GURUKUL INSTITUTE OF ENGINEERING & TECHNOLOGY

IPB-13, RIICO INSTITUTIONAL AREA, KOTA, RAJASTHAN

DEPARTMENT OF ELECTRICAL ENGINEERING

7EE8 – POWER SYSTEM MODELLING & SIMULATION LAB

LAB MANUAL/ OBSERVATION2013-14 ODD SEMESTERS

PREPARED BY Er. Manish Pratap Singh

Assistant Professor

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Dept. of EEList of Assignments

1. Simulate Swing Equation in Simulink (MATLAB)

2. Modelling of Synchronous Machine3. Modelling of Induction Machine4. Simulate simple circuits using

Circuit Maker5. (a) Modelling of Synchronous

Machine with PSS (b) Simulation of Synchronous Machine with FACTS device

6. (a) Modelling of Synchronous Machine with FACTS device (b) Simulation of SynchronousMachine with FACTS devices.

7. FACTS Controller designs with FACT devices for SMIB system.

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Assignment No. 1

Aim: - Model and Simulate the Synchronous Machine whose electrical model is specified by given equation.

i) Vd = Rs id+ddt ¢d – ωR ¢q ii) Vq = Rs iq+

ddt ¢q + ωR ¢d

Rs = 2Ω, id , iq Sine Wave, Amplitude Respectively 5&7A

¢d, ¢q Ramp Function, Slope Respectively 1&1.5

ωR = 8 rad/sec

Software Platform Used: -MATLAB

Sol.: Here we model R & ω by Gain operation & output is modeled by Scope

Modelling of Equation (i)

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Scope Output:

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Modelling of Equation (ii)

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Scope Output:

RESULT: - Thus we have modeled & simulated the Synchronous Machine whose electrical model is specified by some equation.

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Assignment No. 2

Aim: -Model & Simulate the Asynchronous Machine whose electrical model is specified by given equation.

i) Vqs= Rs iqs+ddt ¢qs + ω ¢ds ii) Vds = Rs ids+

ddt ¢ds – ω ¢qs

Rs = 3Ω , id , iq Sine Wave, Amplitude Respectively 8&6A

¢d, ¢q Ramp Function, Slope Respectively 1.7&2.5ω= 6 rad/sec

Software Platform Used: -MATLAB

Sol.: -Here we modeled R & ω by Gain function & output by Scope Modelling of Equation (i)

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Scope Output:

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Modeling of Equation (ii)

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Scope Output:

RESULT: - Thus we have modeled & simulated Asynchronous Machine

whose electrical model is specified by given equation.

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Assignment No.3

Aim: - Simulate simple circuits using Circuit Maker

Software Platform Used: - Circuit Maker Pro 6.0

Theory: - The best way to get acquainted with Circuit Maker’s analog simulation is to build a few simple circuits, set up the analyses, and run the simulations. This tutorial covers:• Simple circuit analysis• Simulating a simple AC circuit• More circuit simulation• Setting up the analyses• Running the simulation• Mixed-mode simulation

Simple Circuit AnalysisLet’s begin with a simple DC circuit:1 Click the New button on the Toolbar.This opens an untitled circuit window.2 Click the Digital/Analog Simulation mode toggle button.You know Circuit Maker is in Analog mode when the transistor icon, not the AND gate icon, is visible on the Toolbar (see pictures at left). If the AND gate icon is displayed (Digital mode), click the button to switch.3 Draw the circuit using the following devices:• 1 Battery [Analog/Power] (b)• 1 Ground [Analog/Power] (0 (zero))• 2 Resistors [Passive Components/Resistors] (r)

Note: Every analog circuit must have a Ground and every node in the circuit must have a DC path to ground.

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4 Use the Wire Tool to wire the circuit together (or the Arrow Tool when the Arrow/Wire option is enabled).5 Choose Simulation > Analyses Setup then click the Analog Options button to display the dialog box

The third option (selected) lets you measure voltage, current, and power with the Probe Tool.

6 From the Analysis data saved in RAW file group box, select the third option, Node Voltage, Supply Current, Device Current and Power then click OK to exit Analog Options. This option lets you to take current and power measurements with the Probe Tool.

7 Click the Run Analyses button to start the simulation.ORClick Exit and click the Run Tool on the Toolbar.An interactive SPICE simulation window appears during the SPICE data collection process showing the progress of the simulation. When the SPICE data collection process is completed, the Multimeter Window appears.

8 Click the wire connected to the + terminal of the battery with the tip of the Probe Tool. Notice that the letter V appears on the Probe Tool when you move it over a wire.

9 Click the wire connected between the two resistors. The DC voltage at that node appears in the Multimeter Window. SPICE data is not collected for theGround node in the circuit; it is always at zero volts.

10 Click the + pin of the battery or one of the resistor pins.

Notice that an “I” displays on the Probe Tool when it is over a device pin.The current through that device appears in the Multimeter Window.

11 Click directly on one of the resistors. Notice that a “P” displays on the Probe Tool when over a device. The power dissipated by that resistor appears in the Value Window.

12 Click the Stop button on the Toolbar to stop the simulation and return to editing mode.

Creating a Simple RC CircuitNow let’s replace one of the resistors with a capacitor to create a simple RC circuit where you can see the charging of the capacitor. Transient Analysis

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begins its simulation in a stable DC condition where the capacitors are already charged. Since you want to see the capacitor charging from time zero, you must set the initial condition of the capacitor to 0V.1 Using the Delete Tool on the Toolbar deletes the second resistor (the one connected to ground) and the wire leading to it.2 Replace the resistor with a Capacitor [Passive Components/ Capacitors] (c).3 Select an .IC device [Analog/SPICE Controls] (I) and connect it to the wire between the resistor and capacitor.This will set an initial condition of 0V on the capacitor for the analysis. Your circuit should now look like the one pictured in Figure

4 Run the simulation again by clicking the Run button on the Toolbar.This time the Transient Analysis window (similar to an oscilloscope) appears.

5 Click the Transient Analysis window to select it, and then click with the tip of the Probe Tool between the resistor and capacitor.Notice a diagonal line across the scope. This is actually the beginning of the charge curve for the capacitor. Your view of the curve is limited by start and stop times of the Transient Analysis that were selected by default.You now have the option of changing the Transient Analysis settings to increase the size of the time segment that you can view with the scope, or you can reduce the component values so the capacitor will charge quicker. For this example, you will change the component values.

6 Stop the simulation by clicking the Stop button.

7 Double-click the Resistor to display the Edit Device Data dialog box.

8 Change the Label-Value from 1k to 100, and then click OK.

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9 Double-click the Capacitor, change the Label-Value from 1uF to .001uF, and then click OK.

10 Run the simulation again.This time you will see the charge curve of the capacitor.

Simulating a Simple AC CircuitNow let’s create a simple AC circuit using a Signal Generator and two Resistors:1 Click the New button on the Toolbar.2 Draw the circuit as shown in Figure 3.8, using the following devices:• 1 Signal Gen [Analog/Instruments] (g)• 1 Ground [Analog/Power] (0 (zero))• 2 Resistors [Passive Components/Resistors] (r)

3 Use the Wire Tool to wire the circuit together (or the Arrow Tool when the Arrow/Wire option is enabled).

4 Make sure you are in Analog simulation mode (the transistor icon is showing on the simulation mode button), then run the simulation.

5 Click the Transient Analysis window to select it, and then click the wire connected to the output of the Signal Generator. The sine wave appears on the scope.

6 Hold down the Shift key and click the wire connected between the two resistors. A second waveform appears on the scope.

7 Stop the simulation.

RESULT: -In This way we can simulate simple electrical circuits using circuit maker.

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Assignment No. 4

Aim: Simulate Swing Equation in Simulink

Software Platform Required: MATLAB

Sol.

STABILITY

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SWING EQUATION

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RESULT: Thus we have simulated swing equation using MATLAB (considering steady state stability)

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Assignment No. 5

Aim: To study the modeling & simulation of power system with FACT controllers & PSS for SMIB system.

Software Platform Required: MATLAB

Theory: This is a systematic procedure for modelling and simulation of a power system installed with a power system stabilizer (PSS) and a flexible ac transmission system (FACTS)-based controller. For the design purpose, the model of example power system which is a single-machine infinite-bus power system installed with the proposed controllers is developed in MATLAB/SIMULINK. In the developed model synchronous generator is represented by model 1.1. which includes both the generator main field winding and the damper winding in q-axis so as to evaluate the impact of PSS and FACTS-based controller on power system stability. The model can be can be used for teaching the power system stability phenomena, and also for research works especially to develop generator controllers using advanced technologies. Further, to avoid adverse interactions, PSS and FACTS-based controller are simultaneously designed employing genetic algorithm (GA). The non-linear simulation results are presented for the example power system under various disturbance conditions to validate the effectiveness of the proposed modeling and simultaneous design approach.Keywords—Genetic algorithm, modelling and simulation, MATLAB/SIMULINK, power system stabilizer, thyristor controlled series compensator, simultaneous design, power system stability.

NOMENCLATUREδ Rotor angle of synchronous generator in radiansωB Rotor speed deviation in rad/secSm Generator slip in p.u.Smo Initial operating slip in p.u.H Inertia constantD Damping coefficientTm Mechanical power input in p.u.Te Electrical power output in p.u.E fd Excitation system voltage in p.u.T' do Open circuit d-axis time constant in secT' qo Open circuit q-axis time constant in secxd d-axis synchronous reactance in p.u.x' d d-axis transient reactance in p.u.xq q-axis synchronous reactance in p.u.x' q q-axis transient reactance in p.u.XC Nominal reactance of the fixed capacitor CX P Inductive reactance of inductor L connected in parallel with C. σ Conduction angle of TCSCα Firing angle of TCSCk Compensation ratio, k = XC / X PVt Generator terminal voltageEb Infinite-bus voltage

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VS Stabilizing signal from power system stabilizerTW Washout time constant

I. INTRODUCTIONITH the advent of flexible ac transmission system (FACTS) devices [1], such as thyristor controlled series compensator (TCSC), static synchronous compensator (STATCOM) and unified power flow controller (UPFC), the unified model of single-machine infinite-bus (SMIB) power system installed with a TCSC, STATCOM and a UPFC have been developed [2]-[4]. These models are the popular tools amongst power engineers for studying the dynamic behavior of synchronous generators, with a view to design control equipment. However, the model only takes into account the generator main field winding and the generator damping windings are not accounted for. Further, these liner methods cannot properly capture complex dynamics of the system, Power System with PSS and FACTS Controller: Modelling, Simulation and Simultaneous Tuning Employing Genetic Algorithm especially during major disturbances. This presents difficulties for designing the FACTS controllers in that, the controllers designed to provide desired performance at small signal condition do not guarantee acceptable performance in the event of major disturbances.

In [5], a systematic procedure for modeling, simulation and optimal tuning of TCSC controller in a SMIB power system was presented where the MATLAB/SIMULINK based model was developed and genetic algorithm (GA) was employed to design the TCSC controller. However, the model only takes into account the generator main field winding and the synchronous machine was represented by model 1.0. For more reasonable evaluation of a SMIB power system with FACTS controller, a higher-order synchronous machine model (model 1.1), which includes one damper winding along the q-axis, is reported in the literature [6]. As power system stabilizers (PSS) are now routinely used in the industry, this paper considers a SMIB power system installed with a PSS and a FACTS controller, where the synchronous machine is represented by a higher order model (model 1.1).

The problem of PSS parameter tuning in the presence of FACTS-based controller is a complex exercise, as uncoordinated local control of these controllers may cause destabilizing interactions. To improve overall system performance, many researches were done on the coordination between PSS and FACTS power oscillation damping (POD) controllers [7]-[9]. A number of conventional techniques have been reported in the literature pertaining to design problems of conventional power system stabilizers namely: the eigenvalue assignment, mathematical programming, gradient procedure for optimization and also the modern control theory.

Unfortunately, the conventional techniques are time consuming as they are iterative and require heavy computation burden and slow convergence. In addition, the search process is susceptible to be trapped in local minima and the solution obtained may not be optimal [10].

GA is becoming popular for solving the optimization problems in different fields of application, mainly because of their robustness in finding an optimal solution and ability to provide a near-optimal solution close to a global minimum. Unlike strict mathematical methods, the GA does not require the condition that the variables in the optimization problem be continuous and different; it only requires that the problem to be solved can be computed. GA employs search procedures based on the mechanics of natural selection and survival of the fittest. The GAs, which use a multiple-point instead of a single-point search and work with the coded structure of variables instead of the actual variables, require only the objective

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function, thereby making searching for a global optimum simpler [11]. Therefore, in the present work GA is employed to simultaneously tune the parameters of PSS and FACTS controller. This paper is organized as follows. In Section II, the modeling of power system under study, which is a SMIB power system with a PSS and a thyristor controlled series compensator (TCSC), is presented. The proposed controller structures and problem formulation are described in Section III. A short overview of GA is presented in Section IV.Simulation results are provided and discussed in Section V and conclusions are given in Section VI.

II. POWER SYSTEM UNDER STUDY

The SMIB power system with TCSC shown in Fig. 1 is considered in this study. The synchronous generator is delivering power to the infinite-bus through a double circuit transmission line and a TCSC. In Fig. 1, Vt and Eb are the generator terminal and infinite bus voltage respectively; XT , X L and XTH represent the reactance of the transformer, transmission line per circuit and the Thevenin’s impedance of the receiving end system respectively.

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B. Modelling the Thyristor Controlled Series Compensator (TCSC)TCSC is one of the most important and best known series FACTS controllers.

PROBLEM FORMULATIONA. Structure of the TCSC ControllerThe structure of TCSC-based damping controller, to modulate the reactance offered by the TCSC, XTCSC (α ) is shown in fig. The input signal of the proposed controllers is the speed deviation (Δω), and the output signal is the reactance offered by the TCSC, XTCSC (α ) . The structure consists of a gain block with gain KT, a signal washout block and two-stage phase compensation blocks. The signal washout block serves as a high-pass filter, with the time constant TWT, high enough to allow signals associated with oscillations in input signal to pass unchanged.

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Fig. Structure of TCSC-based controller

Structure of the power system stabilizer

RESULTS AND DISCUSSIONS

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RESULT: - Thus we have done modeling & simulation of the power system with FACT controllers & PSS for SMIB design.

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