load cycling of thermal power plants: advanced control ... · 11/30/2018 · advanced control...
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Load Cycling of Thermal Power Plants: Advanced Control Technology as Cost-Efficient EnablerDr. Nicolas MertensFlexibilisation of Indian Thermal Power Plants, New Delhi, 30/11/2018
Agenda
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1
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4
5
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Who we are
Motivation for flexible coal operation
Coal fired power plant: A time-dependent system
Enhanced live steam temperature controller
Enhanced power plant load controller
Extended control system
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
8 Summary
Uniper at a glance
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Gas fired power plants
Nuclear plants
Coal fired power plants
Gas storage Regasification
Service
Hydroelectric plants
Gas infrastructureEnergy sales to small and large customers
Trading
Our operations
Power GenerationCommodity TradingEnergy StorageEnergy SalesEnergy Services We operate in 40+ countries. Around the world.
€1.7bnEBITDA in 2017
100 yearsExperience
~36 GWGeneration capacity
Main activities
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Challenging requirements for coal flexibility Increasing network impact of intermittent renewable generation
Variable load following & faster ramp rates
Start-up & shutdown cycling
Longer periods off-load and in standby operation
Bigger swings between maximum and minimum load requirement
More competitive market conditions and pricing
Drivers to burn a changing or broader mix of coal types
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Back to agenda
Load cycling in coal-fired power plants: Secondary control response
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5 minutes
Time
Power
PowerOvershoot is limited!
Time
Power
Rate action
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Load cycling in coal-fired power plants: Secondary control response
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Time
Power
Power
Time
Power
Extended set of controller structures and Parameters required!
Lots of cost-intensive plant tests required for optimization!
High load cycling capability improves market position!
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Rate action
5 minutes
Coal Mill Operation
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Source:Steam and its generation and use
Mill behavior depends on
Coal quality Mechanical wear Plant layout Mill operation parameters Mill load Degree of automation …
Coal Mill: A time-variant system
8Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
New grinding roller
Worn grinding roller
Coal Power Plant: A time-variant system
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Power
Pressure
Time
Pre
ssur
e in
bar
Pow
er in
MW
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Coal type A, test run
Advanced Control Technology as Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Coal Power Plant: A time-variant system
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Each coal type needs a separate control parameter set.The parameter set depends on the maintenance status of the mill.Lots of expensive plant tests for parameter optimization are required.How about a controller that can adapt the parameter set automatically?
Power
Pressure
Time
Pre
ssur
e in
bar
Pow
er in
MW
Coal type B, test run
Live steam temperature control: Static PI controller
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Feed water pump
HP preheater
ECO
Evaporator
SH 1 Spray Attemp. 1
SH 2 + 3
Spray Attemp. 2
SH 4 SH 5
Spray Attemp. 3
Time behavior of SH5 depends on- Load (mass flows)- Coal type- Fouling and slagging
Only measurements upstream anddownstream of the SH are available.
Live steam
Live steam temperature control: State controller adapts to changing system behaviourState controllers with observers
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Observer
State Controller
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
525,0
527,5
530,0
532,5
535,0
537,5
540,0
542,5
545,0
0
10
20
30
40
50
60
70
80
90
100
0 300 600 900 1200 1500 1800
Frischda
mpftempe
ratur [°C]
Kraftw
erksleistung
[%]; Ve
ntilö
ffun
g [%
]
Simulationszeit [s]Sollleistung Kraftwerk brutto Istleistung Kraftwerk bruttoVentilöffnung (Zustandsregler) Ventilöffnung (PI‐Regler)Frischdampftemperatur (Zustandsregler) Frischdampftemperatur (PI‐Regler)
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Live steam temperature control:Comparison of control concepts
Load
Valve position
Temperature (state controller)
Temperature (PI controller)
Setpoint deviation of the state controller is significantly smaller. Reason is that the state
controller anticipates control deviations by considering intermediate states.
Power plant load control: Controlled system
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feeder mill furnace steam generator
turbine +generator
Slow-reacting system, Disturbance on the controlled system cannot be identified. Measurement of a state variable in the middle of the controlled
system would help.
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
∑
Power plant load control: Controlled system
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feeder mill furnace steam generator
turbine +generator
New state variable:Promecon Coal dust measurement system
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Measurement of absolute coal mass flow in kg/sec using microwave resonator technology Direct identification of mill disturbance,
small time constant Signal processing of coal measurement
in Kalman filter for control use, capturing mill dynamics
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Power plant load control: Enhanced state controller
State controller
Feeder, coal mill
Furnace, steam generator,turbine, generator
Feeder, coal mill, furnace, steam generator,turbine, generator
Real power plant
Model correction
K
Observer±
Set point
Coal dust flow Power
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Reference: Wilhelmshaven Power Plant, Germany
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Wilhelmshaven Power PlantCommissioning 1976Power gross: 820 MWFuel: Hard Coal
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Comparison of load controllers in real plant
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Standard controller
Enhanced state controllerMeasurement coal dust mass flow
Setpoint plant load
Setpoint coal dust mass flow
Measurement plant load 1 minute
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Enhanced state controller runs passive and in parallelto existing controller for testing.Coal dust mass flow deviation is identified earlier!Enhanced state controller reacts approx. 1 minute earlier!Load cycling capability will be increased!
Conclusion
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Enhanced state controller delivers 50% increase in secondary
response capability (from 10% to 15% MCR) for the reference plant.
Power plants are time-variant systems, which require adaptive controllers
with automatic parameter adjustment for optimum load-cycling performance.
The coal dust measurement can be used to measure an additional state
variable in the power plant and improve control.
State controllers with observer are very effective in response to process
variation and disturbance of the coal mills.
State controller can be implemented independently from local DCS-OEM
system using external control box.
Advanced Control Technology as Cost-Efficient Flexibility Enabler | Dr. Nicolas Mertens | New Delhi, 30/11/2018
Thank you for your attention!
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Dr. Nicolas MertensSpecialist Plant FlexibilityUniper Technologies [email protected]
Doug WatersSalesUniper Energy [email protected]
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Animesh KumarChief Commercial OfficerIndia Uniper Power Services Pvt. [email protected]