Power System Operation & Control 1 1Power System AnalysisSteady-StateTransient Basic Concepts Parameters & Equivalent Circuits Simple Power System Analysis Power Flow Analysis Active Power & Frequency Regulation Faults (Symmetrical & Unsymmetrical) Short-Circuit of Synchronous Machines Reactive Power & Voltage Regulation Practical Calculation for f(3) Symmetrical Components and Sequence Networks Unsymmetrical Fault CalculationsStability Basic Concepts Steady-State or Small Signal Stability Transient Stability Dynamic Stability2 2Power SystemOperationControl Power Flow Analysis(2) Economic DIspatch(2) Optimal Power Flow(2) Unit Commitment(2) Load Frequency Control(4) Control of Interconnected Systems(4) Voltage & Reactive Power Control(4) Advanced Topics(6)含AGC含Interchange of power and energy3 3States of Power System OperationNormal Secure StateAlert StateEmergency StateIn Extremis StateRestorative StateAll equality (E) and inequality (I) constraints are satisfied.The security level is below some threshold of adequacy.Inequality (I) constraints are violated.Both E and I constraints are violated. The violation of equality constraints implies that parts of system load are lost.This is a transitional state in which I constraints are met from the emergency control actions taken but the E constraints are yet to be satisfied.Economic operationPreventive controlEmergency control action (heroic measures)Emergency control action should be directed at avoiding total collapse.Restorative control4 4Equality constraints (E) express balance between the generation and load demand.Inequality constraints (I) express limitations of the physical equipment.5 51 培养目标培养目标本科生：知识本科生：知识研究生：创新研究生：创新2 教学特点教学特点宏观为主，适当深入宏观为主，适当深入涉及面广涉及面广以思考、提出问题引领学习以思考、提出问题引领学习注意问题的本质、背景、新问题注意问题的本质、背景、新问题例继保：电磁型 晶体管型集成电路型微机型励磁：主系统： 直流励磁机 交流励磁机 静止、旋转控制系统：电磁(相复励) 电子式(晶体管、集成电路)微机型6 6References1 Operation and Control in Power Systems(422p,2008,BS Publications, P.S.R.Murty)2 Power Generation, Operation, and Control_2nd Edition 发电、运行与控制(592p,1996,Wiley,Allen J.Wood, Bruce F.Wollenberg)3 Electric Energy Systems：Analysis and Operation 电能系统：分析与运行(658p,2009,CRC Press,Antonio Gomez-Exposito,etc)4 Power System Analysis(812p,1994,McGraw-Hill,John J.Grainger, William D.Stevenson)5 Modern Power Systems Analysis(573p,2008,Springer,Xi-Fan Wang王锡凡,Yonghua Song宋永华, Malcolm Irving) 有中文版，但内容不尽相同6 Power System Dynamics：Stability and Control_2nd Edition (660p,2008,Wiley,Jan Machowski, Janusz W.Bialek, James R.Bumby)7 Power System Dynamics and Stability 电力系统动态与稳定性(487p,1997,Wiley,Jan Machowski, Janusz W.Bialek, James R.Bumby)8 Power System Control and Stability_2nd Edition 电力系统控制与稳定性(683p,2003,IEEE,P.M.Anderson,A.A.Fouad)7 7 9 Power System Control and Stability 电力系统控制与稳定性(471p,1977,Iowa State University Press, P.M.Anderson, A.A.Fouad)10 Power System Stability and Control 电力系统稳定性与控制(1196p,1994,McGraw-Hill Professional, Prabha Kundur)11 Power System Stability and Control 电力系统稳定性与控制(353p,2006,CRC Press, Leonard L.Grigsby)12 Power Systems in Emergencies：From Contingency Planning to Crisis Management 紧急控制(399p,2001,Wiley,U.G.Knight)13 Real-Time Stability Assessment in Modern Power System Control Centers 现代电力系统控制中心实时稳定性评估(456p,2009,Wiley-IEEE Press,S.C.Savulescu)14 Voltage Stability of Electric Power Systems (375p,1998,Springer,Thierry Van Cutsem, Costas Vournas)15 Nonlinear Control Systems and Power System Dynamics 非线性控制系统与电力系统动态(201x2p,2001,Springer,Qiang Lu 卢强, Yuanzhang Sun 孙元章, Shengwei Mei 梅生伟)8 816 Robust Control in Power Systems 电力系统鲁棒控制(207p,2005,Springer,Bikash Pal,Balarko Chaudhuri)17 Robust Power System Frequency Control 鲁棒电力系统频率控制(225p,2009,Springer,Hassan Bevrani)18 Power Electronic Control in Electrical Systems 电力系统中的电力电子控制(451p,2002,Newnes,Enrique Acha,etc)19 Inter-area Oscillations in Power Systems：A Nonlinear and Nonstationary Perspective 电力系统区域间振荡(278p,2009,Springer,Arturo Roman Messina)20 HVDC and FACTS Controllers：Applications of Static Converters in Power System 高压直流与FACTS控制器(322p,2004,Kluwer,Vijay K.Sood)21 Adaptive Voltage Control in Power Systems：modeling,design and applications 电力系统自适应电压控制(170p,2007,Springer,Giuseppe Fusco,Mario Russo)22 Optimal Economic Operation of Electric Power Systems(Mathematics in Science and Engineering,Vol.142) 电力系统最优经济运行(298p,1979,Academic Press,M.E.El-Hawary,G.S.Christensen)9 923 Optimization of Power System Operation 电力系统运行优化(623p,2009,IEEE-Wiley,Jizhong Zhu)24 Market Operations in Electric Power Systems：Forecasting,Scheduling,and Risk Management 电力系统市场运营：预测、调度与风险管理(549p,2002,Wiley,Mohammad Shahidehpour,etc)25 Modern Heuristic Optimization Techniques：Theory and Applications to Power Systems(616p,2008,Wiley-IEEE, Kwang Y.Lee, Mohamed A.El-Sharkawi)26 Reliability Evaluation of Power Systems_2nd Edition 电力系统可靠性评估(534p,1996,Plenum Press, Roy Billinton, Ronald N.Allan)27 New Computational Methods in Power System Reliability 电力系统可靠性新计算方法(418p,2008,Springer,David Elmakias)28 Risk Assessment of Power Systems：Models, Methods, and Applications 电力系统风险评估：模型、方法与应用(347p,2005,Wiley-IEEE,Wenyuan Li李文沅)29 Power Distribution System Reliability：Practical Methods and Applications 配电系统可靠性：实用方法与应用(556p,2009,Wiley-IEEE,Ali A.Chowdhury,Don O.Koval)101030 Emerging Techniques in Power System Analysis(209p,2010,高等教育出版社+Springer, Zhaoyang Dong董朝阳,Pei Zhang)31 Power System State Estimation：Theory and Implementation 电力系统状态估计：理论与实现(336p,2004,Marcel Dekker,Ali Abur, Antonio Gomez Exposito)32 Embedded Generation (IET Power and Energy,31)(293p,2008,IET,Nick Jenkins,etc)1111Chap.1 Power Flow Analysis1.1 Network Equations1.1.1 Nodal voltage equations based on a nodal admittance matrix Properties of a nodal admittance matrixsymmetricsparse self-admittance mutual admittance12121.1.2 Nodal voltage equations based on a nodal impedance matrix Properties of a nodal impedance matrixsymmetricfull self-impedance (input impedance) mutual impedance (transfer impedance)13131.2 Nodal Power Equations14141.2.1 Nodal power equationsNumber of variables:1.2.2 Classification of node typesPQ nodes: P、Q are specified as known parameters4（6） 、 、 、2Number of equations:PV nodes: P、V are specified as known parametersSlack node: V=constant, 15151.2.3 Constrains for power flow calculation16161.3 Jacobi method & Gauss-Seidel method1.3.1 Jacobi method Convergence condition17171.3.2 Gauss-Seidel method Basic concept of Gauss-Seidel method Power flow calculation based on Gauss-Seidel method18181.4 Newton-Raphson method1.4.1 Basic concept of Newton method Convergence condition19191.4.2 Newton method for simultaneous nonlinear equations Convergence condition20201.4.3 Power flow calculation based on Newton-Raphson method Rectangular coordinates form Polar coordinates form Nodal power error equations (polar coordinates form)2121 Process of solving equations22221.5 P-Q Decoupled method Primary simplification Secondary simplification Fast decoupled method2323Chap.2 Economic Dispatch2.1 Characteristics of Power Generation Units2.1.1 Characteristics of Steam UnitsBoiler-turbine-generator unitInput-output curve of a steam turbine generatorHeat=f(P), or Fuel cost=f(P)2424Incremental heat (cost) rate characteristic H/ P =f(P), or F/ P =f(P)Unit (net) heat rate characteristic of a steam turbine generator unitH/P =f(P)Approximate representations of the incremental heat rate curve H/ P =f(P)25252.1.2 Variations in Steam Unit CharacteristicsCharacteristics of a steam turbine generator with four steam valves26262.1.3 Cogeneration PlantssteamelectricityIndustrial process、district heatingFuel input required for steam demand and electrical output for a single extraction steam turbine generator27272.1.4 Hydroelectric UnitsHydroelectric unit input-output curveIncremental water rate curve for hydroelectric plant2828Input-output curves for hydroelectric plant with a variable headInput-output characteristics for a pumped storage hydroplant with a fixed, net hydraulic head29292.2 Economic Dispatch of Thermal Units2.2.1 The economic dispatch problemObjective functionConstrain functionLagrange functionOptimal conditionorequal incremental cost criterion30302.2.2 Thermal system dispatching with network losses considerationObjective functionConstrain functionLagrange functionOptimal conditioncoordination equationsorpenalty factor of bus i31312.2.3 Transmission system effectscause transmission lines overloadedconstrains on power flow through the network elementspower flow equationsgeneration scheduling equationsignore the constrains on flowsinclude the complete transmission system modelwith no transmission effects considered:loss formulaeOPFincluding the effects of incremental losses:3232YNNY 给定迭代初始值给定迭代初始值 求与求与 对应的对应的K=0 开开 始始结结 束束2.2.4 The -iteration methodK达到规定的次数吗达到规定的次数吗? Y N33332.2.5 Gradient methods of economic dispatch Gradient searchdirection of maximum ascentdirection of maximum descenta scalar to guarantee that the process converges Economic dispatch by gradient searchLagrange function34342.2.6 Newton method Aim of economic dispatch Lagrange function35352.2.7 Economic dispatch with piecewise linear cost functions(a) start with all of them at Pmin(b) then begin to raise the output of the unit with the lowest incremental cost segment(c) If this unit hits the right-hand end of a segment, or if it hits Pmax, we then find the unit with the next lowest incremental cost segment and raise its output(d) Eventually, we will reach a point where a units output is being raised and the total of all unit outputs equals the total load, or load plus losses36362.2.8 Economic dispatch using dynamic programming nonconvex input-output curves cannot use an equal incremental cost methodologymultiple values of MW output for any given value of incremental cost dynamic programming= an allocation problemgenerate a set of outputs, at discrete points, for an entire set of load valuesrate limit37372.2.9 Base point & participation factors base point: a given scheduleLoad changes (by a reasonably small amount) new schedulehow much each generating unit needs to be moved (i.e., participate in the load change)assume that both and exist38382.2.10 Economic dispatch versus unit commitmentEDN units already connected to the systemPurposefind the optimum operating policy for these N unitsUCN units availablea forecast of the demand to be servedGiven that there are a number of subsets of the complete set of N generating units that would satisfy the expected demand, which of these subsets should be used in order to provide the minimum operating cost?ProblemProblema given demand to be servedDefinition:may be extended over some period of time ( 24 h or a week)more complex than EDmore difficult to solve mathematically (integer variables)3939Chap.3 Unit Commitment3.1 Introduction Load variation:Hourly,daily, seasonally Unit commitment: commit enough units and leave them on line It is quite expensive to run too many generating units.4040 Example 5-1: Unit combinationUnit 1: Unit 2: Unit 3: Total load:4141Unit Unit 1 1Unit Unit 2 2Unit Unit 3 3 Example 5-2: Unit commitment schedule using shut-down rule other constraints ? other phenomena ?42423.1.1 Constraints in Unit Commitment Spinning reserve Thermal Unit ConstraintsMinimum up timeMinimum down timeCrew constraints Other ConstraintsHydro-ConstraintsMust RunFuel Constraintsbe allocated between fast- and slow-responding units, orbe spread around the power systemscheduled reserves or off-line reservesquick-start diesel or gas-turbine unitshydro-unitspumped-storage hydro-unitstime to come up to full capacity43433.2 Unit Commitment Solution Methods Assumptions must establish a loading pattern for M periodshave N units to commit & dispatchM load levels & operating limits on the N units: any one unit can supply the individual loads, and any combination of units can also supply the loads The total number of combinations enumeration (brute force)for each period (hour)for the total period of MNN5 5101020204040Too bigToo bigM =24 h Solution methodsPriority-list schemesDynamic programming (DP)Lagrange relation (LR)44443.2.1 Priority-list Methods Example 5-3: Construct a priority list for the units of Example 5-1the full-load average production costUnitUnitFull Load Average Production Cost ( Full Load Average Production Cost ( ) )1 19.799.792 29.489.483 311.18811.188priority-list based on the average production costUnitUnitMin MWMin MWMax Max MWMW1 19.489.481001004004002 29.799.791501506006003 311.18811.1885050200200CombinatiCombinationonMin MWMin MWMax MWMax MW2+1+32+1+3300300120012002+12+1250250100010002 2100100400400commitment scheme (ignoring min up/down time, start-up costs, etc.)4545Ateachhourwhenloadisdropping,determinewhetherdroppingthenextunitontheprioritylistwillleavesufficientgenerationtosupplytheloadplusspinning-reserverequirements.Ifnot,continueoperatingasis;ifyes,goontothenextstep. Priority-list SchemesDeterminethenumberofhours,H,beforetheunitwillbeneededagain.Thatis,assumingthattheloadisdroppingandwillthengobackupsomehourslater.IfHislessthantheminimumshut-downtimefortheunit,keepcommitmentasisandgotolaststep;ifnot,gotonextstep.Calculatetwocosts.ThefirstisthesumofthehourlyproductioncostsforthenextHhourswiththeunitup.Thenrecalculatethesamesumfortheunitdownandaddinthestart-upcostforeithercoolingtheunitorbankingit,whicheverislessexpensive.Ifthereissufficientsavingsfromshuttingdowntheunit,itshouldbeshutdown,otherwisekeepiton.Repeatthisentireprocedureforthenextunitontheprioritylist.Ifitisalsodropped,gotothenextandsoforth.PowerGeneration,Operation,andControl_2ndEdition发电、运行与控制(592p,1996,Wiley,AllenJ.Wood,BruceF.Wollenberg),page1414646Step(1):Computetheminimumaverageproductioncostofallunits,andordertheunitsfromthesmallestvalueofmin.Formtheprioritylist.Step(2):Iftheloadisincreasingduringthathour,determinehowmanyunitscanbestartedupaccordingtotheminimumdowntimeoftheunit.Thenselectthetopunitsforturningonfromtheprioritylistaccordingtotheamountofloadincreasing.Step(3):Iftheloadisdroppingduringthathour,determinehowmanyunitscanbestoppedaccordingtotheminimumuptimeoftheunit.Thenselectthelastunitsforstoppingfromtheprioritylistaccordingtotheamountofloaddropping.Step(4):Repeattheprocessforthenexthour. Priority-list Schemes (another description)OptimizationofPowerSystemOperation电力系统运行优化(623p,2009,IEEE-Wiley,JizhongZhu),page2544747Checkattheendofeveryhourofoperation.iftheloaddemandhasfallen.Ifthedemandhasdecreasedcheckifthelastunitintheprioritylistisdropped,theloaddemandcanbemet,satisfyingthespinningreserverequirement.Statusquoismaintainedifthedemandcannotbemet.IfitispossibletodroptheunitinstepI,thendeterminethenumberofhourshbeforetheunitisrequiredagainforservice.Ifthishislessthantheshutdownandstartuptimesfortheunit,ithastobeleftinservicewithoutremoval.Then,calculatethecostoffloatingtheunitwithinthesystemwithoutsupplyinganygenerationandthecostofshutdownandstartupprocessesandifthereissufficientsavingsfromshuttingitdown,andstartingitagainforserviceitcanberemoved.Theprocessistoberepeatedforthenextunitontheprioritylistandcontinued. Priority-list Schemes (the third description)OperationandControlinPowerSystems(422p,2008,BSPublications,P.S.R.Murty)page17548483.2.2 Dynamic-Programming Solutionsuitable only to multistage decision processesa decision taken at one stage does not influence the preceding events in the sequence but affect only what follows laterAEBCDHFG2123611413thecostoftransportalongtherouteallowedTrafficdirectionthegoal Example: The least cost route4949DGHG via DCG via DFGEGEFHDGBGBCDGAGAEFHDGConclusion:the minimum cost to move from one location P to another location R via Q is given byAEBCDHFG21236114135050 Unit Commitment by Dynamic Programmingdata requiredthe number of units availablethe cost characteristics of these unitsthe load cycletotal loadtotal operating costthe cost of operating (N-1) units to supply a reduced demandthe cost of operating the Nth unit at a power output of5151 Process of solving UC problems by DP525253535454555556565757585859596060616162626363646465656666676768686969707071717272737374747575767677777878797980808181828283838484858586868787888889899090919192929393949495959696979798989999100100101101102102103103104104105105106106107107108108109109110110111111112112113113114114115115116116117117118118119119120120121121122122123123124124125125126126127127128128129129130130131131132132133133134134135135136136137137138138139139140140141141142142143143144144145145146146147147148148149149150150151151152152153153154154155155156156157157158158159159160160161161162162163163164164165165166166167167168168169169170170171171172172173173174174175175176176177177178178179179180180181181182182183183184184185185186186187187188188189189190190191191192192193193194194195195196196197197198198199199200200201201202202203203204204205205206206207207208208209209210210211211212212213213214214215215216216217217218218219219220220221221222222223223224224225225226226227227228228229229230230231231232232233233234234235235236236237237238238239239240240241241242242243243244244245245246246247247248248249249250250251251252252253253254254255255256256257257258258259259260260261261