Phần 20 KHÓA ĐÀO TẠO TÍNH TOÁN ỔN ĐỊNH VÀ ỨNG DỤNG TRÊN PHẦN MỀM PSSE CHO KỸ SƯ HỆ THỐNG ĐIỆN (Nghiên cứu ứng dụng Ổn định dài hạn trên Phần mềm PSSE)

TRANSMISSION &
DISTRIBUTION
A Division of Global Power
POWER SYSTEM STABILITY CALCULATION TRAINING
D9
Aliti fL
T St bilit
D
ay
9
-
A
pp
li
ca
ti
on o
f

L
ong-
T
erm
St
a
bilit
y
July 16, 2013Prepared by: Mohamed El Chehaly
OUTLINE
2
OUTLINE

• Long-Term Stability in PSS®E
• Long-Term Frequency Stability
3
LONG-TERM STABILITY IN
PSS®E
PSS®E
Long
Term Stability
4
LONG-TERM STABILITY IN PSS®E
Long
-
Term

Stability

Si l ti ti i f

Si
mu
l
a
ti
on
ti
mes rang
i
ng
f
rom many

seconds to several minutes
 The need to model additional effects not
normally considered in stability runs of
normally

considered

in

stability

runs

of

several seconds
 Computer time requirements would be
excessive
excessive
Long
Term Stability
5
LONG-TERM STABILITY IN PSS®E
Long
-
Term

Stability
 If simulation time is extended to several
d

secon
d
s
 Tendency of loads to exhibit constant power
characteristics through tap changers
characteristics

through

tap

changers
 Automatic switching of reactors and shunt
capacitors
 Primary movers power changes through primary
speed control and/or AGC (automatic generation
control) and
excitation limiters
control)

and

excitation

limiters
 Detailed modeled of load restoration mechanisms
and prime mover characteristics (boiler effects,
exhaust temperature effects on gas turbine…)
Extended Term Module
6

LONG-TERM STABILITY IN PSS®E
Extended

Term

Module

Additi l d l th t h t b

Additi
ona
l
mo
d
u
l
e
th
a
t

h
as
t
o
b
e
purchased

Includes the following:


Includes

the

following:
 Augmentation of most equipment models
containing state variables to include an implicit
containing

state

variables

to

include

an

implicit

integration algorithm technique for use in
performing extended term simulations

Th bilit t h th i l ti ti t

Th
e a
bilit

y
t
o c
h
ange
th
e s
i
mu
l
a
ti
on
ti
me s
t
ep
during the simulation

Several additions to the model library

Several

additions

to

the

model

library
On
load Tap Changer OLTC1
7
LONG-TERM STABILITY IN PSS®E
On
-
load

Tap

Changer

OLTC1

Mdlf th t f t dj t t

M
o
d
e
l

f
or
th
e
t
rans

f
ormer
t
ap a
dj
us
t
men
t
s
to help control system voltage

Two main components:

Two

main

components:
 Voltage sensor: if the voltage input is out of the
specified bandwidth, the control will operate after
specified

bandwidth,

the

control

will

operate

after

the time delay has been exceeded
 Time delay circuit: enables the transformer to
tlth lt iti thtitf
correc
t
on
l
y
th
ose vo
lt
age var
i
a
ti
ons
th
a
t
ex
i
s
t

f

or
longer than a preset time
On
load Tap Changer OLTC1
8
LONG-TERM STABILITY IN PSS®E
On
-
load

Tap

Changer

OLTC1

Ti d l 30 d

Ti
me
d
e
l
ay =
30
secon
d
s
On
load Tap Changer OLTC1

9
LONG-TERM STABILITY IN PSS®E
On
-
load

Tap

Changer

OLTC1

MdlOLTC1t i l l

M
o
d
e
l

OLTC1

t
yp
i
ca
l
va
l
ues

On
load Phase Shifter OLPS1
10
LONG-TERM STABILITY IN PSS®E
On
-
load

Phase

Shifter

OLPS1

Mdlf th t ti t ft

M
o
d
e
l

f
or
th
e au
t
oma
ti
c movemen

t
o
f

t
aps
on phase-shifting transformers to control
the power flow
the

power

flow

Same two components as OLTC1

Same

two

components

as

OLTC1

Only difference is that the input is real

Only

difference

is

that

the

input

is

real

power instead of voltage
On
load Phase Shifter OLPS1
11
LONG-TERM STABILITY IN PSS®E
On
-
load

Phase

Shifter

OLPS1

M d l OLPS1 t i l l


M
o
d
e
l

OLPS1

t
yp
i
ca
l
va
l
ues
Maximum Excitation Limiters MAXEX1
12
LONG-TERM STABILITY IN PSS®E
Maximum

Excitation

Limiters

MAXEX1

Di dt ttth tfild


D
es
i
gne
d

t
o pro
t
ec
t

th
e genera
t
or
fi
e
ld

with automatic excitation control from
overheating due to prolonged
overheating

due

to

prolonged

overexcitation

Overexcitation
can be caused either by a

Overexcitation
can

be

caused

either

by

a

failure of a component of the voltage
regulators of an abnormal system
condition
Maximum Excitation Limiters MAXEX1
13
LONG-TERM STABILITY IN PSS®E
Maximum

Excitation

Limiters

MAXEX1

I ti h t i ti f MAXEX1

I
nverse
ti
me c
h
arac
t
er
i
s
ti
cs o
f

MAXEX1
Maximum Excitation Limiters MAXEX1
14
LONG-TERM STABILITY IN PSS®E
Maximum

Excitation

Limiters

MAXEX1


Bl k Di f MAXEX1

Bl
oc
k

Di
agram o
f

MAXEX1
Maximum Excitation Limiters MAXEX1
15
LONG-TERM STABILITY IN PSS®E
Maximum

Excitation

Limiters

MAXEX1

M d l MAXEX1 t i l l

M
o
d
e
l

MAXEX1

t
yp
i
ca
l
va
l
ues
Steam Turbine and Boiler TGOV5
16
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5

Rt tiiht

R
epresen
t
s governor ac
ti

on, ma
i
n, re
h
ea
t

and low-pressure effects, including boiler
effects
effects

Can handle any mode of control including

Can

handle

any

mode

of

control

including

coordinated, base, variable pressure and
co
nv

e
n
t
i
o
n
a
l
co e t o a
Steam Turbine and Boiler TGOV5
17
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5

Gdl

G
overnor mo
d
e
l

 Similar to IEEEG1 model

Valve has rate limits as well as minimum and

Valve

has

rate

limits

as

well

as

minimum

and

maximum limits
 Steam flow is
p
ro
p
ortional to the
p
roduct of the

pp p
throttle pressure and the valve area
 Proper selection of time constants and gains
allows the modeling of the
reheater
and
allows

the

modeling

of

the

reheater
and

intermediate and low pressure turbine effects
Steam Turbine and Boiler TGOV5
18
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5

Fl dbil dl

F
ue
l
an
d

b
o
il
er mo
d
e
l
s
 Drum pressure (P
D
) is proportional to the integral
of steam generation less steam flow out of the
of

steam

generation

less

steam

flow

out

of

the

boiler
 Throttle pressure (P
T
) is equal to drum pressure
less a pressure drop across superheaters and
steam leads

The pressure drop varies as square of steam flow

The

pressure

drop

varies

as

square

of

steam

flow

and with density of steam
 The pressure drop coefficient is shown to be a
function of boiler pressure
Steam Turbine and Boiler TGOV5
19
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5
Steam Turbine and Boiler TGOV5
20
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5

Ctiltl

C
onven
ti
ona
l
con
t
ro
l
 Boiler follow mode: changes in generation are
initiated by turbine control valves
initiated

by

turbine

control

valves
 Boiler controls respond with necessary control
action upon sensing the changes in steam flow

and deviations in pressure
 The turbine has access to the stored energy in the
boiler
boiler

 Load changes within reasonable magnitudes with
fairly rapid response
Steam Turbine and Boiler TGOV5
21
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5

Tbi fll

T
ur
bi
ne
f
o
ll
o

w
 Use of the turbine control valves to regulate boiler
pressure
pressure
 Can be done without time delay
 Boiler
p
ressure suffers virtuall
y
no transient
py
deviations
 Stored energy in the boiler is not used

St fl th h th t bi d t bi

St
eam
fl
ow
th
roug
h

th
e
t
ur
bi
ne an

d

t
ur
bi
ne power
follows closely the amount of steam generation

The response of turbine power is considerably

The

response

of

turbine

power

is

considerably

slower than conventional control
Steam Turbine and Boiler TGOV5
22
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5
 Coordinated optimal
 Recognize the advantages of the conventional and
turbine follow modes

Compromise between the desire for fast response

Compromise

between

the

desire

for

fast

response

to load changes and the desire for boiler safety
and good quality control of steam conditions
 New demand signal modified by frequency

deviation to develop the desired MW. Comparison
with actual out
p
ut develo
p
s MW erro
r
pp
 Turbine-speed changer position is directed to
reduce a combination of MW error and pressure
t
error
t
o zero
Steam Turbine and Boiler TGOV5
23
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5

Vibl

V

ar
i
a
bl
e pressure
 The pressure set point is proportional to MW
demand
demand
 The pressure error between set point and actual
throttle pressure drives steam generation
 No coupling occurs between the demand signal
and the turbine control valve position
Steam Turbine and Boiler TGOV5
24
LONG-TERM STABILITY IN PSS®E
Steam

Turbine

and

Boiler

TGOV5
 Typical data for TGOV5
Underfre
q
uenc
y
Load Sheddin

g

25
LONG-TERM STABILITY IN PSS®E
qy g
Models (LDSH)

LDSH type models

LDSH

type

models
 LDSHBL: loads at a specific bus

LDSHOW: loads with a specific owner

LDSHOW:

loads

with

a

specific

owner
 LDSHZN: loads in a specific zone

 LDSHAR: loads in a specific area
 LDSHAL: all loads
 Represent solid-state type load-shedding
relays based on low frequency
 Disconnect either a fraction of load or sets
fl t it h li it
fl
ags
t
o sw
it
c
h

li
nes, capac
it
ors…