sepope 2012 synchronous machine network model full scope training simulator

8/11/2019 SEPOPE 2012 Synchronous Machine Network Model Full Scope Training Simulator

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* GT2 EnergiaAv. das Amricas 500 Bloco 15 / Sala 201 Shopping Dowtown, Rio de JaneiroRJ.

CEP 22640-100. e-mail: [email protected]

XII SEPOPE20 a 23 de Maio 2012

May20th

to 23rd

2012RIO DE JANEIRO (RJ) -

BRASIL

XII SIMPSIO DE ESPECIALISTAS EM PLANEJAMENTO DAOPERAO E EXPANSO ELTRICA

XII SYMPOSIUM OF SPECIALISTS IN ELECTRIC OPERATIONAL

AND EXPANSION PLANNING

A synchronous machine and network model for a full-scope fossil-fuel powerplant training simulator

J.I.R. Rodriguez1*; C.D.R. Shirozaki1; V.D. Souquet1; A.L. Spinola1; M.R. da Silva21GT2 Energia

2UTENFBrazil

SUMMARY

An efficient real-time operator training activity can be achieved using a training simulator. An

example of this application is the full-scope power plant simulator. The term full-scope means that theresponses simulated are identical in time and indication to the responses received in the actual plantcontrol room under similar conditions. The complete software contains modules to represent thethermodynamic cycle and the process of electromechanical energy conversion with their respectivecontrols. The use of the modern software engineering techniques allows to design this software as setof software components (mechanical, electrical, etc.) intended to work together to achieve the full-scope requirements.

In this work the current state of the electrical components development to be used in a full-scope

power plant simulator is presented. Initially, a development methodology that belongs to a familycalled Agile Software Development is presented. It has shown to be satisfactory for small teams

working in the development of engineering application in short intervals of times. Using thismethodology, and following the Object Oriented Paradigm, the software architecture is described andthe electrical component is partially implemented. This component uses a service-oriented architectureand considers a linear algebra solver, a network topology processor, a power flow and a modifiedtransient stability modules. The modifications are proposed in the synchronous machine model to

simulate the generator operating in load and in no-load scenarios. The implementation is done usingthe VisSim

TMenvironment and the C++ language. It has been tested for load and no-load scenarios.

Within the tests there are the steady state and transient analysis. The last test uses a third-partycomponent (real representation of the turbine speed control). The numerical results obtained have beensatisfactorily compared against the recorded operational data of a real combined cycle power plant.

KEYWORDS

Power Plant, Training Operator, Synchronous Machine, Distributed Control System.


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1. IntroductionTraining activities, for each staff person responsible for the real-time operation of power systems, arevital to reduce the risk of operational damages and even blackouts [1]. Experience shows that an

efficient learning can only be properly achieved, in short term, using simulators to train operators [2].

These simulators aim to improve the operators skills, which vary according to the control center theywork in. Depending on the type of control center, it can be distinguished in four main simulatorsgroups: for an Independent System Operator / Regional Transmission Organization (ISO/RTO), for ageneration company (Genco), for a transmission company (Transco) and for a load serving entity

(LSE). The main difference between the first group, historically called Operator Training Simulator(OTS) or Dispatcher Training Simulator (DTS), and the last three is that the first simulates the effectsof systemic operational decisions while the others simulate the effects of local operational decisions.These decisions, systemic and local, influence on each other and, when poorly executed, can introducedisturbances outside their field of action.

Within the Genco operator training simulators, based on the type of prime mover installed, thehydropower, the nuclear power plant or the fossil-fuel power plant training simulators (FPTS) can be

distinguished. According to specific training objectives and to end user requirements, the FPTS areclassified as full-scope, reduced-scope or generic. A full-scope FPTS is a high-realism simulator, anexact duplicate of the power plant control room, containing duplicates of actual controls, instruments,panels and indicators. The unit responses simulated on this apparatus are identical in time and theindication to the responses received in the actual plant control room under similar conditions [3]. Themathematical models represent the thermodynamic cycle and the process of electromechanical energyconversion with their respective controls, involving thermal, hydraulic, mechanical and electricaldevices. In these models, it is necessary to do some simplifications to meet real-time simulationrequirements. The electrical simplifications are used to represent the synchronous machine as avoltage source behind transient impedance and to represent the electrical network as an equivalentload [4]. Actually, the great advances in computing (hardware and software) allow the use of moredetailed electrical models increasing the set of phenomena to be represented and even meet the real-

time requirements.The use of modern software engineering techniques enables design a full-scope FPTS as a set ofsoftware components (mechanical, electrical, etc.) intended to work together to represent the majorityof operational procedures of the power plant [5]. This work summarizes the current state of anelectrical software component development for a full-scope FPTS. The component requirements and abrief summary of the development methodology used are presented initially. This methodologybelongs to the group of Agile Software Development [6], which has interactive and incrementalcharacteristics that allows the end user to achieve measurable results in short and fixed times. Next,the actual state of the components designis described. It considers linear algebra solver [7], a networktopology processor [8], a power flow [9] and modified transient stability [10] modules. This lastmodule contains the well-known power flow models for the network (transformers, transmission lines,loads, etc.) and a modified sixth order model to represent the synchronous machine. Somemodifications were done and they intent to simulate the generator operating on load and on no-load.Subsequently the actual software prototype implemented is presented, which contains the power flowcoded in C++ programming language and the modified transient stability (synchronous machine andnetwork models) coded in VisSim

TM[11]. The VisSim

TM is a visual block diagram language for the

simulation of dynamical systems. Its Automatic C Programming Language Code Generation featurehas also allowed the transient stability code to be translated in a high-level programming language.Finally, some numerical results obtained by the software prototype working alone and also with amechanical and control third-party components are presented. The mechanical component consists ofan approximate model for the gas turbine coded in VisSimTM. The control component consists of anapproximate model for the voltage control and an exact replica of the turbine speed control used by areal power plant. The results obtained are compared satisfactorily against the operational and

oscillography data of a real combined-cycle power plant.


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2. Electrical Software RequirementsIn the development of an electrical component for a full-scope FPTS, the main requirements can betranslated in two major challenges: the choices of the electrical models and the strategy of integration

with the other components.

The choice of the devices models is performed with the objective to reproduce the most operatingprocedures of the power plant. For a synchronous machine a stability transient model with smallmodifications meets this objective [12]. Based on this experience, a generators transient model andnetworkssteady-state model (transmission lines, transformers and loads) were selected.

The choice of the integration strategy is made in order to allow continuous components updates withminimal impact as possible. Within updates there are changes mainly in devices models andcomponents technologies, so for an electrical component the Service-Oriented Architecture (SOA)meets this objective [5]. Therefore this architecture was selected in advance.

To deal with the identified requirements complexity, and the inherent unexpected problems in thedevelopment process, a software methodology was adopted.

3. Software Development MethodologySoftware engineering provides a wide range of development methodologies in which two trendsdominate. The first follows a process with a rigid formality and the second sacrifices part of formalityas compensation for rapid and adaptive development. In the first group, one of the best proposals is theRational Unified Process (RUP) [13]. One successful application of RUP, in power system simulation,can be found in [14]. The RUP is a well-defined methodology but its not suitable fordevelopmentwith small teams or in short intervals of time. In these cases the best alternative is to use a

methodology that belongs to the second group, the family Agile Software Development (ASD) [6].

The ASD advocates frequent software releases (prototypes) in short development cycles, which isintended to improve productivity and introduce checkpoints where new customer requirements can beadopted. Each short cycle is called iteration and the basic idea is that further iterations use fully or

partially previous iterations adding new software functionalities or user modified requirements. Theseadditions determine the incremental feature of the methodology. The life-cycle of generic ASD can beshown inFigure 1.Literature shows a wide variety of ASD proposals and they are mostly dedicated tothe development of business and management software, in fact there isnt any specific proposal forengineering application. The main difference between a business and engineering software is that thelast one is strongly dependent on bibliographic research that consumes a large amount of time. Onemethodology that follows the ASD principles with the literature review taken into account can be seeninFigure 2.In this work this methodology has been adopted.

Time

(Weeks)

1 2 z

Iteration 1

A D I T

Iteration 2

A D I T

Iteration z

A D I T

LEGEND

AAnalysis

DDesign

I Implementation

TTest

System Functionality

(Requirements)

Time

(Months)

1 n n+1 n+2 m

Iteration n+1

Literature Review

A D I T

Iteration 1

Literature Review

Iteration n

Literature Review

Iteration n+2

Literature Review

A D I T

Iteration mA D I T

LEGEND

AAnalysis

DDesign

I

ImplementationTTest

System Functionality

(Requirements)

Figure 1: Life-cycle of generic ASD Figure 2: Life-cycle of modified ASD

The definition of each iteration (with their respective requirements) was achieved based on the

intersection of three main axes: first is the size of the modeled power system; second is the complexity(details) of the devices models and third is the level of integration with other components. Each

iteration had an initial estimated time of one month. Twenty iterations were identified: the first six forreview, and the last fourteen for a prototypes building. Future prototypes have greater details related tothe grid, to the devices model or to the integration component than previous one. The Unified

Modeling Language (UML) [15] was selected for documentation.


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4. Software DevelopmentAfter the Literature Review iterations, each Prototype iteration is basically composed by four mainstages: analysis, design, implementation and tests. In this section the cumulative results from the first

12 iterations (for the analysis, design and implementation) are presented. The test results will bepresented in the next section.

In the analysis stage the initial requirements are improved by making a conceptual model in adeveloper language. The analysis model is refined specifying how the prototype will be built to meetthe established requirements in the design stage. The software architecture and the models should bechosen in this stage. In the implementation stage the design model is translated to a programminglanguage.

4.1. AnalysisThe requirements which comprises, in summary form, the interfaces between the electrical(synchronous machine) with mechanical (turbine) and control (AVR, PSS, etc.) components can beseen in Figure 3.They are understandable by the client (power system engineer) and produced an

analysis model in developers language(software engineer). This model is shown inFigure 4.

GENERATOR

Vre

Vim

Pt

Qt

VOEL Overexcitation

Limiter (OEL)

Ifd

Vs EfdAutomatic

Voltage

Regulator

(AVR)VOEL

VREF

VMOD

VUEL

VUEL

Underexcitation

Limiter (UEL)

Id

Iq

Vd

Vq

VMOD

W

Iq

Vd

Id

Vq

Ifd

Pe

Synchronous

MachineEfd

Pm

Vim

Vre Qt

Pt

W

W

Pe

PREFControl Speed

(GOV)

MWc

TurbineMWcPm

W

VSPower System

Stabilizer (PSS)

Pe

22* VimVreV

MOD

Efd

Ifd

Id

Iq

MWc

Pe

Pm

PREF

Pt

Qt

Vd

Vq

Vre

Vim

Vs

VREF

VMOD

VOEL

VUEL

=> Field voltage

=> Field current

=> d-axis current

=> q-axis current

=> Mega-watt controlled

=> Air-gap electrical power

=> Air-gap mechanic power

=> Reference power

=> Apparent power (real)

=> Apparent power (imaginary)

=> d-axis voltage

=> q-axis voltage

=> Terminal voltage (real)

=> Terminal voltage (imaginary)

=> Stabilizer voltage

=> Reference voltage

=> Terminal voltage (module)

=> Over-excitation limits voltage

=> Under-excitation limits voltage

LEGEND

APPLICATION

EPS

ELECTRICAL

MECHANICAL

DCS

Efd, etc.

Ifd, etc.

Pm, etc.

(Machine, etc.)

(Flow, etc.)

Component

Dependency

Class

Inheritance

Association

UML LEGEND

Figure 3: Electrical requirements Figure 4: Analysis model

4.2. DesignThe design model comprises the architecture of the simulator and can be seen in Figure 5. The

ELECTRICAL, GUI (Graphical User Interface), DCS (Distributed Control System) andMECHANICAL components are integrated through the COMMUNICATION component. This lastprovides an array (Shared Memory) with all variables of interest. The service-oriented architecturewas selected [5]. The COMMUNICATION is a service that meets the request of other services(ELECTRICAL, DCS and MECHANICAL) and client (GUI) for read and/or write variable in theShared Memory. Small tests (with services implemented in C#, C++ and Fortran working together) toprove the architecture have been carried out satisfactorily.

The electrical component is composed by other four components: I/O (interface input/output), EPS

(physical power system), MATH (mathematical functionalities) and APPLICATION (electrical

analysis), which is the main component for this paper. In the Figure 6 the class diagram for theAPPLICATION component is shown. Between these classes it can be seen the NTOPOLOGY(Network Topology Processor), FLOW (power flow) and TSTABILITY (Transient Stability). The twolast classes are the main topic for this work, their core is the network model and the synchronousmachine model respectively, and they are commented as follow.

ELECTRICAL::

APPLICATION

ELECTRICAL::

MATH

ELECTRICAL::

I/O

ELECTRICAL::

EPS

ELECTRICAL

GUI

MECHANICAL

DCS

COMMUNICATION

...

...

Generator Voltage (Vt)

Generator Power (Pt)

...

...

...

...

...

...

SHARED MEMORY

MATH::MATH AN ALY SI S N TOP OL OG Y

FLOW TSTABILITYMATH::VISSIM

APPLICATIONMATH

Figure 5: Design model Figure 6: Class diagram


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4.2.1.Network Model

The network was designed to be represented by two coexisting models. The first describes the network

connectivity in terms of bus-sections and switching-devices (physical model) and is used primarily asa repository of existing devices. The second describes the network in terms of busses and branches(logical model) and is targeted for use in some kind of power system analysis. A Network Topology

Processing (NTP) is responsible for transforming the network from physical to logical model. TheNTP was designed as a class NTOPOLOGY and basically replaces the switching devices by zero orinfinite impedances depending on their states being closed or open respectively. In the process thebusses and their groups (electrical islands) are identified. This process can be shown inFigure 7.One

of the best works about the uses of the NTP is [16].

MAIN ELECTRICAL

GRID

BUS-SECTION 3962

BUS-SECTION 3961

BUS-SECTION 3960

BUS 3962

BUS 3961

BUS 3960

NODE 04

NODE 02

NODE 01

NODE 03

NODE 06 NODE 07

NODE 08

NODE 05

NODE 09NODE 11

NODE 10NODE 12NODE 13

BUS 02

BUS 01

Isle 01

Substation

MAIN ELECTRICAL

GRID

BUS 3961

BUS 3960

BUS 01

Isle 01

MAIN ELECTRICAL

GRID

PHYSICAL MODEL NETWORK TOPOLOGY PROCESSING LOGICAL MODEL

Figure 7: Network Topology Processing

The class FLOW was designed following the Object Oriented Paradigm (OOP) [17] providing a set ofsteady-state models. Among these models there are the well-known VT, PV and PQ for generators, PIfor lines and transformers and PQ and ZIP for loads [9]. These models can be shown inFigure 8 andthey generally calculate the terminal active and reactive power (Pk, Qk) considering the terminal

voltage module (Vk) and angle (Tk ork) known. The overall analysis constitutes a non-linear problemsolved by the Newton- Raphson technique.

NAME PARAMETERS

GENERATOR

PkQk

VkTkVT

esp

k VV

esp

k

?, kkQP

PkQk

VkTkPV

esp

k PPesp

k VV

?, kkQ

PkQk

VkTkPQ

esp

k PP

esp

k QQ

?, kkV

espespV ,

espespVP ,

espespQP ,

NAME PARAMETERS

LOAD

PkQk

VkTkPcte

esp

k PP 0

esp

k QQ 0

?, kkV

Pk,Qk

VkTk

Icte

kesp

k VPP 0

kesp

k VQQ 0

?, kkV

VkTk

Zcte

I = cte

yy = cte

20 kesp

k VPP

20 kesp

k VQQ

?, kkV

Pk,Qk

espesp QP00

,

espesp QP00

,

espespQP

00 ,

NAME CIRCUIT / EQUATIONS PARAMETERS

TRANSMISSION LINE

VkTk

PIPkm

Qkm

shkmkm bbg ,,

VmTm

gkm+jbkm

Pmk

Qmk

TransmissionLine

kmkmkmkmmkkmkkm SenbCosgVVgVP 2

kmkmkmkmmkshkmkkm CosbSengVVbbVQ )()( 2

jbsh jbsh

NAME CIRCUIT / EQUATIONS PARAMETERS

TRANSFORMER

VkTk

PIPkm

Qkm

abg kmkm ,,

VmTm

aykm

Pmk

Qmk

Transformer

kmkmkmkmmkkmkkm SenbCosgVaVgaVP 2

kmkmkmkmmkkmkkm CosbSengVaVbaVQ )()( 2

a(a-1)ykm

(1-a)ykm

CIRCUIT / EQUATIONS CIRCUIT / EQUATIONS

LEGEND

espV

a

kmb

kP

kmP

kmg

kQ

esp

k

espP

0

kV

km

shb

esp

kP

mkP

kmQ

mkQ

mV

espQ

0

espQ

kT

mT

: Tap (p.u.)

: Susceptance k-m

: Shunt susceptance

: Specified angle voltage

: Angle voltage (node k)

: Angle voltage k-m

: Series conductance k-m

: Initial specified active power

: Specified active power (node k)

: Calculated active power (node k)

: Calculated active power k-m

: Calculated active power m-k

: Initial specified reactive power

: Specified reactive power

: Specified reactive power

: Calculated reactive power k-m

: Calculated reactive power m-k

: Specified module voltage

: Module voltage (node k)

: Module voltage (node m)

: Angle voltage (node k)

: Angle voltage (node m)

Figure 8: Devices steady-state models


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4.2.2.Synchronous Machine Model

The class TSTABILITY reuses all steady-state models from FLOW with the exception of generator.

In electrical point of view, such as shown inFigure 3,the generator model is mainly composed by thesynchronous machine model, which is composed by two sub-models. The first (MAIN) is responsiblefor the algebraic / differential equations that determine the behavior transient of the device. The

second (IC) is responsible by the calculus of the state variables initial conditions.Main Equation (MAIN)

The synchronous machine model was obtained from [18] but was originally presented in [19] and isformally known as MD03 model. The equations for this model are shown, in block diagram form, inFigure 9.This model has mainly four inputs: the terminal voltage real (Vre) and imaginary (Vim) part,the field voltage (Efd) and the turbine power (Pm); and four outputs: the apparent power real (Pt)andimaginary (Qt) part, and the current real (Ire)and imaginary (Iim) part. This model is composed by sixsub-models: an interface for generator to machine, an interface for machine to generator, the q-axisequations, the d-axis equations, the electrical equations and the swing equation. All magnitudes andparameters are in p.u. values in the generator base (Apparent Power base and Voltage base). Thismodel can be used for the generator simulation in load and no-load scenarios. In the no-load scenarios

two equations have to be added: the d-axis and q-axis currents (Id,Iq) equals to zero.

ADD

+

- @Elq

INPT

Efd ADD

+

-

-

Pace

ADD

+

+

w-wo

GAIN

InOutDD*(w-wo)

w0

ADD

+

+

+

Pe

ADD

+

-

+

Idl

ADD

-

+

-

Iql

OUTP

Ifd

q

dT delt*

DQ-C

d

q

delt

Im

ReEre

Eim

Vd

Vq

INPT

delt

OUTP

delt

INPT

delt

OutInEld

s

1/Tlqo

INTG

ADD

-

-

+

EdsINPT

Id

INPT

Iq

OUTP

Id

OUTP

Iq

OutInwEllq

s

1/Tlldo

INTG

ADD

-

-

+

@Ellq

GAIN

In Out-1

ADD

+

-

+

Qe

OUTP

Vd

OUTP

Vq

INPT

Vd

INPT

Vq

MOD2

Re

22ImRe

Im

[i]2

GAIN

In Outr r*[I]2

GAIN

In Outxlld-XlE2d

ADD

-

+

+

Eqs

ADD

-

+

+

@ElldOutIn

wElld

s

1/Tllqo

INTG

ADD+

+

Elld

ADD+

+

Ellq

OUTP

Pe

OUTP

Qe

OUTP

Elld

OUTP

Ellq

INPT

Elld

INPT

Ellq

OutInElq

s

1/Tldo

INTGGAIN

In Out(xd-xld)

(xld-Xl)

Eq_

ADD

-

- @Eld

ADD

+

+ Eq

SWING EQUATION

D-AXIS EQUATION

Q-AXIS EQUATION

MACHINE TO GENERATOR

ELECTRICAL EQUATION

OUTP

Pt

OUTP

Qt

INPT

Id

INPT

Iq

OUTP

w

ADD-

+

Itre

ADD+

-

Itim

GAIN

In Out-1Iim*

OUTP

Iim

OUTP

Ire

GAIN

In Outxld-xlldId*()

GAIN

In Out(xlld-Xl)

(xld-Xl)

E1d

GAIN

In Out(xd-Xl)

(xd-xld)

E3d

GAIN

In Out1__

(xd-Xl)

Ifd

GAIN

In Out1_

xlld

Id

GAIN

In Outxllq-XlE2q

GAIN

In Out-1

GAIN

In Out(xq-xlq)

(xlq-Xl)

Ed_

GAIN

In Outxlq-xllqIq*()

GAIN

In Out(xllq-Xl)

(xlq-Xl)

E1q

GAIN

In Out(xq-Xl)

(xq-xlq)

E3q

GAIN

In Out1_

xllq

Iq

INPT

Pm

OutIns

376,99

INTG

delt

MULT

In

OutVq*Iq

In

MULT

In

OutVd*Id

In

MULT

In

OutVd*Iq

In

MULT

In

OutVq*Id

In

INPT

Vre

INPT

Vim

INPT

Vq

GAIN

In OutrIq*r

GAIN

In OutrId*r

INPT

Vd

INPT

WO

INPT

Pe

GENERATOR TO MACHINE

INPT

Vre

INPT

Vim

CONS

-0.5*(xllq+xlld)/

(r*r+xlld*xllq)

Bmq

CONS

r/(r*r+xlld*xllq)Gmq

OutIns

1/2H

INTG

w-wo

CONS

0

CONS

0

d

q

delt

Im

Re

C-DQ

Im

ReT

delt*

reA

imA

reB

imB

Re

Im

CMUL

Ire1

Iim1BA*

H

D

units

r

xd

xq

Xl

xld

xlq

xlld

xllq

Tldo

Tlqo

Tlldo

Tllqo

=> Inertia constant of rotor equivalent (MW.s/MVA)

=> Mechanical damping of rotor equivalent (pu torque/pu)

=> Number of units of machine equivalent ( )

=> Stator resistance (pu)

=> d-axis synchronous reactance (pu)

=> q-axis synchronous reactance (pu)

=> Leakage reactance (pu)

=> d-axis transient reactance (pu)

=> q-axis transient reactance (pu)

=> d-axis subtransient reactance (pu)

=> q-axis subtransient reactance (pu)

=> d-axis transient time constant in open circuit (seg)

=> q-axis transient time constant in open circuit (seg)

=> d-axis subtransient time constant in open circuit (seg)

=> q-axis subtransient time constant in open circuit (seg)

PARAMETERS

INPT

Vre

INPT

Vim

INPT

Efd

OUTP

Pt

OUTP

Qt

OUTP

Iim

OUTP

Ire

INPT

Pm

reA

imA

reB

imB

Re

Im

CMUL

Ire2

Iim2BA*

reA

imA

reB

imB

Re

Im

CMUL

Pt

QtBA*

Figure 9: Synchronous machine MAIN model

I nitial Condition (IC)

In the synchronous machine model, each Integrator Block (INTG) needs an initial condition. Astrategy for the calculation of these values is described below. Two auxiliary variables are adding in

the model for each INTG, one for the input (dx0) and other for the output (x0) of this block. It may benoted that dx0is the derivative ofx0and in the first integration stepx0is the INTGs initial condition.All these auxiliary variables are grouped in a new sub-model called Initial Condition. In this sub-model a new equation is added by each INTG: dx0 equal to zero (x0, unknown). All these newequations are valid only for the first integration step. The new sub-model described works togetherwith the other machines sub-models, which are calculating their initial condition values in a genericmanner. For efficiency reasons this sub-model could be replaced by other customized for a particularmain model or another that sets the initial values to constants filled manually. In analogous manner,this model can also be used if any main models input is unknown, since that for each unknown inputone main models output mustbe known.


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5. Test ResultsNumerical results of the methodology, applied to the UTE Norte Fluminense (UTENF), are shown anddescribed in this section. Twelve iterations were worked out during the project and three of them; due

their representative results for this work, were selected for this presentation. Each iteration lasted onemonth and reuses partially or wholly the previous iterations products. The first one corresponds to a

steady-state analysis of the UTEs main electrical system. The second and third iterations correspondto a transient analysis of one of generators connected and disconnected from the grid respectively. Thecomparison of the Data Simulated with the UTEs Data Plant is shownfor each iteration.

5.1. Steady-State ScenarioIn this iteration the steady-state models of the devices that operates at voltages greater than or equal to15 kV were tested. InFigure 12 a) the electrical system simulated is shown. In this system there are

two substations connected by two transmission lines. In the first substation, owned by UTE, there arefour generating units (three operating with a gas turbine and one with a steam turbine) each oneconnected to a double-busbar through a power transformer. In the second substation, owned byFURNAS, there is a double-busbar that represents the rest of the Brazilian Grid. For this simulation,the switching devices were replaced by zero or infinite impedances depending on their states closed oropen respectively. InFigure 12b) the deviation (error)between the UTEs Plant Data and SimulationData can be seen. The error is separated by: (i) electrical devices: transmission lines, transformers and

generators; and (ii) electrical magnitudes: Voltage (V), Current (A), Active Power (MW) and ReactivePower (MVAr).

345 kVBARRA B BR8A

345 kVBARRA A BR8B

345 kV

BARRA B

ACC10

345 kV

BARRA B

ACC20

LT-1LT-2

TRS TR1TR2TR3

TS1

13BAC12

13BAC11 12BAC11

12BAC12 11BAC12

13BAC13

11BAC11

12BAC13 11BAC13

ACE74

ACE70

ACE73

ACE64

ACE60

ACE63

ACE76 ACE66

ACE71

ACE72

ACE61

ACE62

ACE51

ACE52

ACE41

ACE42

ACE21

ACE22

ACE53

ACD50

ACE54

ACE56

ACE55

ACE43

ACD40

ACE44

ACE46

ACE45

ACE23

ACD20

ACE24

ACE26

ACE25

ACE13

ACD10

ACE14

ACE15

ACE83

ACE82

ACD80

ACE81

ACE03

ACE02

ACD00

ACE01

ACE92

ACD90

ACE91

ACE04 ACEB4

ACE11

ACE12

TG3 TG2 TG1

6 96 4. 9 AFASEA

6 96 4. 9 AFASEB

6977.1 AFASEC

23.1 KVAB

2 3. 1 K VBC

23.1 KVCA

2 74 .8 M W

-55.3 MVAR

AFASEA

AFASEB

AFASEC

KVAB

KVBC

KVCA

462.8

465.4

462.2

354.5

355.2

355.6

A

A

FASEA

A

A

FASEB

AFASEC

663.4

KVBC

356.7

647.2

KVCA

-386.9 MW

132.5

355.2

MVAR

FASEA

FASEB

FASEC

354.5

667.6

KVAB

KV

354.9 KV

KV

MVAR

MW

0.0 KVBC

0.0 KVCA

0.0 HZ

0.0 KVAB

354.3 KVBC

356.8 KVCA

5 9. 9 HZ

353.8 KVAB

A

BC

CA

AB 355.5

629.0

636.0

648.0

355.4

373.6

-140.4

2 76 .5 M W

-84.8 MVAR

ACD30

ACE32

ACE16

Bus-section

Node

Switch Dev.

Generator

Transformer

Line

Load

LEGEND

A

A

FASEA

FASEB

FASEC

KV

355.2 KV

KV

MVAR

MW

A

BC

CA

AB 355.0

671.4

668.4

658.6

354.5

386.4

-147.3

AFASEA

AFASEB

AFASEC

636.2

KVBC

356.2

640.8

KVCA

-374.0 MW

126.3

357.1

MVAR

355.3

627.0

KVAB

AFASEA

AFASEB

AFASEC

KVAB

KVBC

KVCA

283.2

284.9

284.1

353.7

354.7

355.9

1 63 .7 M W

-63.5 MVAR

AFASEA

AFASEB

AFASEC

KVAB

KVBC

KVCA

276.4

275.8

277.0

353.8

354.4

355.4

1 60 .7 M W

-62.5 MVAR

AFASEA

AFASEB

AFASEC

KVAB

KVBC

KVCA

273.0

272.6

274.8

352.5

352.9

355.5

1 58 .4 M W

-62.9 MVAR

6 64 6. 9 AFASEA

6 66 5. 3 AFASEB

6668.3 AFASEC

14.9 KVAB

1 4. 9 K VBC

15.0 KVCA

1 66 .5 M W

-44.9 MVAR

6 49 7. 3 AFASEA

6 51 5. 6 AFASEB

6518.7 AFASEC

15.0 KVAB

1 5. 0 K VBC

15.0 KVCA

1 64 .5 M W

- 42 .4 M VA R

6 51 8. 7 AFASEA

6 54 0. 0 AFASEB

6527.8 AFASEC

15.0 KVAB

1 5. 0 K VBC

15.0 KVCA

1 64 .7 M W

- 41 .9 M VA R

(a) Electrical system (b) ErrorFigure 12: Steady-State simulation results

LT2 - T

LT2 - F

LT1 - T

LT1 - F

0

2

4

6

8

10

VA

MWMVAr

Error(%)

Magnitudes

Transmission Lines

TRS

TR3

TR2

TR1

0

2

4

6

8

10

VA

MWMVAr

Error(%)

Magnitudes

Transformers

TS1

TG3

TG2

TG1

0

2

4

6

8

10

VA

MWMVAr

Error(%)

Magnitudes

Generators


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The Plant Data were obtained from UTEs three-phase operational database. The Simulation Data wascalculated by a power flow application and the models used are the well-known steady-state models[9]. The models parameters values used were obtained from UTEs documentsand the double-busbarin the Furnas substation was modeled as an infinite bus. The deviation (error) presented wascalculated using the Equation(1). Since the maximum error allowed for one training simulator powerplant is 20% [3], the steady-state models (with their selected value parameters) are considered, apriori, validated. These results can be further improved with the use of a more detailed load model.

%100*)(

max

Pi

sPi

x

xxabsE (1)

E Error (V, A, MW, MVAr)xPi Plant Data in the Phase i (a, b, c).xS Simulation Data.

5.2. Transient Load Scenario - GOV Fast Ramp (13.4 MW/min)In this iteration one transient generator model when operating connected to the grid network wastested. The last iterations electrical system was simplified and was used. This system considered onegenerator operating with a gas turbine (TG1), the transformer connected to it (TR1) and the loadcorresponding to auxiliary services. The UTEs double-busbar was modeled as infinite bus and theload and transformer were represented by their steady-state models. The generator model wascomposed by a synchronous machine model, an approximated Automatic Voltage Regulator (AVR)model, an approximated gas turbine model and an exact replica of the UTENF turbine speed control(Governor). The synchronous machine model was described in the previous section 4.2.2. InFigure 13the Governor structure model is shown.Figure 14 andFigure 17 shown the turbine model and theAVR model used respectively.

Figure 13: Turbine speed control model Figure 14: Turbine model

The practice test had two parts. Initially when the generator is operating at 90% of its nominal activepower (Pt = 162 MW), a signal input of -13.4 MW/min was applied at the Governor making thegenerator to operate at 50% of its nominal power (Pt= 90 MW). Finally, after a few minutes thereverse process was performed. The Simulation Data was calculated by a transient stability applicationusing a trapezoidal technique and integration step of 1 millisecond. The results are inFigure 15 andshow the validation of the models. As can be seen, the model developed for this case responded with agood accuracy in comparison to the plant behavior. The fact that the simulated data does not exhibitany oscillation in the first two minutes validates the implementation of the sub-model IC (initial

condition). These results can be further improved with the use of a more detailed turbines model.

(a) Generator reference active power (b) Generator terminal active powerFigure 15: Plots for a turbine GOV fast ramp (13.4 MW/min).

Tb Speed

MWTarget

SelectedMW

MW/MIN

i10

i20

MWController

d10

d20

TURBINE

SPEED

CONTROL

:MWc

:imw20

:imw10:dmw20

:dmw10

:Pref

:Pe

:w 3600

::Sbase

-13.4

:MWmin

SPEED CONTROL (GOV)

:d10

:i10

X(s)

i10

Y(s)

d10

K2

-------

1+sTv

X(s)

i10

Y(s)

d10

1

-------

1+sTe

:i20

:d20

:i10

:i20

:d10

:d20

:Pm

:Pm:MWc

:MWc

::K2

::Tv

2.1

0.5

0.59 ::Te

PARAMETERSTURBINEMWc

i10

i20

Pm

d10

d20

80

100

120

140

160

0 5 10 15 20 25

Power(MW)

Time (min)

Gen. Reference Power (Pref)

Simulation

Plant Data

80

100

120

140

160

0 5 10 15 20 25

Power(MW)

Time (min)

Gen. Terminal Active Power (Pt)

Simulation

Plant Data


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9

5.3. Transient No-load Scenario - AVR Reference Step (5% p.u.)In this iteration one transient generator model when operating disconnected to the grid network wastested. This system considered one generator operating with a gas turbine (TG1). The last iterationsgenerator model was modified and used. These changes correspond to the addition of two equations inthe model of the synchronous machine (the currents in the d-axis and q-axis equals to zero). In no-load

scenarios the synchronous machine voltage terminal (Vt) is calculated in function of the current field(Ifd) following the relation existing in the generators Open Circuit Characteristic curve (OCC). In thispaper the effects of magnetic saturation in the air-gap are disregarding making the relation between theVtandIfd, linear.Figure 16 shown this relation.

Figure 16: Generator OCC curve Figure 17: AVR model

The practice test consisted of applying a step of 5% to AVRs signal Vref(Voltage Reference) at timet =1.0 second with a duration of 9.5 seconds. The AVR model used is shown inFigure 17.The results

are inFigure 18 and show the validation of the models. None of the errors, except those correspondingto the times in which events are applied, exceed 5%. These results could be further improved with theinclusion of the limiter blocks in the AVRs model and the saturation effects in the synchronousmachines model.

(a) Generator field voltage (b) Generator terminal voltage

Figure 18: Plots for a generator AVR reference step (5% p.u.)

6. ConclusionsA development methodology and electrical engine prototype component for a full-scope fossil-fuelpower plant training simulator was presented. The methodology has interactive and incrementalfeatures and has shown adequate in the electrical software development in the last year. The prototypeimplemented includes a power flow and a modified transient stability application in a Service-Oriented Architecture.

The power flow has been implemented following the Object-Oriented Paradigm using the C++language. The modified transient stability is implemented using the Visual Block Diagram Language,VisSimTM. The main modification lies in the synchronous machine model, which has been shown valid

for both load and no-load generator scenarios, and has a generic sub-model for initial conditioncalculation. The Automatic C Programming Language Code Generation VisSim

TMfeature has allowed

the transient stability to be fully implemented in a high-level programming language with a time-saving relationship by 10 times.

0

5

10

15

20

0 500 1000 1500 2000V

t:TerminalVoltage(kV)

Ifd: Field Current (A)

Open Circuit Characteristics

Real OCC

675 760

+

-:Vmod

:Vref

:Vref

:Vmod

:Efd

:Efd

+

+X(s)

i10

Y(s)

d10

Ka

-------

1+sTb

:d20

:i10

:d10

X(s)

i10

Y(s)

d10

KIA

----

s

:i20

:d10

:i10

:i20 :d20

::Ka

::Tb

40

0.05

0.1 ::KIA

PARAMETERSAVRVref

Vt

i10

i20

Efd

d10

d20

0,00

0,20

0,40

0,60

0,80

0 5 10 15

Voltage(pu)

Time (s)

Gen. Field Voltage (Efd)

Simulation

Plant Data

0,90

0,95

1,00

1,05

1,10

0 5 10 15

Voltage(pu)

Time (s)

Gen. Terminal Voltage (Vmod)

Simulation

Plant Data


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10

ACKNOWLEDGMENTThis work has been supported by a discretionary grant from the Research and Development program(P&D) of Usina Termeltrica Norte Fluminense (UTENF) / Agncia Nacional de Energia Eltrica

(ANEEL), Brazil. We would like to thank all the staff of the UTENF for the provision of operationaldata and helpful comments.

BIBLIOGRAPHY

[1] B. Liscouski and W.J.S. Elliott (U.S.-Canada Power System Outage Task Force), Final reporton the August 14, 2003 Blackout in the United States and Canada: Causes andrecommendations,April 2004.

[2] G. Krost, S. Allamby, and P. Lehtonen, Organization and justification of power systemoperators training, WG 39.03; CIGRE SC 39 Session; Paris, 2000.

[3] ANSI/ISAS77.201993, Fossil fuel power plant simulatorsFunctional requirements, May1994.

[4] TRAX International, http://www.traxintl.com/simulator-systems/simulation-software, visitedon 2011.

[5] J.I.R. Rodriguez, A framework proposal for software development for electrical powersystems, Masters thesis, National University of Engineering (UNI), Lima Peru, 2007. (InSpanish).

[6] Manifesto for Agile Software Development, http://agilemanifesto.org/, visited on 2011.[7] L.R. de Araujo, Aplicao de tcnicas de modelagem orientada a objetos a sistemas lineares

esparsos, Dissertao de mestrado, Universidade Federal de Juiz de Fora (UFJF), Juiz de ForaBrasil, 2000.

[8] A.M. Sasson, S.T. Ehrmann, P. Lynch, and L.S. Van Slyck,, Automaticpower system networktopology determination; IEEE Transactions on Power Apparatus and Systems, Vol. PAS-92No. 2, 1973.

[9] A.J. Monticelli, Fluxo de carga em redes de energia eltrica, Edgard Blcher Ltda., 1993

[10] P. Kundur, N.J. Balu and M.G. Lauby, Power system stability and control, McGraw-Hill,1994.[11] Visual Solutions Inc., VisSim Users Guide Version 8.0, 2010.

[12] J.M. Garca-Garca, A generic synchronous machine model for real time training simulators,Proceedings of IEEE Energy Conversion Congress and Exposition, AtlantaUSA, Sept. 2010,pp. 3569-3575.

[13] G. Booch, J. Rumbaugh and I. Jacobson, The Unified Software Development Process,Addison Wesley, 1999

[14] J.J.R. de Oliveira et al., Treinamento e certificao de operadores no sistema SAGEempregando o simulador EPRI/OTS, XI ERIAC, 2005, pp. 1-6.

[15] G. Booch, J. Rumbaugh and I. Jacobson, The Unified Modeling Language: User Guide,Addison Wesley, 1998.

[16] A. Manzoni, Desenvolvimento de um sistema computacional orientado a objetos para sistemaseltricos de potncia: Aplicao a simulao rpida e anlise da estabilidade de tenso, Tese dedoutorado, COPPE/UFRJ, Rio de Janeiro - Brasil, 2005

[17] A. D. Taylor, Object Technology A Management Guide, Addison Wesley, 1997. [18] UTE Norte Fluminense, Relatrio de ensaios da central geradora termeltrica UTE Norte

Fluminense para a unidade geradora a gs no. 1, Fevereiro 2004[19] CEPEL, Programa de Anlise de Transitrios Eletromecnicos. Verso V09-12/01. Manual do

Usurio. Dezembro 2001.[20] LAPACKLinear Algebra PACKage, http://www.netlib.org/lapack/, visited on 2011.[21] SPOOLES Sparse Object Oriented Linear Equation Solver, http://www.netlib.org/linalg/

spooles/spooles.2.2.html, visited on 2011.

sepope 2012 synchronous machine network model full scope training simulator

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