Project memo AN 01.12.40
Modelling of generator trains in
PSCAD/EMTDC
SINTEF Energy Research
1
Objectives
„ Test and describe models of generator trains such that
these are easily available for future studies in the project
„ Study of generator train modelling in general
„ Study and test of PSCAD / EMTDC simulation software
models in particular
„ Focus on models suitable for studies of:
„ weak, possible autonomous, power systems
„ Diesel or gas-turbine generator trains connected to large power
electronic converter loads or connected to other converters
connected power sources.
SINTEF Energy Research
2
Models described in memo
„
„
„
„
„
„
Generator models
Exciter models
Diesel engine models
Gas turbine models
Speed governor models
Dynamic shaft models
SINTEF Energy Research
3
Simple exciter model
„ Alternative to the standard IEEE based
models in PSCAD/EMTDC
„ Transparent (no hidden details)
SINTEF Energy Research
4
Diesel engine (Level 1 model)
z
(fuel command)
KD
Tm
(Torque)
1
BD + sJ D
SINTEF Energy Research
wm
(mech. angluar
veloc.)
5
Diesel engine (Level 4 model)
1
1 + sTT
Minimum
z
(fuel
command)
NT
”Turbo charger
speed”
look-up table
zmax = f (NT)
1
1 + sTFI
zmax
(Max. usable
fuel injection)
*
Tm
(Torque)
1
B D + sJ D
wm
(mech.
angluar
veloc.)
look-up table
KD = f (Pm)
Pm
(Power)
*
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6
Inclusion of torque ripple in diesel
engine model (level 1 model)
wm
(p.u.)
Kw,pu
wm
(rad/s)
z
(fuel command)
1
s
θm
(rad)
Look-up table
TR = f(z, θm)
TR
+
KD
Tm
(Torque)
+
1
BD + sJ D
wm
(mech.
angluar
veloc.)
SINTEF Energy Research
7
Speed governor model with droop
wmeasure
wref
(speed ref.)
+
-
Kdroop
Time lag
/ filter
PID
Max: 1.0
Min: 0.0
d/dt
limiter
z
(fuel
command)
Pout,gen
(Output power of
generator)
SINTEF Energy Research
8
Gas turbine models
„ Focused only on generators without cogeneration (i.e.
exhaust is not used for electric power generation)
„ Sub-systems included in model:
„ Speed governor
„ Temperature limit controller
„ Fuel injection system and turbine time constants
„ Mechanical system (inertia and mechanical damping)
„ Acceleration control
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9
Gas turbine model (excl. mechanical
inertia and mechanical damping)
w
(turbine
speed)
1.0
+
-
From
acceleration
controller
+
-
wref
(speed ref.)
Low value
select
PID
Max: 1.0
Min: -1.0
+
+
Load limit
controller
* 0.5
Gain
*
Fuel
command
Time lag
(fuel sys.)
Time lag
(turbine)
VMax
VMin
+
+
Tturb
(turbine
mech.
torque)
Texhaust
Time lag
(thermal)
+
Tmax
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Possible realisation and modelling of
acceleration controller
Acceleration limit
(typ.: 0.1p.u / sec)
w
(speed)
s
1 + Tds
-
+
+
1
Ts
To low value
select block
Max: >1.0
Min: 0
Typical:
T = 0.01
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Example:
Untitled
no name
+1.015
w
+1.009
+1.003
Dieselgenerator
train
+0.997
+0.991
+0.985 3
6
9
12
15
18
12
15
18
12
15
18
15
18
no name
+0.45
PGen (p.u.)
QGen (p.u)
+0.35
+0.25
+0.15
+0.05
-0.05 3
6
9
no name
+1.4
If
+1.12
+0.84
+0.56
+0.28
- Speed
- Power (P , Q)
- Field current
- Load current
+0 3
6
9
no name
+1
Ib
Ia
Ic
+0.6
+0.2
-0.2
-0.6
-1 3
6
9
12
Time (sec)
SINTEF Energy Research
12
Untitled
Example:
no name
+1.04
w
+1.022
+1.004
+0.986
+0.968
Gas
turbine
generator
train
+0.95 4
9.2
14.4
19.6
24.8
30
19.6
24.8
30
19.6
24.8
30
24.8
30
no name
+0.45
PGen (p.u.)
QGen (p.u)
+0.35
+0.25
+0.15
+0.05
-0.05 4
9.2
14.4
no name
+1.4
If
+1.12
+0.84
+0.56
+0.28
- Speed
- Power (P, Q)
- Field current
- Load current
+0 4
9.2
14.4
no name
+1
Ia
Ib
Ic
+0.6
+0.2
-0.2
-0.6
-1 4
9.2
14.4
19.6
Time (sec)
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13
Shaft dynamics can be included
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Conclusions
„ The presented models and the simulation software
PSCAD/EMTDC are suited for studies of interaction
phenomena between generator trains and converters
„ The generator train models are also considered suited in
simulation analysis for optimal design of power converter
control.
„ The conclusion is however (as usual): More problems to
obtain relevant data (parameters) for the system, than to
implement these data in accurate models.
SINTEF Energy Research
15
PROJECT MEMO
MEMO CONCERNS
Energy Research
SINTEF Energy Research
Address:
Reception:
Telephone:
Telefax:
N-7465 Trondheim,
NORWAY
Sem Sælands vei 11
+47 73 59 72 00
+47 73 59 72 50
http://www.energy.sintef.no
Modelling of generator trains in PSCAD/EMTDC
DISTRIBUTION
Magnar Hernes (SINTEF Energiforskning)
Nils Arild Ringheim (SINTEF Energiforskning)
Kjell Ljøkelsøy (SINTEF Energiforskning)
Olve Mo (SINTEF Energiforskning)
Enterprise No.:
NO 939 350 675 MVA
AN NO.
CLASSIFICATION
REVIEWED BY
AN 01.12.40
Åpen
Magnar Hernes
ELECTRONIC FILE CODE
AUTHOR(S)
DATE
010808Mo143726
Olve Mo
2001-08-08
PROJECT NO.
NO. OF PAGES
12X12702
Olve.Mo@energy.sintef.no
59
DIVISION
LOCATION
LOCAL FAX
Energy Systems
Sem Sælands Vei 11
+47 73597250
SUMMARY
This memo presents the results of a study of generator train modelling in general and particularly
implementation of generator train models in the PSCAD/EMTDC simulation software.
The scope is generator train models suitable for studies of weak, possible autonomous, power
systems, where typically a diesel or gas-turbine generator trains is connected to large power
electronic converter loads or to other power sources connected to the power system via
converters.
The models will be especially suited in studies of interaction phenomena between generator trains
and converters, and also as a tool for optimal design of power converter control.
Presented in this memo are:
·
·
·
·
·
·
Generator models
Exciter models
Diesel engine models
Gas turbine models
Speed governor models
Dynamic shaft models
The intention has not been to establish new models of these system components, but rather to
collect and test models presented in literature and in the PSCAD/EMTDC manuals, making them
easily available for further investigation of studies like the one outlined above.
This study has shown that generally the problem is more to obtain relevant data for the system,
than to implement these data in accurate models in PSCAD/EMTDC.
12X12702
AN 01.12.40
2
Energy Research
TABLE OF CONTENTS
Page
SUMMARY ............................................................................................................................... 1
1
INTRODUCTION ............................................................................................................ 4
2
GENERATOR .................................................................................................................. 5
2.1
Generator model.................................................................................................... 5
2.2
Exciter ................................................................................................................... 7
2.2.1
Exciter models in PSCAD / EMTDC ..................................................... 7
2.2.2
Initialisation of the PSCAD/EMTDC exciter models........................... 12
2.2.3
Alternative exciter model...................................................................... 13
2.3
Power system stabilizers ..................................................................................... 14
2.4
Parallel operation of generators .......................................................................... 14
2.5
V/f – control ........................................................................................................ 15
3
DIESEL ENGINES......................................................................................................... 16
3.1
Diesel engine....................................................................................................... 16
3.1.1
Characteristics of diesel engines ........................................................... 16
3.1.2
Level 1 model of diesel engine ............................................................. 16
3.1.3
Level 2 model of diesel engine ............................................................. 17
3.1.4
Level 3 model of diesel engine ............................................................. 18
3.1.5
Level 4 model of diesel engine ............................................................. 20
3.1.6
Inclusion of constant friction torque ..................................................... 23
3.1.7
Inclusion of torque ripple...................................................................... 23
3.2
Speed governor.................................................................................................... 26
3.3
Modifications of speed governor for parallel operation...................................... 26
4
GAS TURBINE .............................................................................................................. 29
4.1
Gas turbine .......................................................................................................... 29
4.2
Modifications of speed governor for parallel operation...................................... 32
4.3
Model parameter extraction from measurements................................................ 32
5
COMPLETE PSCAD / EMTDC MODEL OF A DIESEL GENERATOR TRAIN ..... 33
5.1
Modelling ............................................................................................................ 33
5.1.1
Generator............................................................................................... 33
5.1.2
Exciter ................................................................................................... 33
5.1.3
Diesel engine......................................................................................... 33
5.1.4
Speed governor ..................................................................................... 33
5.1.5
Generator load....................................................................................... 33
5.1.6
The model ............................................................................................. 34
5.2
Parameters used in the model.............................................................................. 36
5.3
Simulated examples for illustration of correct behaviour ................................... 36
5.3.1
Step loading and load rejection............................................................. 36
5.3.2
Terminal short circuit............................................................................ 37
6
COMPLETE MODEL OF A GAS TURBINE GENERATOR TRAIN ........................ 40
6.1
Modelling ............................................................................................................ 40
6.1.1
Generator............................................................................................... 40
6.1.2
Exciter ................................................................................................... 40
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AN 01.12.40
3
Energy Research
6.2
6.3
6.1.3
Gas turbine and speed governor............................................................ 40
6.1.4
Generator load....................................................................................... 40
6.1.5
The model ............................................................................................. 40
Parameters used in the model.............................................................................. 45
Simulated examples for illustration of correct behaviour ................................... 45
6.3.1
Step loading and load rejection............................................................. 45
7
INCLUSION OF SHAFT DYNAMICS ......................................................................... 47
7.1
Modelling of shaft dynamics............................................................................... 47
7.2
Example of simulation including shaft dynamics ............................................... 48
7.3
Parameters used in the model.............................................................................. 51
8
CONCLUDING REMARKS.......................................................................................... 52
REFERENCES ......................................................................................................................... 53
APPENDIX A
12X12702
PARAMETERS FOR THE EXAMPLES ............................................ 54
AN 01.12.40