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
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 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


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

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
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Principle Scheme of Excitation
8
TYPES OF EXCITERS
Principle

Scheme


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

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

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



design

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

Excitation

Systems

The field voltage values E
1
and E
2

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

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

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


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


p
 V
RMIN
is set to - V
RMAX
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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


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

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


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