AGC Governing

7/24/2019 AGC Governing

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Lecture 1Lecture 1

ECE842ECE842

Automatic GenerationAutomatic Generation

ControlControl(AGC)(AGC)

Copyright 2009Copyright 2009

Ali KeyhaniAli Keyhani

Mechatronic!Green

Energy La"



The Basics

# $he "aic %unction o% Automatic Generation Control(AGC) i to match the changing loa& &eman& 'ith thepo'er pro&uce& "y all generating ource o% the po'ergri&

# n the AC po'er gri& all generating ource areoperating in parallel an& all inect po'er into the po'ergri&

# $hi mean that all AC po'er ource are operating atthe ame ytem %re*uency

# $he ytem %re*uency generator are operating at theytem %re*uency+ they are all ynchroni,e& an& all areinecting po'er to the po'er gri&

# -ynchronou pee&

sec/,2

rad P

s syn ω ω = s s f π ω 2=

rpm P

f n syn

120=

,



# $here%ore+ %or t'o . pole machine+ operating at i/ty hert, (% 0 ert,)+ the ha%t pee& o% the machine i rotating at 300rpm

# $here%ore+ i% the prime mo5er po'er ha a lo'er pee&+ uch

a+ hy&ropo'er+ the generator ha more pole 6or e/ample+ i% 7 12+ the prime mo5er pee& i 00 rpm

# -ynchronou operation mean that all generator o% the po'ergri& are operating at the ame %re*uency+ namely the ytem%re*uency+ regar&le o% the pee& o% each prime mo5er

# Energy cannot "e tore& in AC ytem it can only "ee/change& "et'een an in&uctor an& capacitor

# ence+ %or ta"le %re*uency+ the generate& po'er an& the loa&mut "e e*ual

n1 i the no o% ytem generator+ n2 i the no o% ytem

loa&

# Loa& i controlle& "y uer "y 'itching : an& 66 o%electrical appliance

# A the ytem loa& &eman& increae+ the ytem %re*uency

losses

n

i

L

n

i

G P P P

ii

+=∑∑==

21

11



Governor Control System

# $he o"ecti5e o% the go5ernor control i to ;eep thetur"ine ha%t pee& contant at the &eire& ynchroni,e&

pee& to generate the po'er at the ytem %re*uency

The Governor Control Systems



# $o aure+ the a%ety o% the "oiler an& tur"ine+ the "oiler controlytem control the con&ition o% team that i e/pree& "yteam preure an& team temperature

# $he "oiler control ytem control the tur"ine 5al5e in the &eire&

poition uch that the team preure an& temperature are 'ithintheir peci<e& range

# $he go5ernor control %ee& "ac; control the tur"ine ha%t pee& $hat i a the ytem loa& change= the go5ernor %ee& "ac; openor cloe the tur"ine 5al5e

# o'e5er+ the opening an& cloing tur"ine 5al5e i %unction o%

Boiler Control System



Turbine-Following Control# $o match the ytem generation to the ytem loa&+ t'o

control metho& are implemente& $hee metho& are

# n the tur"ine . %ollo'ing control+ the tur"ine generator iaigne& the reponi"ility o% throttle preure

# $hi mean the tur"ine 5al5e are controlle& 'ithinpeci<e& range that aure that team con&ition+team preure an& temperature are 'ithin the a%erange

# $he M> loa& &eman& correpon& to team ?o'&eman& an& it i reponi"ility o% "oiler

$ur"ine!6ollo'ing

Control

@oiler 6ollo'!up

Control



# >hen the tep increae in loa& control comman& i iue&+ thecontrol comman& i ent to the "oiler $he "oiler control ytem'ill increae the %uel rate+ %ee& 'ater an& air ?o' 'hich 'illincreae the throttle preure

# $he change in the throttle preure i meaure& "y the tur"inecontrol ytem

# $he tur"ine 5al5e are controlle& "y tur"ine control ytem $hetur"ine 5al5e are opene& to increae the team ?o' an& M>output o% the generator

# >hen the team ?o' increae &ue to opening o% the tur"ine5al5e+ the tur"ine ha%t 'ill accelerate

# >ith increae in loa&+ the 5al5e open to inect more po'er an&a ne' e*uili"rium i eta"lihe& at ytem %re*uency

Turbine-Following Control —contd.



Turbine Following Control System



Boiler Follow-up Control# n thi control approach to "alancing the ytem loa&

an& generation+ the "oiler i aigne& the reponi"ilityo% throttle preure

# $he M> loa& &eman& i the reponi"ility o% the tur"ine

generator# n thi mo&e o% operation+ a tep increae in generation

&ue to a tep change in loa& &eman& goe &irectly to thetur"ine 5al5e

# $he loa& &eman& increae+ the tur"ine 5al5e open an&

there%ore+ it 'ill increae the team ?o' an& M> outputo% the generator

# o'e5er+ the "oiler i controlling the throttle preure+an& i% the preure &rop out o% the range aigne& "ythe "oiler+ the "oiler control ytem 'ill o5er rule the

tur"ine control action in or&er to maintain the preure



Boiler Follow-up Control System



Comparison of the ControlSystems# @oth o% the propoe& control ytem can pro5i&e

ati%actory control per%ormance

# $he "oiler . %ollo'ing control ha %ater repone an&'i&ely ue&

# $he tur"ine . %ollo'ing control ytem ha lo'errepone= ho'e5er+ it protect the "oiler an& aurethat team i con&itione& "e%ore energy i e/tracte&%rom the "oiler



ntegrated Boiler ! Turbine !Generator Control# $he tur"ine . %ollo'ing an& "oiler . %ollo'ing control

ytem ha5e "een com"ine& into the integral controlytem 'hich pro5i&e the a&5antage o% "oth ytem



"oltage #egulator and Turbine !Governor Controls for a Steam

Turbine ! Generator.



"oltage #egulator and Turbine !Governor Controls for a Steam

Turbine ! Generator# $he go5ernor control the main team 5al5e o% thetur"ine an& control the team ?o' to the tur"ine

# $he team ?o' to the tur"ine i the primary mechanicalpo'er on the ha%t o% the generator

# the generator terminal 5oltage i controlle& "y the5oltage regulator $he <el& 5oltage i applie& to thegenerator e/citation 'in&ing "ae& on the regulator etpoint+ (ie re% )

# @y applying the mechanical po'er to the rotor 'in&ing

that i upplie& 'ith &c current+ a time 5arying <el& ieta"lihe& in the air gap o% the machine

# @ae& on the 6ara&ayB la' o% in&uction+ the 5oltage iinclu&e& on the tator 'in&ing

# Again+ ince the generator i ynchroni,e& to the po'er

gri&+ the po'er i inecte& to the ytem



# A it can "e e/pecte& the &ynamic &uration o% a po'er gri& can"e %rom a %e' cycle to e5eral minute

# 6or e/ample+ the generator an& e/citation control ytem can "eu"ecte& to &ynamic pertur"ation %rom a %e' cycle to a %e'

econ&# >hen a po'er gri& i u"ecte& to an outage+ that i lo o% agenerator+ the po'er gri& 'ill "e u"ecte& to the &ynamicta"ility pro"lem that can "e ta"ili,e& i% the po'er gri& canpro5i&e the po'er nee&e& to "alance the ytem generation tothe ytem loa&

# epen&ing on the i,e o% outage generator+ the go5ernor o% allunit 'ithin po'er gri& 'ill react to inect a&&itional po'er to thegri& to match the generation to the ytem loa&

# $here%ore+ 'e can i&enti%y &iDerent &ynamic pro"lem that a

po'er gri& can "e u"ect to it

1. Electrical dynamics and excitation controls may have

duration of several cycles to a few seconds.2. Governing and load freuency control may have a dynamicduration of several seconds to a few minutes.

!. "rime # mover and energy su$$ly control system mayhave a dynamic duration of several minutes. By $rime #mover, we mean, steam generating $ower system.



$utomatic Generation Control# $he automatic generation control (AGC) intro&uce a&&itional

o"ecti5e than maintaining po'er "alance

# t i recogni,e& that the ytem loa& increae ha a generalpattern o% increaing lo'ly &uring the &ay an& then &ecreaingat night

# -econ&+ it i recogni,e& that the cot o% generate& po'er i notthe ame %or all generating unit $here%ore+ it i &eira"le+ toaign more generation to the cheaper unit

# n a&&ition+ there are a %e' line that are connecting a po'er

company to another po'er company $hee line are re%erre&to a tie line

# 6or ecure operation o% po'er net'or; that are connecte&through a %e' . tie line+ it i &eira"le to control the po'er?o' through thee line to a pre . peci<e& che&ule that ha

"een agree& to "ae& on ecure operation an& economictranaction

$ l " h h ? h h i i i li



# $o control "oth the po'er ?o' through tranmiion tie . linean& the ytem %re*uency+ the concept o% Area Control Error(ACE) i ue&

>here

7ch $he -che&ule& po'er ?o' "et'een t'o po'er net'or;

7Actual $he actual po'er ?o' "et'een t'o po'er net'or;

% $he re%erence %re*uency

% Actual $he actual meaure& ytem %re*uency

# $he AGC ytem control the ACE a it 'ill "e e/plaine& in the%ollo'ing

# $he %unction an& o"ecti5e o% Automatic Generation Control(AGC) are a %ollo'

f P ACE TL ∆−∆= β

Actual SchTL P P P −=∆

Actual S f f f −=∆

1. %atching area generation to area load. That is, to match thetie # line interchanges with the schedules and to control thesystem freuency.

2. &istri'uting the changing loads among generators so as tominimi(e the o$erating costs su')ect to additional constraints

such as might 'e introduced 'y security considerations.

$h < t " ti i t " % l t



# $he <rt o"ecti5e i met "y mean o% a upplementarycontroller in 'hich the concept o% tie . line "ia i uni5erallyue&

# A mall change in the ytem loa& pro&uce proportionalchange in the ytem %re*uency $hat i+ the Area Control Error(ACE 7 $L !β % ) pro5i&e each area 'ith appro/imate

;no'le&ge o% the loa& change an& &irect the upplementarycontroller %or the area to manipulate the tur"ine 5al5e o% theregulating unit

# n or&er to o"tain a meaning%ul regulation (ie+ re&ucing the ACEto ,ero)+ the loa& &eman& o% the ytem are ample& e5ery %e'econ&

# $he econ& o"ecti5e i met "y ampling the loa& e5ery %e'minute (1 . F minute) an& allocating the changing loa& among

&iDerent unit o a to minimi,e the operating cot $hi preaume the loa& &eman& remain contant &uring each perio&o% economic &ipatch

# $o implement the a"o5e o"ecti5e+ nearly all AGC o%t'are i"ae& on unit control 6or unit i+ the &eire& generation at timeintant K 'hich i normally ample& e5ery t'o or %our econ&+i gi5en "y

)()()()( K K K K P P P P i

EA

i

R

i

E

i

D ++=

)(),(),( K and K K P P P i

EA

i

R

i

E

$h t % & i & ti l l t & i



# $hee component o% &eire& generation are calculate& uingthe %ollo'ing e*uation

KK i the time intant+ normally one to <5e . minute tep+ at'hich the economic participation %actor E76 i + an& economic"ae point are compute& %or unit i "y the Economic

ipatch $he 5alue o% E76i(;;) an& 7E@

i(;;) ue& in the calculation o% 7Ei

are thoe calculate& "y the mot recent e/ecution o% theeconomic &ipatch n ome intallation+ the calculation o%economic "ae point an& participation %actor i per%orme&

e5ery ten minute an& or upon large loa& change in unittatu

A6i an& H6i are the emergency ait %actor an& regulating%actor per unit i+ repecti5ely+ an& G i the ytem regulatinggain %actor A6+ H6+ an& G are uually tune& in the <el& %or proper

unit control action

)()()()( KK K KK K P P EPF P i

EBT

ii

E +∆×=

)()( K ACE G K RF P ii

R ××=

)()( K ACE K AF P ii

EA ×=

P i

EB

7 (;) i th h i t t l it i & i & ti



# 7 $(;) i the change in total unit economic &eire& generation

ince the mot recent e/ecution o% the Economic ipatchCalculation %unction at time intant KK

# t i calculate& uing e*uation

>here 7Ai (;) i the actual generation o% unit i at time intant K+

ACE i the 5alue o% Area Control Error at time intant K+ 7E@ i the

economic "ae point %or unit i calculate& "y the mot recente/ecution o% the Economic ipatch at time intant KK+ an& : ithe num"er o% unit operating in the Automatic Control Mo&e

∑∑==

−+=∆ N

i

i

EB

N

i

i

AT KK P K ACE K P K P

11

)()()()(

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AGC Governing