modelling of generator trains in pscad/emtdc€¦ · 12x12702 an 01.12.40 project memo memo...
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1SINTEF Energy Research
Project memo AN 01.12.40
Modelling of generator trains in PSCAD/EMTDC
2SINTEF Energy Research
Objectives
Test and describe models of generator trains such that these are easily available for future studies in the projectStudy of generator train modelling in generalStudy and test of PSCAD / EMTDC simulation software models in particularFocus on models suitable for studies of:
weak, possible autonomous, power systemsDiesel or gas-turbine generator trains connected to large power electronic converter loads or connected to other converters connected power sources.
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Models described in memo
Generator modelsExciter modelsDiesel engine modelsGas turbine modelsSpeed governor modelsDynamic shaft models
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Simple exciter modelAlternative to the standard IEEE based models in PSCAD/EMTDCTransparent (no hidden details)
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Diesel engine (Level 1 model)
z
(fuel command) Tm (Torque)
KD DD sJB +
1
wm (mech. angluar
veloc.)
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Diesel engine (Level 4 model)
z (fuel
command)
Tm (Torque)
*
look-up table KD = f (Pm)
*
DD sJB +1
wm (mech. angluar veloc.)
Pm (Power)
Minimum
TsT+11
NT ”Turbo charger
speed” look-up table zmax = f (NT)
zmax (Max. usable fuel injection)
FIsT+11
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Inclusion of torque ripple in diesel engine model (level 1 model)
θm (rad)
Tm (Torque)
wm (rad/s)
z (fuel command) KD
DD sJB +1
wm (mech. angluar veloc.)
+
+
s1
Kw,pu
wm (p.u.)
Look-up table TR = f(z, θm) TR
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Speed governor model with droop
Pout,gen (Output power of
generator)
-
Kdroop
wref (speed ref.)
PID
Max: 1.0Min: 0.0
z (fuel
command)
wmeasure
+
- Time lag / filter
d/dt limiter
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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 governorTemperature limit controllerFuel injection system and turbine time constantsMechanical system (inertia and mechanical damping)Acceleration control
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Gas turbine model (excl. mechanical inertia and mechanical damping)
Texhaust
PID
Max: 1.0 Min: -1.0
Tturb (turbine mech. torque)
w (turbine speed)
+ - Time lag(fuel sys.)
VMax VMin
wref (speed ref.)
Time lag (thermal)
Low value select
Time lag(turbine)
-
+
Load limit controller
Tmax
Gain
+
+
Fuel command
From acceleration controller
+*+
-
+1.0
* 0.5
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Possible realisation and modelling of acceleration controller
Ts1
Max: >1.0Min: 0
Typical: T = 0.01
Acceleration limit (typ.: 0.1p.u / sec)
-+
w (speed)
Tdss
+1 +To low valueselect block
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Example:
Diesel-generator train
Untitledno name
3 6 9 12 15 18+0.985
+0.991
+0.997
+1.003
+1.009
+1.015w
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3 6 9 12 15 18-0.05
+0.05
+0.15
+0.25
+0.35
+0.45PGen (p.u.) QGen (p.u)
no name
+1.12
+1.4If
Time (sec)
3 6 9 12 15 18 +0
+0.28
+0.56
+0.84
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3 6 9 12 15 18 -1
-0.6
-0.2
+0.2
+0.6
+1Ib Ia Ic
- Speed- Power (P , Q)- Field current- Load current
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Example:
Gas turbine generator train
- Speed- Power (P, Q)- Field current- Load current
no name
4 9.2 14.4 19.6 24.8 30+0.95
+0.968
+0.986
+1.004
+1.022
+1.04w
no name
4 9.2 14.4 19.6 24.8 30-0.05
+0.05
+0.15
+0.25
+0.35
+0.45PGen (p.u.) QGen (p.u)
no name
4 9.2 14.4 19.6 24.8 30 +0
+0.28
+0.56
+0.84
+1.12
+1.4If
no name
-0.2
+0.2
+0.6
+1Ia Ib Ic
Untitled
Time (sec) 4 9.2 14.4 19.6 24.8 30 -1
-0.6
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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 convertersThe 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.
12X12702 AN 01.12.40
PROJECT MEMO MEMO CONCERNS
Modelling of generator trains in PSCAD/EMTDC
DISTRIBUTION
SINTEF Energy Research Address: N-7465 Trondheim, NORWAY Reception: Sem Sælands vei 11 Telephone: +47 73 59 72 00 Telefax: +47 73 59 72 50 http://www.energy.sintef.no Enterprise No.: NO 939 350 675 MVA
Magnar Hernes (SINTEF Energiforskning) Nils Arild Ringheim (SINTEF Energiforskning) Kjell Ljøkelsøy (SINTEF Energiforskning) Olve Mo (SINTEF Energiforskning)
AN NO. CLASSIFICATION REVIEWED BY
AN 01.12.40 Åpen Magnar Hernes ELECTRONIC FILE CODE AUTHOR(S) DATE
010808Mo143726 2001-08-08 PROJECT NO.
Olve Mo NO. OF PAGES
12X12702 [email protected] 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.
Energy Research
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12X12702 AN 01.12.40
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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Energy Research
6.1.3 Gas turbine and speed governor............................................................ 40 6.1.4 Generator load....................................................................................... 40 6.1.5 The model ............................................................................................. 40
6.2 Parameters used in the model.............................................................................. 45 6.3 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 PARAMETERS FOR THE EXAMPLES ............................................ 54