chandra bhushan

8/6/2019 CHANDRA BHUSHAN

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PRESENTED BY:PRESENTED BY:--

CHANDRA BHUSHANCHANDRA BHUSHAN

Dr. M.G.R. Educational And Research Institute,chennaiDr. M.G.R. Educational And Research Institute,chennai--9595



Normally, the power system operates in normalstate which is characterized by constant frequencyand voltage profile with certain system reliability.

For a successful operation of power system underabnormal conditions, mismatches have to becorrected via supplementary control.

Automatic Generation Control (AGC) or LoadFrequency Control is a very important issue in

power system operation and control for supplyingsufficient and reliable electric power with goodquality.




An interconnected power system can beconsidered as being divided into control areas,which are connected by the tie lines. In eachcontrol area, all generators are assumed to form acoherent group.

The power system is subjected to local variationsof random magnitude and duration.

The frequency of a system depends on activepower balance.

Due to unnecessary error in the past, conventional

PI controller use for provide adequate controlperformance with the consideration of non-linearities and boiler dynamics.




The model to represent the boiler dynamics, Boileris a device meant for producing steam underpressure.

The model is basically for a drum type boiler. Anoil/gas fired boiler system has been employed in

this study, since such boilers respond to loaddemand changes more quickly than coal-firedunits.

The changes in generations are initiated by turbinecontrol valves and the boiler controls respond with

necessary control action. Changes in steam flow and changes in throttle

pressure, the combustion rate and hence the boileroutput.




Boiler is a device for producing steam under pressure.

this model is drum type boiler. An oil/gas fired boilersystem has been considered in this study, because suchboilers respond to load demand changes more quicklythan coal fired units (Chen et al., 2008).

Drum type boiler is otherwise known as recirculationboilers which rely on natural or forced circulation ofdrum liquid to absorb energy from the hot furnacewalls, called water walls for generating steam.

The boiler receives feed water which has been preheated

in the economizer and provides saturated steamoutflow.




The proportional-integral (PI) controller has received agreat deal of attention in the process control areas. It is

used as a feedback controller which drives the plant tobe controlled with a weighted sum of the error and theintegral of that value.

To achieve better dynamic performance and to provideaccuracy, Proportional Integral (PI) controller isadopted.

The main idea of implementing PI controller is to

actuate the load reference point until the frequencydeviation becomes zero.




Literature survey shows that many utilities such asfrequency control and voltage control use PIcontroller to achieve improved dynamicperformance.

The task of load frequency controller is to generatea control signal (u) that maintains dynamicparameter at predetermined values.

Where,

F = change in frequency andPtie = change in tie line power




Simulation result of PI controller:-

Simulations were performed using conventional PIcontrollers applied to a two area interconnected hydro-thermal system considering non-linearities and boilerdynamics.

The system is simulated with 1 step load disturbance in

hydro area (Nanda et al., 2006) have concluded that forthe same perturbation, hydro area takes more settlingtime than in thermal area.




The thermal system is incorporated with both non-

linearities (GDB and GRC) and boiler dynamics. The hydro area includes both non-linearities. To

design conventional PI controller gains, IntegralSquare Error (ISE) technique is used.

Due to the fixed value of these gains the dynamicperformance is not satisfactory. So an alternatecontroller i.e., fuzzy logic controller is proposed.

The simulation results shows that FLC has bettercontrol performance over conventional PIcontroller even with the consideration of non-linearities and boiler dynamics.




UNDER THE EXCELLENT GUIDANCE OFUNDER THE EXCELLENT GUIDANCE OF

Ms.P.Banu


chandra bhushan

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