sequence ensures correct completion of boiler air purge and satisfies safety permissives before fuel firing, preventing operator error. Continued monitoring of boiler conditions actuates a safety shutdown trip if unsafe conditions develop. Operator maintains control capabilities from the operator console or burner front digital logic stations. First-out indications are provided for identification of the cause of boiler trip Automatic Boiler Purge Prior to Restart Flame Detection, Monitoring & protection Master Fuel Trip Burner/Mill Start-Up and Shutdown Sequences Safety Interlocking Alarming of Abnormal Conditions Burner Management SystemBurner Management System
- 58. 6 to8 Pulverizers (Mills) needed in each boiler to supply Pulverized coal to the burners One mill normally supplies pulverized coal to one burner level. Additional mills supply each additional burner level on a one-for-one basis. There are between four and eight burners per level. This depends upon the type of furnace, e.g. wall fired, tangential, split furnace, etc. With dual fuel firing, there will also be oil guns /gas nozzles on one or more burner levels. There will be four to eight guns / nozzles per level. Mills, Burners and LevelsMills, Burners and Levels
- 59. Burner ArrangementsBurner Arrangements Wall-FiredTangential Corner-Fired Slag Crushed Coal Air Secondary Furnace Primary Furnace Cyclone (B&W Exclusive)
- 60. Burner ArrangementsBurner Arrangements Multiple Elevations Toother burners this elevation Drive Motor Pulvorizer or ‘Mill’ Feeder Coal Bunker Air in Boiler One of six; one per burner elevation
- 61. The Burner "Front"TheBurner "Front" Startup Sequence (Light-off by burner pairs) - Purge air-10 Minutes - Purge air Off - Open Dampers - Ignition Spark ON - Ignition Valve OPEN - Prove Igniter ON - Main Fuel ON - Prove Main Flame ON - All Ignition OFF on Combustion Control Fuel Ignition Transformer Igniter Damper Damper Purge Air Main Burner Ignition Flame Main Flame Ignition Flame Det. Main Flame Det Cooling Air Wind Box
- 62. Enhanced safetyand availability Greater operational flexibility Significant auxiliary fuel savings Continuous safety monitoring Consistent start-up and operation Full integration of all facets of the firing system Integrated Air damper controls Improved plant availability Reduced maintenance costs Prevention of boiler explosion NFPA 8502 code compliance Expandable solutions Ovation BMS FeaturesOvation BMS Features
- 63. Turbine Master Boiler Master Feedwater Combustion Fuel Valve FD FanID Fan Pump (Turbine) Pump (Shaft) Pump (Standby) Load Demand Computer High Limit Low Limit Ramp Rate Operator Set Limits Runbacks Rundowns Block Increase Block Decrease Contingency Digital Control LocalRemote Valve Positioner Pass Dampers Spray Steam Temp. Steam Turbine ControlsSteam Turbine Controls
- 64. Ovation Turbine ControlArchitectureOvation Turbine Control Architecture Redundant systems - Processor - I/O interface - Power supplies - Network interface System same as rest of plant Controller hardware and I/O User Interfaces Network Standard I/O cards for specialized turbine applications Speed cards Valve cards
- 65. Turbine Control RequiresSpecialized I/OTurbine Control Requires Specialized I/O Speed Detector Module Valve Positioner Module Servo Driver Module
- 66. Speed Detector ModuleSpeedDetector Module 5ms update rate for overspeed detection Variable update rate for speed regulation Controller-independent speed detection and tripping using dual on-board form C outputs for fast reaction to over speed conditions Open-wire detection for low resistance source less than 5000 Ohms Redundant power feeds 1000V dielectric withstand electrical isolation between logic signal and field inputs Hot swap capability
- 67. Self calibrating& Self Diagnostics PI control loop with 10 millisecond loop time Programmable PI gain and integral time constants Normal mode or SLIM interface for local manual operation Up to three redundant servo valve actuator coil drive outputs Supports redundant coil and redundant LVDT capability (Redundant configuration) Interfaces to LVDT interface to primary excitation and dual secondary feedback windings 24/48V dc input for emergency valve closure independent of controller 16 bit micro-controller watchdog timer for servo valve actuator coil drive Supports single mode (full arc) or sequential (partial arc) modes of valve operation Watchdog timer for I/O bus Redundant configuration option Redundant 24V power auctioneering Local calibration & tuning capability without trim pots Open-coil and shorted-coil diagnostics Runs seating and back-seating logic Valve Positioner ModuleValve Positioner Module
- 68. Self calibrating& Self Diagnostics PI control loop with 10 millisecond loop time Programmable PI gain and integral time constants Normal mode operation only 2 servo valve actuator coil drive outputs Supports redundant coil and dual LVDT capability. 2 DC-LVDT or AC-LVT outputs & 2 DC-LVDT or AC-LVT inputs 16 bit micro-controller Watchdog timer for servo valve actuator coil drive Watchdog timer for I/O bus Redundant feedback option for AC-LVT Redundant 24V power auctioneering Local calibration & tuning capability without trim pots Open-coil and shorted-coil diagnostics Runs seating and back seating logic Hot swap capability Servo Driver ModuleServo Driver Module
- 69. Main StopValves or Throttle Valves, used primarily during start-up, machine protection Governor Valves or Control Valves, control the turbine over most of the operating range Reheat Stop Valve, on-off type valve to backup the intercept valve Intercept Valve, used to prevent steam from entering turbine after load loss Full Arc Admission / Partial Arc Admission Single Valve Mode / Sequential Valve Mode Steam Turbine Valve TerminologySteam Turbine Valve Terminology
- 70. Governor Control FunctionsGovernorControl Functions Control of: Turbine stop valves Control valves Reheat stop valves Intercept valves Monitor & Control of: Speed Main steam pressure Chest pressure 1st stage pressure Reheat pressure Load
- 71. Typical Large SteamTypicalLarge Steam TurbineTurbine HP TURBINE IP TURBINE LP TURBINE SPEED SENSING CONTROL SYSTEM CONTROL INPUT STEAM GEN INTERCEPT VALVE(S) REHEAT STOP VALVE(S) REHEAT AND/OR MOISTURE SEPARATOR CONDENSER (W) GOVERNOR/ (GE) CONTROL VALVE(S) (W) THROTTLE/ (GE) STOP VALVE(S) CROSSOVER GENERATOR GENERATOR BREAKER
- 72. 1 3 5 2 6 3 5 1 2 4 6 4 Main Steam Supply Governor/ Control Valves Governor/ Control Valves Throttle/ Stop Valve1 Throttle/ Stop Valve 2 Nozzle Block Full Arc / Single Valve Mode = All Governor/Control Valves opened together Partial Arc / Sequential Valve Mode = Governor/Control Valves opened independently Steam Flow Through Nozzle BlockSteam Flow Through Nozzle Block
- 73. Typical Startup andLoading ProgramsTypical Startup and Loading Programs Pre Warm Pre Roll Conditions 1st Stage Shell Metal Temp Change Hot Reheat Temp Change HP allowable Ramp Rate Reheat allowable Ramp Rate 1st Stage Shell Steam Temp Speed Soaks (1000, 3000 and 3600 RPMs) Initial Load Pickup and Soak
- 74. Steam Turbine SystemAuxiliariesSteam Turbine System Auxiliaries Motor Operated Valves Solenoid Operated Valves Vapor Extractors Turning Gear Turbine Drain Valves Jacking Oil Pumps Gland Steam System Seal Steam System Lube Oil System Auxiliary Steam System Emergency Leak-off System Vacuum Breakers Bentley Nevada Modbus Link Turbine Supervisory
- 76. Turbine bypasssystems can contribute to flexible plant operation mainly by supporting: Repeatedly attainable fast startups with the greatest possible regard to the lifetime of heavy-walled components. Quickest possible restoration of power supply to the grid after any disturbance Saves startup time by avoiding boiler trip on turbine trip. Ensures high reliability and availability of the plant Bypass systems contribute to the overall target of safe and efficient supply of electric power at minimum total cost. Steam bypass systems bring substantial fuel savings while they solve many of the problems caused by using baseload generating units for cyclic operation Turbine Bypass SystemTurbine Bypass System
- 77. The steambypass system is generally used during the following modes of operation: Start-up and shutdown, Steam turbine trip, Steam turbine no-load or low-load operation Fast Run back Fast load throw off House load operation Turbine Bypass SystemTurbine Bypass System
- 78. Turbine Bypass Systemfor Thermal PlantTurbine Bypass System for Thermal Plant
- 79. Turbine Bypass Systemfor CCP PlantTurbine Bypass System for CCP Plant
- 80. Typical Large SteamTurbineTypical Large Steam Turbine Extraction Steam and Heater SystemsExtraction Steam and Heater Systems I P Turbine H P Turbine High Pressure Heaters High Pressure Heaters High Pressure Heaters Boiler Feed Pumps Low Pressure Heater Low Pressure Heater Deaerater Heated Feedwater to Boiler BFP Recirc. Condensate To Hotwell LP Turbine
- 81. Automatic Turbine Start-upControl &Automatic Turbine Start-up Control & Rotor Stress MonitoringRotor Stress Monitoring Safe Turbine Start-up and Shut down Sequencing OEM guidelines are incorporated using the flowcharts and rotor stress constants ATC mode automatically determines: Speed & Load Targets Speed Rates & Speed Holds Load Rates & Load Holds Run backs Integral Turbine Protections
- 82. Typical ATC andRSM ProgramsTypical ATC and RSM Programs HP and IP rotor stress calculations Steam chest metal required temperature calculations Turning gear checks before startup Eccentricity and vibration monitoring Water detection and drain valve control Bearing temperature monitoring Generator monitoring and checks before synchronization Heat soak calculations allowing for shorter heat soak time
- 83. Damper Control Steam Temp Feedwater HRSG Turbine Turbine Master S-heat Spray R-heat Spray BF- Pump Turbine Valves Load Demand Computer HighLimit Low Limit Ramp Rate Operator Set Limits Runbacks Rundowns Block Increase Block Decrease LocalRemote GT #1 GT #2 ST MWST MW DELTADELTA BALANCERBALANCER + - Load Demand Computer – CCP PlantsLoad Demand Computer – CCP Plants
- 84. Front end(LDC Indexer) develops total plant MW demand GT MW demand is total plant demand minus actual ST MW generation GTs are in megawatt control mode ST is in IPC control mode As plant load index increases, the ST TP set point increases f(x) has minimum pressure (floor value) f(x) curve slides pressure on 100% valve point Basic CC PlantBasic CC Plant ControlControl
- 85. Emerson Gas TurbineEmersonGas Turbine ControlControl Automatic startup and shutdown Surge control limited starting and under load Feed-forward fuel control schedule during starting Temperature override control during starting Speed control from tuning gear to minimum load Load control from minimum to base load Loading rate control Temperature control at load Minimum and maximum limits on fuel flow
- 86. Ovation Gas TurbineControls OfferOvation Gas Turbine Controls Offer Numerous AdvantagesNumerous Advantages Advanced control and turbine protection schemes Local and remote operation capability Improved data acquisition for predictive maintenance and scheduling Integrated power and BOP control systems Maximize efficiency through load management More precise and reliable fuel control Advanced graphical interface Historical logging and trending Diagnostics for preventative maintenance
- 87. Modern Power PlantConsiderationsModern Power Plant Considerations Power industry is experiencing a dramatic changes fueled by Deregulation and consolidation. Older business models are changing to cope with Competition between utilities, environmental concerns, and increasing power demand. Availability, reliability, efficiency & lesser operating costs have become key elements of everyday plant operation considerations. Today’s control system networks have become Information networks Modern power plants tending to achieve vertical and horizontal integration of plant wide controls under single hardware/software platform, using Smart Filed Devices and Industrial standard communication across various layers of information & control networks. Integrated Plant Optimization suites enable efficient optimized continuous plant controls throughout the plant operation range. Plant Web Digital architecture enables easy integration of field devises while ensuring high quality field intelligence made available to the right persons, minimizing operational & maintenance costs while maximizing safety. Integrated Plant Simulator for efficient operation and management of the plant
- 88. Air Controls Fuel Management Feedwater Control Burner Management Condensate Control Emergency Diesel Circulating Water Turbine Bypass Combustion Control Coordinated Controls AGC Cooling Tower Switchyard/ Metering SCR Injection Reagent Handling Ammonia Handling Sootblower PLCI/O FlyAsh PLCI/O Bottom Ash PLCI/O Dry ESP PLCI/O Wet ESP PLCI/O Condensate Polishing PLCI/O Air Preheater PLCI/O Coal Handling PLCI/O Limestone Stockout PLCI/O Gypsum Handling PLCI/O Aux Boiler PLCI/O Makeup Water PLCI/O Demin Water PLCI/O PLCI/O Limestone Reclaim PLC Stations Hardwired DataLinks Turbine StationEmissions StationVibration Monitoring Station Hardwired DataLinks Turbine Control Emissions Monitoring Motor/ Transformer UPS Monitoring Vibration Monitoring Fire Detection DCS Operator Stations DCS Engineer Station Historian Typical Power Plant Controls ArchitectureTypical Power Plant Controls Architecture PLCsPLCs DCSDCS 33rdrd PartyParty SystemsSystems Local Display Local Display Local Display Emerson Confidential
- 89. Air ControlsAir ControlsFuel Management Fuel Management Feedwater Control Feedwater Control Burner Management Burner Management Condensate Control Condensate Control Emergency Diesel Emergency Diesel Circulating Water Circulating Water Turbine Bypass Turbine Bypass Combustion Control Combustion Control Coordinated Controls Coordinated Controls AGCAGC Cooling Tower Cooling Tower Switchyard/ Metering Switchyard/ Metering SCR Injection SCR Injection Reagent Handling Reagent Handling Ammonia Handling Ammonia Handling Turbine Control Turbine Control Emissions Monitoring Emissions Monitoring Motor/ Transformer Motor/ Transformer UPS Monitoring UPS Monitoring Vibration Monitoring Vibration Monitoring Fire Detection Fire Detection Engineer Station Historian SootblowerSootblower Fly AshFly Ash Bottom AshBottom Ash Dry ESPDry ESP Wet ESPWet ESP Condensate Polishing Condensate Polishing Air Preheater Air Preheater Coal Handling Coal Handling Limestone Stockout Limestone Stockout Gypsum Handling Gypsum Handling Aux Boiler Aux Boiler Makeup Water Makeup Water Demin Water Demin Water Limestone Reclaim Limestone Reclaim Emerson’s Modern Power Plant ControlsEmerson’s Modern Power Plant Controls Asset Mgmt Station Wireless and Web-based Interfaces Fieldbus-based Ovation Expert System SimulatorOperator Stations Emerson Confidential
- 90. Total Solutions FromThe Power IndustryTotal Solutions From The Power Industry SpecialistsSpecialists Business Level Optimization & Predictive Maintenance Expert Control Instrumentation Applications
Editor's Notes
- #7 THE ABOVE IS A PICTURE OF A MODERN COAL FIRED ELECTRIC UTILITY UNIT. As you can see it is a rather complex interactive system.
- #27 This page shows our expertise in the Turbine area.
- #34 This is an overview of the boiler control system, as you can see this basically applies to the modulating control as opposed to the BMS, Data Acquisition, etc. which is a carry over from the past, since many of these are integrated into a single system now. Basically it regulates the modulating control associated with the main process.
- #35 The front end is displayed, as you can see it is the master for both the boiler and turbine and coordinates their activities.
- #36 CFE is the application of advanced control to the front end. Its unique features is its predictive control capability which permits controlling the rate of change which takes place. Note no separation between boiler and turbine control.
- #39 The standard offering permits operation in any one of the four modes listed and provides bumpless transfer between modes. Coordinated - both the boiler and turbine respond together to satisfy the load requirements Turbine Following - the turbine controls throttle pressure and responds based on what the boiler does Boiler Following - the boiler controls throttle pressure based on what the turbine does Manual - the operator controls the boiler and turbine separately Interlocks are included such that the upstream decisions are limited by the mode of control of the downstream devices.
- #41 The turbine master basically controls MW, but to prevent system instability it recognizes the boiler’s limitations and will not over extend the boiler. This provides fast response with stability.
- #42 With variable pressure operation the turbine valves are ideally never moved. Throttle pressure is changed to effect a load change. To improve response we move the turbine valves to achieve the new load setting and then return the turbine valves to their desired position. Throttle pressure set point is programmed off of load but trimmed to return the turbine valves to the proper position (normally a valve point). Because this moves thermal stress from the turbine to the boiler, not all boilers can operate in this mode.
- #43 The boiler master basically sets the firing rate for the boiler. The boiler master can only be placed in automatic if the down stream control loops are in automatic. Boiler runbacks and rundowns are initiated here, the controls are placed in turbine following, and are based on boiler capabilities and not load (MW) values.
- #44 Fuel control is the next section we will discuss. It basically consists of the Fuel Master and the fuel control, which for the standard is presently CE coal mills.
- #45 The fuel master determines the amount of fuel that each mill needs to send to the boiler. The fuel demand can not exceed the available air for safe combustion. Mills have coal storage capacity which means that their response isn’t constant, to recognize this a model is incorporated to bring coal flow measurement (typically feeder speed) into line with actual coal flow to the boiler. To properly control fuel flow the fuel BTU value needs to be known, the controls use the boiler as a calorimeter to calculate the coal BTU value.
- #46 The mill control is the actual regulation of the mill which consists of coal flow to the mill (feeder speed typically) and primary air flow (the air required to transport the coal to the boiler from the pulverizer). The primary air must be at the proper temperature to assure drying of the coal. To prevent plugging of the mill, on either high mill amps or high mill differential the feeder speed is reduced until the problem clears. Proper primary air flow takes precedent over primary air temperature. Our normal offering includes interlocks on the mill which are tied into the burner management system for proper positioning the dampers during mill start/stop and emergency conditions.
- #47 Air control consists of regulating both the FD and ID fans
- #48 The FD fans provide the secondary air to the boiler for safe complete combustion of the fuel. Air flow is based on the fuel entering the boiler and trimmed by the flue gas O2 observed. The air flow can not decrease below that calculated as being required for safe combustion of the fuel entering the boiler. The controls include the interlocks for both the inlet and discharge dampers required for fan starting, stopping, and fan idle conditions. The FDs can’t be place into automatic unless an ID fan is already in automatic control, this assures the ability to control furnace pressure.
- #49 The FD push air into the boiler while the ID fans suck it out, these must be properly balanced if furnace pressure is to be properly controlled. Fluctuating furnace pressure will impact air flow which impacts combustion resulting in (as a minimum) an unstable process and potentially unsafe operation . The controls fully meet the NFPA requirements including triple redundant furnace pressure transmitters, directional blocking, and an MFT kicker. Note that on an MFT the FD fans are placed in manual to hold air flow constant. Like the FD fans damper interlocks are included with our base offering, to start/stop and position as required based on operating conditions.
- #50 Feedwater control regulates the water input to the boiler.
- #51 Single element control refers to the fact that drum level is the measurement used to control the flow of feedwater to the boiler. This is used during low loads since flow measurements are inaccurate at these values. Three element is the normal control method it matches feedwater flow to steam flow and uses drum level as a trim. To maintain accuracy the drum level is density compensated, this is important during startup and on variable pressure units.
- #52 Single element control refers to the fact that drum level is the measurement used to control the flow of feedwater to the boiler. This is used during low loads since flow measurements are inaccurate at these values. Three element is the normal control method it matches feedwater flow to steam flow and uses drum level as a trim. To maintain accuracy the drum level is density compensated, this is important during startup and on variable pressure units.
- #53 Steam temperature control regulates the final steam temperature of both the main steam and the reheat steam entering the turbine. If this temperature is low, the unit becomes less efficient (there is less energy for the turbine to extract from the steam) while if the temperature is to high damage to the turbine can result.
- #54 Superheat temperature control refers to controlling the temperature of the main steam, typically at a value of 1005 F. The standard consists of two stage attemperation, that means that spray water is applied twice to the steam as it travels from the drum to the turbine to control steam temperature. Interlocks are included to close valves on MFTs, the block valve is controlled so that it doesn’t needlessly cycle as intermittent spray is required. The controls also include windup protection for when control isn’t possible.
- #55 Reheat steam is steam which has gone through the high pressure turbine and is returned to the boiler to be reheated before going to the next turbine stage. Reheat is often controlled by adjusting the heat distribution within the furnace thru the use of burner tilts, pass dampers, or gas recirculation based on boiler design. Common to all boiler designs is the use of sprays, which is minimized because it is inefficient. The standard only covers the spray control, we have experience with all other variations . Like the SH spray, integral tracking is provided to prevent windup until spray control is active. And similar to the SH spray interlocks are provided for both the spray and block valves, and the block valves are operated in a manor to prevent unnecessary cycling.
- #64 Interface to plant LDC sends a MW set point as well as load limits and runbacks over the network.
- #67 Onboard relay with 2 Form C contacts for wiring 2 out of 3 voting for overspeed tripping at 5 mSec Speed control at 3600 RPM is at 16 mSec
- #74 ATC continually monitor the following system parameters and alarms. Programs depend on available I/O When not in control it monitors
- #76 Briefly review then use next slide for explanation Valve indication and testing Turbine in hand Turbine in manual Turbine in auto (remote)
- #79 Briefly review then use next slide for explanation Valve indication and testing Turbine in hand Turbine in manual Turbine in auto (remote)
- #80 Briefly review then use next slide for explanation Valve indication and testing Turbine in hand Turbine in manual Turbine in auto (remote)
- #82 Based on existing flowcharts and constants provided by the customer. If flowcharts do not exists, the customer must request them from the turbine OEM. Generates speed targets, rates and holds (for soaking, etc. ) Generates load rates and holds ATC combined with RSM will automatically accelerate the unit from turning gear to synch speed as well as monitoring the loading rate after the breaker is closed
- #83 ATC continually monitor the following system parameters and alarms. Programs depend on available I/O When not in control it monitors Up to 10 graphics.
- #84 Feedwater control regulates the water input to the boiler.
- #89 Derived from actual I&C architecture diagrams provided by various AEs/EPCs on new coal plant projects
- #90 Derived from actual I&C architecture diagrams provided by various AEs/EPCs on new coal plant projects
- #91 Power industry is experiencing a dramatic change in dynamics than any other industry. Deregulation and consolidation has altered the century old business model. Competition between utilities, environmental concerns, and increasing power demand have combined to create a new market reality. There is a strong pressure among the utilities to increase the avilability, reliability and effeciciency of the operating plants Emerson Process Management Power & Water Solutions, Inc. has energized the power industry with revolutionary control solutions for more than 40. We understand the changing dynamics of the industry with our products and solution tailor made for the power industry. Our wide portfolio of solutions can help you achieve your objectives; -Fleet optimization software & enterprise management, Fleet financial performance and emissions, optimizers, Fleet performance monitoring and visualization, Fleet historian and report generator -Enterprise-wide systems integration -Fleet-wide asset management and reliability programs Plant Optimization Software including Plant financial performance, boiler efficiency, emissions, steam temperature, and sootblower optimizers Unit Controls and Monitoring Systems -Distributed control for burner management, boiler, turbine, fuel handling, balance of plant, emissions control, etc. -Smart instrumentation and bus technologies (HART, FOUNDATION™ fieldbus, PROFIBUS DP, DeviceNet, etc.) Our power resume includes: Convention furnace operations with drum, once through, and fluidized bed boiler types, Over 1000 steam and gas turbine control systems, including retrofits to General Electric, ABB, Westinghouse, and Siemens machines , Hundreds of combined cycle, cogeneration, and district heating plants Hydro electric plants around the world use our systems for control and fleet management including: