4_Presentation on Measurement and Regulation 5&6
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Transcript of 4_Presentation on Measurement and Regulation 5&6
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Measurement
andRegulation
George Markogiannakis
Mechanical Engineer MSc
Energy Policy Analysis Department
Centre for Renewable Energy Sources and Saving
Potenza October 2010
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Regulation
Regulation of process variable in order tomaintain process operate at a conditionset by control variable.
Good control/regulation ensures thatprocess operates when and how neededthereby saving energy.
(Example: Cruise control in a car and a house thermostat are commonexamples of how controllers are used to automatically adjust some variableto hold the measurement (or process variable) at the set-point.
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Actual value:The measured value is each physical value of interest for the application, e.g. roomtemperature. For example, this actual value is measured by means of a sensor.
Desired value:The value which is required! This value is entered into the regulator and serves asthe preset value or target value for the regulation process.
Correction variable:(i.e. error)The signal that the regulator puts out in order to match the actual value with the
desired value! Positioning element:
The device that receives the signal from the regulator (= the correction variable)and puts into effect a response to produce the desired value, e.g. a valve or mixeror electrical drive
Disturbance variable:This is every variable which negatively affects the measured value and makesfurther compensatory regulation necessary. In the case of room temperature, thiscan be incoming sunshine or an open window for example.
Regulation device:A regulation device is defined as being a combination of a sensor, regulator and
positioning element
Regulation -Basic terms
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RegulationConventional control Process
Set Point
Actuator
Valve
Controller
Controller OutputProcess Variable
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Regulation - Types of regulators
Electrical regulating device:The valve positioning is influenced electrically;
Pneumatic regulating device:Compressed air is necessary in order to influence the positioning element;
Electro-pneumatic regulating device:The actual value is measured and reinforced electronically. However, influencingthe positioning element occurs pneumatically.
Electro-hydraulic regulating device:The actual value is measured and reinforced electronically. However, influencingthe positioning element occurs hydraulically.
Additionally, regulators can be differentiated by means of their regulating behaviour. Aregulator can either be continuous or discontinuous.
Discontinuous means that it can only accept particular values e.g. a valve that can eitherbe open or closed.
In the case of a continuous regulator, the positioning element itself alters the correction
variable independently of the regulation difference.
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RegulationControl Station
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Regulation
SCADA - Reactor
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Regulation - Measurement: Pressure
Absolute Pressure
Differential
Pressure
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Regulation
Pressure Transducer
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RegulationInfrared Thermometer
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Regulation
Thermocouple
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Regulation
pH Electrode
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RegulationButterfly valve
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Regulation
Control Valves
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Regulation
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RegulationBasic principle
Disturbing jump answer of control loop
Leading jump answer of control loop
Tolerance area
o ve rs w
ing ing d i s t a nc e
Settling time
Tolerance area
Regulation start timeSettling time
Over swinging distance
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D=0 undamped oscillationD=0,2 damped oscillation
Proportional-Regulator
RegulationP-Regulator
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RegulationPID Control
P actionD action
I action
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RegulationTemperature Programmer
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LufterhitzerAuenluft
Auenluft-klappe
Filter
Temperatur-whler
Stellglied
Regler
VentilatorZuluft
Temperaturesensor
Cooling recorder
External air Input air
External airflap valve
Positioning
element
Regulator
Temperature
selector
Regulation - Scheme, example air conditioning
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Regulation - Scheme, example oven
exhaust
Volume flowPressureTemperatureAnalysisTemperatur
Volume flowDensityQuality
Oil temperature oven outletTemperature of exhaustLocal temperature
From
oil atoveninlet
Burninggas
Process data measurement for amodern oven regulation
Modern oven temperature regulation
exhaust
Burning gasair
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RegulationRegulation Scheme
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RegulationOptimising Regulation
Energy Savings
Maintenance Costs
Energy Saved
Energetic Costs
Investment Costs
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RegulationOptimising Regulation
Traditional load regulation
Variable speed
Pressure
Potential energy saving
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RegulationOptimising Regulation
Time (s)
Current peak due to
S/T starter
Triangle
conection
Star
conectionCurrent
Nominal current 160 A
Normal Star/Triangle Starting
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Thank you for your attention