pv modeling

Paladin DesignBase May 2011

Photovoltaic Modeling

POWER ANALYTICS CORPORATION 16870 West Bernardo Drive, Suite 330

San Diego, CA 92127 U.S.A.

© Copyright 2011 All Rights Reserved


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Table of Contents

Page:

1. Introduction ........................................................................................................................................... 1

1.1 Photovoltaic Systems Modeling .................................................................................................... 5

2. Power Flow (steady-state) Model of PV System: ................................................................................ 9

3. Short Circuit (steady-state) Model of PV System: ............................................................................. 14

4. Transient Stability (time domain) Model of PV System. Open Source Application Programming Interface (API) ................................................................................................................................... 17

4.1 Generic PV Inverter model – DesignBase Transient Stability Model Builder .......................... 17

4.2 User-Defined Solar Irradiance ................................................................................................. 18

4.3 Irradiance Measurement File ................................................................................................... 20

4.4 PV Generic Inverter Model in a Sample Power System .......................................................... 22

5. Tutorial on modeling PV system ....................................................................................................... 27

5.1 PV Steady-Sate Load Flow Model: ................................................................................................... 29

5.2 PV Steady-Sate Short Circuit Model: ................................................................................................ 35

5.3 PV Dynamic Model ............................................................................................................................ 40


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List of Figures Page:

Figure 1: Schematic Diagram of a PV inverter for Grid Connected Operation .......................................... 1 Figure 2: PV cell equivalent circuit (Lorenzo, 1994) ................................................................................... 2 Figure 3: A typical V-I Characteristics of a solar cell .................................................................................. 3 Figure 4: Influence of the ambient irradiation on the PV cell – a); ............................................................. 4 Figure 5 : Series (a) and parallel (b) connection of identical cells............................................................... 5 Figure 6: Typical Structure of a Grid Connected PV Generator ................................................................. 6 Figure 7: PV Cell Equivalent Circuit ........................................................................................................... 7 Figure 8: Typical PV array V-I characteristics ............................................................................................ 8 Figure 9: The steady-state and dynamic PV model ................................................................................. 10 Figure 10: PV Power Flow User Interface .................................................................................................. 11 Figure 11: PV Power Flow User Interface – PV in Voltage Control Mode ................................................. 12 Figure 12: PV Scenarios Implementation ................................................................................................... 14 Figure 13: Short Circuit Analysis Standards ............................................................................................... 15 Figure 14: Short Circuit Analysis Basic Options ......................................................................................... 15 Figure 15: Short Circuit Control for ANSI/IEEE Std. .................................................................................. 16 Figure 16: Short Circuit Back Annotation Features .................................................................................... 16 Figure 17: Control Block Diagram of a Generic PV Inverters Implemented in DesignBase’s

Transient Stability ...................................................................................................................... 18 Figure 18: Selecting “Measurement” Block for Irradiance Measurements ................................................. 19 Figure 19: Defining the Irradiance Measurements Data File ...................................................................... 20 Figure 20: Example of Irradiance Measurement File ................................................................................. 21 Figure 21: Sample Power System for Testing the PV Generic PV Plant Model ........................................ 23 Figure 22: Dynamic Data for Generic PV Inverter Plant ............................................................................ 24 Figure 23: Variables related to generators, buses, branches; PV, etc. can be examined ......................... 25 Figure 24: DesignBase Transient Data and Event Manager ...................................................................... 25 Figure 25: Photovoltaic / Inverter Dynamic Model ..................................................................................... 26 Figure 26: Graphs of Monitored PV Variables (P0 and POUT).................................................................. 27 Figure 27: Test PV model ........................................................................................................................... 28 Figure 28: PV Steady – State Power Flow Model ...................................................................................... 29 Figure 29: Power Flow Results displayed on the drawing model............................................................... 30 Figure30: Power Flow Results .................................................................................................................. 35 Figure 31: Power Flow Results .................................................................................................................. 36 Figure 32: Bus Short Circuit and Branch Short Circuit Contribution .......................................................... 37 Figure 33: PV does not contribute to the short circuit ................................................................................ 38 Figure 34: Short Circuit at all buses ........................................................................................................... 39 Figure 35: DesignBase “Transient” folder .................................................................................................. 40 Figure 36: Irradiance data selected by the user ......................................................................................... 41 Figure 37: Irradiance data .......................................................................................................................... 42 Figure 38: PV /Inverter Dynamic model user interface .............................................................................. 43 Figure 39: Testing system .......................................................................................................................... 45 Figure 40: PV steady state model – User Interface ................................................................................... 46 Figure 41: PV dynamic models library ........................................................................................................ 47 Figure 42: Generic PV-Model – User Interface .......................................................................................... 48 Figure 43: Generic PV dynamic model ....................................................................................................... 49 Figure 44: PV Dynamic Model – User interface ......................................................................................... 50


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1. Introduction The photovoltaics (PVs) are attractive sources of renewable energy for electric power generation due to their relatively small size and noiseless operation. Their applications are expected to significantly increase all over the world. PV generating technologies have the advantage of being modular (more units can be added) to meet the increased demand. Major advantages of the photovoltaic power are:

• Static structure with no moving parts, hence quiet operation • High power density per unit of weight • Short lead time to design, install, and start up • Highly modular structure, hence the plant economy is not a function of size • Power output matches well with peak load • Expected longer life with low maintenance • Highly mobile

Photovoltaic cells can be divided into four groups: thin-film, crystalline, dye-sensitised (DYSC or Grätzel-cell) and multilayer cells. The multilayer cells can also be considered as several layers of thin-film PV cells. These types are described in [50]. Figure 1Error! Reference source not found. shows the schematic diagram of an inverter for a small PV grid connected system. As part of this project, Power Analytics team also developed a user-defined model to incorporate the actual solar irradiance measurements into account for the time domain simulations.

A schematic diagram of a PV system is presented in the Figure 1 below:

• Maximum power point tracking (MPPT) circuit • Optional energy storage element, usually a capacitor (and/or batteries) • Optional DC/DC converter for higher voltage • An AC inverter (DC to AC) • An Isolation transformer to prevent DC from being injected into the power system

Figure 1: Schematic Diagram of a PV inverter for Grid Connected Operation

The PV uses semiconductor cells (wafers), each of which is basically a large area p-n diode with the junction positioned close to the top surface. PV results in the generation of direct voltage and current from the Sun’s (light) rays falling on the cell. To achieve higher voltage and current, multiple cells are used as needed. The PV cell can be represented by a simple equivalent circuit shown in Figure 2. The output current is a function of solar radiation, temperature, wind speed and coefficients that are particular to the cell technology.


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The PV current Ipv is a function of the array output voltage Vpv (V-I) characteristic of the array) which is given in Figure 2. The maximum power output is obtained when the array operates at point M on the V-I characteristic.

Figure 2: PV cell equivalent circuit (Lorenzo, 1994)

The model contains a current source Iph, one diode and a series resistance Rs, which represents the resistance inside each cell and in the connection between the cells. The net current is the difference between the photocurrent Iph and the normal diode current ID.

)1)((exp0 −+

−=−=c

SphDph mkT

IRVeIIIII

where:

m – idealizing factor k – Boltzmann’s gas constant Tc– the absolute temperature of the cell e – electronic charge V – the voltage imposed across the cell I0 – the dark saturation current (strongly depends on temperature – Lorenzo, 1994)


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Figure 3: A typical V-I Characteristics of a solar cell

In the above representation of I-V characteristic, a sign convention is used, which takes as positive the current generated by the cell when the sun is shining and a positive voltage is applied on the cell’s terminals.

A real solar cell can be characterized by the following fundamental parameters:

Short Circuit Current: It is the greatest value of the current generated by a cell. It is produced under short circuit conditions: V = 0 Open circuit voltage Corresponds to the voltage drop across the diode (p-n junction), when it is traversed by the photocurrent Iph (namely ID=Iph) when the generator current is I = 0. It reflects the voltage of the cell in the night and it can be mathematically expressed as:

where:

Vt - known as thermal voltage and Tc is absolute cell temperature


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Maximum power point:

Is the operating point A (Vmax, Imax) at which the power dissipated in the resistive load is maximum: Pmax = Imax * Vmax

Maximum efficiency: Is the ratio between the maximum power and the incident light power

Figure 4: Influence of the ambient irradiation on the PV cell – a); and of the cell temperature on the cell characteristics – b).


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Figure 5 : Series (a) and parallel (b) connection of identical cells

In current practice, the performance of a module or another PV device is determined by exposing it at known conditions. The module characteristics supplied by the manufacturer are usually determined under special conditions, as for example nominal or standard conditions (Lorenzo, 1994) – see Table below:

1.1 Photovoltaic Systems Modeling

The typical structure of a grid connected PV unit is shown in Figure 6. Its main components are the PV array, the DC/DC, DC/AC converters and the associated (converter and overall system) controls. A storage device is absent in large grid-connected installations (except maybe for small critical loads).


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Figure 6: Typical Structure of a Grid Connected PV Generator

In Figure 6 the series resistance Rs represents the internal losses due to the current flow, whereas the shunt resistance Rsh corresponds to the leakage current to the ground and it is normally ignored. In an ideal cell Rs= Rsh=0, which is a common assumption. The equivalent circuit of a PV module, which consists of a combination of series and parallel-connected cells are the same.


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Figure 7: PV Cell Equivalent Circuit

The governing equations of the equivalent circuit are:

IRVV s−= 0

)1000

(

)1(

1

0

0

IscL

shsh

shAkTqV

DL

PII

RVI

IeIII

=

=

−−−=

Where:

V, I – output voltage and current q – electron charge (1.6*10-19 Cb) k – Boltzmann constant (1.38*10-23 J/K) T – temperature in K A – quality factor (constant) ID – reverse saturation current of the diode IL – photocurrent, dependent on T PI – insolation level in W/m2 Isc1 – short circuit current at 1000 W/m2 solar radiation

Multiple PV modules are connected in series and in parallel to form the PV array. Similar equations hold for the whole array, provided that all modules are identical and subject to the same insolation. In Error! Reference source not found. the V-I characteristics of a 250 kW array are shown at three solar radiation (PI) levels. On the same diagram three constant power curves (red lines) have been drawn. It is clear that, for a given insolation, the array produces maximum power only when operating near the knee point of the corresponding V-I curve (maximum power point). The task of tracking the maximum power point (MPPT) is usually


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performed by a DC/DC converter at the output of the array, which regulates the voltage to the desired value. Since no moving parts are employed in this process, the response of the MPPT can be considered instantaneous for system studies.

Figure 8: Typical PV array V-I characteristics

A device that may affect the response of the PV generator output in case of solar radiation changes is the sun-tracking system of the panels, which adjusts the orientation of the panels with respect to the sun, a task performed by the use of properly controlled servomotors. However, these are relatively slow acting devices and may be ignored in transient stability studies. As discussed, the remaining system components (dc bus, inverter and grid-connection devices) are of similar nature and characteristics as for other dispersed generators (e.g. variable speed wind turbines) as are the modeling requirements. The following conclusions are based on the literature survey:

• Lack of industry-standard validated models has been identified as a major issue for variable

generation • As per NERC Special Report: Accommodating High Levels of variable Generation “Validated, generic, non-confidential, and standard power flow and stability (positive-sequence) models for variable generation technologies are needed. Such models should be readily and publicly available to power utilities and all other industry stakeholders. Model parameters should be provided by variable generation manufactures and a common model validation standard across all technologies should be added. The NEREC Planning Committee should undertake a review of the appropriate Modeling, Data and Analysis (MOD) Standards to ensure high levels of variable generation can be simulated”.


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2. Power Flow (steady-state) Model of PV System:

An equivalent Photovoltaic Power Plant may be modeled for Power Flow purposes as a Generator connected to a system bus, having the bus voltage 208 or 480 V. The aggregated MVA of the plant must be specified as an integer multiple of the individual inverter MVA rating. For Power Flow Analysis the following should be considered:

• One can connect in parallel only the inverter of the same type • The active power dispatch for power flow simulation will be between 0 to MVA plant ratings • The default operating mode of the inverter is with fixed unity power factor. However, the

generator reactive power will be Qmax = Qmin = 0 • Some inverters operate with +/- 0.95 power factor. In this case only 95% of the equivalent

inverter current is available for active power dispatch. The difference remains for reactive power control

• If the inverter operates at non unity power factor / desired power factor, then Qg, Qmax and Qmin should be provided by the user and Q should be in the remain limits

• If the inverter will control the voltage of a given system bus, then the PV-G will operate in PV mode, and the controlled bus should be specified

Photovoltaic Unit (photovoltaic panel, inverter) is an electrical AC generator with the following particulars:

• Generates Active Power • May generate reactive power flow, within the limits of +/- 95 power factor • While generate active power only, +Q and –Q are set to zero • In voltage control mode, the control bus should be defined and the photovoltaic reactive

power output should be set up to +/- 0.344 P • Maximum aggregated active power, should be set up to an integer multiple of inverter rated

power • Only photovoltaics driven by identical inverter can be aggregated together

The PV steady state model developed has the following attributes:

• General PV attributes: Manufacturer, PV rated and actual voltage, manufacturer information • Power Flow attributes, like operation mode: PV control mode or P, Q mode, controlled bus

ID, reactive power limits, PV rated and actual voltage • Short Circuit attributes, like PV equivalent impedance • Dynamic model, an open architecture of the PV dynamic model, including panel dynamic

model, inverter dynamic model and its controls and protection functions


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Figure 9: The steady-state and dynamic PV model


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Figure 10: PV Power Flow User Interface


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Figure 11: PV Power Flow User Interface – PV in Voltage Control Mode Note:

PV Output Power (AC and DC) depends on irradiance. Irradiance is a function of time. However, the PV Active Power Output depends on time.

The followings are examples of measured irradiance at UCSD, San Diego, CA, Gilman Parking Structure.


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Table 1: Table – Gilman Parking Structure, UCSD, field measurements

However, in order to consider the “Sun irradiance” for Power Flow purposes, the DesignBase team has developed the PV Generator Scenarios.


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The number of Scenarios are unlimited and depends on the user’ measurement data in the field. Consequently, the PV Active Power Output depends on irradiance. Irradiance is a function of time, and however the Photovoltaic unit Active Power Output depends on time. The time frame depends on the user available data. One can consider any time steps, from 1 minute to 2 or 3 hours.

Figure 12: PV Scenarios Implementation

3. Short Circuit (steady-state) Model of PV System:

The equivalent aggregated inverter will not contribute to the system short circuit current. It’s a good idea considering the inverter equivalent impedance 999 pu. Inverter short-circuit ratio: Ksc =1.1-1.5 The short circuit algorithms are based on either IEEE or IEC standards. The user has the entire control over the algorithms and over the ways of displaying the short circuit results.


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Figure 13: Short Circuit Analysis Standards

Figure 14: Short Circuit Analysis Basic Options


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Figure 15: Short Circuit Control for ANSI/IEEE Std.

Figure 16: Short Circuit Back Annotation Features


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Regarding the short circuit regime:

In high PV penetration scenarios the generators must:

1. Not disconnect during grid faults 2. Contribute to short circuit current 3. Provide reactive power during normal operation 4. Reduce the active power injection when frequency increases 5. Critical issues:

i. Growing complexity and diversity of requirements may create an increasing barrier to effectively apply the potential of new inverter functionalities in practice

ii. There is a need for international exchange of experiences and harmonized standards

4. Transient Stability (time domain) Model of PV System. Open Source Application Programming Interface (API)

A generic PV/Inverter dynamic model has been implemented as a user-defined model in the DesignBase’s Advanced Transient Stability Program. For most transient stability studies, the response of the plant to grid disturbances (faults) is of most interest. For these studies, the model should calculate the initial solar radiation based on the plant’s active power output in the power flow solution. This radiation should be kept constant throughout the transient simulation time. The output power of the inverter and radiation result in a DC voltage that is a predictable function of the PV characteristics with virtually no dynamics. The DC voltage error is processed through a proportional-integral regulator whose output is the inverter direct axis current that results in active power production. Additional control for voltage regulation is also supported in this model. The model also supports under/over voltage protection in addition to under/over frequency protection. Three levels of overvoltage tripping, three levels of under-voltage tripping and one level of over and under- frequency tripping are included in the generic PV/inverter model. Each of these trip functions has an independent associated time delay.

4.1 Generic PV Inverter model – DesignBase Transient Stability Model Builder

Using DesignBase ULC a generic model has been developed and implemented in DB 4.0 release. The control block diagram of the “generic model” is shown in Figure 17.


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Figure 17: Control Block Diagram of a Generic PV Inverters Implemented in DesignBase’s Transient Stability

One can identify the following parts:

• Photovoltaics arrays models considering the Lorenz equation • Active are reactive power controls • Over and under voltage protection • Over and under frequency protection • Irradiance input control

4.2 User-Defined Solar Irradiance

The generic model can accept the field irradiance measurements when this is available. The irradiance changes can be introduced to the model as shown in Figure 18. The irradiance values can be stored in a text file with simple format (*.csv format is supported). To define the irradiance (i.e. the file containing the irradiance measurements) select the block “Measurement” from the PV model functions as shown in the Figure 18 below:


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Figure 18: Selecting “Measurement” Block for Irradiance Measurements

Then, drag the “Measurement” icon into the model area and connect it to the solar radiation point in the model (see Figure 18 above). Double click the left mouse button on the “Measurement” block in order to enter the irradiance file information as shown in Figure 19.


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Figure 19: Defining the Irradiance Measurements Data File

Use the file browser and locate the irradiance file in the DesignBase Data folder as seen in Figure 19. Also, the output of the “Measurement” block can be given any name of user’s choice (in the above example the name “UCSDLookup3.csv” is entered).

4.3 Irradiance Measurement File

The irradiance values corresponding to field measurements can be used in the transient simulation of PV/Inverter power plant. The irradiance values should be stored in a text file such CSV format. One example of irradiance measurements used in the generic model is shown in table below:


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Figure 20: Example of Irradiance Measurement File Time (seconds) kt (Irradiance in pu) 0 0.8

1 1.18

2 1.11

3 1.02

4 1.00

5 1.04

6 1.07

7 1.05

8 1.08

9 1.10

10 1.16

11 1.16

12 1.11

13 0.94

14 0.61

15 0.31

16 0.34

17 0.40

18 0.67

19 1.05

20 0.65

21 0.43

22 0.35

23 0.42

24 0.39

25 0.40

26 0.38

27 0.65

28 0.58

29 0.50

30 0.50

31 0.55

32 0.57

33 0.57

34 0.77

35 0.73

36 0.66

37 0.75

38 0.81

39 0.94

40 1.06

41 1.22

42 1.22


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Time (seconds) kt (Irradiance in pu) 43 1.15

44 1.02

45 0.97

46 0.85

47 0.66

48 0.61

49 0.62

50 0.76

51 0.65

52 0.51

53 0.45

54 0.47

55 0.42

56 0.49

57 0.45

58 0.43

59 0.62

60 0.84

2000 0.84

*

Note that the last row (line of the data file) should be “*” to mark the end of the file.

4.4 PV Generic Inverter Model in a Sample Power System

The power system shown in Figure 21 is used to test the PV model. To prepare a transient stability simulation case for this system, we need to specify the dynamic data for the Generic PV model. This can be done by first selecting transient stability icon and then selecting “Event and Data Manager”. Add a PV model and select the Generic from the list of PV library.


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Figure 21: Sample Power System for Testing the PV Generic PV Plant Model (Paul M. Anderson, A.A. Fouad – Power System Control and Stability. Revised Printing. IEEE Press, NY

1977, pag.38)


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Figure 22: Dynamic Data for Generic PV Inverter Plant

The disturbance that we will examine for this test power system with PV plant is the application of a fault at bus 5 for a period of 6 cycles (0.1 second). To start the time domain simulation, select “Analyze” and in the simulation dialog press “Start Simulation” to perform the simulation. Upon completion of the simulation the result can be viewed by selecting “View Graphic Result” (please consider the DesignBase Transient Manual). All of the monitored variables related to generators, buses, branches; PV, etc. can be examined. Figure below shows several tabs.


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Figure 23: Variables related to generators, buses, branches; PV, etc. can be examined

Figure 24: DesignBase Transient Data and Event Manager


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Figure 25: Photovoltaic / Inverter Dynamic Model


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Figure 26: Graphs of Monitored PV Variables (P0 and POUT)

To examine the monitored variables for the PV model select “PV” tab shown above. The variables to be monitored are defined at the time PV model is added to the PV library. EDSA’s transient stability program gives the user the option to monitor any of the internal variables (signals) within the model. This unique feature helps the user to assess the performance of the control system of the PV inverter and optimize its performance (e.g. by examining the effect changing gain, time constant, etc. on the performance of any controller internal to the inverter). The above figure shows the irradiance measurements as defined in the data file which is used in the above simulations.

5. Tutorial on modeling PV system

Consider the file: “TEST-PV GENERAL-MODEL located in the DesignBase “Transient Folder”.


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Figure 27: Test PV model


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5.1 PV Steady-Sate Load Flow Model:

Figure 28: PV Steady – State Power Flow Model

In this example the PV system does not generate reactive power. However, QGMin = 0 and QG Max = 0.


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Figure 29: Power Flow Results displayed on the drawing model

As can be seen in Figure 29 PV unit does not generate reactive power.


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32


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34


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Figure30: Power Flow Results

5.2 PV Steady-Sate Short Circuit Model:


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Figure 31: Power Flow Results If inverters are used, in general there is no contribution to short circuit. Induction generators, on the other hand, would inject fault currents in accordance with the magnitude of the machine reactance. This could be either the subtransient (X"d) or transient (X'd) reactance. Since the generator may represent an aggregate, the reactance used would be the same value if all the generators have the same characteristics on a machine base which is the sum of the MVAs of the individual machines.

The PV system does not contribute to the short circuit. However R and X are 9999 Ohms.


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Figure 32: Bus Short Circuit and Branch Short Circuit Contribution


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Figure 33: PV does not contribute to the short circuit


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Figure 34: Short Circuit at all buses


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5.3 PV Dynamic Model

Open the “PV-GENERIC-MODEL “file from “transient folder.

”P

Figure 35: DesignBase “Transient” folder

Double click on the “Irradiance” measurement icon, and select “UCSDLookup3.csv” file from the DesignBase Data subfolder:


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Figure 36: Irradiance data selected by the user


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Figure 37: Irradiance data

The PV inverter equations are created:

Click “OK”.


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Click “Yes”.

The PV dynamic user interface is displayed:

Figure 38: PV /Inverter Dynamic model user interface


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Click “Yes”.

Click “OK”. The dynamic model of the PV unit has been generated. Next step is to insert the PV dynamic

model. Open the “TEST-GENERAL-MODEL” file – from Transient folder.


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Figure 39: Testing system

Select the PV symbol and double click on it:


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Figure 40: PV steady state model – User Interface

Click on “Machine Dynamic data” button:


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Figure 41: PV dynamic models library Click “Select” button and select PV-GENERIC-MODEL


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Figure 42: Generic PV-Model – User Interface

Click “View” button:


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Figure 43: Generic PV dynamic model


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Figure 44: PV Dynamic Model – User interface

Note: TIRAD – is the time at which the input is switched to “User-Defined” solar irradiance. This is user defined input data.

Using the DesignBase Transient program any dynamics can be simulated. Please consult the DesignBase Transient Manual.

The salient features of the DesignBase Power Flow program:

• Advanced Solution Techniques for Fast Convergence (Newton Raphson, Fast Decoupled, and Accelerated Gauss Seidel)

• HVDC • Power Factor Correction and Automatic Temperature Adjustment • Active Power Flow Control using Phase Shifting Transformer • Simulate single-phase networks tapped from 3phase network • Local and Remote Bus Voltage Control via Static Var Compensation • Local and Remote Bus Voltage control 1, 2 and 3 winding Transformers • Combined SVC, Generator and Transformer Voltage Control


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• Local and Remote Bus voltage control through generators • Area Interchange Control • Transformer Impedance Adjustment based on Transformer Taps • Hybrid Simulation Method • Transformer ULTC simulation and auto voltage control • Governor Response solution

The salient features of the DesignBase Short Circuit program:

• Three-Phase Fault, with or without ground (3P, or 3P-G); • Single line to ground Fault (L-G); • Line to Line Fault (L-L); • Line to line to ground Fault (L-L-G). • Exact short circuit current and contributions computation using Three-Sequence Modeling • Simulate sliding and open conductor faults • High speed simulation by utilizing the state-of-the-art techniques in matrix operations (sparse

matrix and vector methods) • Automated reactor sizing for all types of networks • Exporting and importing data from and to Excel • Import system data from Siemens/PTI format • Customize reports • Support of both ANSI C37 and IEC 909 standards • Fully integrated with ARC flash program • Fully integrated with PDC (protective device coordination)

The salient features of the Advanced Transient Stability

• Trapezoidal Integration Technique • Transformer Inrush Model • Changing Mechanical Torque of Induction Motors • MG-Set Simulation • Dynamic ULTC simulation • Integrated Control Logic Modeling and Simulation • User Defined Control Logic Modeling System with full on-board oscilloscope • Real-time Simulation • Frequency Dependent Machine and Network Models • Static Automatic Bus Transfer Simulation • Doubly Fed Induction Generator Model • Fault Isolation Unit • Static Frequency Converter • Relay Models • Fault Cables and Transmission lines at any length • User defined actions including CB operation • Automatic Load Shedding • Induction/Synchronous Motor/Generator Dynamic Models • Phase-shifting transformer • User-defined Dynamic Models (UDM) interface for: • Exciter/AVR • Governor - Turbine • Power System Stabilizer • IEEE & Selected Manufacturer Exciter, Governor, & Power System Stabilizer Models


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• Impedance Relay Simulation • MOV Starting • Import Test and Field data for comparison of actual vs. simulation • Loss of excitation simulation • Critical Fault Clearing Time and System Islanding • Fast Bus Transfer • Impact Loading & Generator Rejection • SVC • HVDC

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