CA1246667A - Steam turbine-generator thermal performance monitor - Google Patents

Abstract

STEAM TURBINE-GENERATOR THERMAL
PERFORMANCE MONITOR
ABSTRACT OF THE DISCLOSURE
A thermal performance monitor informs the operator and result's engineer of the economic losses, efficiencies, deviation in heat rates and power losses of operating a steam turbine-generator system at its controllably selected pressure and temperature. Specifically temperature and pressure signals are generated at various points in the system along with the control valve position signal and the electric output signal from the electric generator.
This data is processed along with the corresponding design values and the economic losses due to temperature deviation, pressure deviation and exhaust pressure deviation from design are calculated. Other calculations produce a comparison of efficiencies of the turbines in the system and consequential power losses.

Description

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STEAH TURBINE-GENERATOR THERMAL
PERFOR~NCE MONITOR

The pres~nt lnvent~on relates to ~team turbin~
and, more particularly, to thermal performance monitors for evaluating the in~tantaneous per~ormance of steam turbine-generator ~y~tems.
L~rge ~team turbine-generato~ fiystems represent - major c2pital investment~ for ~he~r owner~ and their economic benefit to the owners varies with the thermal ef~iciency with which the steam ~urbines are opera~d. To highlight the importance of theem~l ~fficient operation, $t is believed that a difference of one percent in the efficiency of a steam t~rbine d~ivin~ a one gigawatt electric generator i& worth .
on the order of tens of millions of dollars over the life of the unlt. Thu~, the owners of a large ~team turbine-generator are vita}ly ~nterested in maintaining the operating parameter6 of the sy~tem as ~lo~e as po~ible to the optimum ~et of operating : parame~er~ a~ de~ign~d for the ~y~tem, a~d/or developed during operational t~sting following i~:itial in~:tallation of the sy~tem, since departure fro~ these parameter~ tend~ to reduce the thermal : efficiency. ~n additlon, unavoidable degradatlon in performance over time ca~ occur due to deter~oration :

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-6~i~7 of intarnal part~ and other cau~es. ~e~n~ for d~t~cting the on~et and æeverity of ~uch deterior~tion 1~ u~eful. ~urth~r~ore~ lt i8 desirable to ~onitor ~he ~urbine or intern~l problems, e~pecially thc type which nece 6itate rapid dete~tlon ther~by peraitting tl~ely ~ction to be taken.
De~p~te ~he il~por~ance o~ maint~ining the operatlng para~eters at l~vels which max~m~ze therl~al e~ficlency, in normal pr~otlce, enco~pa~sing th~
mlnute~to-minute control of the controllable parameters of a large steam turbine, the turbine ~hift operator3 cu~tomarlly maint~in such operating parameters at values clo~e to optimu~ levels but still far enough di~ferent from the optimum to produce subst~ntial efficiency d~viations w~lich result in cost penalties. Addit~onally, conventional power station instrumentation does not provide a class of information which h~s either the accuracy or the informatlon content to guide an operator in ad~ustinq and keeping a st~am turbine ~t its best perfor~ance levels. In f~c~, it iB po~sible, during the attempt to optimize 8y8tem performance using moni~oring sy~te~R of the prlor art, for ~he shift 2S operator to make adjustment~ which~ in~tead of changing ~he operating parameter~ in the direction of improved efficiency, change tbe op~rat~ng parameters ln direction~ resulting ln degraded efficiency.
AB part of the $nsta~1Atlon p~ocedure of a steam turbine-generator sub6y~tem, it i6 customary for the owners and/or the contractor or turbine manuf~cturer to conduct very accurate tests to demon6trate or --3~
determine th~ heat rate of the ~ystem. Neat rate is a mea~ure o therDal efflciency of ~1 ~team ~urbine-ganerator sy~tem de~ined ~ ~he nu~ber of uni~s of thermal lnput per unit of ~lectric~l power ou~put. In ~ne convenlent ~yste~ of units~ heat rate is measur~d in BTU~ per ~ilowat~ hour of power output. One ~tandard te~t of heat rat~ ls known as th~ ASME test and is def$ned in ~n hSME publication ANSI/~SME PTC 6 ~ 1976 ~t~a~ Turbines. A 6implified ASME test is described in ~ S~E
AcceDtance:~es~ Procedure Por S~eam ~urblnes~
presented ~t the Joint Power Conference, 8eptember 30, 1980, in Phoenix, Arl~ona. A requirement and characteristic of both o the above test~ is accurate instru~entation ~or temperatures, pre~ure~ and flows within a ~team turbine along with the resulting generator power output to determine accurately the ener~y content of such condition~ ~nd tbe resulting power out~ut. The accuracy of measurement i~
sufficiently great that no mea~urement tolerance need be applied to the results. Such te~ts are costly to perform. For example, the s~andard ASME test re~uires a substantial in~tallation of specialized mea3uring eguip~ent æ~ a ~ubstanti2l cos~ in conjunction with a great amount of manpower to admini~er the test. Thu~, economic reality keeps the admin~stratlon <: f sllch te~ts limited to the inltial commi~sion~ng of a new ~tear~ -tu~bin~-g~n~r~tor ~ystes~ ~nd lles~ ~r0qu~ntly~ to the 30 recommi~s~oning s:~f a ~team turbin~-gener~tor system at a ~ubsequent time ater a refurbishmen~, ~ esides their COfit, AS~lE-type tests have the addltional drawback ~hat they ~re not ~uitable ~or , .
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use in d~y-to-day opera~ion of a ~teiam turbine-g@nerator 8y5tem. The typ~8 of instrumentatlon required ~ay not retaln u~eful accuracy ~ver extended periods. In ~ddi~ion, even if ~uch testing could be condu~ed on a sub~tantially ccncurrent, in6santaneou~ and da~ly baals, the type of ~nor~tion ~onvent~onally produced durlng ~uch ~est~, although invalu~ble in the lnltlal engineering evaluation of the ~y~tem7 18 of a type wh~ch require~
~uch ~ubst~ntial interpret~tlon and calculation to derive control adjust~ent6 that lt is, ~t bestr of marginal v~lu~ in ~uiding an operator in ~nipulaeiny the controls ~hlch are available to him.
Custom~rlly, the ~hlf~ op~r~tor, directly 1i controlling th~ ~ta~m turbine ~ystem, do~ not h~ve the time, the inclination, nor the ~ophi~tication to reduce the t~chnical result~ of the ASME type tests into an understandable format on a ~ub~tan~ially instantaneou~ ba~ primary functlon is to monitor the turbine-generator performance as it relates to other t~rbine-generator B2tS tied into the electrical tran~mi~ion Isystem~ In thi~ view, a thermal p~rform~nce monltor must g~ther relatlvely instan~aneou~ data Prom th~ turbine-generator ~y~tem and pr~en~ a limit~d ~ount of in~or~ation to the ~hift operator in a v~ry conci~e, quickly ~eadable and under~tandable format, ~uch th~t the operator ~n adjust the turbine-gen~rator set to oper~t~ ~ore efficiently.
In cont~a~t, a re~ults engin~er r~iews the periodic performance statist~c~ for the turbine generator set in a more sophi~ticated and detailed ~anner~ Since the result~ engineer's attention is not im~edia~ely focused on the ~team pressures and temperatures and other parameters - affecting the turbine, he can leisurely proceed ~ith a more detailed analysi~ vf the turbine'~ operation.
From the result~ ~ngineer~ perspective, a detailed presentation at a ~uch higher ~e~hnical level of the thermal performance of each ~ajor co~ponent in the steam turbin2-generator ~y~t~m ~a d~eirable. A an example, ~he de~iled thermal performance data compiled, throughout one week of turbine operation, may illuminate an incipient problem with the steam condensor as reflected in an increased exhaust pressure value. By focusing his attention on the exhaust pressure Vi8 a-vis the other components of the turbine over an extended period of time, e.g., 2 months, the results engineer could approach the owners of the turbine-generator unit with a request for a cleaning or modification of the condensor.
Further trend analysi~ would be facilitated by a sophisticated thermal performance monitor.
ASME-type testing can, however, be relied on initially to produce reference or a de~i~n data base from whi~h optimum se~ of operating parameters and the related heat rates and other parameters throughout a new stea~ turbine-generator system can be derived. Once such optimu~ sets of opera~ing data are established, oper~ting parameters ~uring later operation of the 6yste~ may be co~pared to i~ for determining correct operation of the system.
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Accordingly, it is an object of the invention to provide an apparatus or guiding op~imum operation of a steam turbine-generator system, -It ia ~ furth2r vb~ect of the lnvsntion to provlde an appara~us ~or lnstrumen~$ng a steam turbine-generator ~y~e~ ~nd for produclng ~ output which may be u~ed on ~ eub~tantially lnst~ntaneDus basis to control the contro~la~le par~meters o~ the steam turbine and obtain lmproved ~y~tem efflciency, It i~ a till further ob~ect of the invention to provide an app~ratus for lnstrumenting a steam turbine~generator ~y~e~ and for producin~ an output effective for directly in~3r~ing ~n cperator of the e~onomio consequences of an e~i~ting set o operating parameterq ~nd for guiding the operator toward modifying the operating par~meter6 in ~ ~irection tending to improve the system efficiency.
It i8 an additlorlal ob~ect o thia invention to provide for means for in~orming the results engineer of detailed information and analy~i~ regarding each major component in the ~team flow path of the turbine-generator system.
It i~ a further object of the inven~ion to provide an apparatus for in3trumentlng ~ steam turbine-gerlerator system which i6 ef fective to monitor and di~play the thermal perfor~ance of each major component i~ the steam flow path of the turbine~generator ~y~tem.
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A ste~m turbin~-generator thermal performance : ~onitor lnclude~ ~ev~ral ~nsor~ or ~a~uring the pressure and t~mperature of the steam ln ~ steam turbine generator ~y~tem. The po~ition of th~ ~team admi~ion co~trol valve is al60 s~nsed~ An operator'~ thermal performance ~on~to~ obt~in~ the pressure a~d ~e~perature upstream of the con~rol _7~ 17~u-2967 valve and the exh~u~t pr~8 ure of the ~te~m downEtrea~ of the turbine~ A p~wer output ignal rom th~ electric generator 1~ obtained and a means for determining the percentage of rat~d load ~t which the turbine 1~ instantan~ou~ly operating at 1~ al~o provided, An initial temperature heat r~te correction ~actor i~ generated~ in ad~ition to an iLnitial pres~ure heat rate corre~ion Pactor and an exhaust pre~ure heat rate correctic~n iEactor. ~eans 10 fs~r determining the sub tantially instantaneous design heat rate for the turbin~-generator system is prov$ded which ifi ba~ed upon the temperature and prefiaure signal~, the.control valve po~ition s~gnal and the design pressure and te~perature v~lues for the steam turbine. ~ main ffte~m temperature 1088 signal is generated by multlplying the fir~t temperature heat rate correction signal, the power signal, the design heat rate signal t a~d a signal repre~en~ative of the co~t per unit heat factor of

2~ operating the ~team generator in the turbine-generator ~y~tem. ~he ~ain steam temperature loss signal is displayable in cost per unit time to the turbine operator. A ~team pressure loss ~ignal, al30 displayahle in cost p~r unit time, is generated in a simil~r ~ashion utili2ing a pres~ure he~t rate correction signal and other siqnals. An exhau~t preS5~re 1oS6 signal is generated by utilizing the exh~u~t pres~ur~ heat rate ~orroction signal ~nd ~imilar 6ig~al~. ~he oper~tor~s ~on~tor includes ~e~ns for displ~ying, on a ~ubstantislly con~lnuou~
ba ist the ~ain ~team temperature loss ~ignal, the ~team pre~sure 1099 signal and the exhaust pressure , . .

loss sign~l, all in cost per unit time format. This presentation informs the operator~ of the econo~ic consequances of operating the ~urbine at the controllably ~elected tempera~ure and pre~sure and at a certain exhaust pre~sure.
The ~team turbin~-g~n~rator ~y~tem ~ay include a flr~ econd and ~ third turbln~ and additional te~np~ra~ure and pres6ure ~ignal6 are generated and 6upplied ~o the monito~. ~ reh~at steam temperature 10 loss sign~l~ displayable in co~t per unit time, is summed with the first steam temperature loss signal to provide a total steam t~mperature loss signal, The displaying means present~ the total s~eam temperature los~ signal, in the co~t per unit 1~ time format, to the operator of the steam turbine generator system.
A results engineer's thermal per~ormance monitor measures the sub6tantially instantaneous temperature and pressures throug~.out the steam turbine system.
20 An actual enthalpy drop and an isentropic enthalpy drop is calculated for the first, or high pressure turbine ~hereinafter the HP turbine), and the second, or intermediate pres~ure turbine ~hereinafter the IP
turbine). The substantlally instan~aneous de~i~n r erf ic, cnC~
~, 25 e_ for the BP turbinc i8 calculated based upon the f ir~t temperature, f irst pre~sure, and the control valve position, in addition ~o the ~esign pressure and temperature values for ~he ~lP turbi~e.
The IP turbine has an in~tallation dependent constant for its design efficiency, The actual efficiencies - of the HP and IP turbine are calculated ba~ed upon the ratio of the ac~ual enthalpy drop6 and the isentropic enthalpy drops. A pair of 66'r7 deviation ln heat r~te from deslgn calc~ tor~s generate sppropraate ~lgnals for the ~P and IP
turbine re~pectively. P~ean~ for presentlng the actual efficiencies of the ~P and IP turbinel the 5 design eiEf ~clencies of ~he HP and IP tur~ine, and the HP and IP deviation~ in heat rate rom design allows ~he results engineer to identify the overall performance of the turbine at a particular time.
The results engirleer's thermal performance 10 moni~or may also include ~eans for calculating a main steam te~perature power loss, a main ste~ pressure power loss r a reheat steam temperature power loss, a turbine efficiency power 1088~ and an exhaust pressure power loss. These power los6 8ign~1~ are ~5 presented to the results ~ngineer and provide a basis for ~lter~ng the operating param~ters of the ste~m turbine-generator 8y8tem, effecting the maintenance of the system or reco~ending modifications of the system.
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The su~ject matter which is regarded as the invention is particul~rly pointed out and distinctly claimed in the concluding portion of the specification. The invent~on, however, together with 2~ further objects and advantages thereof, may be be~t understood by reference to the ~ollowlng descrip~ion taken ln connection with the accomp~nying drawings in wh~ch;
Fig, 1 1~ a si~plified b70ck di~gram of a s~eam 30 turbin~-generator ~ys'cem according to an e~odimerlt o the inv~nt ion;

~6~7 FigO 2 i~ a simplified schematic d~agram of a steam turbi~e-generator ~howing Mon~l:or~ng points employed in the present ~nvention;
Fig. 3 i~ a flow cbart illustratlng the function~l a8p~ct8 of an op~r~tor~ th~r~al performance ~oni~or ~ part of the ~ta processing sub~ystem of Fig. 1~
Figo 4 is an exemplary Init~al Temperature Correction ~actor Graph;
Fig. S is an exemplary Reheat Temperature Correction Factor Graph;
Fig. 6 is an exemplary Initial Pres~ure Correction Factor Graph;
Fig~ 7 is an exemplary E~haust Pres~ure Correction Factor Graph;
Fig, ~ illu~trate3 an operator'~ display for the operator's thermal performance monitor;
Fig. 9 i~ a partial flow chart illustrating the unct~ onal aspects oP the result~ engineer's thermal performance monitor a~ part of the data proces~ing sub~ystem of ~lgure 2:
Fig. 10 is the balance of the flow chart ~h~wn in Fig. g~ which ~urther illu~trates the ~unctional aspects of a result ~ngine~r's monitorS and Fig. 11 illustrates a re~ult engineer'~ display for the thermal perfor~an~e ~onitor.
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The principal control~ ~vailable to a shif~
: operator vf a ~team turbine-genera~or ~yg~em i~clude boiler controls which det~rmlne the temperature and pressure of the main steam and r~hea~ ~eam ~uppl ies :

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and a main steam admi~ion control valve or valves which d~termin~ the ~ount of ste~m ~d~ltted to the fir~t or hig~ pre~sure ~ur~lne ~tage~ Pr~ctic~l guidance to ~n oper~tor of ~uch ~ st~
turbine-gener~tor ~y~tem include~ evaluation~ o~ the substantially instantaneou operating para~eter~ in a manr,er which can be ~nte~pret@d easily, qui~kly and without detailed technical analy~i~ to fscilitate the manipulation of the~e principal controls.
Referring now to Pig. t, there i~ ~hown, generally a steam turbine-senerator ~y~tem 10. Steam turbine-generator ~ystem 10 includes a ~team turbine-generator 12 receiving a thermal input from a ~team boiler 14. Boller 14 may be of any convenient 1S type, such a~ ooal-fired or oil~fired. Both ~te~n turbine-generator 12 and boile~ 14 are controlled by operator inputR represented by a line 1~ from an operator 18 to produce an electrie power output represented by a line 2~. A ~et of measur~d parameter~ ~rom ~team turbine-generator 12 are applied on a line 22 to a data processing subsystem 24. A~ will be more fully discussed hereinafter, the types of mea~ured para~eter~ are tho~e whlch can be obtained with ~ufficient reliability and accuracy over the long ter~n and whicb can ~e interpr~ted by datd proce~sing ~ub~y~tem 24 in a ~ashlon which can guide opera~or 18 in con~rolling ~team turbine-generator 12 ~nd boiler 14 on a minute-by-minute ba i~. Th~ outputs of data proce~sing ~u~ystem 24 are applied to an operator interface subsyst~m 26 which may be o~ a conven~onal type uch as, for example, a c~hode ray tube display, ~ pri~ter or other type~ of analog or :
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, :~2~6~i67 digital d~æplay devic2s. The output from data proces~ing sub~ystem 24, ~ay also be appli~d to data ~torage Rubsys~em 28 wherein ~he data may be stored for ~hort ter~ or long-term purpo~e-q, Data storage ~ubsy6te~ 28 may be of any conv~nient type including a printer, however, in the preferred embodiment, data proce~ing ~ub~ys~e~ 24 includes a digital proce~sor ~nd data ~torage ~ubsy~tem 2B
preferably includes a digital ~torage device ~uch as, for ~xample a magnetic or optical di6c or a ~agnetic tape storage device.
Coupled parallelly with operator interface subsystem 26 iB a results engineer interface æub~yæ~em 27. Intersce 27 allow a re~ults engineer 29 to study the output6 of data processing ~ublsy~tem 24 on a more lelsurely ba~is an compared wlth operator 18. Result6 engineer 29 communicates with operator 1a to impro~e the long term performance of turbine-yenerator syætem 10 due in part to the higher level, sophistic~ted analysis with which the engineer views the data. The engineer al80 determines the : maintenance procedures for the ~ystem and subsystem 27 as~iæt6 in the promulgation of thoRe procedures~
Referri~g now to Fig. 2, a ~lmplified ~chematic diagram o~ ~team turbine-generator 12 i8 ~hown including only sufficien~ detail to fully di8cloæe the present ~nvention~ Ste~m turbine-generator 12 is : conventional except for ~he ~ea~ure~en~ device8 lnstalled therein to ~upport the pre~en~ invention.
Thus, a deta~led de8cr~ption of :~team turbine-gener~tor 12 i~ o~ltted. In g~n~ral, the pre~ent invention rel~e~ on ~emperature and pressur~
: measurements at variou~ lo~ations thrGughoNt ~team ~. .

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turbine-generator ~ystem, including a ~*~surement of the gene~ated elec~ric~l pow~r output ~nd co~pares their relationship ~o corresponding ~e~i~n values to determlne the power lo~ , effic~en~les ~nd h~at rates throughou~ the ~y~t~ on a sub~tanti~lly in6tan aneous b~sis.
St~am turbln~-gener~tor 12, of Fi~ur~ 1, consi~ts of ~ steam turbina 30 coupl~d throu~h ~
mechanl~al connectlon 32, to an electric generator 34 which gener~tes an elect~ic power o~tput. A
tran~ducer ~not ~hown) in ele¢tric generator 34 ;.~ produce~ an electr~ c power ou~put signal W1 which iB
appli~d to line ~ or transmi~sion to data proce~sing subsy~t~m 24. The operator input on line 16 is ~pplied by hydraulic, ~lectrohydraulic, digital or other well known mean~, to a main control valve actuator 36 which affects a main control st~am admission valve 3B ~ illustrated by line 4~. A
valve position ~ignal V1, is generated by appropriate means and repre~ents the amount by which main con~rol ~lve 38 is opened, and the ~ignal is appli~d to line for transmission to data proc~sslng ~ub~ystem 24.
It i~ to be understood that valve 38 is repre6entative o~ a number of st~am admission control valve co~only a~sociated with a steam turbine.
A steam generator 42, wh~ch i~ part of boiler 14, produces a ~upply 4f hQt prQssurized ~team which i~ appli~d to main ~ontrol valve 38 on a line ~4.
The ste~m p3~8ing through main con~rol v~lve 3~ iB
applied on a main ~t~am line 46 ~o an i~put of a high pres~ure turbine 48~ As utili2ed herein, the term aHP~ refers t~ high pre~sure turbine 48. The ~team exiting fro~ 8P turbine ~, now parti~lly expanded 6~

and cooled~ but s~ill containing ~ubstantial energy, is applied on a cold rehea~er line 50 to a reheater 52 which is al~o part of boiler 14. The pre~ure and temperature of the Bteam in line 44 r upstream of S m~in control valve 38 ~nd generally ~t lt~ inl~ ~re measured by ~n~ors (not ~hvwn) ~o produce a repr~sentatlve ~ir~ pr~sure ~ignal P1 And a first temperature ~ignal ~1 which are tran~mitted to data pro~e~slng ~b~y~t~m 24. ~he pre~ure ~nd temperature o~ the steam in cold reheater line 50, downstream of high pre~sure turbine 48 at substan~ially its exit, are measured by sensors ~not ~hown) to produce a representative third pressure signal P3 and a third temperature signal T3 which are also transmitted to data processing ~ubsy~tem 24.
A pre~sure ~en30r (not 6hown) produces a pressure signal P2, representing the pres ure sensed proxi~ate the f irst stage of ~P turbine 48, and ~he signal is transmitted to data processing sub.system 2~ 2~.
An intermediate pressure turbine 54 (hereinafter ~IP" turbine) receives reheated s~eam from reheater 52 on a hot reheater line 5S, expands the ~team to ex~ract energy from i~ and exhausSs the steam through an exh~ust line 58 to a low preR~ure turbint~ 60.
Mechanical output~ of ~P ~urbine ~ P turbine 5 and low pres~ure turbine 60 (hereinafter ~LP"
turbine~ are interconnec~ed mechanically as shown by coupling means 62 and 64 which are~ in turn, mechanical~y coupled to connection 32 ~nd to the genera~o~ A four~h ~emperature T4 and pre sure P4 in hot reheater line 56, upstrea~ of ~P turblne 54 are measured by sensor~ (not ~hown~ and represenative :;:
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~ 66~7 ~ignals are ~ransmit~ed to data proceq~ing subsystem 24. In addition, a fifth temperature T5 ~nd pres~ure PS of the steam in line 58, downs~ream of IP turbine 54, i~ measured by sen~ors Inot ~hown) and ~ignals r~presenting ~ho3~ quantitle~ ~re ~l~o ~ransmittecl to data processing subsy~tem 24. In another embodimen~, T5 and P5 3re measured at the low pres R ure bowl of LP turbine 60~
Exhaust ~team from LP turbine 60 i~ ~pplied on a line 66 to a c3ndenser 6~ wherein ~he s~eam is condensed to water and thereafter conveyed ~n a line 70 to steam genera~or 42 for reu6e. One of th~
factors which can degrade sy6tem efficiency i5 deficient operatiQn of cond~nser ~B which can result in higher than normal back pre~s~re at the exhaust o~
low pressure turblne 60. Such back pre~sure is an indication that the operation of condenser 68 requires ~dju~tment or imp~oved efficiency. A
pressure sensor (not shown) in line 66 produces an exhaust pres~ure signal P6 which is transmitted to data processing ~ubRystem ~4 for further processing and display.
It ~hould be noted that the temperature sensors used may be of any convenient type, howeYer, in the 25 preferred embodiment, each temperature ~ensor include~ a plurality of high accur~cy chromel con~tant~n lType E~ thermocouples di~posed in a weIl and posltioned to give access to the stea~ whose temperature i~ to be ~easured. ~y u8in~ a plurali~y of thermocouple6 for e~ch ~ensor9 the results Prom the plurality of thermocouples m~y be av~ra~ed to substan~ially reduce in~ividual thermocouple : errors or minor diff~rences in syst~m ~emperatures.
~n addition~ ~the av~ilability of ~ore than one thermocouple offers a mea~ure of redundancy in case of failùre of one or mo~e of ~he thermocouples at a sensor location. Transmi~ion of the temper~ture signals may be acco~plished using analog voltages or the te~perature ~ignal~ ~ay be digitized before tr~n~mission to m~ke tbe mea~ure~ent~ lea~ ~us~eptible to th~ lengths o~ cable runs and to noise. Similarly, ~he pres~ure sensors m~y be of any convenient type ~uch ~6~ for sx~mple, 10 pressure sensors commercially available under ~he r~ame Heise Model 71 5T having appropriate pressure, accuracy and environmental temperature ranges.
Referring now to Fig. 3, there ~s ~hown the flow chart for the principal elements making up ~t'l operator's thermal p~rformance monitor 72 as part of data processing subsystem 24. T~e flow cl~art functionally describes the various components in t}ie operator'~ thermal performance monitor 72. ~eginning at the top left hand corner of ~ig . 3, temperature and pressure input~ are ~upplled to moni~or 72. All the temperature and pressure i~puts are s~pplied to a temperature and pressure deviation fr~m design calculator 74. Calculator 74 ha~ a data base therein which maintains the design temperature and pressure value~ for ~ach sensed temperature ~nd pr~saure signal. Hence, pressure Pl, ~en~ed at the inlet of control valve 3~, ba~ a corresp~nding first design pres~ure v~lue, P1DES. Similarly, temperatures T1, T3 etc., have corresponding design temperat~re values T1DES, T3DES, etc. These design pre~sure and tempera~ure values are illustrated within the brackets of calculator 74. The ~team temperature and pres~ure de~ign values are establi~hed by the turbine-generator manufacturer or ~re e~tabllshed during the ~nl~ial co~issloning of ~he turblne-generator u~ The ~ub~tan~aally in~tantaneous te~peratures ~nd presE;ures sen~ed throu~hout th~ turbine-gen~rator ~y~tem ~r~ played to the operator by operator di~play 76~
Calculator 74 subtracts the design value6 from their corresponding instantaneously sensed ~ignals to obtain temperature and pres~ure deviations from design. The temperature and pre~ure deviations from designs ar~ supplled to operator display 76.
It ifi important to note that ~he oper~tor display 76 i~ part of operator interface subsystem 26 and that the aub~ystem mu~ present information in a simpli~ied, easily understood fashion to operator 18.
As is commonly recognized in the art/ operator 18 is responsible ~or over~eeing ~everal other major control systems in the turbine-generator system.
Hence, operator display 76 presents very refined information ba~ed upon certain operating parameters, i.e~ ~elect~d ~mperature and pre~sures, to the operator.
Central to the dat2 proces~ng of the raw temperature and pres6ure data, i8 an economic loss calculator 78. B~sic~lly, economic 1068 calculator 78 has ~upplied ~o it ~everal heat r~te correction factors, the electricll power output ~gnal Wl, and a ~esign heat rate signal ~3. A~ ~ill be described later, 108s calculator 78 manipulates thi~
information ~nd presents ~peclflc economle loss igure~, in a C06t per unlt time fo~at, which i6 :

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-~8-normally dollar~ per day, So ~he oper~tor through operator display 76.
Specific~lly, ~n initial temperature heat rate correction factor ~ignal F~R1 i~ generated by an initial t~mper~ture heat r~ e correction factor calculator BO. Calculator 30 obtains ~ignal T1 and a ~lgn~l r~pr~ent~tlve of th~ eub~S~ntl~lly in~tantaneou6 percentage of rated load at which the 8yBtem is op~rat1ng. ~he ~ign~ illustrat~d ~0 herein a6 W~LGADn. The percent~ge of rated load signal is easily computed and i~ well known in the art. The initial temperature heat rate correction factor, FHR1, is a funct.ion of T1 and ~LOAD 8ignal.
The initial temperature ~unction i8 a rel~tionship between the deviation of T1 from the design temperature value TlDES which result~ in a percentage change in a design heat rate value.
Fig. 4 graphically illu~trates the initial temperature correction factor values fvr ~n exemplary system. F~1 is illustrated by the lin~s extending through the lower left quadrant and into the upper right quadran~. As lllu~trsted therein, the ~lope of the initial temperature function i6 ~f~ected by the percentage of rated load. The initial temperature cvrrec~ion fac~or gr~ph, a~ well a~ the reheat temperature correction factor graph of Fig. 5, the ~nitial pre~sure correction ~actor ~raph of Fig~ 6, and ~he exhau t pre~sure correcti4n fa~tor graph of Fig. 7 ~re ba~ed up~n theoretically calculated data relating ~o a ~ert~in group of ~team turbi~e~ and verified by testing o~ actual ~team turbine6. These graphs are well known in tbe art. As 1~ well known :

" , .

,: , ..

in the art, the graph~ illu~trated in Figs. 4, 5t 6 and 7 are ~upplied by the turbine=generator manufacturer~ nor~ally ~t th* ti~e the turbine-generator ~yste~ i~ sold to the utility 5 co~pany or owners of ~he ~ystem. ~he g~aph6 illu~trated h~rein relate only generally to a ~ystem ~ch~etically ~hown ~n ~ig. 2~
A~ i6 well recognized in the art, ~P turbine 48 has an associa~ed design temperature T1~ES at which a design heat rate value should be attai~ed. When T1 deviates from T1DES, the h~at rate change~
graphically as illu~trated in Fig. 4.
A reheat temperature heat rate correctiQn fact~r calculator 82, of Fig. 3, provides means for determining a corresponding ~ignal, F~R2, which is a function of T4 and ~LOAD~ IP turbine 54 should be operated at a ~pecific design te~perature, i.e., T4D~S, hence, the FHR2 fa~tor i~ a percentage change in heat rate as displayed graphically by the lesser sloped lines in Fig. 5.
An initiAl preRsure he~t rate correction f~ctor, FHR3, calculator 84 i8 ~upplied with pres~ure P1 and the %LOAD ~ignal as illustrated in Fig. 3. ~he FHR3 aignal is a function of P1, ~LO~ and the d~ign pre~ure value ~or HP turbine 48, PlD~S.
Graphically, the ~HR3 correction factor i~
illu~rated in F.ig. 6. Basical~y, ~P turbine 4~ is das~gn~d to operate at ~ de~ign pre~sur~ P1~ES a~d deviation~ ~ro~ that design pres~ure affect the heat rate. As clearly illu~trated in Fig. 3, the ~HR1 ~ignal, tha F~R2 signal, and the F~R3 s~gnal are suRplied to economic loss calcula~or 78. All the signal6 are percentage changes in heat r~te ,.

66~7 _~Q ;~
from design and are related to lthe deviation from design o certain oper~ting paramets~r3.
Generally, the overall perfor~ance of the turbin~-gener~tor 8yf3te~m iB affe~ted by the b~ck S pressure or exhau~t pre~ure pre~enlt st the exit of the la t turbine in the ~ystem. Hellce, LP turbine 60 has a sensor located on line 66 to determine exhau pressure P6. P6 i6 ~upplied to exhau~t pre6sure hea~
rate correction faol:or, ~R~, calculator ~6 as is an t0 adjusted flow ~igrlal AF from an adjusted flow calculator 88. AF ~ignal can be calculated in many ways as is commonly reoognized in the art. One method of calculatlng adjusted flow AF i8 based upon T1, Vl (the po~ition of steam admis~ion control valve 15 38), Pl, PlDES, the steam design flow value FLl, and T1~ES. One algorithm 'co ob~ain the ad~u6~ed flow ignal AP i~ as follows:
. ~ A~ z FLl~ l~Tl + 46a)/(TlDES ~ 460)1 1/2*P1/P1DES
where FL1 is in poun~s per hour and T1, T1DES is in l-a l~ re n h ~i 20 degrees ~r~F}he~t and AF i5 in pounds per hour.
q~he AF ~ignal and the exha!Jst pre~sure ~ignal P6 is applied to calculator 86. ~ig. 7 graphically illustra~e an exemplary function for determining the factor FH~4, The FHR4 factor i8 a relationship 25 between the deviation of P6 from a de~ign exhaust pres6ure value P6DES which r~sults in ~ perc~ntage change in the deslgn heat rate value for th~
~:: turbine-generator system. A illu~trated in Fig. 7, the instantaneous ~lope of the exhause pressure ~ s : ~ :

~ " ' .

i7 -Zl-~ffected by the ratio of adju~ed flow ~P to ~he design low value PLl. The ratio provide~ the percentage of design flow. ~ignal F~R~ i6 supplied to economic 10RS calculator 780 A6 1~ well ~nown ln the art, the turbine-generator 6y8tem ha~ aasociated with lt a daslgn hea~ rate ~alue ~t ~pe~lfl~ a percent~ge of rated load. The design heat rate value for the turhine-generator 5y8tem 18 dependent ln part upon the turbine b~ing ~upplied with Btea~ at design temperature T1Dæs and de~ign pressure PlDES~ Hence, when Pl and T1 dævlate~ from the design values, the design heat rate for the turbine system ch~nges. A
de~ign heat rate calculator gO provides means for determinLning the substanti~lly instantaneous design heat rate H3 for the sy~tem including the turbine and ~he electric generator. ~ de~ign heat rate signal H3 is generated by calculator 90. The ~ntrol ~alve signal Vl, signal T1 and signal P1 are supplied to calculator 90. The ~3 aignal is related to a corrected percentage of flow (PCF2) through the turbine ~yste~, and by comparing PCF2 to a data base developed by the turbine generator manufacturer at or af~er the inltial testing ~t the ~om~ ionlng of the turbine-gene~ator u~lt, th~ design heat rAte ~i~nal ~3 is obtained. PCF2 can be calcula~ed by many well known methods, one of which follows from the equa~ions PCF2-f(Vl~l(Pl/VOL~P1,T~))/(P1D~S/VO~(P1~ES,~1DES))]l/?

,.

,;, where f~V1) is the percent 8team flow through the control valve, VOL(P1,T1) i8 the splecific volume of the steam at the pressure and temperature P1, T1, and YOL~PlDES, TlDES) is the design specific volume of the ste~m at design pr~6 ure and design temperature values. It is well known in ~he ~rt how to determine percent steam flow through the ~ontrol valve a~ a f~nction of V1~
Calculator 78 obtains FHR1 ~ignal, PHR2 6ignal, FHR3 signal, F~R4 signal, electrical output ~ignal W1, and H3 signal. Calculator 78 ha~ stored within it a cost per unit heat factor CF at which the system operates. In o~her words, boiler 14 output~ heat or thermal energy at a certain cos~ per unit heat, such as in dollars per million ~TU. ~enerally, calculator 7 a includes means for multiplying the several inputs .- together along with ~ several conversion constant~
i, ,..~
thereby developing economic loss 6ignal~ displayable in co~t per uni~ time. A main ~team temperature loss signal LOSS1 ls developed by multiplying W1, F~ 3 and the cost per unit heat factor ~ignal CF, together with a first con6tant. With re~pect to the steam turbine sy~tem under di~cu~sion herein which includes HP turbine ~a~, IP tur~ine 5~ and LP turbine 6D, the main ~team temperature 1088 ~ignal LOSS1 i& added to a reheat steam ~smperature loss signal LOSS2 to ~btain a total temperature 1068 ignal LOSS5. As is well reco~nized in the art, if the st~am turbine system included only one turbine ~echanic~lly coupled to an electromagn~tic generator, main ~team ~. . .

, ~ .

. I
, .

6~

1QSS signal LOSS1 would be dlrectly displayed ~o ~he operator of that single turbine sy~tem~
One algorithm for determlnlng the ~in steam tempera~ure 10~6 signal LOSS1 i~ as follows:

LOS$1~(~HR1lT1,%LOAD)/100)*H3~10 3~W1~106~24~CF*10 6 In the above equation, the main steam te~perature loss signal ~OSS1 is di~playable in dollars per day~
The reheat ~team temperature loss ~ignal LOSS2 repre~ents the economic 108s of operating IP turbine 54 at a temperature and pressure different from the ~esign temperature and pressure. One algorithm for determining the reheat ~team ~emperature loss signal LOSS2 is as followfi:

3 6 -6 LOSS2=(FHR2~T4,~0AD)/100)*H3*10 ~Wl~tO *24~CFblQ

The economic loss of operating th~ steam turbine system 30 ~t a certain pres~ure i8 provided by a main steam pressure los~ signal LOSS3 which is derived from the equation:

LOSS3~FHR3~Pt,~OAD~ 0)~H3~10 3*W1~106*24~CF*10 S

An exhaust pressure 108S signal LOSS4 relates the e~onomic 108S of operatlng the steam ~urbine ~ystem at ~n exhaust pres~ure P6, and one ~quation for deter~inlng the exhaust pressure 1088 ~iqnal LO~S4 is ~s ~o~lows:

~ LOSS4-tPHR4lP6~AF~/1QO~H3*10 3~W1~106~24~CF*t0 6 :

~ ., ~ .
, .................... .

~2~i6~

As ~tated ear~ier~ the total k~mperature economic 10~8 LOSS5 is the ~um o~ LOS~1 ~nd LOSS~.
Total temperature lo 6 LOSS5, ~a~n ~tea~ pressure los~ LOSS3 ~nd exhaust pre~ure lo8~ LO$~4 are applied to oper~tor di~play 76. In thl~ ~annerD
operator 1~ ~ pres~nted, ~n dQll~rs p~r day, the economic consequences o~ operati~g xtea~ turbine ~y~tem 30 at a ~ontrolla~le tempera~ure ~nd pre~sure.
The exhau~t pre~ure 108~ indi~ate~ that el~ment~
downstream of ~P turbine 60 are rai~ing the bac~
presæure and thereby affecting the exp~nsion of the steam through the steam turbine ~y6tem generally. By altering the control valve position V1, and the input into boiler 14, operator 18 c~n affect the pre~sure and temperature of the steam ~upply to steam turbine system 30 to increase the thermal performan~e and economic per~rmance of the syste~,. Operator display 76 also indicates electrical power output aignal Wt and total control valve position V1 in megawatts and percent re~pectively.
Fig. 8 illustrates the operator'~ di~play for the operator thermal performance ~onitor, The oper~tor ' ~ display may be a CRT or ot}ler human readable mechanism. The component~ of tbe operator' 6 25 display haYe been explained hereinabovec ~8 18 recognized in the art, the da~a ~upplied t~ the operator ' 8 di~play coulû be continuously recorded on appropriate means by dat~ ~tored 8ubsy8tem 28. Al~o, a~ well recognized in the art, the operator~'~ th~rmal 30 perfc~rmance monitor may be coupled 'co an ele~!tronic .

,..
.

~` ~

~6~6~

~ 7TU 2967 control system which directly control~ 6team turbine syste~ 30~ In this vi~w, the control ~yBtem would have acceptable rangse of economic los8 value~. If Bteam turbine ~y~em 30 wa~ not operating wlthin S ~ho~e pre-establish~d r.anges, the ~lectronic control 8y8te~ would al~er the v~riouC oontrollable para~eter~ to bring 8te~m turbine ~y~tem 30 within the accept~ble r~ng~s of operati~n, ~he displ~y, ln Fig. 8, of ~aasured t~mperatureR, pressure~ and their corresponding deviation from design simply highlight selected area~ in steam turbine ~y6te~ 30. The di8play al80 presents P2, P3, P5 and kheir related deviations from design.
Data proce~sing ~ubsystem 24, illustrated i~
15 Fig. 1, also includ~-~ a re6ults engineer thermal perfor~ance monitor. Generally, the results engineer's th~rmal per~ormanee ~onitor calculates the actual ~fficiency of the HP and ~P turbine, the deviation from design heat rate for those turbines, and the power lo~s ~ssociated with the st~am turbine ~ystem operating at an in~tantaneous supply temperature, and instantane~us reheat temperature, insta~tan~ou~ ~upply pressure and an ~n~t~ntaneous exhau~t pressur~. Due to the result~ engineer'~
~S extensive technical training, edu~ation and tur~ genera~or syQtem experience, he or 4he, when presented with this information, can recommend : ~intenance proc~dur~ or æubstantial chan~es in the oveYa}l operation oP ~h~ steam ~urbine fiystem 30, bo~ler 14, condensor 6B, and other rel~ted elements .
in the steam ~urbine plant~ Co~only, the results engineer reviews the turbine ~ys~em performance over .

2 ~ 6~ J l7TU-2967 2~-a ~ubstantially long perlod of tl~e, ~uch a~ one week~ as compared to the ~hift op0r~tor' Q BUpervi~ion o~ the turbine ~ystQm oper~tion. ~ub t~nti~lly longer p~rlod~ of tl~e ~re util$~d ~or long term S trend analy~
Flg. 9 illu~tra~a ~ flow ch~rt ahow~ng the functional aspects of a portlon of the re~ults engineer'~ thermal perfor~ance ~onitor ~hlch i~
included in d~ta proc~ing ~ubsy~tem 24. Pri~arily, Fig. 9 deal~ with ~eans for calculating the entha:ipy of the steam entering and leaving the HP turbine and IP turbine, converting tho~e enthalpy valuas to efficiency values for the HP and IP turbine, and sub~equently calculatlng the HP and IP devia~ion in heat r~te from d~sign. ~n input enthalpy calculator 110 obtains temperature ~1 and pressure P1 a~ the inlet of control valve 38. Calculator 110 ~ay include.a data base which can be characterized by Mollier diagram. Hence, the input enthalpy J1i f 20 the steam i~ calculated and a sîgnal i~ applied to an actual ~P efficiency calculator 112. ~n output enthalpy ~alculator i14 18 ~uppl ied wlth T3 3nd P3, determines ~he output enthalpy J1~ of the steam, ~nd thereafter applie~ sign~l 31e to calcula~or 112. ~he slgnal J1i and ~ign~l Jle ~re calculated on a substan~ially in~antaneou6 basis with the ~en~lng of the temperature~ ~nd pre~ures.
Hence7 cal~ulator 112 i~ continu~lly u~ ~ting the eff1ciency signal represent~tlve of the oper~ting : 30 condition of HP turbine 48.
: An i6entropic output enthalpy calculator 116 .~ receiv~s T1, P1 and P3. The i~entropic enthalpy d~
e~h is bAsed upon tbe in8tant~n~0u8 temperature ~nd pres~ure reading~ and ~asume~ an .~ , .

. ~ . . .. . . .... . .. ... . . ... . .. . . . . . . . ..... . . . . . .. . ... ... .. . ... ... ..

6~

adiaba~ic ~nd rever3able proce~s in the steam turbine and the control valv~. Thl~ ~alcul~tion 1B well known in ~he art and ~ay be ob~ai~d fro~ a data base charact~rized.~ a~ ~ Molli~r diAgram.
Calc~lator 112 obtains the ratlo be~ween the actual enthalpy drop 5J1i-J1e) and ~he i~entropic enthalpy drop (J1i-J1eth) and generate~ E3 signal. That actual HP efficiency signal E3 is ~upplied to a results engineer'fi displ~y 116 which is p~rt of the re~ult6 ensineer interface sub ystem 27 ~llustrated in ~ig. 1.
The ePficiency of IP turbine 54 is also of concern to the results engineer. Hence, calculator 11 a receives ~ignal T4 and 6ign~1 P4 6en~ed at the 15 inlet of IP turbine 54 and determines the input enthalpy J2i for that turbine~ Calculator 120 receives 6ignal T5 and ~ignal P5, repre~enting the condition of the ~te~m exlti~g IP turb1n~ 54, and determines the output Pnthalpy ~ignal J2e.
Calculator 122 receives fiignal T4i ~ignal P4 and signal P5 to determine the isentropic output entha}py J~eth fcr IP ~urbine 54. The&e three enthalpy signal~ are applied to an ac~ual IP ~fficienry calculator 124. Cal~ulator 124 ~ubtracts output enthalpy signal J2e from input enthalpy ~lgnal J2i, a6 well ~ subtr~ct~ the i~entropic enthalpy signal J2eth ~rom input enthalpy signal ~2i~
A ratio of the actual enthalpy drop ~nd i~entropic enthalpy drop for ~P ~urbine 5~ produces the ac~ual IP efficiency ~ignal E4. E4 is ulti~ately ~upplied to r~8ult8 engineerls d~play 116.

, , ~ Z ~8 - 17TU-2~67 A design efficiency calculator 126 obtains control valve position signal Vl to determine the substantially instantaneous design efficiency of the steam turbine. The design efficiency signal El is based upon the above input for the steam turbine. Specifically, calcula-tor 126 includes therein a data base formulated by the turbine-generator manufacturer or established during the initial commissioning of the turbine-generator unit. Signal El could also be based upon the corrected percentage of steam flow, PCF2, through the turbine system if the boiler 14 did not utilize fossil fuel. One of the methods of determining PCF2 is disclosed by the algori-thm discussed above in relationship to clesign heat rate calculator 90 and utilizes Vl, Pl and Tl as inputs.
Signal El is supplied to HP deviation in heat rate from design calculator 130 as is actual HP efficiency signal E3. Calculator 130 provides means for obtaining the deviation heat rate from design, Hl, by subtracting the instantaneous design HP efficiency El from the actual efficiency E3 and dividing the resultant by the instantaneous design efficiency ~1 and a conversion factor. The algorithm for the HP deviation in heat rate signal Hl is as follows:
Hl = -(100* ( (E3-El)/El) )/6.7 The Hl signal is applied to result engineer's display 116. The divisor 6.7 depends upon the ~ specific turbine design, and hence is exemplary only.

,.~.. : : : ,~

- 29 - 17~U 2~67 A design efficiency constant 132 for the IP -turbine 54 is supplied by the turbine manufacturer as an installation dependent constant E2.
It is well known in the art that the IP turbine's design efficiency is substantially constant due to the absence of valves or other devices obstructing the flow of steam therethrough. A
person of ordinary skill in the art recognizes that the IP design efficiency is constant over the substantially entire range of steam flow. Design efficiency signal E2 is supplied to an IP deviation in heat rate from design calculator 134. Also supplied to calculator 134 is actual IP efficiency signal E4. Calculator 13A subtracts signal E2 Erom signal Eg, divides the resul-tant by signal E2 and multiplies by a conversion factor to generate the IP deviation in heat rate from design signal II2. One algorithm for H2 follows:

H2 = ~(100* ( (E4-E2)/E2) )/10) Signal ~2 is supplied to results engineer's display 116 as is signal E2 and signal E4. The factor 10 is exemplary only and relates to a specific turbine system. As illustrated in Fig. 9 t both the HP deviation from design signal Hl and IP deviation from design signal H2 are transmitted to other elements functionally shown in Fig. 10.
Fig. 10 is a flow chart illustrating 3Q the remaining portion of the results engineer's thermal performance monitor. sasically~ Flg. 10 relates to the power losses associated with operating the s-team ;

,~

turbine ~y~tem 30 at controllable temperature~ ar~d pressures which may difer frorQ des:ign ~alues.
An initial temperature kilowatt loald correctian factor t~LOAD1 ) c~lculator 1~0 ~6 supplied with 5 T1 and the percentage c: f rated load ~gn~l %I,O~ .
The function or determining factor ~LOAD1 is ar~
expression ba~ed upon the dev~tion of te~p rature T1 from 'che de~ign ten~perature T-1D~S which re~ults in a percentage change in the design heat rate va) ue for 10 the turbine ~ystem. The 810pe 0f thi~ initial temperature power expression i8 affected by 4~0AD
signal. One FLOAD1 function ifi graphically illustrated in Fig. 4 by the lines ext~nding rom the upper lef t quadrant to the lower right guadrant . In a similar faah1on to the ~nltial temperature heat rate correction factor functlon, P~1, de~cribed ln rel~ionship to calculator 80 of ~ig. 3, the function is based vn theoretical calcul~tiona whlch are conf lrmed by f ield tests on actual tl~rbine sy tems .
The signal FLOAD1 i6 applied to a main steam temperature power loss, W6, calcul~tor 142.
Calculator 142 is supplied with the electrical power output ~ignal W1 and one method of calculating W6 i~ ~s f~llow~:

W6 ~ (PLOAD1(Tl,~LO~D)/100~W1 Signal W5 may be directly ~pplied to result6 engineer's display 116b or may be ~upplied to summer 144 as i}lustral:ed in Fig. 10.
A reheat temperature kilowa~ct load correct ion (E~hOAD2) f~ctoe calcul~tor 146 iB ~upplied wlth T4 :

:,, .

and 4~0AD. The Eunction for deterlDining the ~LOAD2 factor i~ an ~xpres~ion ba~ed upon the ~evlation of temperature T4 from a reh~at design teloperature v~lue T4DES which results in a percentage ~h~nge in the 5 de~ign heat ra~ value for th~ 'eurbine ~yste~. The FLOAD2 uncti~n is graphically illustrated in ~iy. 5 and is generated subRtantially eimil~r t6:~ PEIR2 ~LOAD 1 and ~HRl .
The ~LOAD2 signal is ~upplied to 2 reheat steam tempera~ure power 108s, W7~ calculator 148 as is signal W1. Calculator 148 divide~ the FLOAD2 factor by ~ correction factor and multiplies by signal W1 as follows in one ~xemplary algorithm:

W7 ~ (FLOAD2~T4, ~LOAD)~100)~W1 Slgnal W7 is ~upplied to summer 144 wherein that signal is added to signal W6 to provide a total temperature power 1088 fii9nal W9. Signal W9 i8 u~timately pre3ented to re~ults engineer'~ display 1 1 6b .
An lnltial pressure kilowatt load correction .
factor (FLOAD3) calcu}ator 150 obtains Pt and ~6LOAD~ The funct~on for deter~ining the signal FLOAD3 i~ ~n expres~ion based upon the deviation of ~ignal P1 ~rom PlDES ~hich re~ults in a percentage ~hange in the de~ign heat rat~ v~lue for the ~team turb~ne 8y5tela. In a 6imilar fash~on to the initial pre~sure heat r~te s:orr~ction ~ctor FHR3, the F~OAD3 f actor has a slope which is af ected by the percentage o r~ted load signal. One example of the initial pressure ~orrection factor as it rela~e6 to ` ' .

.

l7TU-2967 ~hange~ in kilowatt load i~ graphi~ally illu~tr~ted in Fig. 6. It i to be recQgnized that the FLOAD1 f~ctor, the PLOAD2 fac~or and the FLOA~3 factor functions are e~tabli~hed in the ~ame manner as the corre~ponding heat rate corr@stion f~ctor6 discus~ed earlier.
The PLOAD3 signal is applied to a ~ain ~team pressure power los~, W8, ~alculator ~52 as is signal W1. Calculator 152 provides ~eans for determining ~ignal W~ ~y dividing ~LOAD3 signal by a conversion factor and multiplying by signal W1 as follows:

W8 ~ -tFLoAD3(p1~Lo~D)/loo)*w1 Signal W8 is applied to di~play 116b.
A poor exhaust pressure power loss signal W3 indicates to the resultR engineer a power 10~8 based upon unduly high turbine exha~st press~re du~ to elements in the system down~tream of ~P turbine 60~
Signal W3 is generated by an exhau~t pre~sure power loss calculator 154 whlch receives signal W1 and th~
exhaust pressure heat r2te correction ~actor signal FNR~. The exhaus~ pre~ure heat rate correction factor lgnal ~HR4 i~ generated by an appropr~ate calculator 1S6. Calculator 156 and an ~djusted low, AF, calculator 158 ~re ~ubstantially similar to cal~ulator B6 and calculator 88 of Fig. 3. It 6bould : be apprecia~ed tha~ the resul~ engineer'~ thermal performance ~onitvr may be independent from the : operator'~ thermal perfor~ance ~onitor or may be ~ 3~ combined wi~h the operator's monitor~ ~n ~he latter t~

~2~i6~

~ 3--~ituation, dupli~tion of calculator 15~ and 156 would be unnecessary. One algorithm to obtain W3 is as f ol lo~s:

W3 ~ [F~IR4(P6,AF)/( îO0 ~ FHR4(P6,P,F))]~Wl An E~P and IP turbine ef f iciency power loss calculator ï60 receive~ the ~IP deviation in hea~ rate from design signal ~1 and the IP deviation in heat rate from de6ign ~ignal ~12 as illu~trated in Fi~. tO.
5ignal W1 i~ also Rupplied to calculator 160~ An HP
and IP t~lrbine eff iciency power loss signal W2 is calculated by multiplying signal ~11 by a conversion factor, adding to the resultant signal H2 and by multiplying the re~ulting sum by signal W1 and another conYersian fa~tor. On~ equation for deriving the HP and ~P efficiency power loss 6ignal W2 is as follow6:

W2 ~ ((1.7~H1) ~ H2)~(W1~100) Signal W2 i8 ~upplied to displ~y 1~Sb. The 1.7 conversion factor in the above equation is related to the specific turbine 6ys~em. That actor illu~trate~
that the HP devlation in heat rate from design contributes more to ~ power 105s th~n tha IP
deviation in heat rate from design. This greater : effect i~ no~ed becau~e ~aller enthalp~ within the 25 ~P t~rbi:net a~ reflected in H1, r~duce the enthalpy : : which ean be added to the ~team in the reheater.
Hence, the energy which can be extracted fro~ the steam by~ the IP turb~ine is reduced.
:
:
: ~ ,....

6~

Design te~perature and pre~Bure data base 162 supplies the design pres~ure a~d tel~perature~ ~o the result engineer'~ dlsplay 116b. Allso iupplied to the re ults engineer's di6play 116b are all the 6ensed pre6sures and temperature-~ P1, P29 ~P3~ ~4~ P5, P6 and T1, T~ , T4 and TS. The origln of the~e ~ensed ~ignals are ~learly shown in Fig. 2.
Fig. 11 generally lllu~trate6 ,a re~ult engineer's display which pre~ent~ the control valve position V~, ~he de~ign ~fficlencie~ P,1 ~nd E2, the actual efficiencies E3 and E4, the deviation in heat rate from design H1 and H2, a~ well as the varioL1s power los~ signa}s W~, W8, W2, and W3 and their relat~on~hip to the m~a6ueed load or the electrical power output signal W1.
A per~on of ord~nary ~kill ln the Ar~ recognizes that the ~urbine-ge~er~tor ~y~tem can be oper~ted beyond itq r~commended design parameters, i.e., T1 and P1 can be higher than T1DES and P1D~S. Carrying this point further, the ~y tem can be operated at higher efficiencies which re~ult in negative economic losses la~ ~n the operator's monitor) and in negative power los~es (as in the re~ult~ engineer'~ monitor).
The monitor~) discu~sed and claim2d herein ~re meant to cover ~uch a situ~tion.
It i~ ~o be recogniz~d tha~ the operator 1 6 thermal perfor~ance monitor ~nd the re~ults engineer'~ th r~al p~eformance ~o~itor ~ay be ~ombined into one qeneral ther~al perfor~ance monitor. One of ordinary ~klll in the art would recognize ~he fea~ibillty of ~uch a combina~ion. The claims ~ppended hereto are meant to cov~r 3uch a general thermal performance ~onltor.

,~

, . .. , . . .. ,, .,. . ... ...... ,.... ... . . . . . . . .. ...... .. .... . . ...... . ~

~66~7 -3~-~ hroughout the dicussion of tha ~mbodi~ent of the present invention, ~te~m turbine sy tem 30 included HP turbine ~, IP turbine 54, and LP turbine 60, One of ordinary ~kill in the art would S recognize th~t other steam turbine yste~s could uti~ize the turbine thermal peror~ance monitor a di~closed herein. In fact, a single steam turbine could be driving an electromagnetic generator and the thermal performance monitor could operate in conjunction with that single ~team turbine. For clarity ~he foregoing di~cu~slon only focused on a three turbine system. ~owever, some of the claims appended hereto relate to a ~ingle turbine Rystem.
~o diferentiate between the various sign~ls in either aystem, lower ~ase letters identi~y ~ignals in the single turbine 8y8t~m and upper cass letters identify ~ignals in the multiple turbine system. For -~ example, in the 6in~1e turb~ e ~ystem, the first temperature is designated ~ and the first substantially instantaneous design efficiency is designated ne1U. In contras~, the ~orresponding s ~nals in the mu}tiple turbine sy~tem are designated n~ and ~E2~ respectively. This nomencl~ture is used ~or clarity and is not ~Qant to be }imi~ing in ~ny ~ense.
From another perspective, A turbine ~ystem ~ay include two or ~ore high pre~nure steam turbines m~chanically coupled to ~n intermediate pr~s~ure ~ ~: turbine and ~ low pre~3ure turbine and ule~mataly : 30 coupled to a electrio generator. One of ordinary skill in the art could utilize the pres~nt inventiOn by adding appropriate means to ~nclude this 6~

17TU-29~7 sdditional ~urblne's performance into the thermal performance monitor. The clai~ appended hereto are meant to cover auch a ~team turbine sy~tem~
Although several ~en90r8 are di~cussed to obtain S P,T signals herein, ~t ehould be recogniz~d that conditioning me~ns or o~her ail-~,afe mean~ could be utilized with the senRors to in ure the integrity of the inputs into the thermal perfor~ance monitor.
These conditioning means could be ~d~usted periodically~ such as annually, to ~orrec~ the raw P,T data~
One of ordinary ~kill in t~e art will recognize that many types of electrical devices could be ~tilized as a thermal per~ormance mvnitor disclosed herein. In one embodiment, a E~ewlett Packard HP 1000 minicomputer a3sociated with a ~et o~ Fortran subr~utines ~e utiliz~d. In a second embodiment, ~S~ . rn, e ro co~nP~ter an Intel ao86 ~ e~m~e~, manufa~tured by Intel Corporation, was utilized with the ~ortran subroutines. However, it is to be understood that even though ~everal working embodiment6 utilized : : digital electronic equipment, the operAtion of a completely analog thermal perormance monitoring device could be developed by one of ordinary ~kill in 25 the art as disclo~ed herein.
The claims appended hereto are meant to cover all modifi~ation~ apparent to those individualS of ordinary ~kill in the art. ~he recognition oP
variou~ ~onstant~ proportionali~ies, nu~bers and conversion factors stated in the claims is not meant to be limiting.

,. .

. ,~

, : ..

Claims (29)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. In combination with a steam turbine driving an electric generator for producing electrical power and a steam generator controllable for supplying steam through a control valve to said turbine at a controllably selected pressure and temperature, said steam turbine operable at a known cost per unit heat factor [CF] and said turbine having a first design temperature [T1DES], pressure [P1DES] and steam flow FL1] values, a thermal performance monitor for providing information about the operational status of said turbine on a substantially continuous basis, comprising:
means for sensing the substantially instantaneous first pressure [P1] and first temperature [T1] of said steam upstream of said control valve and providing representative pressure and temperature signals;
means for sensing the substantially instantaneous position of said control valve [V1] and providing a representative valve position signal;
means for sensing the substantially instantaneous first exhaust pressure [P3] of said steam downstream a steam exhaust of said turbine and providing a representative first exhaust pressure signal;
means for sensing the substantially instantaneous electrical power output [W1] from said electric generator and providing a representative power signal;
means for determining the percentage of rated load [%LOAD] at which said turbine is instantaneously operating at and providing a representative signal;
means for determining a first initial temperature heat rate correction factor [FHR1] t which is a function of said first temperature signal [T1] and the percentage of rated load signal [%LOAD], and providing a first temperature heat rate correction signal;
1. Claim 1 continued:
   means for determining a first exhaust pressure heat rate correction factor [FHR4], which is a function of said first exhaust pressure signal [P3], said first temperature signal [T1], said first design temperature value [T1DES], said valve signal [V1], and the first design steam flow value [FL1], and providing first exhaust pressure heat rate correction signal;
   means for determining a substantially instantaneous first design heat rate [113] for said turbine and said electric generator and providing a signal, said substantially instantaneous first design heat rate [H3] being related to said first temperature [T1] and first pressure [P1] signals, said valve signal [V1] and said first design pressure [P1DES] and first design temperature [T1DES] values for said turbine;
   means for multiplying said power signal [W1], said first temperature heat rate correction signal [FHR1], said design heat rate signal [H3] and a signal representative of said cost per unit heat factor signal [CF] together with a first constant to provide a first main steam temperature loss signal [LOSSl] displayable in cost per unit time;
   means for multiplying said power signal [W1], said first initial pressure heat rate correction signal [FHR3], said first design heat rate signal [H3] and the cost per unit heat factor signal [CF] together with a second constant to provide a first steam pressure loss signal [LOSS3] displayable in cost per unit time;
   means for multiplying said power signal [W1], said first exhaust pressure heat rate correction signal [FHR4], said design heat rate signal [H3] and said cost pex unit heat factor signal [CF] together with a third constant to provide a first exhaust pressure loss signal [LOSS4] displayable in cost per unit time;
   means for displaying on a substantially continuous basis said first main steam temperature loss signal [LOSS1], said first steam pressure loss signal [LOSS3] and said first exhaust pressure loss signal [LOSS4], all in said cost per unit time format for informing of the economic consequences of operating said turbine at said controllably selected temperature and pressure and of the economic consequences of operating the elements in the balance of said turbine system downstream of said turbine; and means coupled to said control valve and to said steam generator for minimizing the total of the first main steam temperature loss [LOSS1], first steam pressure [LOSS3] and first exhaust pressure loss [LOSS4], thereby minimizing cost to operate the system for producing a predetermined amount of electrical power, without direct measurement of actual steam flow in the system.
   2. A combination as in claim 1 wherein said first temperature [T1] and first pressure [P1] are sensed at the inlet of said control valve, said thermal performance monitor further including:
   means for measuring a substantially instantaneous outlet temperature [T3] and said exhaust pressure [P3]
   being a substantially instantaneous outlet pressure;
   means based on said instantaneous first temperature [T1] and pressure [Pl] said outlet temperature [T3] and pressure [P3] for calculating a first actual enthalpy drop [deltaJ] in said steam turbine and said control valve;
   means for calculating a first isentropic enthalpy drop [deltaJeth] in said steam turbine and said control valve based on said first temperature [T1]
   and said first pressure [P1] and said outlet pressure [P3]
   assuming an adiabatic and reversible process in said steam turbine and said control valve;
   means for determining a substantially instantaneous first design efficiency [E1] of said steam turbine based upon said control valve position [V1] for said steam turbine;
2. Claim 2 continued:
   means for calculating a first actual efficiency [E3] for said steam turbine based upon the ratio between said first actual enthalpy drop [deltaJ] and said first isentropic enthalpy drop [deltaJeth];
   means for calculating a first deviation in heat rate from design [H1] for said steam turbine by subtracting said instantaneous first design efficiency [E1] from said first actual efficiency [E3], dividing by said first design efficiency [E1] and multiplying by a first proportionality and means for presenting said instantaneous first design efficiency [E1], said first actual efficiency [E3] and said first deviation in heat rate [H1].
3. 3. The combination as in claim 2 further including:
   means for determining a first initial temperature kilowatt load correction factor [FLOAD1]
   based upon said first temperature [T1] and said percentage of rated load [%LOAD];
   means for calculating a first main steam temperature power loss [W6] by multiplying said first initial temperature kilowatt load correction factor [FLOAD1] by said instantaneous electrical power output [W1] and multiplying by a second porportionality;
   means for determining a first initial pressure kilowatt load correction factor [FLOAD3] based upon said first pressure [P1] and said percentage of rated load [%LOAD];
   means for calculating a first main steam pressure power loss [W8] by multiplying said first initial pressure kilowatt load correction factor [FLOAD3]
   by said instantaneous electrical power output [W1] and multiplying by a third proportionality;
   means for calculating a first deviation from design efficiency power loss [W2] by multiplying said first deviation in heat rate from design [H1] by said instantaneous electrical power output [W1] and by a fourth proportionality;
   means for calculating a first exhaust pressure power loss [W3] by dividing said first exhaust pressure heat rate correction factor [FHR4] by the sum of a first number and said first exhaust pressure heat rate correction factor [FHR4] and multiplying the resultant by said electrical power output [W1]; and said means for presenting also displays said first main steam temperature power loss [W6], said first main steam pressure power loss [W8], said first deviation from design efficiency power loss [W2], said first exhaust pressure power loss [W3].
   4 A In combination with a steam turbine-generator system including at least a first, a second, and a third steam turbine driving an electric generator for producing electrical power and a steam generator controllable for supplying steam through a control valve to said first turbine at a controllably selected temperature and pressure, said steam exiting said first turbine and flowing through a reheating means then into said second turbine and subsequently flowing to said third turbine, said turbine-generator system operable at a known cost per unit heat factor [CF], said turbine-generator system having a first design temperature [T1DES], pressure [P1DES] and steam flow [FL1} values, thermal performance monitor for providing information about the operational status of said turbine-generator system on a substantially continuous basis, comprising:
   means for sensing a substantially instantaneous first pressure [P1] and first temperature [T1] of said steam upstream of said control valve and providing representative pressure and temperature signals;
   means for sensing a substantially instantaneous position of said control valve [V1] and providing a representative valve position signal;
   
   Claim 4 continued:
   means for sensing a substantially instantaneous fourth temperature [T4] of the steam upstream of said second turbine but downstream of said reheating means and providing a representative fourth temperature signal;
   means for sensing a substantially instantaneous exhaust pressure [P6] of said steam downstream of said third turbine and providing a representative exhaust pressure signal;
   means for sensing a substantially instantaneous electrical power output [W1] from said electric generator and providing a representative signal;
   means for determining a percentage of rated load [%LOAD] at which said turblne is instantaneously operating at and providing a representative signal;
   means for determining an initial temperature heat rate correction factor [FHR1], which is a function of said first temperature signal [T1] and the percentage of rated load signal [%LOAD], and providing an initial temperature heat rate correction signal;
   means for determining a reheat temperature heat rate correction factor [FHR1], which is a function of said fourth temperature signal [T4] and said percentage of rated load [%LOAD] signal, and providing a reheat temperature heat rate correction signal;
   means for determining an initial pressure heat rate correction factor [FHR3], which is a function of said first pressure signal [P1] and said percentage of rated load signal [%LOAD], and providing an initial pressure heat rate correction signal;
   means for determining an exhaust pressure heat rate correction factor [FHR4], which is a function of said exhaust pressure signal [P6], said first temperature signal [T1], said first design temperature value [T1DES], said valve signal [V1], and said design steam flow value [FL1], and providing an exhaust Claim 4 continued:
   pressure heat rate correction factor [FHR4], which is a function of said exhaust pressure signal [P6], said first temperature signal [T1], said first design temperature value [T1DES], said valve signal [V1], and said design steam flow value [FL1], and providing an exhaust pressure heat rate correction signal;
   means for determining a substantially instantaneous design heat rate [H3] for said turbine-generator system and providing a design heat rate signal, said substantially instantaneous design heat rate [H3] being related to said first temperature [T1] and pressure [P1] signals, said valve signal [V1] and said first design pressure [P1DES] and temperature [TlDES] values for said turbine-generator system;
   means for multiplying said power signal [W1], said first temperature heat rate correction signal [FHR1], said design heat rate signal [H31 and a signal representative of said cost per unit heat factor signal [CF] together with a first constant to provide a main steam temperature loss signal [LOSS1] displayable in cost per unit time;
   means for multiplying said power signal [W1], the reheat temperature heat rate correction signal [FHR2], said design heat rate signal [H3] and said cost per unit heat factor signal [CF] together with a second constant to provide a reheat steam temperature loss signal [LOSS2]
   displayable in cost per unit time;
   means for multiplying said power signal [W1], said first pressure heat rate correction signal [FHR3], said design heat rate signal [H3] and the cost per unit heat factor signal [CFl together with a third constant to provide a steam pressure loss signal [LOSS3] displayable in cost per unit time;
   means for multiplying said power signal [W1], said exhaust pressure heat rate correction signal [FHR4], said design heat rate signal [H3] and said cost per unit heat factor signal [CF] together with a fourth constant to provide an exhaust pressure loss signal [LOSS4]
4. Claim 4 continued:
   displayable in cost per unit time;
   means for summing said main steam temperature loss signal [LOSS1] and said reheat steam temperature loss signal [LOSS2] to provide a total steam temperature loss signal [LOSS5];
   means for displaying on a substantially continuous basis said total steam temperature loss signal [LOSS5], said steam pressure loss signal [LOSS3] and said exhaust pressure loss signal [LOSS4] for informing of the economic consequences of operating said turbine-generator system at said controllably selected temperature and pressure and of the economic consequences of operating the elements in the balance of said turbine-generator system downstream of said third turbine; and means coupled to said control valve and to said steam generator for minimizing the sum of the total steam temperature loss [LOSS5], steam pressure drop [LOSS3] and exhaust pressure loss [LOSS4], thereby minimizing cost to operate the system for producing a predetermined amount of electrical power, without direct measurement of actual steam flow in the system.
5. 5. A combination as in claim 4 wherein said turbine-generator system having a design heat rate value established at said first design pressure [P1DES] and said first design temperature [T1DES], a reheat design temperature value [T4DES] and an exhaust design pressure value [P6DES];
   wherein the function for determining said initial temperature heat rate correction factor [FHR1] is based upon the deviation of said first temperature [T1] from said first design temperature value [T1DES] which results in a percentage change in said design heat rate value, and the slope of the initial temperature function being affected by said percentage of rated load [%LOAD];
   the function for determining said reheat temperature heat rate correction factor [FHR2] is based upon the deviation of said fourth temperature [T4] from said reheat design temperature value [T4DES] which results in a percentage change in said design heat rate value, and the slope of the reheat temperature function being affected by said percentage of rated load [%LOAD];
   the function for determining said initial pressure heat rate correction factor [FHR3] is based upon the deviation of said first pressure [P1] from said first design pressure value [P1DES] which results in a percentage change in said design heat rate value, and the slope of the initial pressure function being affected by said percentage of rated load [%LOAD]; and the function for determining said exhaust pressure heat rate correction factor [FHR4] is based upon the deviation of said exhaust pressure [P6] from said design exhaust pressure value [P6DES] which results in a percentage change in said design heat rate value, and the instantaneous slope of the exhaust pressure function being affected by the adjusted steam flow value [AF] through said first turbine, said adjusted steam flow value [AF] being calculated from said first temperature signal [T1], sa.id first design temperature value [T1DES], first pressure signal [P1], first design pressure value [P1DES], said design steam flow value [FL1], and said value position signal [V1].
   6. In combination with a first, second and third turbine driving an electric generator for producing electrical power and a steam generator controllable for supplying steam through a control valve to said first turbine at a controllably selected pressure and temperature, said steam turbine having a first design temperature [T1DES], pressure [P1DES] and steam flow [FL1]
   values ! and said second turbine having an installation dependent design efficiency constant [E2], a thermal performance monitor for providlng information about the Claim 6 continued:
   operational status of the turbine-generator system on a substantially continuous basis, comprising:
   means for measuring the substantially instantaneous position of said control valve [V1];
   means for measuring a substantially instantaneous first temperature [T1] and a first pressure [P1] at an inlet of said control valve;
   means for measuring a substantially instantaneous third temperature [T3] and a third pressure [P3] at an outlet of said first turbine;
   means for measuring a substantially instantaneous fourth temperature [T4] and pressure [P5] at the inlet of said second turbine;
   means for measuring a substantially instantaneous fifth temperature [T5] and pressure [P5] between the outlet of said second turbine and the inlet of said third turbine;
   means for measuring a substantially instantaneous exhaust pressure [P6] at the outlet of said third turbine;
   means based on said instantaneous first and third temperatures and pressures [T1, P1, T3, P3.] for calculating an actual enthalpy drop in said first turbine and said control valve [deltaJ1];
   means for calculating an isentropic enthalpy drop [deltaJ1eth] in said first turbine and said control valve based on said instantaneous first temperature [T1], said instantaneous first pressure [P1] and said third pressure [P3] assuming an adiabatic and reversible process in said first turbine and said control valve;
   means for determining a substantially instantaneous design efficiency [E1] for said first turbine based upon said control valve position [V1];
   means for calculating the actual efficiency of said first rubine [E3] based upon the ratio between said actual enthalpy drop [deltaJ1] and said isentropic Claim 6 continued:
   enthalpy drop [deltaJ1eth] of said first turbine;
   means for calculating the deviation in heat rate fromdesign [H1] for said first turbine by subtracting said instantaneous design efficiency [E1] from said actual efficiency [E3] for said first turbine and dividing by said design efficiency [E1] for said first turbine and multiplied by a first conversion factor;
   means based on said fourth and fifth temperatures and pressures [T4, P4, T5, P5] for calculating an actual enthalpy drop for said second turbine [deltaJ2];
   means for calculating an isentropic enthalpy drop for said second turbine [deltaJ2eth] based upon said fourth temperature and said fourth pressure and said fifth pressure [T4, P4, P5] assuming an adiabatic and reversible process in said second turbine;
   means for calculating the actual efficiency of said second turbine [E4] based upon the ratio between said actual enthalpy drop for said second turbine [deltaJ2] and said isentropic enthalpy drop for said second turbine [deltaJ2eth];
   means for calculating the deviation of heat rate from design for said second turbine [H2] by subtracting said design efficiency constant for said second turbine [E2] from said actual efficiency of said second turbine [E4] and dividing by said design efficiency constant of said second turbine [E2] and multiplying by a second conversion factor;
   means for measuring the substantially instantaneous electric power output [W1] from said electric generator;
   means for calculating a deviation from design power loss [W2] by multiplying said deviation in heat rate from design for said first turbine [H1] by a third conversion factor adding to the resultant said deviation heat rate from design for said second turbine [H2], and Claim 6 continued:
   by multiplying the resulting sum by said electric power output [W1] and a fourth conversion factor;
   means for determining the percentage of rated load [%LOAD] at which said steam turbine is instantaneously operating at;
   means for determining an initial temperature kilowatt load correction factor [FLOAD1] based upon said first temperature [T1] and said percentage of rated load [%LOAD];
   means for calculating a main steam temperature power loss [W6] by multiplying said initial temperature kilowatt load correction factor [FLOAD1] by said instantaneous electrical power output [W1] and dividing by a fifth conversion factor;
   means for determining a reheat temperature kilowatt load correction factor [FLOAD2] based upon said fourth temperature [T4] and said percentage of rated load [%LOAD];
   means for calculating a reheat steam temperature power loss [W7] by multiplying said reheat temperature kilowatt load correction factor [FLOAD2] by said electrical power output [W1] and dividing by a sixth conversion. factor;
   means for determining an initial pressure kilowatt load correction factor [FLOAD3] based upon said first pressure [P1] and said percentage of rated load [%LOAD];
   means for calculating a main steam pressure power loss [W8] by multiplying said initial pressure kilowatt load correction factor [FLOAD3] by said instantaneous electrical power output [W1] and dividing by a seventh conversion factor;
   means for determining a total temperature power loss [W9] by summing said main steam temperature power loss [W6] and said reheat steam temperature power loss [W7];
   
   Claim 6 continued:
   means for determining an exhaust pressure heat rate correction factor [FHR4] based upon said exhaust pressure [P6], said first temperature [T1], said first design temperature [T1DES], said valve position [V1], and said design steam flow value [FL1];
   means for calculating an exhaust pressure power loss [W3] by dividing said exhaust pressure heat rate correction factor [FHR4] by the sum of a first number and said exhaust pressure heat rate correction factor [FHP]4; and multiplying the resultant by said electrical power output [W1];
   means for presenting said design efficiency for said first turbine [E1], said design efficiency constant for said second turbine [E2], said actual efficiency of said first turbine [E3], said actual efficiency of said second turbine [E4], said deviation in heat rate from design for said first rubine [HL] and for said second turbine [H2], said deviation from design efficiency power loss [W2], said exhaust pressure power loss [W3], said main steam pressure power loss [W8] and said total temperature power loss [W9];
   means for creating a history over a predeter-mined operating interval of said design efficiency [El]
   for said first turbine, said design efficiency constant [E2] for said second turbine, said actual efficiency [E3]
   of said first turbine, said actual efficiency [E4] of said second turbine, said deviation in heat rate from design [H1] for said first turbine, said deviation in heat rate from design [H2] for said second turbine, said deviation from design efficiency power loss [W2], said exhaust pressure power loss [W3], said main steam pressure power loss [W8] and said total temperature power loss [W9], whereby an operational trend of the system is determinable from said history without direct measurement of actual steam flow in the system; and
6. Claim 6 continued:
   means coupled to said steam generator and to said control valve and responsive to the operational trend for minimizing cost to operate the system for producing a predetermined amount of electrical power.
   7. A combination as in claim 6 wherein said turbine-generator system having a design heat rate value at said first design temperature and pressure values, [T1DES, P1DES], a reheat design temperature value [T4DES] and an exhaust design pressure value [P6DES], wherein said means for determining said initial temperature kilowatt load correction factor [FLOAD1]
   is based upon a relationship between the deviation of said firs-t temperature [T1] from said design temperature value [T1DES] which results in a percentage change in said design heat rate value, and the initial temperature relationship having a slope affected by said percentage of rated load [%LOAD};
   said means for determining said reheat temperature kilowatt load correction factor [FLOAD2] is based upon a relationship between the deviation of said fourth temperature [T4] from said reheat design temperature value [T4DES] which results in a percentage change in said design heat rate value, and the reheat temperature relationship having a slope affected by said percentage of rated load [%LOAD];
   said means for determining said initial pressure kilowatt load correction factor [FLOAD3] is based upon a relationship between the deviation of said first pressure [P1] from said design pressure value [P1DES] which results in a percentage change in said design heat rate value, and the initial pressure relationship having a slope affected by said percentage of rated load [%LOAD,]; and said means for determining said exhaust pressure
7. Claim 7 continued:
   heat rate correction factor [FHR4] is based upon a relationship between the deviation of said exhaust pressure [P6] from a design exhaust pressure value [P6DES] which results in a percentage change in said design heat rate value, and the exhaust pressure relationship having an instantaneous slope affected by an adjusted steam flow value [AF] through said turbine system, said adjusted flow [AF] being based upon said first temperature [T1], said design temperature value [T1DES], said design steam flow value [FL1], first pressure [P1], design pressure value [P1DES], and said value position [V1].
8. 8. In combination with a steam turbine-generator system including a steam turbine coupled to an electric generator for producing electrical power and a source of steam for supplying steam through control valve means to an input of said turbine at a controllable pressure and temperature, said turbine having an output, a design temperature [T1DES.], a design pressure [P1DES] and a design steam flow [FL1] value associated therewith, and said system operable at a predetermined factor times rates load of the turbine [%LOAD] and at a cost per unit heat factor [CF], thermal performance apparatus for minimizing cost to produce a predetermined amount of electrical power without direct measurement of actual steam flow in the system, the apparatus comprising:
   first means for generating a main steam temperature loss [LOSS1] in response to the position [V1]
   of said control valve, the position [V1] of said control valve means being indicative of actual steam flow into said turbine;
   second means for generating a steam pressure loss [LOSS3] in response to the position [V1] of said control valve means;
   third means for generating an exhaust pressure loss [LOSS4] in response to the position [V1] of said control valve means; and fourth means coupled to said control valve means for minimizing the sum of the main steam temperature loss [LOSS1], steam pressure loss [LOSS3] and exhaust pressure loss [LOSS4], thereby minimizing cost to operate the system for producing the predetermined amount of electrical power without direct measurement of actual steam flow in the system.
9. 9. Thermal performance apparatus as in claim 8, wherein said source of steam includes a steam boiler controllable for supplying steam at a predetermined temperature and pressure to said control valve means, and further wherein said fourth means is coupled to said steam boiler for minimizing the sum of the main steam temperature loss [LOSS1], steam pressure loss [LOSS3] and exhaust pressure loss [LOSS4].
10. 10. Thermal performance apparatus as in claim 9, wherein said first means is further responsive to the pressure [P1] and temperature [T1] of steam input to said control valve means, to electrical power output [W1] from said electric generator, to the predetermined factor times rated load of the turbine [%LOAD] and to the design pressure [P1DES] and design temperature [T1DES].
11. 11. Thermal performance apparatus as in claim 9, wherein said second means is further responsive to the pressure [P1] and temperature [T1] of steam input to said control valve means, to electrical power output [W1] from said electric generator, to the predetermined factor times rated load of the turbine [%LOAD], and to the design pressure [P1DES] and design temperature [T1DES].
12. 12. Thermal performance apparatus as in claim 9, wherein said third means is further responsive to the pressure [P1] and temperature [T1] of steam input to said control valve means, to electrical power output [W1]
    from said electric generator, to the predetermined factor times rated load of the turbine [%LOAD], to the design pressure [P1DES] and design temperature [T1DES] and to exhaust pressure [P3] at the output of said turbine.
13. 13. Thermal performance apparatus as in claim 9, wherein said first, second and third means are each responsive to the pressure [P1] and temperature [T1] of steam input to said control valve means, to electrical power output [W1] from said electric generator, to the predetermined factor times rated load of the turbine [%LOAD], to the design pressure [P1DES] and design temperature [T1DES], and further wherein said third means is responsive to exhaust pressure [P3] at the output of said turbine and a design steam flow value [FL1].
14. 14. Thermal performance apparatus as in claim 13, further comprising:
    fifth means for generating an actual efficiency [E3] of said turbine in response to the temperature [T1]
    and pressure [P1], the exhaust pressure [P3] and exhaust temperature [T3] at the output of said turbine; and sixth means for generating a deviation in heat rate from design [H1] in response to the actual efficiency [E3] and a design efficiency [E1], wherein the design efficiency [E1] is responsive to the position [V1] of said control valve means.
15. 15. Thermal performance apparatus as in claim 14, further comprising:
    seventh means for generating a main steam temperature power loss [W6] in response to the electrical power output [W1], temperature [T1] and the predetermined factor times rated load of the turbine [%LOAD];
    eight means for generating a main steam pressure power loss [W8] in response to the electrical power output [W1], pressure [P1] and the predetermined factor times rated load of the turbine [%LOAD];
    ninth means for generating a design efficiency power loss [W2] in response to the electrical power output [W1] and the deviation in heat rate from design [H1];
    and tenth means for generating an exhaust pressure power loss [W3] in response to the electrical power output [W1] and temperature [T1], exhaust pressure [P3], design temperature [T1DES], the position [V1] of said control valve means and the design steam flow [FL1].
16. 16. Thermal performance apparatus as in claim 15, further including display means for displaying the main steam temperature loss [LOSS1], the steam pressure loss [LOSS3], the exhaust pressure loss [LOSS4], the design efficiency [E1], the actual efficiency [E3], the main steam temperature power loss [W6], the main steam pressure power loss [W8], the design efficiency power loss [W2] and exhaust pressure power loss [W3] and the deviation in that rate from design [H1].
17. 17. Thermal performance apparatus as in claim 15, further including eleventh means for creating a history over a predetermined operating interval of the main steam temperature loss [LOSS1], the steam pressure loss [LOSS3], the exhaust pressure loss [LOSS4], the design efficiency [E1], the actual efficiency [E3], the main steam temperature power loss [W6], the main steam pressure power loss [W8], the design efficiency power loss [W2], the exhaust pressure power loss [W3] and the deviation in heat rate from design [H1].
18. 18. Thermal performance apparatus as in claim 17, further including twelfth means for storing the history.
    19. In combination with a steam turbine-generator system including a first, second and third steam turbine coupled to an electric generator for producing electrical power [W1] and a source of steam for supplying steam through control valve means to an input of said first turbine at a controllable pressure and temperature, said first turbine having an output Claim 19 continued:
    coupled to reheat means for increasing the entropy of at least a portion of the steam supplied to said reheat means, said reheat means having an output coupled to an input of said second turbine, said second turbine having an output coupled to an input of said third turbine, said third turbine having an output, said system having a design temperature [T1DES], a design pressure [P1DES]
    and a design steam flow [FL1] value associated therewith, said system operable at a predetermined factor times rated load of the system [%LOAD] and at a cost per unit heat factor [CF], thermal performance apparatus for minimizing cost to produce a predetermined amount of electrical power without direct measurement of actual steam flow in the system, the apparatus comprising:
    first means for generating a total steam temperature loss [LOSS5] in response to electrical power output [W1] of said generator, temperature [T1] and pressure [P1] upstream said control valve means, temperature [T4]
    upstream the input of said second turbine, the position [V1] of said control valve means indicative of actual steam flow into said first turbine, the design temperature [T1DES], the design pressure [P1DES] and the predetermined factor times rated load of the system [%LOAD];
    second means for generating a steam pressure loss [LOSS3] in response to electrical power output [W1] of said generator, temperature [T1], pressure [P1] upstream said control valve means, the position [V1] of said control valve means, the design temperature [T1DES], the design pressure [P1DES] and the predetermined factor times rated load of the system [%LOAD];
    third means for generating an exhaust pressure loss [LOSS4] in response to electrical power output [W1]
    of said generator, temperature [T1] and pressure [P1]
    upstream said control valve means, pressure [P6] down-stream the output of said third turbine, the position [V1]
    
    of said control valve means, the design temperature [T1DES], the design pressure [P1DES] and the design steam flow [FL1]; and fourth means coupled to said control valve means for minimizing the sum of the total steam temperature loss [LOSS5], steam pressure loss [LOSS3] and exhaust pressure loss [LOSS4], thereby minimizing cost to produce the predetermined amount of electrical power, without direct measurement of actual steam flow in the system.
    20. Thermal performance apparatus as in
19. claim 19, wherein said source of steam includes a steam boiler controllable for supplying steam at a predetermined temperature and pressure to said control valve means, and further wherein said fourth means is coupled to said steam boiler for minimizing the sum of the total steam temperature loss [LOSS5], steam pressure loss [LOSS3]
    and exhaust pressure loss [LOSS4].
    21. Thermal performance apparatus as in
20. claim 20, wherein said first turbine has a design efficiency [E1] associated therewith, the design efficiency [E1] responsive to the position [V1] of said control valve means and said second turbine has a predetermined design efficiency constant [E2] associated therewith, the thermal performance apparatus further comprising:
    fifth means for generating an actual efficiency [E3] of said first turbine in response to the temperature [T1] and pressure [P1] upstream said control valve means, and the temperature [T3] and pressure [P3] upstream the input to said reheat means by assuming reversible adiabatic steam flow through said control valve means and said first turbine;
    sixth means for generating an actual efficiency [E4] of said second turbine in response to temperature [T4] and pressure [P4] upstream the input to said second turbine, and to temperature [T5] and pressure [P5] upstream the input to said third turbine by assuming reversible
21. Claim 21 continued:
    adiabatic steam flow through said second turbine;
    seventh means for generating an exhaust pressure power loss [W3] in response to electrical power output [W1] from said generator, pressure [P6] downstream the output of said third turbine, temperature [T1] upstream said control valve means, the design temperature [T1DES], the position [V1] of said control valve means and the design steam flow [FL1];
    eighth means for determining a main steam pressure loss [W8] in response to electrical power output [W1] of said generator, pressure [P1] upstream said control valve means and the predetermined factor times rated load of the system [%LOAD]; and ninth means for determining a total temperature power loss [W9] in response to temperature [T1] upstream said control valve means, temperature [T4] upstream the input of said second turbine and the predetermined factor times rated load of the system [%LOAD].
22. 22. Thermal performance apparatus as in claim 21, further including display means for displaying the total steam temperature loss [LOSS5], steam pressure loss [LOSS3], exhaust pressure loss [LOSS4], actual efficiency [E3] of said first turbine, actual efficiency [E4] of said second turbine, exhaust pressure power loss [W3], main steam pressure power loss [W8] and total temperature power loss [W9].
23. 23. Thermal performance apparatus as in claim 22, further including tenth means for creating a history over a predetermined operating interval of the total steam temperature loss [LOSS5], steam pressure loss [LOSS3], exhaust pressure loss [LOSS4], actual efficiency [E3] of said first turbine, actual efficiency [E4] of said second turbine, [E4] of said second turbine, exhaust pressure power loss [W3], main steam pressure power: loss [W8] and total temperature power loss [W9].
24. 24. Thermal performance apparatus as in claim 23, further including eleventh means for storing the history.
25. 25. In combination with a steam turbin-generator system including a steam turbine coupled to an electric generator for producing electrical power and a source of steam for supplying steam through control valve means to said turbine, said control valve means for controlling the amount of steam supplied to the turbine, a method for minimizing cost to produce a predetermined amount of electrical power without direct measurement of actual steam flow in the system, comprising:
    determining a main steam temperature loss [LOSS1] a steam pressure loss [LOSS3] and an exhaust pressure loss [LOSS4] in response to the position [V1]
    of said control valve means, the position [V1] of said control valve means indicative of actual steam flow into said turbine; and minimizing the sum of the main steam temperature loss [LOSS1], steam pressure loss [LOSS3] and exhaust pressure loss [LOSS4], thereby minimizing cost to produce a predetermined amount of electrical power without direct measurement or actual steam flow in the system.
26. 26. The method as in claim 25, wherein the source of steam includes a steam boiler and the step of minimizing includes;
    controlling the position [V1] of said control valve means; and controlling the pressure and temperature of steam provided to said control valve means.
27. 27. The method as in claim 26, wherein the step of determining further includes determining in response to pressure [P1] and temperature [T1] of steam provided to said control valve means, electrical power output [1] from said electric generator, a predetermined factor times rated load of the turbine [%LOAD], a design pressure [P1DES] and a design temperature [T1DES] and exhaust pressure [P3] at the output of said turbine.
28. 28. The method as in claim 27, further comprising displaying the steam temperature loss [LOSS1], the steam pressure loss [LOSS3] and the exhaust pressure loss [LOSS4].
29. 29. The method as in claim 27, further comprising:
    determining a deviation in heat rate from design [H1] and an actual efficiency [E3] of said turbine in response to temperature [T1] and pressure [P1], exhaust temperature [T3] and exhaust pressure [P3], and a design efficiency [E1] of said turbine wherein the design efficiency [E1] is responsive to the position [V1] of said control valve means.