class i item no.: 0001-9447 v04 generic user manual
TRANSCRIPT
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Date: 2011-08-22
Issued by: Technology Class: I
Type: Page 2 of 30
Class I
Item no.: 0001-9447_V04
2011-08-22
GENERIC USER MANUAL Simulation model
Version 7
In DIgSILENT PowerFactory®
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Date: 2011-08-22
Issued by: Technology Class: I
Type: Page 3 of 30
DISCLAIMER
VESTAS MAKES NO WARRANTY OR REPRESENTATION EITHER EXPRESS OR IMPLIED IN RESPECT OF
THE POWERFACTORY MODEL, INCLUDING WITHOUT LIMITATION AS TO ACCURACY, COMPLETENESS,
FUNCTIONALILTY, PRECISION, USEFULNESS, FITNESS FOR A PARTICULAR PURPOSE OF THE
POWERFACTORY MODEL OR OTHERWISE. THE POWERFACTORY MODEL IS PROVIDED “AS IS” AND
VESTAS SHALL HAVE NO RESPONSIBILITY OR LIABILITY WHATSOEVER FOR RESULTS OF USE OR
PERFORMANCE OF THE POWERFACTORY MODEL. TO THE MAXIMUM EXTENT PERMITTED BY LAW, IN
NO EVENT VESTAS SHALL BE LIABLE FOR ANY CONSEQUENTIAL DAMAGES, DIRECT, INDIRECT,
SPECIAL, PUNITIVE OR OTHER DAMAGES WHATSOEVER ARISING OUT OF OR IN ANY WAY RELATED
TO THE USE OF OR INABLITY TO USE THE PSS/S MODEL, WHETHER BASED IN CONTRACT, TORT,
NEGLIGENCE, STRIT LIABILITY OR OTHERWISE.
For the avoidance of doubt, Vestas makes no warranty or representation either express or implied as to
the performance of the wind turbine model in terms of it being in accordance with the performance of the
actual wind turbine generator, as other circumstances, including, but not limited to deviations in the
markets and optional features might have influence on the performance of the actual wind turbine
generator. The performance of the wind turbine model is expected only to be indicative to the
performance of the actual wind turbine generator.
Copyright Notice
The documents are created by Vestas Wind Systems A/S and contain copyrighted material,
trademarks, and other proprietary information. All rights reserved. No part of the documents may be
reproduced or copied in any form or by any means—such as graphic, electronic, or mechanical,
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permission of Vestas Wind Systems A/S, and its respective parent companies, subsidiaries, affiliates,
successors, assigns, licensees, representatives and agents (together "Vestas"). The use of these
documents by you, or anyone else authorized by you, is prohibited unless specifically permitted by
Vestas. You may not alter or remove any trademark, copyright or other notice from the documents.
Item no.: 0001-9447_V04
GENERIC USER MANUAL
History of this Document
Date: 2011-08-22
Issued by: Technology Class: I
Type: Page 4 of 30
History of this Document
Rev. no. Date Description of changes
00 2008-08-14 -
01 2009-04-15 Disclaimer and copyright update
02 2009-06-08 Change from Class II to I
03 2010-12-28 Updated to cover more turbines in the generic model structure
Added information about spikes at switching events at LVRT
04 2011-08-22 Updated to cover more turbines in the generic model structure
Table of Contents
1 Introduction .......................................................................................................................... 6 2 Example project ................................................................................................................... 7 3 Static model set-up ............................................................................................................ 10 3.1 WTG PWM converter Data .................................................................................................. 10 3.2 WTG Terminal ..................................................................................................................... 12 3.3 Internal DC node and DC Voltage Source ............................................................................ 12 4 Dynamic model set-up ....................................................................................................... 12 4.1 Bus Voltage Slot .................................................................................................................. 15 4.2 WTG Element Slot ............................................................................................................... 15 4.3 Frequency Measurement Slot .............................................................................................. 16 4.4 PQ Grid Slot......................................................................................................................... 17 4.5 WTG Slot ............................................................................................................................. 18 4.6 External Grid ........................................................................................................................ 19 5 Vestas V80 2MW VCS 50Hz model .................................................................................... 20 5.1 Control Parameters .............................................................................................................. 20 5.2 Model Input Signals ............................................................................................................. 23 5.3 Model Output Signals ........................................................................................................... 24 6 Integration of the model to a user network model ........................................................... 24
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Table of Figures
Date: 2011-08-22
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Table of Figures
Figure 1 - Example project tree and model grid contents ........................................................................ 7
Figure 2 - Terminal and Point-terminal graphic elements ........................................................................ 8
Figure 3 - WTG Static Element with Vestas-defined Symbol................................................................... 8
Figure 4 - Vestas Frame Version 7 ....................................................................................................... 13
Figure 5 - ―Frame WTG Vestas V80‖ Composite model: location in the example project tree ............... 14
Figure 6 - ―Frame WTG Vestas V80‖ Composite model: contents and edit dialog window .................... 15
Figure 7 - Vestas V80 2.0 MW 50Hz Model Dialog ............................................................................... 18
Figure 8 - Event Definition Page ........................................................................................................... 21
Figure 9 - Unit Trip Events Definition .................................................................................................... 22
Figure 10 - User Project and Grids ....................................................................................................... 25
Figure 11 - User Grid ............................................................................................................................ 26
Figure 12 - User Grid (Detail)................................................................................................................ 27
Figure 13 - WTG Composite Model ...................................................................................................... 28
Figure 14 - Connection of grids "Part 1" and "Vestas V80 2MW VCS 50Hz" ......................................... 29
Figure 15 - Load Flow Results with WTG Model ................................................................................... 30
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GENERIC USER MANUAL
Introduction
Date: 2011-08-22
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1 Introduction
This document provides guidelines for the user to include the Vestas WTG dynamic simulation models in a network model, using the DIgSILENT PowerFactory® software tool.
This user manual refers to model version 7 and makes reference to the example project “Vestas V80 2MW VCS 50Hz”. This example contains the WTG model set-up for load flow and dynamic simulation, using the single machine – Infinite Bus network model.
The Vestas type specific simulation model is provided along with this document to be used as a tutorial and for the user to import the WTG model to other projects in DIgSILENT PowerFactory® software tool.
The WTG model may be used both for steady state analysis purposes (Load Flow and other related calculations), and for dynamic stability studies with a time range in excess of 10 seconds. The model supports aggregation of wind turbines in order to simulate a whole wind park with a minimum number of individual elements. The model not only simulates the response of the WTG to changes in the grid voltage and frequency, but can also initiate disconnections of the WTG groups according to its defined protection criteria.
The model is intended to be linked to a static network element representing the current/power injection of the WTG group to the grid. For this purpose, a PWM converter element (ElmVsc) is used in association with the dynamic model.
DIgSILENT GmbH developed this implementation based on a model description provided by VESTAS.
This model has been developed for PowerFactory® version 14.
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Example project
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2 Example project
The single machine – Infinite Bus network model provided in the simulation model file
consists of two separate grids:
- ―Grid‖ represents a generic external grid - ―WTG VXX contains the Vestas WTG model.
This set-up facilitates the creation of remote system stages to include the WTG model into
the user’s existing grid models.
Two separate library folders are provided in the network model. The library folder ―Vestas
Library‖ contains the DSL model and frame specific to the WTG model are stored.
Figure 1 indicates the elements in the example project tree.
Figure 1 - Example project tree and model grid contents
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Example project
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The static element selected for this example to represent the WTG group in a network model
is the ―PWM-converter‖-Element, which allows for various modes in load flow setup. This
model behaves like a controllable current source in dynamic simulation. Such PWM-
converter element will be connected to a node/busbar representing the WTG terminal. The
terminal can be alternatively represented in the graphic by means of a point-terminal graphic element, as shown in Error! Reference source not found..
Figure 2 - Terminal and Point-terminal graphic elements
The PWM-converter element graphic symbol can be changed by a Vestas-defined symbol,
so that the element will look as shown in Figure 3.
Figure 3 - WTG Static Element with Vestas-defined Symbol
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Example project
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The procedure to change the symbol is quite straightforward:
- Multi-select the PWM converter, DC node and DC voltage source.
- Right-click the selection.
- On the pop-up menu, select ―Group as new symbol‖.
- Select the symbol ―VestasWTGcomp‖ on the menu appearing.
- Press ―OK‖.
The data needed for setting up the PWM converter, internal DC node and internal DC
voltage source elements will be described in the following chapter.
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Static model set-up
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3 Static model set-up
3.1 WTG PWM converter Data
For the set-up of the PWM-Converter element, some issues have to be considered:
- WTG General Settings, Rated AC Voltage: This value should be equal to the AC
terminal voltage of the WTG, in this case 0.69 kV.
- WTG General Settings, Rated DC Voltage: This value corresponds to the rated
voltage of the internal DC node, in this case 1.0 kV.
- WTG General settings, Rated Power: this value must be equal to the rated power of
the WTG units group, i.e., if the rated power of a single WTG is 2.0 MVA, and a
group of 5 units is represented, the Rated Power of the PWM must be 5*2.0 = 10.0
MVA
- WTG General Settings, Short circuit impedance: This value can be set to 5%.
- WTG General Settings, Modulation: Sinusoidal PWM.
- WTG control mode: in the load flow edit dialog, the control mode for the WTG
element should be set to P, Q mode, in order to define both the active and reactive
setpoints of the element.
- WTG active power setpoint: The PWM element must represent an active power
injection to the grid. The desired total output active power of the WTG group should
be defined in the load flow edit dialog of the PWM converter, in the field active power
setpoint. (Example: if 4 units are considered to be in the group, and generation of 1.5
MW per each machine is desired, the PWM element active power operating point
should then be 4*1.5 = 6.0 MW.)
- WTG reactive power setpoint: The PWM element must represent a positive or
negative reactive power injection to the grid. The desired total output reactive power
of the WTG group should be defined in the load flow edit dialog of the PWM
converter, in the field reactive power setpoint. (Example: if a single unit is considered
to be in the group, and absorbing 0.2 MVar in under-excited operation, the PWM
element reactive power operating point should then be -0.2 MVar).
In the example grid, the output of the WTG group is set to 2.0 MW / 0 MVar (power factor
=1). At this point in time, no specification has been made concerning the number of units
in the group, so that the load element could either represent a single unit at full load, or,
for example, two units at 50% load.
The user will be warned if they introduce P reference values in the load element over the capability limits defined in the DSL WTG model. The limits are defined by the parameter Nunits (see Chapter 5) and the following message will be shown in the output window when calculating initial conditions:
DIgSI/pcl - message: Warning: WTG initialized at P>1
In the same manner, if Q reference value is out of the capability limits defined by parameter Nunits and beyond the V80 2MW VCS 50Hz PQ capability chart (found in standard product documentation) the following message will be shown:
DIgSI/pcl - message: Warning: WTG Q limits exceeded
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Static model set-up
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After executing the ―Calculate Initial Conditions‖ command, the following text messages will appear in the display window as a result of the successful initialization of the model:
DIgSI/info - Derivative of a not equal 0!
DIgSI/info - Derivative of b not equal 0!
DIgSI/info - Derivative of vd_dynamic not equal 0!
DIgSI/info - Derivative of vq_dynamic not equal 0!
DIgSI/info - Derivative of xRateLimiter not equal 0!
DIgSI/info - Derivative of xRdummy not equal 0!
DIgSI/info - Derivative of xlvrtprot not equal 0!
DIgSI/info - Derivative of xril not equal 0!
DIgSI/info - Derivative of xusuago not equal 0!
DIgSI/info - (t=-02:000 s) Initial conditions calculated
When running the simulation the user will get similar DSL messages as the simulation model enters different control modes, timers and limiters being activated etc. These messages can be used to monitor the state of the model during dynamic events.
The reactive power output of the model in dynamic LVRT simulations sometimes can show small spikes after fault insertion and right after fault clearance. These spikes are due to the fact that no time delays are considered in the model for voltage measurements or for enabling AGO2 in the WTG. Due to the numerical properties of the PowerFactory® solution algorithm, enabling AGO2 and fault insertion/removal is not always executed simultaneously and hence, these small spikes in reactive power can occur. These spikes are a numerical artefact and do not represent the real performance of the WTG.
As the simulation model is a reduced model and applies switched logics during LVRT the user might get the following warning on non-convergence during such a switched event. By reducing the simulation integration step size these warnings and the derived spikes in simulation results can be mitigated. In general short spikes <10ms after switching operations do not necessarily reflect the real turbine behavior. In general a simulation integration step size of 1 ms or less is recommended.
DIgSI/wrng - (t=801:000 ms) No convergence in iteration-loop
These warnings do not bring the general stability of the model, or the general validity of the results into question.
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Dynamic model set-up
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3.2 WTG Terminal
To represent the stator terminal of the WTG, either a terminal bus element or a station bus
element can be used. In this case, a bus terminal has been used. The only parameter
needed for this element is the nominal voltage, which must be equal to the rated WTG
voltage in kV (0.69 kV).
3.3 Internal DC node and DC Voltage Source
The nominal voltage of the DC node and DC source should be compatible with the voltage
defined as the Rated DC voltage of the PWM Converter.
4 Dynamic model set-up
In order to connect the WTG dynamic model to the network element representing the WTG
power injection to the grid, a model frame (composite model) is needed. Figure 4 shows the
use of the frame.
This frame can be found in the project library folder ―Vestas Library‖, sub-folder ―Frame‖
under the name ―Vestas Frame Version 7‖.
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Vestas Frame Version 7:
WTG Converter ElementWTG Model
PowerMeasurement
Stator Frequency Measurement
Stator Voltage Measurement
Qgrid
Pgrid
Frequency measurementElmPhi*,ElmPll
0
1
2
WTGmodelElmV*
Pset
Reactive_ref
0
1
2
3
4
5
0
1
6
7
PQ gridStaPqmea
0
1
Bus VoltageStaVmea*
0
1
2
WTGelementElmVsc*
0
1
2
3
Vestas Frame Version 7:
sinr
e.. co
sre.
.
ur
ui
us
f
iq_ref
id_ref
DIg
SIL
EN
T
Figure 4 - Vestas Frame Version 7
A composite model element, named ―Vestas Frame v7‖ has been created in the grid ―WTG V80‖ from the frame in Figure 4. Its content and edit dialog are shown in Figure 6 and Figure 6.
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Figure 5 - “Frame WTG Vestas V80” Composite model: location in the example project tree
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Figure 6 - “Frame WTG Vestas V80” Composite model: contents and edit dialog window
Each one of the elements needed by the composite model will be discussed in the next
sections.
4.1 Bus Voltage Slot
The slot identified as ―Bus Voltage‖ contains the element representing the measurement of
generator terminals voltage. The element used for this purpose will be a ―Voltage
Measurement‖ element (element StaVmea) and is stored inside the Composite Model folder.
This slot will provide the stator voltage in p.u. of the unit rated voltage (variables us, ur, ui).
4.2 WTG Element Slot
This slot contains the PWM Converter element (ElmVscmono) representing the WTG in the
grid. Since this element is external to the composite model, the selection has been made by
right-clicking the corresponding field. The WTG dynamic model will feed to this element the
required active and reactive reference currents (WTG dynamic model output variables id
and iq).
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4.3 Frequency Measurement Slot
This slot contains an element providing the stator frequency in Hz for use of the WTG
dynamic model (variable “f”), and the voltage reference angle to the PWM element (PWM
converter input variables cosref and sinref). The element foreseen for the purpose is a
―Phase Measurement Device PLL_Type‖ (ElmPhi_pll), and has been created inside the
composite model itself, so that the selection can be made simply by clicking the ―Slot
Update‖ button in the composite model edit dialog.
This element mimics a frequency/angle measurement device, and it is to be preferred rather
than obtaining the frequency directly from the bus, since in the latter case, discontinuities in
the grid will appear as ―spikes‖ in the frequency values.
In this element, the measurement point must be defined: in this case, the WTG terminal.
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4.4 PQ Grid Slot
This slot contains an element providing the feedback active and reactive power measurements from the static element representing the WTG to the dynamic model (variables Pgrid and Qgrid). For this purpose, a ―PQ measurement‖ (ElmStaPqmea) element is needed.
In the example project, for this element, the measurement point of the active and reactive power injected to the grid is left blank in the PQ measurement element dialog, being such measurement point the cubicle where the element is stored (the cubicle to which the WTG PWM converter element is connected). The Power Rating of the element should be set to 1 MVA, and the measurement should be ―Generator oriented‖, so to compensate for the inverse sign convention of the load element.
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4.5 WTG Slot
This slot contains the actual simulation model for the specific Vestas wind turbine, and therefore is the key element for the overall WTG model set-up. The ―Common Model‖ element (ElmDsl), named ―Vestas V80-2.0 MW 50Hz‖ has been created inside the composite model folder from the DSL model with the same name that can be found in the library folder ―Vestas Library‖, sub-folder ―WTG Model‖. The input and output signals, as well as the parameter needs for this model will be described in detail in chapter 5. Figure 7 shows the edit dialog for the common model element of the Vestas WTG, as it can be found in the composite model ―WTG V80-2.0 MW VCS 50 Hz.
Figure 7 - Vestas V80 2.0 MW 50Hz Model Dialog
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4.6 External Grid
The WTG model must be connected to a grid model.
The example provided presents, as stated before, a single unit-Infinite Bus system. The external grid, identified simply as ―Grid‖ in the example, is composed of:
- External network element (ElmXnet). Since the External network must represent an infinite bus, its acceleration time constant has been defined as ―very large‖ (9999 s). The MVA rating has been set at 1000 MVA, and the R/X ratio at 0.1, but these two last parameters can be set at other values representing the conditions at the point of common coupling (PCC).
- HV connection bus for the WTG (HV Bus, ElmTerm). The HV bus representing the high voltage connection point (PCC) of the WTG has been set with a nominal voltage of 33 kV
- Step-up transformer. ―Grid‖ includes a 2 winding transformer element (ElmTr2), representing the parallel aggregation of nacelle transformers. The example project uses the type ―2-Winding Trafo 33/0_69 kV 2.1MVA Dyn5‖ that can be found in the ―Grid Library‖ Folder. That type definition is based on generic transformer characteristics, and cannot substitute more accurate data available from specific transformer models.
The step-up transformer element can be parameterized in the element edit dialog to represent up to 99 parallel identical units, in the example project it represents 1 unit.
The user can introduce other transformer types corresponding to different MV levels and different transformer characteristics contemplated as options by Vestas specifications.
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Vestas V80 2MW VCS 50Hz model
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5 Vestas V80 2MW VCS 50Hz model
This section presents how to use the Vestas simulation model.
5.1 Control Parameters
This category includes parameters governing the modes of operation of the WTG model.
They are settable by the user according to its specific requirements. Table 1 lists such
parameters. A detailed description is also given in this chapter.
Name Description value units
Nunits Number of Units Conforming the WTG group >=1
ModeSel PF or Q Model selector 1/0
AGO_enable LVRT Functionality Enable/Disable Flag 1/0
Prot_enable Protection Trip Enable/Disable Flag 1/0
Table 1 : “Vestas V80 2MW VCS 50Hz” Model Control Parameters
Nunits:
The model allows aggregation of units in a group. This parameter defines the number of
units in the group. This parameter is set to 1 in the example project.
Mode_Sel:
The reactive power reference for the group of units can be calculated to obtain Defines the
way in which model input signal Reactive_ref (see section 5.2) provides an external power
reference to the model:
- A constant reactive power at the generator (ModeSel = 0).
- A constant power factor (ModeSel = 1).
In the example project, the value of ModeSel is set to 1.
AGO_enable:
The AGO functionality of the model (LVRT conditions detection, switching between power
and current control, and activation of the LVRT Under-voltage protection) is enabled
(AGO_enable = 1) or disabled (AGO_enable = 0) by this user flag. By default, AGO_enable
is set to 1.
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Prot_enable:
This flag allows the user, when set to 1, to activate the actual trip (disconnection) of the unit
group whenever the protection module settings are exceeded. Such disconnection can be
performed locally in the model by defining the appropriate event(s) in the ―Events‖ definition
page of the model dialog. The event(s) must be named ―SwitchGen‖.
An example of this is given in the provided network model. Figure 8 shows the model dialog
event page. It can be seen that three events have been defined in this case.
Figure 8 - Event Definition Page
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Figure 9 - Unit Trip Events Definition
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Figure 9 shows the definition of such events. As it can be seen, the first event (event
―SwitchGen‖, element EvtSwitch), causes the breaker connecting the WTG element to the
grid to open. This event is in principle enough to ensure the disconnection of the unit group.
The second event (event ―SwitchGen(1)‖, element EvtOutage) takes the WTG simulation
model out of service. This last event is not strictly necessary, but it has been included as a
security measure to prevent eventual numerical problems that may arise (but not necessarily
so) when the model is running with its associated element not connected.
It is to be noted that, when the protection trip is disabled by setting the flag Prot_enable to
0, as is the case in the example project, warning messages indicating that protection limits
have been exceeded will nevertheless be issued in the output window.
5.2 Model Input Signals
As from Figure 4, the following input variables and set-points to the model can be identified:
us, ur, ui, f, Pgrid, Qgrid, Pset, Reactive_ref. Of all these, the input variables obtained
from the grid are:
us: Stator voltage in p.u., from the Bus Voltage slot (Stator terminal bus).
ur: Stator voltage (real part) in p.u., from the Bus Voltage slot (Stator terminal bus).
ui: Stator voltage (imaginary part) in p.u., from the Bus Voltage slot (Stator terminal bus).
f: Stator frequency in Hz, from the Frequency Measurement slot (stator terminal bus).
Pgrid: Active Power input in MW (Grid active power feedback from the WTG element), form
the PQ Grid slot.
Qgrid: Reactive power input in MVAR (Grid reactive power feedback from the WTG
element) from the PQ Grid slot.
The set-points for the WTG are automatically defined by the model at initial conditions time
from the power values defined by the user for the WTG load element associated to the
model, and considered to be constant, therefore are not linked to any other slot/model:
Pset: Active power set-point in MW.
Reactive_ref: Reactive power set-point reference, either in MVAR or as Power Factor.
The model will issue warning messages to the output window whenever the initial settings of
active and reactive power defined for the load element exceed the WTG internal constraints.
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5.3 Model Output Signals
From Figure 4 it can be seen that the model has two main output variables, and an auxiliary
one.
The main output variables are:
- id: Active Power reference current to be fed into the PWM converter model to obtain
the desired active power injection to the grid, in p.u.
- iq: Reactive Power reference current to be fed into the PWM converter model to
obtain the desired reactive power injection to the grid, in p.u.
The auxiliary variables are defined as:
- Pgout: WTG active power output to the grid, in p.u. of the WTG. This variable is
used mainly for supervision and testing purposes.
- Qgout: WTG reactive power output to the grid, in p.u. of the WTG. This variable is
used mainly for supervision and testing purposes.
- Trip: Protection trip signal for the unit/group: this variable will initiate the unit/group
disconnection by means of a user-defined event defined locally in the model, as will
be described at a later time, and it is made available for eventual external models.
6 Integration of the model to a user network model
To integrate the hereby presented WTG model to an existing network model, it is not
necessary to create from scratch the previously described elements and models, but, by
creating a remote system stage, this same model in the example network can be included
easily in a large existing network model. The procedure will be illustrated by means of an
example.
We will start from supposing that a user wants to include the V80 2MW VCS 50Hz v6.1.0
model to the project ―User Project‖. The Network in this project consists of two grids, named
―Part 1‖ and ―Part 2‖, activated by the study case ―Case1‖ (see Figure 10).
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
Issued by: Technology Class: I
Type: Page 25 of 30
Vestas Wind Systems A/S · Alsvej 21 · 8900 Randers · Denmark · www.vestas.com
Figure 10 - User Project and Grids
By opening the single-line diagram of the grid ―Part1‖, we can see that a current source is
connected to the bus‖BusBar1‖ of the substation ―Station 4‖, with a nominal voltage of 11 kV.
The Current source is injecting 1.9 MW / 0 MVar. We will suppose now that this current
source is a simplified representation of a WTG that now we need to model in a more detailed
way using the Vestas model, (see Figure 11 and Figure 12), using as WTG element a PWM
converter.
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
Issued by: Technology Class: I
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Figure 11 - User Grid
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
Issued by: Technology Class: I
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Figure 12 - User Grid (Detail)
The first steps are:
- Deactivate the User Project, so to enable the data import.
- Import the file ―Vestas V80 2MW VCS 50Hz‖.
- Activate again the User Project
Once the example project is part of the user data manager tree:
- Right click the ―Vestas V80 2MW VCS 50Hz‖ grid in the ―Vestas V80 2MW VCS
50Hz‖ project.
- Select ―Add to Study Case‖ in the pop-up menu that will appear
A ―remote system stage‖ will appear in the user project‖, called also ―Vestas V80 2MW VCS
50Hz‖. This name may be changed by editing the remote system stage. The contents of the
remote system stage and the WTG composite model current definition are shown in Figure
13.
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
Issued by: Technology Class: I
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Figure 13 - WTG Composite Model
Since all elements of the WTG are contained in the grid ―Vestas V80 2MW VCS 50Hz‖, and
all element and links in the remote system stage are maintained, no further adjustment are
needed in this sense.
Also, a new graphic tab is now present in the original project graphics board, corresponding
to the ―Vestas V80 2MW VCS 50Hz‖ grid single line diagram.
The WTG model is now included in the user’s grid, but it is still not connected to it. To do so,
it is possible, for example, to create in the single line graphics an 11 kV/0.69 kV step-up
transformer connecting the WTG terminal to the ―Station 4/Busbar 1‖ 11 kV busbar, and at
the same time taking out of service the current source. The grids ―Part 1‖ and ―V80 2MW
VCS 50Hz‖ in the user project will now look as in Figure 14.
To finish the integration of the WTG model to the user grid, it is only needed to define (if it
doesn’t already exists in the user library) a type for the step-up transformer, assign it , and
set the WTG Element operating point according to the power injected by the current source.
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
Issued by: Technology Class: I
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Figure 14 - Connection of grids "Part 1" and "Vestas V80 2MW VCS 50Hz"
Grid ‖Part 1‖
Grid ‖Vestas V80 2MW VCS 50Hz‖
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GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
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Figure 15 - Load Flow Results with WTG Model
The WTG model is now fully integrated to the user grid. It is to be noted that, because of the
presence of the transformer, setting the reactive power in the PWM converter at 0 MVar as
in the current source will not result in a 0 reactive power injection to the grid. To obtain the
desired injection at the PCC, the reactive power operating point should be adjusted
accordingly (Q = 0.12 in this case)
Item no.: 0001-9447_V04
GENERIC USER MANUAL
Integration of the model to a user network model
Date: 2011-08-22
Issued by: Technology Class: I
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Aggregated WTG representation
An aggregated WTG group representation can be created by changing accordingly the
following settings:
- Parameter “Nunits” in the WTG model.
- Number of step-up transformers in parallel.
- Rated power of the WTG PWM-Converter Element.
In case that more than one WTG group has to be represented individually, than the WTG
model elements (PWM converter, DC node, DC source elements, Terminal and Composite
model) in the ―Vestas WTG V80 2MW 50Hz‖ grid can be created by ―copy/paste‖ of the
existing WTG element and model.
It must be noted that, when doing so, the contains of the ―WTG Element‖ slot, along with the
measurement point definition of the voltage measurement, phase measurement etc.
elements in the newly replicated composite models, and the events in the WTG models must
be updated, linking all of them to the corresponding new elements and cubicles.
The connection of the so created WTGs to the desired busbar (PCC) can be defined, for
example, as an arrangement of step-up transformers and cables, as per the user
requirements.