Phần 5 KHÓA ĐÀO TẠO TÍNH TOÁN ỔN ĐỊNH VÀ ỨNG DỤNG TRÊN PHẦN MỀM PSSE CHO KỸ SƯ HỆ THỐNG ĐIỆN (Lựa chọn bộ kích từ trong mô phỏng ổn định và mô hình kích từ trên Phần mềm PSSE)

TRANSMISSION &
DISTRIBUTION
A Division of Global Power
POWER SYSTEM STABILITY CALCULATION TRAINING
D2
Sl ti fE it
D
ay
2
-
S
e
l
ec
ti
on o
f

E
xc
it
ers
November 19, 2013Prepared by: Mohamed El Chehaly
eBook for You
OUTLINE
2
OUTLINE
• Types of Exciters
• Exciter Models in PSS®E
• Identification of Typical Exciters
eBook for You

3
TYPES OF EXCITERS
TYPES

OF

EXCITERS
eBook for You
Introduction
4
TYPES OF EXCITERS
Introduction
 Important to model excitation system of
titl ill
genera
t
ors as
it
p
l
ays a cruc
i
a
l
ro
l
e
during fast disturbances (first 10
seconds)
seconds)

 Functions of an excitation system:

To provide
direct current
to the synchronous

To

provide

direct

current
to

the

synchronous

generator field winding
 To perform control and protective functions
essential to the satisfactory operation of the
power system

To meet the specified requirements for operating

To

meet

the

specified

requirements

for

operating

flexibility
eBook for You
Introduction
5
TYPES OF EXCITERS
Introduction
 Performance requirements:
 Generator considerations:
 Supply and adjust field current as the generator output
varies within its continuous capability
varies

within

its

continuous

capability
 Respond to transient disturbances in order to prevent

damage of the generator such as:

Rotor insulation failure due to high field voltage

Rotor

insulation

failure

due

to

high

field

voltage
 Rotor heating due to high field current
 Stator heating due to high VAR loading

Ptidti

P
ower sys
t
em cons
id
era

ti
ons:
 Contribute to effective control of system voltage

Improve system stability with fast response

Improve

system

stability

with

fast

response
eBook for You
Principle Scheme of Excitation
6
TYPES OF EXCITERS
Principle

Scheme

of

Excitation
eBook for You
Principle Scheme of Excitation

7
TYPES OF EXCITERS
Principle

Scheme

of

Excitation
 Exciter
 Provides DC power to the generator field winding
 Regulator
 Processes and amplifies input control signals to a
level and form appropriate for control of the
exciter
exciter
 Terminal voltage transducer and load
compensator
compensator
 Senses generator terminal voltage, rectifies and
filters it to DC quantity and compares with a
reference
eBook for You
Principle Scheme of Excitation
8
TYPES OF EXCITERS
Principle

Scheme

of

Excitation
 Power system stabilizer
 Provides additional in
p
ut si
g
nal to the re
g
ulator to
pg g
damp power system oscillations
 Limiters and protective circuits
 Wide array of control and protective functions
which ensure that the capability limits of the
exciter and the generator are not exceeded
exciter

and

the

generator

are

not

exceeded

eBook for You
Types of Excitation Systems
9
TYPES OF EXCITERS
Types

of

Excitation

Systems
 DC excitation systems
 Utilize a direct current generator with a
commutator as the source of excitation system
p
owe
r
p
 AC excitation systems
 Use an alternator and either a stationar
y
or
y
rotating rectifiers to produce the DC current
needed for the synchronous machine field
 ST excitation systems

Excitation power is supplied through transformers

Excitation

power

is

supplied

through

transformers

or auxiliary generator windings and rectifiers
eBook for You
DC Excitation Systems
10
TYPES OF EXCITERS
DC

Excitation

Systems
 Utilize DC generators as source of power
 Represent early systems (from 1920s to
mid 1960s)

S d db AC dST it

S
uperse
d

e
d

b
y
AC
an
d

ST
exc
it
ers
 Many are still in service and therefore
itb dld
requ
i
re
t
o
b
e mo
d
e
l
e
d
eBook for You
DC Excitation Systems
11

TYPES OF EXCITERS
DC

Excitation

Systems
 Advantages
 Less dependent on voltage oscillations
 Require a small transformer
 Drawbacks
 Very slow response time
 Small amplification of control signals

Uf
li i
d
tt
hi h i

U
se o
f
s
li
pr
i
ngs an
d
commu
t

a
t
o
r
w
hi
c
h
requ
i
re
maintenance
eBook for You
DC Excitation Systems
12
TYPES OF EXCITERS
DC

Excitation

Systems

IEEE recommended excitation system

IEEE

recommended

excitation

system

models represent the exciter by the
following block diagram and nonlinear
function S
e
eBook for You
DC Excitation Systems
13
TYPES OF EXCITERS
DC

Excitation

Systems

The saturation function S
is a design

The

saturation

function

S
e
is

a

design

characteristic of the exciter and is
specified by the two values S
e
(E
1
) and
e
1
S
e
(E
2
)
eBook for You
DC Excitation Systems
14
TYPES OF EXCITERS
DC

Excitation

Systems

The field voltage values E
1
and E
2

should

The

field

voltage

values

E
1
and

E
2

should

normally be chosen near the knee of the
exciter’s magnetization curve and near
the exciter ceiling
eBook for You
DC Excitation Systems
15
TYPES OF EXCITERS
DC

Excitation

Systems

Amplifiers

Amplifiers
 In order to automatically control the terminal
voltage of the machine, a transducer voltage
must be compared to a reference voltage and
amplified to produce the exciter input signal V
R
eBook for You
DC Excitation Systems
16
TYPES OF EXCITERS
DC

Excitation

Systems
 Stabilizers
 In order to achieve the desirable dynamic
performance and to shape the regulator
response a stabilizing circuit is used by a series
response
,
a

stabilizing

circuit

is

used

by

a

series

transformer whose input is connected to the
output of the exciter and its output is subtracted
from the amplifier input
eBook for You
DC Excitation Systems
17
TYPES OF EXCITERS
DC

Excitation

Systems
 Type DC1A
eBook for You
DC Excitation Systems
18
TYPES OF EXCITERS
DC

Excitation

Systems
 Separately excited exciter (requires a
“ilt” it t t
“
p
il
o
t”
exc
it
er = separa
t
e permanen
t

magnet DC machine)
eBook for You
DC Excitation Systems
19
TYPES OF EXCITERS
DC

Excitation

Systems
 Shunt-excited exciter (self-excited
it )
exc

it
er
)
eBook for You
Automatic Calculation of DC Exciter
20
TYPES OF EXCITERS
Parameters

Specif
K
and control so rce range as

Specif
y
K
e
and

control

so
u
rce

range

as

constants without adjustable field

resistance (Westinghouse excitation
resistance

(Westinghouse

excitation

systems)

Allow
K
e
and control source range to be

Allow

K
e
and

control

source

range

to

be

calculated by activity STRT to recognize
slow reset adjustment of field resistance
(GE-built DC exciter systems)
eBook for You
Automatic Calculation of DC Exciter
21
TYPES OF EXCITERS
Parameters

E citation s stem models ith a tomatic

E
x
citation

s
y
stem

models
w
ith

a
u
tomatic

calculation of DC exciter parameters
eBook for You
Automatic Calculation of DC Exciter

22
TYPES OF EXCITERS
Parameters

Calc lation of V
the normali ed

Calc
u
lation

of

V
RMAX
the

normali
z
ed

control source maximum output

Set the CON specifying V
to zero and the

Set

the

CON

specifying

V
RMAX
to

zero

and

the

model will compute V
RMAX
and set the CON to
this value
 When the CON containing K
e
is zero or negative
 When the CON containin
g
K
e
is
p
ositive
g
e

p
 V
RMIN
is set to - V
RMAX
eBook for You
Automatic Calculation of DC Exciter
23
TYPES OF EXCITERS
Parameters

Calc lation of
K

Calc
u
lation

of

K
e
 Set the CON specifying K
e
to zero and the model
will compute
K
e
but will not set the CON to this
will

compute

K
e
but

will

not

set

the

CON

to

this

value
 K
e
is set to the value that will require a voltage
regulator output of (V
/10) to maintain the present
regulator

output

of

(V
RMAX
/10)

to

maintain

the

present

value of excitation voltage E
fd
eBook for You
Automatic Calculation of DC Exciter
24
TYPES OF EXCITERS
Parameters

Notes

Notes
 V
RMAX
may usually be treated as a constant for a
given machine after it is determined for one

given

machine

after

it

is

determined

for

one

typical loading condition
 K
e
is a variable that depends on the initial
di i l f
E
dh h
con
di
t
i
on va
l
ue o

f

E
fd
an
d

h
ence on t
h
e
generator loading condition

The value of V
RMAX
estimated will not necessarily

The

value

of

V
RMAX
estimated

will

not

necessarily

produce the required excitation system response
ratio. It may have to be adjusted following the
use of the excitation system response ratio test
use

of

the

excitation

system

response

ratio

test
eBook for You
Automatic Calculation of DC Exciter
25
TYPES OF EXCITERS
Parameters

Recommended application of these

Recommended

application

of

these

automatic parameter estimation options:

Use automatic determination of V
only once

Use

automatic

determination

of

V
RMAX
only

once

in activity STRT, before executing ESTR and
ERUN, to obtain an initial estimate of V
RMAX
 The value of the CON specifying V

RMAX
should
be nonzero and should have the value
determined in the previous step
determined

in

the

previous

step
 Use automatic determination of K
e
in all normal
initialization of dynamic cases
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