power system other

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

1-

Fundamentals of Excitation Systems

Chapter 1

ABB Switzerland AG

Learning CenterPower ElectronicsTurgi, Switzerland

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

2-

1. Fundamentals of Excitation Systems

Excitation Basics

• What is an Excitation System?

• Synchronous Machine Operation Modes and Characteristics.

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

3-

1.1 What is an Excitation System

North

South

Current

Rotor The rotor of a synchronous machine is an electromagnet.

The effect of the rotating flux on the stator windings

produces an induced voltage.

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

4-


Excitation System

Current Control

Voltage Regulation Voltage

Rotor Current Production

Power Supply

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

5-

STEP UP TRANSFORMER

GENERATORBREAKER

1GOVERNOR

1

AC & DCAUXILIARY SYSTEMS

LV SWITCHGEAR

AUX.TRANSF.

EXCITATIONSYSTEM

PT’s&CT’s

STARPOINT

CUBICLE

CONTROL SYSTEMS

CONTROL ROOM

SYNCHRONIZING

HV SYSTEM HV- BREAKER

PROTECTION

EXCITATIONTRANSFORMER

SYNCHRONOUSGENERATORTURBINE


Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

6-

Primary Mechanical Electrical ConsumerEnergy Energy Energy

Turbine Generator

Excitation System

GeneratorVoltage

FieldCurrent

Chain of energy conversion Chain of energy conversion

1.2 The Synchronous Machine

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

7-


Disturbance

If Ug

Controlled Object

SynchronousMachine

Network

ExcitationSystem

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

8-


The solid pole synchronous machineThe solid pole synchronous machine

High speed application for speed range > 1500 rpm

Rotor Stator

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

9-


The salient pole synchronous machineThe salient pole synchronous machine

Slow speed application for speed range < 1500 rpm

Rotor

Stator

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

10-

1.2 The Synchronous MachineSynchronous machine triphase representation

URIR

US

IS

UT

IT

UfIf

IDR

IDT

IDS

Rotor

Stator

120° 120°

120°

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

11-

1.2 The Synchronous Machined-q axes representation

UdId

Uf If

IdD

Uq

Iq

IQ2

IQ1

Ψd

ΨfΨq

ΨdD

ΨQ1 ΨQ2

D axis

Q axis

δω

ra

ra

rdD

rf

rQ1 rQ2

Rotor

Stator

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

12-


The simplified equivalent circuit for the synchronous machine

E

Xfσ Xaσ

XmRotor Stator

P

Xd,q

EP

Synchronous Reactance

Uf

Rotor Stator

If

ω

UG

q-axis

d-axis

Fig. a Fig. b Fig. c

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

13-

1.2 The Synchronous MachineWhat values can you find on the name plate of your synchronous machine?

Physical values of your machine AbsoluteValue

Per unitvalue

Unit

Link to data sheet of real SM

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

14-


Generator no load characteristic

Ug

IfIfo

UGn

Saturation

No load field current

Generatornominal voltage

Xd

EpUG

Speed n = constant

If ,n

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

15-

1.2 The Synchronous MachineGenerator short circuit characteristic

I g

IfIfo

I G

No load field current

Generatorcurrent at Ifo

Xd

Ep UG = 0

Speed n = constant

If ,n

Ep = UGn

UGn

For If = Ifo ⇒ Xd = IG/IGn IG at (If = Ifo)Example:Measurement at If = Ifo: IG/IGn = 2.43

⇒ Xd = 2.43 pu

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

16-


Generator on load

ϕ

δ

ΔU = Xd Ig

UgEp ~If

Xd

Ep

UG =

con

st.

Load

IG

ΔU = IG • Xd

Fig. bFig. a

Ep ϕIG

Load angle

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

17-

1.3 Operation of the Synchronous Machine

The power chart of the synchronous machine

ActivePower

Reactivepower

Motor

GeneratorOperation

P

+ Q- Q 1xd

-1 +1

1 pu

overexcited

underexcited

STurbine Power

ϕ

P(Ep)~If

δ

1

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

18-


The synchronizing torque

δ=45

ωel

ωmech

ωel

ωmech

δ=90

ωel

ωmech

δ=0

ω

"rubber band"

T95_0154.DRW

o o o

FDrive

Fsyn

r

Fig. a) Fig. b) Fig. c)

Fig. d)

P = T• ωT = F• r

Some equations:

P Active powerT TorqueF Forcer Rotor radius ω Speed

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

19-


Stability limitMd

δ

Μ d2

Md1

~

~

I

I

f2

f1Drive torque

δ δ 12

The torque characteristic of the generator

δδ sinsin ⋅⋅

=⋅⋅=d

GpGpd X

UEIEM

The torque equation

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

20-


ActivePower

Reactivepower

Motor

GeneratorOperation

P

+ Q- Q 1xd

-1 +1

1 pu

overexcited

underexcited

safe operatingarea

The safe operating area of the synchronous machine

Drive Limit

Sn~Ifn

ϕ

Rated Power

δmax= 90°

Stability Limit

Field CurrentLimiter

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

21-


P [MW]

-Q 1/Xd1/Xq

FieldField CurrentCurrent LimiterLimiter

Minimum Minimum FieldField CurrentCurrent LimiterLimiter

StatorStator CurrentCurrent LimiterLimiter

UnderUnder excitationexcitation, P/Q , P/Q LimiterLimiter

The power chart of the synchronous machine with limiters

Save operating area

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

22-


The V-curves of the synchronous machine

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

23-

1.4 The Network

The Network

12

3

T95_0157.DRW

Tie

Regional grid

Substation

Power station

The Network

UNet

Infinite bus voltageExternal reactance

Xe

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

24-

1.4 The Network

Substitution diagram of the network with the generator

RLUNet

GXT Xe

Consumer

Infinite bus voltage

Transformer reactance External reactance

Networkvoltage

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

25-

1.4 The Network

Calculation of reactive power

RL UNet

GXTr Xe

UG = 1.05 pu

= 0.1 pu = 0.2 pu

Consumers

UN = 1.0 pu

IQReactive Power

IQ = ?.............Q = ?............

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

26-

1.4 The Network

Voltages and impedances of the generator-grid system

US~

GXT XE

AVR

RERT

Ug UN US

I

UN

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

27-

1.5 Reactive Power DistributionReactive power distribution

AVR

Generator 1

AVR

Generator 2

BusbarGrid

Uref1 Uref2

IQ

Q, IQ

U

Busbar voltageUref1

Uref2

IQ IQ

Generator 2 Generator 1

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

28-

1.5 Reactive Power Distribution

AVR

Q, IQ

U

Generator 1

Grid (HV) Reactive power distributionΔU

Uref

UG

Uref

UGΔU

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

29-

1.5 Reactive Power Distribution

UG

pos. static

neg. static

+Q-Q

Static behavior of AVR (Reactive power influence to AVR)

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

30-

1.6 Transient behaviour of the synchronous machine

Transient behavior of the synchronous machine

Behavior of Generator voltage in case of reactive power surgewith constant field current

S

UgX E

If = konst.

t

Ug

Ugo

t = 0

ΔU = Ig *Xd

Td’’ Td’ Tdo’

Td’’ Sub transient time constant 10…50msTd’ Transient time constant 0.5…1.5 sTdo’ Time constant

ΔU”=Xd”•IQ

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

31-


Faults and surges for the generator

UNet~

G

XT XE1

AVR

XE2S

Load

infinite bus

1) Reactive power surge

2) Active power surge

3) Load rejection

4) Long distance short circuit

5) Short circuit at generator terminal

High voltage lineGenerator

Xd’

4)

3)

1, 2)5)

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

32-


Behavior of generator voltage in case of reactive power surge

with rotating exciter

t

Ug

Ugo

t = 0

ΔU = Ig *Xd

static excitation systems

Manual mode

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

33-


δ

UE

I · XDP = ω· M

P = U · I = U ·

Torque Equation

M - M = Θ

A

E

A

X D

E · sin δ

A Edωdt

θ Inertiaω speed

ω

PA U

Con

sum

er

PE

Active power surgewith power oscillations

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

34-


Overvoltage relay

IQ x Xd "

t = 0 1 Sec.

t

Ug

Uo

with AVR (static excitation system)with constant field current

Generator voltage in case of reactive load rejection

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

35-


1 sec

UO

with constant field current

with voltage regulatorUG

t = 0t

Generator voltage in case of long distance short circuit

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

36-


Supply of excitation taken from generator terminals (shunt supply)

Supply of excitation system taken froman auxiliary supply

Short circuit at the medium voltage busbars or at generator terminals

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

37-

1.7 Definition of Excitation Systems

Duties of the Excitation SystemMaintain the generator terminal voltage

Operate the synchronous machine within its operating limits

Prevent the synchronous machine from being in asynchronous mode

Fast response in case of network disturbances

Share reactive power with other synchronous machines connected in parallel

Stabilize power oscillations

High reliability

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

38-

1.7 Definition of Excitation SystemsGlossary and Definitions (IEEE STD. 421.2)

Ifo No load field or excitation currentRequired field current to achieve 100% generator terminal voltage at rated speed

Ifn Nominal field or excitation currentRequired field current to operate the synchronous machine at rated power

Icl Ceiling field currentMaximum field current that excitation system is able to supply from its terminals for a specific time

Ufo No load field voltageRequired field voltage to obtain the no load field current considering the field resistance

Ufn Nominal field voltageRequired field voltage to obtain the rated field current considering the field resistance

Ufcl Ceiling field voltageRequired field voltage to obtain the ceiling field current

KPl Excitation Ceiling factorCeiling field voltage divided by no load field voltage Ufcl/Ufo

δ Load anglePhysical angle between rotor field and stator field

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

39-

1.7 Definition of Excitation SystemsGlossary and Definitions cont…

ϕ Phase angleElectrical angle between machine voltage and machine current

cosϕ Power factorRatio of machine’s active power to apparent power

Xd Machine synchronous reactance in direct axeXq Machine synchronous reactance in quadrature axeRs System nominal response

The rate of increase of the excitation system output voltage divided by the nominal field voltage

Tv Excitation system voltage response timeThe time in second for the excitation voltage to attain 95% of the difference between ceiling field voltage and nominal field voltage

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

40-

1.8 Excitation System: Supply ModesExcitation Systems „State of the Art“

~=

SM E

1 to 200 A

Rotating ExciterBrushless Excitation System

100 to 10000 A

Static Excitation System

~SM =

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

41-

1.8 Excitation System: Supply Modes

• Just positive ceiling voltagecapability

• Exciter response limited by theexciter machine time constant(>200ms)

• Field discharge with natural timeconstant

• Supply from PMG possible providing supporting of shortcircuit currents

• Relative large size of exciter machine for low speed generators

• No sliprings (less maintenanceand dust)

• Positive and negative ceiling voltagecapabilities

• Fast response (<20 ms) in both directions

• Fast field discharge by discharge resistoror inverter operation

• Size of excitation of transformer dependson field requirements only

• Shorter shaft (torsional oscillations)

• Maintenance on power rectifier themachine must not be at standstill

• Direct measurements of field quantitiesUf, If possible

Comparison: Indirect - Static Excitation System

Brushless excitation Static Excitation System

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

42-


~=

SM ~

~=

SM ~

~=

SM =

DC Exciter AC Exciter withstationary diodes

AC Exciter with rotatingdiodes“Brushless”

Main types of rotating exciters

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

43-

1.8 Excitation System: Supply ModesMain supply modes

MS

Supply taken from machine terminals ( shunt supply )

SM

MS

Series Compounding System

SM- +

+ -

MSSM

Vectors Compounding System

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

44-


MS

Supplied from a permanent magnet generator (PMG)or from a pilot exciter

SM

~

Main supply modes (cont.)

MS

Supplied from a safe auxiliary supply

SM

Auxiliary supply

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

45-


High voltage line

~=

SM

Unit step up transformer

Excitation transformer

Sensing PT

Power Converter

Synchronous machine

AVR

Design Example of Static Excitation System

Sn = 210 MVAUn = 15.75 kVCos ϕn = 0.85fn = 50 HzIfn = 1600 AUfn = 230 VIfo = 400 AXd = 2.1

Aux. Supply

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

46-

1.9 Excitation System: Basic ConfigurationsBasic Configurations

UG

T96_0005.DRW

IG

If

Uc

Uc

Uc

=Uc

Uc

Uc

Single channel (AUTO and MAN mode)

Power supply

FCR

AVR

Power supply I

AVR

Dual AUTO channel(Each channel with AUTO and MAN mode)

AVR

FCR

FCR

AVR = Autom. Voltage Reg.FCR = Field Current Reg.

Power supply II

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

47-

1.9 Excitation System: Basic Configurations

~=

SM =

Voltage set point

A

M

==

Supply

~

UNITROL AVR Single Channel System with integrated manual facilityfor indirect Excitation Systems

Field currentsetpoint

Manualmode

follow up

Autom.mode

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

48-

1.9 Excitation System: Basic ConfigurationsTrue-Dual Channel UNITROL AVR with 2 x Automatic & Manual modesfor Indirect Excitation Systems

SM =

Supply

~

Voltagesetpoint

A

M

==


Follow-up

~=

VOltagesetpoint

A

M

==


follow-up

~=

Autom.Mode

ManualMode

ManualMode

Autom.Mode

Channel I

Channel II

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

49-


~=

VoltageSetpoint

A

M

==

Supply

SM


ManualMode

Follow-up

Autom.Mode

Single Channel Excitation System for Static Excitation System

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

50-

1.9 Excitation System: Basic ConfigurationsVoltagesetpoint

A

M

==


follow-up

Voltage Setpoint

A

M

==


Follow-up

~=

Autom.Mode

ManualMode

ManualMode

Autom.Mode

Channel I

Channel II

Pulse busto converter

SM

~=

True- Dual Channel configurationfor Static Excitation

Pulse busto converter

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

51-


M

Gate controlunit

Pulse amplifiers

1 converter

Supply

To the field circuit ofthe machine

Supply

M

M

Gate controlunit Channel1

Pulse amplifiers

To the field circuit ofthe machine

Gate controlunit Channel2

Pulse amplifiers

Power Converter ConfigurationsEconomy Configuration(Single Channel)

Twin Configuration(Double Channel)

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

52-

1.9 Excitation System: Basic ConfigurationsParallel bridges with n-1 redundant configuration

Supply

To the field circuit

M

M

Final pulsestages

M

Gate controlunit ofchannel I

M

1

2

3

nPulsebus

Gate controlunit ofchannel II

Channel1

Channel2

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

53-

1.9 Excitation System: Basic ConfigurationsMTBF Value of Redundancy

Control Power converter MTBF (Years)electronics Thyristors/fuses Cooling fan redundant? redundant ? redundant?

No No No 3

No No No fan 4

No No Yes 4

No Yes (1+1) Yes (1+1) configuration 5

No Yes (n-1) Yes (n-1) configuration 5

Yes No No 5

Yes No No fan 14

Yes Yes (1+1) Yes (1+1) configuration 46

Yes Yes (n-1) Yes (n-1) configuration 44

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

54-

1.10 Excitation System: Field FlashingField flashing feature

AVR

Generator

Auxiliaryvoltage

~ +

DiodeBridge

Thyristorbridge

Usyn

U>40%

Field flashing breaker

Ug

t

Field flashing off

Thyristor bridgestarts to conduct

U>40%

U>10%Field flashing characteristic

Field flashing failedFCB Trip

10sField flashing OFF

5s

100%Softstart

Ug

• Order Fieldbreaker CLOSE• Order Excitation ON• Field Flashing breaker closes• Stator voltage raises• Pulses to thyristors are released• Field flashing breaker opens• The softstart function bringsthe generator voltage smoothly to itsnominal value.

Sequence:

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

55-

1.11 Excitation System: Field Suppression

GeneratorGeneratorbreaker

MediumvoltageBusbars

Thyristor bridge

a

b

cd

a

c

d

Field suppression andField suppression andinternal faultsinternal faults

b

Field Suppression Feature

Field Discharge ResistorRE

Field Discharge Circuit

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

56-


If, Uf[p.u.]

tt=0

With non-linear resistor

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

57-

1.11 Excitation System: Field SuppressionField Suppression Circuit (Crowbar)

5 6 3 4

7 8

LfRf

RE

If (field suppression)

If (operation)

inverter (WR)

+

- +

-+

- +

--Lf.dIf/dt

WR

Q02

Uarc

Uarc

UarcU

disc

harg

e

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

58-

1.11 Excitation System: Field SuppressionStatic Field Suppression Circuit (Crowbar) with Firing units

1011

K1

K2

K3

+

T T

-R02

I>

BOD

-V334

12

567

1 3

2 4

Firing PCB

Fielddischarge I

Fielddischarge II

Freewheeling

F iel

dwi

ndi n

g

+

DCbreaker

_

V1 positive overvoltagethyristor

V2 discharge and negative overvoltagethyristor

V3 redundant discharge or free wheeling thyristor

CROWBARDC Breaker

-V2

-V1

Current Measurement

Discharge resistor

Crowbar design

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

59-


Invertermode

Field Suppression from no Load Condition

Field breakeropens

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

60-

1.12 Excitation System: DesignDesign Aspects

SM

Excitation Transformer

Sensing PT

Power Converter

Synchronous machine

AVR ~=

Sn = 210 MVAUn = 15.75 kVCos ϕn = 0.85fn = 50 HzIfn = 1600 AUfn = 230 VIfo = 530 AXd = 2.1

-

Uc

Uf Ufc+

Ufc

+100%

-100% Ufo

UfIfdc

Ifac = 0.816xIfdcU2 = Ufc/1.35 = 340V

DY5

Ufo = 1puUfn = xd(xd +1+2 1-cos2ϕ ) in pu = 2.97 puUfc = kcl×Ufn = 460V = 6 pukcl = Ceiling factor acc. = 2

standards ≈ 1.5…2.5

Sn=1.1×U2×Ifn×0.816 ×√3 = 848kVA

16%

Uc

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

61-

1.12 Excitation System: DesignDesign AspectsResponse ratio

Exercise using Generator Simulator

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

62-

1.12 Excitation System: Design

UNITROL 5000 (Digital)UNITROL D (Digital)UNITROL P (Digital)

UNS2110

UNS3214

UNITROL M (Analog)UNITROL F (Digital)

SYSTEMS WITH ROTATINGEXCITERS

STATIC EXCITATION SYSTEMS

SYST

EM C

OM

PLEX

ITY

GENERATOR / EXCITATION SYSTEM RATINGS

UN1000

Application Ranges of UNITROL Excitation Systems

Exci

tatio

n Sy

stem

s Ba

sics

/ J9

90 T

rain

ing

©20

05 A

BB L

td -

63-

1.12 Excitation System: DesignMilestones of Excitation System

1908 First mechanical rolling sector regulator

1940 Oil-pressure regulator KC is added to the mechanical regulator

1950 Magnetic amplifier combined with diode bridge has been introduced

1956 The KC regulator is supplemented by load angle limiter

1957 First static excitation system with electronic AVR (Baureihe) accomplished by mercury-arc rectifier

1965 Mercury-arc rectifier replaced by thyristor converter

1967 Brushless excitation system with rotating diodes

1969 Improvement of stability by electronic power system stabilizer (PSS)

1975 UNITROL® C analog AVR-electronic replaces Baureihe-electronic

1976 UNITROL® S2210/3214 AVR with low complexity has been developed for small synchronous machines.

1977 Static excitation system for positive and negative excitation current applied to rotating synchronous compensator

1983 UNITROL® M with high integrated analog circuits applied in indirect excitation systems and direct excitation system of low complexity

1989 UNITROL® D introduces the microprocessor technologyand replaces the UNITROL® C analog technology.

1993 Second generation of numeric voltage regulator of type UNITROL® P as a free programmable regulator replaces UNITROL® D

1995 A new microprocessor based voltage regulator of type UNITROL® F replaces the old analog regulator UNITROL®M. This voltage regulator is applied for indirect excitation system and direct excitation system up to medium sized synchronous machines

1999 UNITROL® 5000 excitation system has been introduced. It combines the capacities of UNITROL® F and UNITROL® P in one high integrated system.

2001 UNITROL® 1000 microprocessor based AVR System replaces UNITROL® S2210/S3214.

power system other

Documents