Pscad Course Notes 01 PDF

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Manitoba HVDC Research Centre Inc. 244 Cree Crescent Winnipeg, Manitoba, Canada R3J 3W1 T 204 989 1240 F 204 989 1277 [email protected] www.hvdc.ca

Introduction to PSCAD and Applications Training Course Presented by the Manitoba HVDC Research Centre

Course Date: Location: Lead Instructor:

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PSCAD GETTING-STARTED TUTORIALS

Getting Started and Basic Features

Prepared by: Date: Revision: Date:

Dharshana Muthumuni August 2005 3 March12, 2007

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Getting Started - Tutorial 1 Objective(s): · Getting familiar with PSCAD. · Getting familiar with different sections of the Master Library. · Different ways to access the master library. · Creating a simple case. · Data entry. · Plotting and control. · Interactive controls.

T1.1 Create a new case by using either the Menu or Toolbar. A new case should appear in the Workspace settings entitled noname [psc]. Right-click on this Workspace settings entry and select Save As… and give the case a name. NOTE: Do not use any spaces in the name! Create a folder called c:……/PscadTraining/Tutorial_01. Save the case as case01.psc T1.2 Open the main page of your new case. Build a case to study the inrush phenomena when energizing a transformer. The component data is as shown. The transformer is rated 66/12.47 kV. RL RRL Ia

66 kV BUS

66 kV,60 Hz Source Z+ = 3.9Ohms / 75.58 deg Z0 = 14.95 Ohms / 80.46 deg

BRK

E_66

BRK

#2

#1

Y-YTransformer 7.5 MVA Z = 6.14 % Full load loss = 0.3% No load loss = 0.5% No load current 1 %

Timed Breaker Logic Open@t0

1e6

Fig.1 Transformer energizing circuit. T1.3 Plot the currents (Ia) and voltages (E_66) on the HV side of the transformer. Note: Ia and Ea contains the three waveforms of the three phases. 3 / 72

Fig.2 Basic steps to create a graph with a selected signal. T1.4 The LV side of the transformer is not connected to a load or any other system equipment. The breaker is closed at 0.5 s to energize the transformer 66 kV side. Inrush is related to core saturation. Verify that saturation is included in the model used for this simulation. Ask your instructor to explain the large resistance connected to the HV side. Inrush current magnitude depends on the ‘point on wave’ switching conditions. Use a manual switch to operate the breaker. Note the point on wave dependency of the inrush peak. Main ... BRK Control C

O

BRK

1

Fig.3 Two state switch attached to a control panel.

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T1.5 Modify the case to include a 12.47 kV/0.5 MVA (Wound rotor type) induction machine. This case will be used to study the process of starting an Induction motor. The component data is as shown. 12.47 kV BUS

81m U/G 54m OH

Main ... R_C1

Capacitor 800 KVars per phase

C

R_C1

42.5 [uH]

40.94 [uF]

O

R_C1

Ib

Feeder

1

EN484

COUPLED

PI SECTION

Short line of 7.4 km Z+ = 0.2 E-4 + j0.3 E-3 Ohms/m Z0 = 0.3 E-3 + j0.1 E-2 Ohms/m Use default values for the capacitances B_mot

Etrv Timed Breaker Logic Open@t0

N

Emot

B_mot

0.001 IM

This block models the mechanical characteristics of a typical load.

W

TL

* 0.8

S

2 X

W

Mechanical Torque TIN 0.0

0.0

500 kVA Induction machine. Squerriel Cage Type. 13.8 kV(L-L) 7.697 kV (Phase) Irated = 0.02804 [kA] Inertia = 0.7267 [s] Stator resistance = 0.005 PU Rotor Resistance = 0.008

TIN

You may use the wire mode to connect different components. T1.6 Enter the component data. Note: Use ‘typical’ data for the machine. T1.7 Plot the currents on either side of the transformer (ia and ib). T1.8 The input torque to the machine is equal to 80% of the square of the speed. Derive this signal using control blocks. i.e

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Tm  0.8 w 2

Use control blocks to implement the above equation.

Your instructor will explain the calculation program structure of EMTDC and the definition of ‘electric’ and ‘control’ type models. T1.9 The breaker (initially open) should be closed at 0.2s to start the motor. T1.10 Plot the machine speed, the mechanical torque and the developed electric torque. Note: Some variables can be measured from within the component. These are normally listed under the parameter section ‘Internal output variables’

If time permits…

T1.11 Add a load of 1 MVA at 0.8-power factor at 12.47 kV. The same transformer supplies this load. Does the load see an unacceptable voltage sag during motor start?

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Data: Motor 500 kVA Induction machine. Wound rotor Type. 13.8 kV(L-L) 7.697 kV (Phase) Irated = 0.02804 [kA] Inertia = 0.7267 [s] Stator resistance = 0.005 PU Rotor Resistance = 0.008 PU

Short Line Short line of 7.4 km Z+ = 0.2 E-4 + j0.3 E-3 Ohms/m Z0 = 0.3 E-3 + j0.1 E-2 Ohms/m Use default values for the capacitances

Mechanical Load model This block models the mechanical characteristics of a typical load. Mechanical Torque 2 X

W

* 0.8

TIN

Capacitor leg Capacitor 800 KVars per phase R_C1

42.5 [uH]

40.94 [uF]

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PSCAD ESSENTIAL TRAINING Tutorials 1 – 6 1. 2. 3. 4. 5. 6. 7. 8.

Initializing a simulation Switching study Transformers and inrush Transmission lines Power electronic switching Induction machine dynamics Synchronous Machines and controls Wind farms and doubly fed machines

Prepared by: Dharshana Muthumuni Date: August 2005 Revision: 2 Date: Feb 16, 2007

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Tutorial 1 – Two Area Power System – Initializing the simulation to a specific load flow. T1.1 Create a new case by using either the Menu or Toolbar. A new case should appear in the Workspace settings entitled noname [psc]. Right-click on this Workspace settings entry and select Save As… and give the case a name. NOTE: Do not use any spaces in the name! Create a folder called c:……/PscadTraining/T_01. Save the case as T_01_a.psc T1.2 Open the main page of your new case. Build a case representing a simplified two area power system as shown in the figure below. A 55 km transmission line connects Station A to a 100 MW wind farm. All other connections to Station A are represented by an equivalent 230 kV source. The equivalent source impedance is derived from a steady state fault study at 60 Hz. The line is represented by its series reactance. The transformer is represented by its impedance, referred to the 230 kV side.

Station A 55 km line 230 kV

0.14

0.074

RRL

100 MVA Transformer 33/230 kV, Z = 0.1 pu

230 kV Eq. source

RRL

Wind Farm

Z_positive = 10 Ohms at 88 deg. Z_zero = 7 Ohms at 82 deg.

Q1

RL

RL

P1

P2 Q2

Q2

Fig1. Two area system T1.3 The wind farm is also represented by a network equivalence. The positive sequence impedance of this source at 33 kV is 1 Ohm at 89 deg. NOTE: Referred to the 230 kV side the impedance value Ans:48.577 at 890

T1.4 The voltage behind the equivalent impedance at the wind farm is 35 kV. The phase angle is 7 degrees. Determine the power flow across the line. Note: Converted to the 230 kV side, the equivalent voltage is 243.939 kV at 7 deg Note: The simplified calculations are outlined in the accompanying MathCAD worksheet. T1.5 Plot the power and reactive power flow at both ends of the line. These signals can be obtained from the voltage source models as internal outputs. 9 / 72

T1.6 Use proper scale factors inside the Output Channels’ to convert PU values to MW and MVar. Verify the results. T1.7 How do you change the time step, the simulation time and the plot time? How do you determine the simulation time step? T1.8 Can you save results to external output files for post processing? T1.9 If you specified to write data to output files, where are they located?

Save the case!

The case should be saved as T_01_b.psc before proceeding. Different parts of the simulation model can be arranged inside page modules. PSCAD allows ‘nested’ page modules. If you make a change to your existing case, PSCAD will identify the page modules where changes took place. Only these modules will be recompiled. (Time savings in large cases) T1.10 Create a page module and include the equivalent source for the wind farm inside this module as shown in the figures 2 and 3. What is the use of the ‘XNODE’ component? Note: Your instructor will briefly discuss the use of ‘signal transmitters’ which can also be used to transmit (control) signals from a page to another.

Wind

a

Farm

0.074

RL

RRL

0.14

P2 Q2

Q2

Fig.2 Main page

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RRL RL

a

P1 Q1

Fig.3. Subpage

Save the case! The case should be saved as T_01_c.psc before proceeding. T1.11 Modify the source at Station A to control its parameters externally. Add a control panel to specify these values. Can the values be changed during a simulation? Note: Make sure that the angle is specified in degrees (parameter setting inside the source model) Note: Observe the effect of varying the voltage angle/magnitude on P and Q flow

Ph

Main: Controls

F

RRL

V230

FTYPE

250

90

220

-90

10 9 8 7 6 5 4 3 2 1

60.0 V RL

230

0

1

Fig.4. External control of the source parameters.

T1.12 Modify the circuit to include breakers, breaker controls, meters and the PSCAD ‘fault component’. The case should look like as shown in figure 5. Plot, E1, I1 and the rms value of E1.

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Wind Farm

a

BRK2

BRK1

E1

E1

BRK3 Timed Fault Logic

BRK2

Tim ed Breaker Logic Closed@t0

RL

I1

Timed Breaker Logic Closed@t0

60.0 BRK1

V

Q2

F

Q2

A V

E1

RRL

Timed Breaker Logic Closed@t0

P2

0.074 [H]

Ph

0.14 [H]

BRK3

I1

Fault inception - 0.4 s and at 0.404 s

0 = No Fault 1 = Phase A to Ground 2 = Phase B to Ground 3 = Phase C to Ground 4 = Phase AB to Ground 5 = Phase AC to Ground 6 = Phase BC to Ground 7 = Phase ABC to Ground 8 = Phase AB 9 = Phase AC 10 = Phase BC 11 = Phase ABC

V230

Main : Controls Ph230

250

90

220

-90

230

0

FTYPE

10 9 8 7 6 5 4 3 2 1

1

Fig.5. Meters, breakers and faults. T1.13 Simulate an A-G fault. The fault inception time is 0.4s. The fault duration is 0.5 s. Note the dc offset of I1. (The dc offset can cause mal-operation of protection due to CT saturation. We will study this in later on as a separate example.)

T1.14 What factors influence the initial dc offset and its rate of decay? Change the fault inception time to 0.404 s and observe the results. T1.15 Breaker 3 is initially closed. Open and close this breaker at 0.5 s and 0.65 s respectively. Save the case! The case should be saved as T_01_d.psc before proceeding. T1.16 Include a FFT block in your simulation cases shown in figure 6. Convert I1 to its sequence components. Verify the results of the FFT for different fault types. Add a ‘poly-meter’ to observe the frequency spectrum. Note: The instructor will demonstrate the use of the ‘phasor meter’.

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1

1

1

2 I1 1

XA

2

XB

3

XC

I1 I1

Mag+ Mag- Mag0 (31) (31) (31) Ph+ (31) FFT Ph(31) Ph0 (31) dcC

F = 60.0 [Hz] dcA

dcB

Fig.6. FFT Block. T1.17 Load the case T_01_e.psc from the example cases given to you as course material. Study the ‘sequencer units’ available to define a series of timed events. Save the case!

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Tutorial 2 – Capacitor Switching Study: T2.1 Create a folder called c:……/PscadTraining/T_02. Save the case T_01_e.psc as T_02_a.psc. The utility plans to add 300 MVars of capacitive reactive power at station A to support the 230 kV bus voltage. A transient study is required to design equipment of this installation. Calculations and simulations are required to determine the values/ratings of the associated limiting reactors (inrush and outrush) Modify the simulation case to include a sub-page as shown in fig. 1. GT230

230 kV Voltage support Cap. Bank

Ph F

RRL

60.0 V RL

Fig.1 Capacitor banks at Station A. The circuit inside the sub page represents a 230 kV capacitor bank with 4 steps per phase (see attached diagrams). Each step is rated at 25 Mvar/phase. The capacitor banks are solidly grounded. The inrush and the outrush reactors sizes are to be determined so that the switching transients do not exceed the breaker capabilities and are within the IEEE standards. The values of the outrush/inrush reactors have been determined using IEEE C37.06.2000. T2.2 Use manual breaker controls to switch the breakers R1, R2 and R4. Also measure the currents in the breakers. T2.3 Add a timed breaker component to control breaker R3, measure the currents in R3. Note: Discuss with your instructor the purpose of making R3 operation controllable.

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T2.4 Add meters to measure the currents and voltages on the system side of the outrush reactor. T2.5 Run the case with R1 closed, R2 and R4 open, and R3 set to close at 0.2 s. T2.6 Observe the peak value and frequency of oscillation of the current in R3. T2.7 Observe the peak value and frequency of oscillation of the current at the outrush reactor. T2.8 Note the differences between (7) and (8). Discuss the results. Important: Ensure that you are using the proper time step and for visualization purposes, the proper plot step! T2.9 A Peak inrush current depends on POW switching. This should be studied to ensure that the breaker meets the TRV and di/dt capabilities. T2.10 Use the Multiple Run component to control the R3 closing time. Also record the currents in Breaker R3 and main feeder current. Set the multiple run to switch for 5 sequential points on the wave. Can we do random switching over a cycle? Can we optimize the run length using a snapshot? Take a snapshot at 0.199sec and the run multiple run for 20 sequential points on the wave. Compare your results with IEEE standard results. Can the simulation time step be changed when the case is run from a snapshot file? T2.11 What are some considerations for the selection of time-step for this type of simulation?

T2.12 EXTRA: Check the impedance spectrum using the ‘Harmonic Impedance’ component. This is an important step in the design of capacitor banks. The addition of the capacitors can give rise to system resonances that are not acceptable. Is this circuit appropriate to check for system resonances? Why? (not enough details of the system around the Station A bus is included to capture the frequency effects)

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1.00E-06 1.00E-06 1.00E-06 1.00E-06 1.00E-06

Series1

1.00E-06 1.00E-06 1.00E-06 1.00E-06 1

3

5

7

9

11

13

15

17 19

Save the case!

The case should be saved as T_02_b.psc before proceeding. T2.13 Modify the circuit as shown in figure 2 to include surge arrestors. The surge arrestors should protect the capacitors from switching over voltages. Re-strike of capacitors breaker can cause large over-voltage transients and is usually the criteria for the selection of MOVs. Discuss the data entry for the MOV model.

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0.00317

0.05635 [MW] -3.988e-005 [MVAR]

0.09202 [MW] -79.7 [MVAR]

Closed@t0 Logic Breaker Tim ed

R3

R2 R2

MOV

0.05635 [MW] -3.988e-005 [MVAR]

R2

0.08013 [MW] -79.82 [MVAR]

R1 R1

kJoules Imov

Closed@t0 Logic Breaker Timed

Outrush Reactors MOV

R3

R4 R4

Fig.2. Surge arresters. T2.13 Breaker R3 is initially closed. It is opened at 0.204 s but re-strikes at 0.2124 s. Observe the energy accumulation in the MOV of phase A. can the MOV handle this energy? Is a statistical study required to design the MOV ratings? Save the case!

The case should be saved as T_03_a.psc before proceeding.

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Tutorial 3 – Inrush current and line energizing. T3.1 Create a folder called c:……/PscadTraining/T_03. Save the case T_02_b.psc as T_03_a.psc. Open the capacitor main breaker R3. Keep all other breakers closed. Make the ‘fault’ component inactive. Most transient studies require the accurate modeling of transformers and transmission lines. Transformer inrush requires the accurate modeling of the non-linear iron core. Switching transient studies require the modeling of transmission lines to include the effects frequency dependent line parameters and traveling wave phenomena. T3.2 Use detailed models to represent the 33/230 kV transformer and the 55 km transmission line. The transformer has a Y-Y configuration and consists of three single phase units. The no load current is 1 %. The no load and copper losses are 0.003 pu and 0.002 pu respectively. The conductor arrangement of the line is as shown below. dependent phase model to represent the line.

G1 10 [m]

C2 5 [m]

C1

Use the frequency

G2 10 [m] C3 10 [m]

30 [m]

Tower: 3H5 Conductors: chukar Ground_Wires: 1/2"HighStrengthStee 0 [m ]

Fig.1. 230 kV Transmission tower.

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Timed Breaker Logic Open@t0 Timed Breaker Logic Open@t0 Wind Farm

a

I2BRK1A

Three Phase RMS Voltage Meter BRK1B 3 Phase RMS GT230

BRK1C

BRK2 #1

Line_01

E1

F 60.0 V

Timed Breaker Logic Open@t0

RRL

BRK3

Ph

Line_01 Line_01

P2

RL

Q2 Timed Breaker Logic Open@t0

I1 E1

BRK3 I1

#2

E2

Q2

230 kV Voltage support Cap. Bank

E1

Timed Fault Logic BRK2 Fault inception - 0.4 s and at 0.404 s

Fig.2. Two-area system model for a transient study.

Inrush Study: T3.3 Open the breakers #2 and #3. The transformer is energized on no load by closing the breaker #1. Close breaker 1 at 0.15s and observe the inrush currents. T3.4 Add a 1 Ohm resister in series with the 33 kV winding and observe the results. What effect does the resistance have on the decay of the inrush current? T3.5 Does the breaker closing instant influence the magnitude of inrush? Close the breaker at 0.1535 s and observe the current on phase A. T3.6 Enable the ‘single pole operation’ m...