Tutorial Simulator

Rodito Tutorial - NEPLAN Simulator

Tutorial - NEPLAN Simulator Introduction This module substitutes the Transient Stability PROST, which is described in section Transient Stability and the normal Tutorial.

Input Dynamic Data (Regulators, Control Circuits) In this section, you will learn how you may enter dynamic data like exciters governors, regulators and control circuits (CCT). In NEPLAN you may enter regulators and control circuit in many different ways. Below we show you how to define and enter regulators like exciters and governors in different ways and what are the advantages and disadvantages thereof: • • • •

Entering a NEPLAN predefined standard regulator Entering a user defined regulator with function blocks Entering a user defined regulator with function blocks using a CCT library Entering a user defined regulator as DLL file, written in C++ and modeled with MATLAB • Entering a predefined standard regulator in a “CCT Signal-Block” element • Entering a user defined regulator with function blocks in a “CCT SignalBlock” element • Entering signal connections between regulators and elements with a “CCT Signal-Block” element Please note: The preferred and easiest way to enter a regulator (like exciter, turbine and governor) is using a predefined NEPLAN standard regulator (see below)!

Enter predefined NEPLAN standard regulators

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This is the preferred and easiest way to enter an exciter! You have to insert regulator (e.g. exciter) and the controlled element (e.g. generator) into the network (single line diagram). Then you have to assign the regulator (e.g. exciter) to the element (e.g. generator). Below is a detailed description of how to add an exciter to a generator. 1. Add an exciter graphically. You have to enter the standard regulator just like any other element in the network. You find the regulator symbol in the “Symbol Window -> FACTS/DC/Specials”. 2. Add a generator to the network. 3. You may assign an exciter to a generator in the dialog below with the button “…”. 4. If the exciter is not yet in the network you may add and edit the exciter directly in the synchronous machine dialog. The exciter will then not appear on the single line diagram. You may also add the exciter first graphically (see above).

Fig. 16.1 Generator dialog: Assign a predefined NEPLAN standard exciter to the generator

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Fig. 16.2 Insert graphically a predefined NEPLAN standard exciter

Once again: if a predefined type is available you should use this standard type. These predefined NEPLAN regulator types are optimized for the NEPLAN simulator.

Enter a user defined CCT with function blocks NEPLAN allows entering a user defined CCT in a very comfortable way with the help of a function block editor. Normally you will design this CCT in a separate NEPLAN diagram. A nested CCT element may be entered first. Then you may with the right mouse button directly open the diagram through the popup menu (popup menu item “Subsystem”). 1. Click on the CCT button 2. Click in the diagram near a synchronous machine to enter the CCT. NEPLAN User's Guide V5

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3. 4. 5. 6.

A “CCT” dialog appears. Enter a name for this CCT. Press the OK button. A new diagram will be created. You may now insert your CCT with function blocks. The functions block may be accessed wit menu item “Insert”. 7. You may access the function block diagram directly through the popupmenu by clicking the right mouse button on the CCT element. 8. Remark: “The Select CCT Type” radio button and the “Add CCT Type from Library to Project” button should not be used anymore. For compatibility reasons to earlier NEPLAN versions they are still in the dialog. If you have many CCT with same structure and different parameters in your network you should instead consider to make a MATLAB modeled CCT.

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Fig. 16.3 Insert CCT symbol and create diagram for CCT

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Fig. 16.4 Create a CCT with the NEPLAN function block editor

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Fig. 16.5 Accessing the CCT diagram directly with the popup-menu (right mouse button)

Enter a CCT with function blocks using a predefined library NEPLAN offers a pre-built control circuit library which has been built up with function blocks (note: the library is not available in the demo version). You may make use of this library instead of building up the block diagram from scratch (see above how to create a new CCT and an empty diagram).

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Fig. 16.6 Insert CCT from a CCT NEPLAN library

This is not the preferred option to enter standard regulators like IEEE exciters. The CCT library may help if you have to enter a new CCT which is not in the standard library and therefore you have to define your own regulator. If you have to use the structure of this user defined CCT many times in your networks (e.g. an exciter structure which is used for many generators) you should build up this regulator model with our NEPLAN component modeling tool in MATLAB and generate a user defined DLL model. It is easier to add the regulators in NEPLAN and the overall performance in NEPLAN is better. Generating a CCT with function blocks is the preferred option, if that CCT is used only a few times (about 1-5 times) within the network.

Enter a MATLAB modeled user defined regulator (DLL model in C++) If no standard NEPLAN regulator exists and a regulator has to be used many times in the network, then this would be the preferred way to use regulators in NEPLAN. The regulator has the same structure (same CCT) only the parameters of the regulators (function blocks) differ. The MATLAB defined model may also be used for other components than regulators (e.g. new synchronous machine models, new facts models, special line models, etc.). Therefore this might also be the preferred way for researchers or manufacturers of new devices, who want to build up new control strategies or new devices. 1. Insert the regulator symbol from the symbol window 2. Click the button “Defining User Defined Components with MATLAB” in the regulator dialog. 3. In the dynamic model dialog you have to select (button “…”) the corresponding user defined DLL (dynamic link library) file. This DLL file contains the model, which must have been developed as C++ program. Instead of developing the model in C++ we provide a NEPLAN - MATLAB modeler, which allows the user very easily defining new component models. The DLL file will then be automatically generated by the NEPLAN MATLAB modeler (see separate manual “Defining Models with NEPLAN – MATLAB”). 4. Assign the parameters of the user defined regulator DLL in the dynamic dialog window.

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Fig. 16.7 Insert regulator symbol and insert user defined created C++ model (DLL File)

Enter signal connections between components (regulators and elements) For advanced control systems it is sometimes necessary to define externally interconnection between signals (variables) of components (regulators and/ or elements). An example might be a regulation of a wind farm, where the different controller interacts with each other (voltage controller, pitch controller, speed controller). Another example is a master controller which controls the power output of generators (AGC automatic generation control). Therefore NEPLAN provides an element, which allows interconnecting graphically any signal (variable) of any component (regulators and elements). Together with the possibility of developing new user defined models with the NEPLAN – MATLAB modeler, this allows the user to build up any control strategy within NEPLAN. 1. Insert a “CCT and Signal Block” from the menu item “Insert”. 16-8

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2. In the “Port Selection” tab you may know define the input and output signals (variables). You need to select a variable with the “Port Selection” button. 3. In the “Port/Signal Selection” list you should define which ports/signals are input or output pins. You may also define a pin name, which will be displayed on the single line diagram. Very important is to know if the signal will be used in SI units or in per unit. If the signal will be used in per unit, is very important to know in which per unit system the signal will be used. Normally P, Q and I are used in the “system” per unit system (with 100 MVA as base system). When defining regulators for elements (e.g. exciters) then the corresponding element per unit system (with rated power of the element as base) will be used within the regulator. If you define a master controller with P, Q, I as input, then the “system” per unit system should be used. Therefore NEPLAN provides the possibility to convert the signal to the corresponding per unit system. 4. After you have defined the input/outputs of the element you may connect the “Signal Block” elements with links, like any other element. In the example below there is a “Signal Block” for the DFIG which connects its output variables (P and Q) to the input of the PWM controller. The voltage of the DC node is input to the second PWM controller.

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Fig. 16.8 Enter “CCT and Signal Block” element

Fig. 16.9 Defining ports/signals of the “CCT and Signal Block” element

Enter predefined standard regulators from a “CCT and Signal Block” element Instead of entering a predefined standard regulator (defined in the “Symbol Window”) and then enter a “CCT and Signal Block” element to make the connections between the regulators it is possible to add and define the predefined standard regulator directly in the “CCT and Signal Block” element. This makes only sense if you need to make external connections to other regulators/elements. Otherwise you should select and enter the regulator as described above from the “Symbol Window”. 1. Insert a “CCT and Signal Block” from the menu item “Insert”. 2. In the “Model Definition” you may add a predefined regulator or turbine. After the selection of the regulator you must close the dialog. 3. Now re-open the dialog again. Then a new tab should be available for defining the regulator or turbine data. 16-10

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4. Now you may also define the signals (input/output ports) which will be connected to other regulators/elements.

Fig. 16.10 Defining a standard regulator in the “CCT and Signal Block” element

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Fig. 16.11 “CCT and Signal Block” dialog with added standard regulator

Entering a user defined CCT with function blocks in a “CCT and Signal Block” element If you need a CCT which was build up with function blocks more than once (same CCT structure only with different parameters), then you would need to make another diagram with the same CCT and change the parameters of the function blocks accordingly. To avoid making several diagrams with same CCT (with only different function block parameters) you may make use of the “CCT and Signal Block” element. The “CCT and Signal Block” element allows you using the same CCT with block diagrams several times and the CCT diagram has to be building up only once. 1. Insert a “CCT” element and create a new diagram. In this diagram you may now design your CCT with function blocks (see above “Entering a CCT with Function Blocks”. 2. If you need to have the same CCT again for another element, then insert a “CCT and Signal Block” from the “Insert” menu (see above). 3. In the “Model Definition” you may select this CCT. After the selection of the regulator you must close the dialog. 4. Now re-open the dialog again. Then a new tab “CCT Block-Model” should be available for defining the parameters of the function blocks of the CCT. 5. With double click you may change the parameters of the function blocks.

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6. Do not forget to assign the new input/outputs of the input, output and network source function blocks.

Fig. 16.12 Add a CCT with function blocks in a new diagram

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Fig. 16.13 Add a CCT in a “CCT and Signal Block” element

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Fig. 16.14 Defining the function block parameters in a “CCT and Signal Block” element

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Calculation Parameters for the NEPLAN Dynamic Simulator Before you can start the NEPLAN dynamic simulator you must define some calculation parameters: - Calculation parameters for the mathematical calculation engine. At leas you should define the end time of the simulation. Normally you should not change the other parameters. Use the assigned default values. - Disturbances have to be defined. You normally need to define one or several disturbances (e.g. short circuit) and the times at which the disturbances happen. - Signal (variables, e.g. P,Q, U, f, etc, ) which you want to display at run time and the signals which should be stored for reporting purposes in the NEPLAN chart manager should be defined.

Fig. 16.15 Calculation parameters for the dynamic simulator

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Calculation parameters for the calculation engine The most important parameters for the calculation engine are the type of simulation that should be executed and the simulation end time. The following simulation types are available in NEPLAN: - Transient stability (RMS with DQ0 models). Use this simulation for balanced systems with balance faults (3-phase fault). RMS in DQ0 is the fasted solution if you have a balanced system. It is also very useful for designing and developing controllers. - Transient stability (RMS with ABC models). Use ABC mode calculation if you have an unbalanced system (e.g. with 1-phase faults). - Electromagnetic transients (EMT with DQ0 models). Use this EMT in DQO mode for balanced systems. - Electromagnetic transients (EMT wit ABC models). Use ABC mode calculation if you have an unbalanced system (e.g. with 1-phase faults). - Phasor dynamic simulation with ABC models. Use the “Phasor Dynamic” mode if you need to make fast EMT like simulations. The other parameters are: -

TEND RTOL ATOL HMIN ORDER

(simulation end time) (relative tolerance) (absolute tolerance) (min. step size after an event has occurred) (max. order used in the gears method)

Defining disturbances Disturbances have to be defined. You normally need to define one or several disturbances (e.g. a short circuit on a busbar) and the times at which the disturbances happen. A disturbance is defined as a change in the parameter of a component model. NEPLAN allows you to change any parameter of all element and regulator models. This gives the user the highest possible freedom for defining any possible disturbance. To help the user defining standard disturbances (e.g. a 3-phase fault), there are some predefined disturbances included in NEPLAN. With the button “Add Standard Disturbances” the parameters of the models which should be changed for this standard disturbance will be automatically added to the parameter list. In case of a 3-phase fault it is R

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and X of the fault and the duration of the fault. The fault will be treated internally like an element. It may be connected at certain time and disconnected after the fault clearing time. With the “General Fault Element” any type of short circuit may be defined (see below).

Fig. 16.16 Disturbances: changing of any parameter of all models

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Fig. 16.17 Standard disturbances: 3-phase fault element will be added

Fig. 16.18 Disturbances: defining parameters of a general fault

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Fig. 16.19 Disturbances: General fault element

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Defining signals (variables) to be displayed and reported on the chart Before you start the simulation you need to now which results you want to display. Per default no result will be saved. Since saving of all signals (variables) during the simulation of a large network would decrease the overall performance, it is necessary to define the signals (variables, e.g. P,Q, U, f, etc, ) which you want to display at run time and the signals which should be stored for reporting purposes in the NEPLAN chart manager. The “Pos” flag in the dialog below defines the position of the curve in the run time chart. The “File” flag indicates that the signal result will be saved and the curve might be displayed later in the NEPLAN chart manager for reporting purposes. Since there is only one y-axis on the run time charts, you should take care that the curves on the same chart (same “Pos” flag) have about the same value ranges (e.g. p.u. values 1...0). Since all internal and external variable of all models as well as some additional measurement variables (I, P, Q, f) may be selected, NEPLAN offers the greatest possible access to the results after the dynamic simulation.

Fig. 16.20 Screen plots: Define any variable to display on chart

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Fig. 16.21 Screen plots: run time plot wind turbines (blade angles and power in pu)

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Examples for the NEPLAN Dynamic Simulator Since the NEPLAN dynamic simulator is a very strong tool, allowing entering data in many different ways, we have included many examples specifically for the dynamic simulator module. Among many others we have included these IEEE benchmark systems: - IEEE 9-Bus, - IEEE 14-Bus - IEEE 39-Bus - IEEE 68-Bus Some examples are benchmark examples, where the input data and the results are available from universities on the web. The results of the NEPLAN simulator may be compared and validated with the corresponding benchmark data. Other examples included are: - Kundur Two-Area-System - Nordel system - WSCC system - New England system - SSR Sub-synchronous resonance benchmark (EMT simulation) - DFIG and wind farm applications - Simple FACTS applications - User defined modeling with C++ and MATLAB

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