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8/9/2019 Power System Stability Prime Mover-governor
1/27
IEEEG1
• A common stream turbine model, is the IEEEG1,originally introduced in the below 1973 paper
1IEEE Committee Report, “Dynamic Models for Steam and Hydro Turbines in Power System Studies,Transactions in Power !pparatus " Systems, #olume $%, &o' (, &o#')Dec' *$+, pp *$-./*0
In t1is model 23*)RIt can be used to represent
cross/compound units, wit1
1i41 and low pressure steam
5o and 5c are rate
limits
8/9/2019 Power System Stability Prime Mover-governor
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IEEEG1
• Blocks on the right model the arious steam stages• About 1!" o# $E%% goernors are currently IEEEG1s
• Below #igures show two test comparison with this
model with one matching well and one not
!Ima4e Source6 7i4s %/., %/( of IEEE PES, 8Dynamic Models for Turbine/9o#ernors in Power System Studies,8 :an %-*
8/9/2019 Power System Stability Prime Mover-governor
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Deadbands
• Be#ore going #urther, it is use#ul to brie#ly considerdeadbands, with two types shown with IEEEG1 and
described in the !&13 IEEE 'E( Goernor )eport
• *he type 1 is an intentional deadband, implemented to
preent e+cessie response
–ntil the deadband actiates there is no response, then
normal response a#ter that- this can cause a potentially
large .ump in the response
–Also, once actiated there is normal
response coming back into range
–sed on input to IEEEG1
3
8/9/2019 Power System Stability Prime Mover-governor
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Deadbands
• *he type ! is also an intentional deadband,implemented to preent e+cessie response
–/i##erence is response does not .ump, but rather only starts
once outside o# the range
• Another type o# deadband is theunintentional, such as will occur
with loose gears
–ntil deadband 0engages0
there is no response
–nce engaged there is
a hysteresis in the
response
2
8/9/2019 Power System Stability Prime Mover-governor
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Deadband Example: ERCOT
• 'rior to oember !&&4, E)%* re5uired that thegoernor deadbands be no greater than 68 &&3: ;<
• A#ter 113&4 deadbands were changed to 68 &&1:: ;<
=
%--; did1a#e
two
mont1s
wit1 t1e
lower #alues
Ima4e Source6 Sydney &iemeyer, &R9, %)$)*- presentation to TeT?
8/9/2019 Power System Stability Prime Mover-governor
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Gas Turbines
• A gas turbine >usually using natural gas? has acompressor, a combustion chamber and then a turbine
• *he below #igure gies an oeriew o# the modeling
:Ima4e from IEEE PES, 8Dynamic Models for Turbine/9o#ernors in Power System Studies,8 :an %-*
HRS9 is
t1e 1eat
reco#ery
steam
4enerator =if it is a
combined
cycle unit?
8/9/2019 Power System Stability Prime Mover-governor
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GAST Model
• @uite detailed gas turbine models e+ist- well .ustconsider the simplest, which is still used some
7
It is somew1at similar
to t1e T9>@*' T*
is for
t1e fuel #al#e, T%is for t1e turbine, and
T is for t1e load
limit response based
on t1e ambient
temperature =!t?A
T is t1e delay in
measurin4 t1e e
8/9/2019 Power System Stability Prime Mover-governor
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Play-in Playba!"# Models
• #ten time in system simulations there is a desire to testthe response o# units >or larger parts o# the simulation?
to particular changes in oltage or #re5uency
–*hese alues may come #rom an actual system eent
• 0'lay8in0 or playback models can be used to ary anin#inite bus oltage magnitude and #re5uency, with data
speci#ied in a #ile
•'ower$orld allows both the use o# #iles >#or sayrecorded data? or auto8generated data
–achine type GE%C(D'CABA%F can play back a #ile
–achine type In#initeBus(ignalGen can auto8generate a
signal 4
8/9/2019 Power System Stability Prime Mover-governor
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Po$er%orld In&ini'e (us
Si)nal Genera'ion
• Below dialog shows some options #or auto8generationo# oltage magnitude and #re5uency ariations
9
S'ar' Time tells w1en to startA #alues are
t1en defined for up to fi#e separate time
periods
*ol' Del'a is t1e ma4nitude of t1e pu
#olta4e de#iationA *ol' +re, is t1e
freBuency of t1e #olta4e de#iation in H
=ero for dc?
Speed Del'a is t1e ma4nitude of t1efreBuency de#iation in HA Speed +re, is
t1e freBuency of t1e freBuency de#iation
Dura'ion is t1e time in seconds for t1e
time period
8/9/2019 Power System Stability Prime Mover-governor
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Example: S'ep Can)e *ol'a)e
Response
• Below graph shows the oltage response #or the #our bus system #or a change in the in#inite bus oltage
1&
@ =pu?us us %gfffff @ =pu?us us .ffffff
*-$;+(0.%*-
*'*%0
*'*%
*'**0
*'**
*'*-0
*'*
*'-$0
*'-$
*'-;0
*'-;
*'-+0
*'-+
*'-(0
*'-(
*'-00
*'-0
*'-.0
*'-.
*'-0
*'-
*'-%0
*'-%
*'-*0
*'-*
*'--0
*
Case name6 .Si4nal9enIEEE9%
8/9/2019 Power System Stability Prime Mover-governor
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Simple Diesel Model: DEGO*
• (ometimes models implement time delays >/EG? –#ten delay alues are set to
8/9/2019 Power System Stability Prime Mover-governor
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DEGO* Delay Approxima'ion
• $ith */ set to &= seconds >which is longer than normal
in order to illustrate the delay?
1!
Transien' S'abili'y Time S'ep Resul's *ariables
9en us . F* States of 9o#ernorG!ctuator
9en us . F* >t1er 7ields of 9o#ernorGEn4ine
Time
0.';.'(.'..'%.';'('.'%%';%'(%'.%'%%*';*'(*'.*'%*-';-'(-'.-'%-
@ a l u e s
*'%
*'*$
*'*;
*'*+
*'*(
*'*0
*'*.
*'*
*'*%
*'**
*'*
*'-$
*'-;
*'-+
*'-(
*'-0
*'-.
*'-
*'-%
*'-*
*
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.ydro /ni's
• ;ydro units tend to respond slower than steam and gasunits- since early transient stability studies #ocused on
.ust a #ew seconds >#irst or second swing instability?,
detailed hydro units were not used
–*he original IEEEG! and IEEEG3 models .ust gae the linearresponse- now considered obsolete
• Below is the IEEEG!- le#t side is the goernor, right
side is the turbine and water column
13
7or sudden c1an4es
t1ere is actually an
in#erse c1an4e in
t1e output power
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+our (us $i' an IEEEG0
• Graph below shows the mechanical power output o#gen ! #or a unit step decrease in the in#inite bus
#re5uency- note the power initially goes downH
12Case name6 .Si4nal9enIEEE9%
Speed9en us % F*gfffff Mec1 Input9en us . F*ffffff
*-$;+(0.%*-
(-
0$'$0
0$'$
0$';0
0$';
0$'+0
0$'+
0$'(0
0$'(
0$'00
0$'0
0$'.0
0$'.
0$'0
0$'
0$'%0
0$'%
0$'*0
0$'*
0$'-0
0$
*+0
*+-
*(0
*(-*00
*0-
*.0
*.-
*0
*-
*%0
*%-
**0
**-
*-0
*--
$0
$-
;0
;-
+0
+-
(0
P1ysically t1is iscaused by a transient
decrease in t1e water
pressure w1en t1e
#al#e is opened toincrease t1e water
flow
8/9/2019 Power System Stability Prime Mover-governor
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IEEEG
• *his model has a more detailed goernor model, but thesame lineariresulting in less o# a power change?
1=
ECC 1as
about *- of
t1eir 4o#ernorsmodeled wit1
IEEE9s
8/9/2019 Power System Stability Prime Mover-governor
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%asou' +il'ers
• A washout #ilter is a high pass #ilter that remoes thesteady8state response >ie, it 0washes it out0? while
passing the high #re5uency response
• *hey are commonly used with hydro goernors and >as
we shall see? with power system stabili
8/9/2019 Power System Stability Prime Mover-governor
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IEEEG +our (us +re,uen!y Can)e
• *he two graphs compare the case response #or the#re5uency change with di##erent ) temp alues
17
Speed9en us % F*gfffff Mec1 Input9en us . F*ffffff
*-$;+(0.%*-
(-
0$'$0
0$'$
0$';0
0$';
0$'+0
0$'+
0$'(0
0$'(
0$'00
0$'0
0$'.0
0$'.
0$'0
0$'
0$'%0
0$'%
0$'*0
0$'*
0$'-0
0$
*-+
*-('0
*-(
*-0'0
*-0
*-.'0
*-.
*-'0
*-
*-%'0
*-%
*-*'0
*-*
*--'0
*--
$$'0
$$
$;'0
$;
$+'0
$+
Rtemp 3 -'0, Rperm 3 -'-0
Speed9en us % F*ffffff Mec1 Input9en us . F*ffffff
*-$;+(0.%*-
(-
0$'$0
0$'$
0$';0
0$';
0$'+0
0$'+
0$'(0
0$'(
0$'00
0$'0
0$'.0
0$'.
0$'0
0$'
0$'%0
0$'%
0$'*0
0$'*
0$'-0
0$
**+
**(
**0
**.
**
**%
***
**-
*-$
*-;
*-+
*-(
*-0
*-.
*-
*-%
*-*
*--
$$
$;
$+
Case name6 .Si4nal9enIEEE9%
Rtemp 3 -'-0, Rperm 3 -'-0
8/9/2019 Power System Stability Prime Mover-governor
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(asi! 2onlinear .ydro Turbine Model
• Basic hydro system is shown below –;ydro turbines work be conerting the kinetic energy in the
water into mechanical energy
– assume the water is incompressible
• At the gate assume a elocity o# , a cross8sectional penstock area o# A- then the
olume #low is AJ@-
14Source6 $'%, 2undur, Power System Stability and Control , *$$.
8/9/2019 Power System Stability Prime Mover-governor
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(asi! 2onlinear .ydro Turbine Model
• Krom ewtons law
• As per LaM paper, this e5uation is normali
8/9/2019 Power System Stability Prime Mover-governor
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(asi! 2onlinear .ydro Turbine Model
• $ith h base the static head, 5 base the #low when the gate is
#ully open, an interpretation o# *w is the time >in
seconds? taken #or the #low to go #rom stand8still to #ull
#low i# the total head is h base
• I# included the head losses, hloss, ary with the s5uare o#
the #low
• *he #low is assumed to ary as linearly with the gate
position >denoted by c?
!&
or
2q
q c h hc
= = ÷
8/9/2019 Power System Stability Prime Mover-governor
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(asi! 2onlinear .ydro Turbine Model
• 'ower deeloped is proportional to #low rate and head,with a term 5nl added to model the #i+ed turbine >no
load? losses
–*he term At is used to change the per unit scaling to that o#
the electric generator
!1
( )m t nl P A h q q= −
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8/9/2019 Power System Stability Prime Mover-governor
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4ineari5ed Model Deri6a'ion
• *he preiouslymentioned
lineari ?
> ?
And #or the lineari
8/9/2019 Power System Stability Prime Mover-governor
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+our (us Case $i' .3GO*
• *he below graph plots the gate position and the poweroutput #or the bus ! signal generator decreasing the
speed then increasing it
!2
Mec1 Input9en us . F*gfffff
States of 9o#ernorG9ate9en us . F*ffffff
*-$;+(0.%*-
**%
***
**-
*-$
*-;
*-+
*-(
*-0
*-.
*-
*-%
*-*
*--
$$
$;
$+
-'$(
-'$00
-'$0
-'$.0
-'$.
-'$0
-'$
-'$%0
-'$%
-'$*0
-'$*
-'$-0
-'$
-';$0
-';$
-';;0
&ote t1at Lust
lie in t1elinearied
model, openin4
t1e 4ate
initially
decreases t1e
power output
8/9/2019 Power System Stability Prime Mover-governor
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PID Con'rollers
• Goernors and e+citers o#ten use proportional8integral8deriatie >'I/? controllers
• 'I/s combine
–'roportional gain, which produces an output alue that is
proportional to the current error
– Integral gain, which produces an output alue that aries with
the integral o# the error- this will eentually drie the error to
8/9/2019 Power System Stability Prime Mover-governor
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PID Example: Posi'ion Con'rol
• (ay we wish to get an ob.ect to a position in 18dimensional space by controlling its acceleration >#orce?
–Error is distance #rom desired position
–%ontrol is speed
• $ith .ust proportional control, acceleration will bedecreasing, but wed reach ma+imum speed at the
desired point, oershooting
•$ith deriatie control, well be slowing down,aoiding the oershoot
• *he integral term will make sure we stay at the desired
point
!:
8/9/2019 Power System Stability Prime Mover-governor
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.3G
• *he ;G3 models either a 'I/ or a double deriatie
!7
Noos more
complicated
t1an it is
sincedependin4
on cfla4
only one of
t1e upper pat1s is
used