pscapscad-wind-power-training

8/10/2019 PSCAPSCAD-Wind-Power-Training

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dm / Tutorial_01 2 / 4

Tutorial 1 Effect of variable wind on grid operation..

T1.1Create a new case by using either the Menu or Toolbar. A new case shouldappear 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. Save the case asWind_variation_01.psc

T1.2 Open the main page of your new case. Build a case representing asimplified two area power system as shown in the figure below. A 145 kmtransmission system connects a small wind farm to the 345 kV transmissionsystem. All connections to Bus 1 are represented by an equivalent 345 kV

source. The equivalent source impedance is derived from a steady state faultstudy at 60 Hz.

The wind farm has 10 generators, each 0.75 MW at 0.69 kV. The voltage isstepped up to 13.8 kV at each machine before connecting to the 13.8/115 kVtransformer. The 10 wind generator installations are modeled as an equivalentmachine of 7.5 MW and a 5 MVA transformer.

All required network data are provided in Appendix 1.

Fig1. Single line diagram of the system

WindA Generators

#1 #2TLine_01T

TLine_02

T

RL

RRL

Ea

Ia

#1 #2

45 km line

100 km line

345 kv'Weak system

P = 5.485

Q = -3.064V = 115.9

V

A

Bus 1

Bus 2

P+jQ

P = 3.639Q = -2.344

V = 13.48

V

A


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Fig2. Details of the wind farm

T1.3Discuss different components of the system model and the input data withthe instructor.

T1.4Run the case with a constant -0.5 pu torque input to the machine. Observepower and reactive power in different line sections.

T1.5 The power in the wind (Pw) is 3

....2

1VCAP pw = . Implement this equation

using the control blocks available in the PSCAD Master Library. Assume aconstant Cpvalue of 0.35 for the exercise.

Wind turbine rotor radius 23.5 mAir density 1.22 kg/m3

Fig 3. Using the wind model in a PSCAD simulation.

T1.6Run the simulation with a mean wind speed of 10 m/s. This will result in atorque of approximately 0.5 pu.

ABRK1

BRK1

TimedBreaker

LogicClosed@t0

P = 3.648Q = -1.908

V = 0.6438

V

A

1.00499

TIMES

TL

I M

W

#1 #2

Tin *-1

Transformer 2

* *

*

3.0

PwN

D

N/D

log X

*Pw

10x

*

X

2

*

Wind Speed

23.5Rotor Radius

3.14159PI

1.22Air Density

0.5Constant

Convert Power to Torque

0.35

N

D

N/D

750000.0W

Vw

Wind Source

GustMean

Tin

Constant Cp assumed

Cp = 0.35

0.75 MW = 750000 W


4/36


T1.7Use the wind model to study the response of the system to a sudden windgust. The gust should be applied when the system is in a steady state.

Gust duration 2 s

Peak gust 2 m/s

Change the gust magnitude and duration to different values and observe results.

Note the voltage fluctuations at the 115 kV load bus.

Note the possible overloading of lines and transformers.

T1.8 Use the wind model to study the response of the system to noise(turbulence) in the wind.

Note the voltage fluctuations at the 115 kV load bus.

Can the voltage fluctuations be controlled using FACTS solutions?

T1.9Discuss how field data of wind can be used in a simulation. The data inwindvariation.txt is from a field recording. Use this data in the simulation study.

Fig 4. Reading recorded data of wind speed.

T1.10Discuss how field data of wind can be used in a simulation. The data inwindvariation.txt is from a field recording. Use this data in the simulation study(Fig 4).

T1.11 Load the PSCAD case Wind_variation_02.psc . A STATCOM isconnected at the 115 kV load bus. Observe the voltage variations at the 115 kVload bus during wind speed variations. FACTS devices can be used to solvepower quality problems resulting from wind speed fluctuations.

windvariation.txtw indvariation.txt D+

F

+

4.0

2

Ws


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PSCAD WIND POWER TRAINING

Tutorial 2

Prepared by: Dharshana MuthumuniDate: April 2008Revision: 1Date:


6/36


Tutorial 2 Wind turbine characteristics and pitch control

T1.1Load the case used in Tutorial 1(Wind_variation_01.psc).Save the caseas Wind_pitch_control_01.pscbefore making changes.

T1.2Figure 1 shows the connection of wind related models to be used in a study.The output torque Tinwill be the input to the wind generator.

Discuss each model with your instructor.

T1.3The data and the details of the wind turbine characteristics are listed in aMathCAD worksheet included with your course material. Use the data in thisMathCAD sheet (Turbine_characteristics_V52)

T1.4What is the purpose of the signal CNT?

T1.5At a steady wind speed of 15 m/s, what would be the required pitch angle toregulate the turbine power to 0.5 pu of its rating? (Hint: use the MathCADworksheet)

T1.6 Implement the wind system shown in Figure 1. Study the response of thesystem to wind gusts and ramps.

T1.7 Study the response of the system to wind noise. Does the blade pitchactuator respond to noise.

T1.8Once the simulation is in a steady state (with 15 m/s wind), apply a stepchange in wind speed of 2.5 m/s (15 m/s to 17.5m/s). Does the pitch angle settleat the expected value?

T1.9Apply a larger step change in wind speed (3 m/s). Discuss results.


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Fig1. Wind system models

Fig2. Details of the wind farm

BETA

Vw

TmVw

Beta

W P

Wind TurbineMOD 2 Type

TIME

Wind TurbineGovernor

Beta

PgMOD 2 Type

A

B

Ctrl

Ctrl = 1

CNT

0.5

A 6 Pole MachineMechanical speed =W(pu)*2*pi*f/(pole paris)

Vw

Wind SourceMean

Noise

1.0

A

B

Ctrl

Ctrl = 1

CNT

*N

D

N/D

3.0Pole pairs

Actual hub speedof machine

2 Pi *60.0

Tin

W

P1 *0.133

ABRK1

BRK1

TimedBreaker

LogicClosed@t0

P = 3.648Q = -1.908

V = 0.6438

V

A

1.00499

TIMES

TL

I M

W

#1 #2

Tin*-1

Transformer 2


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Tutorial 3



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Tutorial 3 Voltage sourced converters

T1.1Load the case used PWM_inverter_01.psc .

T1.2 Use this case to understand the basic operation of voltage sourcedconverters.

T1.3In a sinusoidal PWM scheme, a high frequency (triangular) carrier signal iscompared with a low frequency modulating sinusoidal signal to generate thefiring pulses. The resulting voltage at the converter terminals will have a strong

voltage component of the same low frequency. The phase and the magnitude(modulation) of the modulating signal will shape the phase and the magnitude ofthe dominant low frequency voltage component at the converter.

Fig 1. PWM signals used to generate the firing pulses.

T1.4Verify the correct operation of the control system. (i.e. P and Q should settleto the set points)

T1.5 Observe the frequency spectrum of the inverter voltage.

gt1

gt2

gt3

gt4

gt5

gt6

1

EaEcEb

Eab

Ebc

Idc

35

2 6 4

135

2 6 4

dcVltg R=0

P = 147.8Q = -0.8703V= 173.3

V

A

R

=0

Einv

0.5968 [H] 2.5 [ohm]

R=0

26

0.5968 [H] 2.5 [ohm]

260

00

26000

0.5968 [H] 2.5 [ohm]

0.5968 [H] 2.5 [ohm]

#1 #2

Main : Gra hs

7.7950 7.8000 7.8050 7.8100 7.8150 7.8200 7.8250 7.8300 7.8350

-1.00

-0.75

-0.50

-0.25

0.00

0.25

0.50

0.75

1.00

1.25

y

Trig sine1


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T1.6Change the control settings (Kp and Ki) and observe the response. At highgains, will the system become unstable?

T1.7 A more detailed VSC based system is given in the PSCASD caseVSCTrans_wind_01.psc. The synchronous machine on the sending end may

represent wind generation.

Fig 2. VSC transmission example.

The DC link voltage is used as the reference to control the power flow into thenetwork. Discuss this principle.

T1.8Apply a step change in torque (0.15 pu step at 2.5 s). Observe the responseof the system.

a. Note the following signals:b. Machine power and reactive power

c. Machine speedd. Power flow into the network.e. Angle order and its limits of the sending end PWM modulating signal.

T1.9The control of the converters can be used to optimize the performance ofthe wind system.

Can you think of a simple method to limit the power flow into the network during awind gust?(hint: angle of the PWM modulating signal influences power flow)

T1.10 Limit the angle order of the sending end PWM signal. This will limit thepower flow in some way (provided the angle limits are reached).

Observe the machine speed. Does the machine speed settle down aftertransients?

Cable2

C

SE RE

Sending End


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DFIGAssignment:

LoadtheincompletePSCADcasenameddfig_case_01_inc.psc.Usethiscaseasthestartingpointto

buildthe

DFIG

controls

of

the

rotor

side.

1) Usecurrentsourcestorepresenttherotorsideconverter.

2) Usingcontrolblocks,implementaschemetodeterminethepositionofthestatorfluxvector.

S

TL

I M

W

V

Irot

Ira_ref

Irb_ref

Irc_ref

Vbeta

Vsmag

Vc

Va

Isc

C-

D

+

Isb

VbC

-D

+

phisy

phisx

phsmag

G sT

1 + sT

phis

Valfa G

sT

1 + sT

1

sT

1sT

phis

A

B

C

3 to 2Transform

alfa

beta

*0.037Isa

C-

D+

*0.037

*0.037

Y

X

M

P

M

PY

X


12/36

3) Determine the slipangle.This is theanglebetween the rotorAaxisand thepositionof the

statorfluxvector.

4) ThefollowingblockcanbeusedtoconverttheDandQaxisrotorcurrentstorespectivephase

currents.

5) UsesliderstoassignvaluesforIrdandIrq.(Note:StartwithIrd=0.05andIrq=0.2)

6) NotetheresponseofthemachinepowerandthereactivepowerwhenIrdandIrqarechanged.

7) Themachineissettorunat1.1puspeed.Inarealsetup,thesignalIrqwillcontrolthemachine

speed.Canwechangethemachinespeedsetpointandmaintainunchangedsteadystatepower

andreactivepower?

8) ConstructasimplecontrolcircuitthatwillmaintainPandQatdesiredlevels.

angC

+D -

phis

slpangAngleResolver

Iraa

Irbb

Ircc

Ira_ref

Irb_ref

Irc_ref

slpang

to Stator

D

Q

Rotor

alfa

beta

A

B

C

2 to 3

Transform

alfa

beta

Ird

Irq

I

P

*D

+

F

-

I

P

*D

+

F

-

P1

Q1

1.0

1.0

Ird

Irq

25.0

30.0 A

B

Ctrl

Ctrl = 1

A

B

Ctrl

Ctrl = 1

P1

Q1

CNT

CNT

*0.25

*0.25


13/36

9) DiscussthedetailsofamoredetailedDFIGmodelDFIG_Model_Feb_07_*.psc


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Tutorial 5



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Tutorial 5 Low vol tage fault ride through

T1.1Open a new PSCAD case and build the circuit shown in fig 1. (see attachedsheet for data)

Fig 1.Induction machine connected to the system through a step-up transformer.

T1.2 Using the breaker (BRK), apply a fault at the 230 kV bus. The faultimpedance should be selected so that the voltage drop near the wind generatoris around 80%. The fault should be cleared after 2 sec.

T1.3Observe the response of the machine.a. During the faultb. After the fault clearance.

Note the speed change during the event. Note the reactive power requirement of the machine soon after the fault is

cleared.

T1.4Load the case frt_case_SM.psc that is included in with the course material.In this case, the induction machine is replaced by a synchronous machine (fig 2)

RL

RRL

0.037 [H]

100 MVA Transformer

33/230 kV, Z = 0.1 pu 55 km line

230 kV

Station AWind Farm

#1 #2V

AS

TL

I M

W1.004

Stot0.037 [H]

BRKTimed

BreakerLogic

Open@t0BRK

-0.5

Add faultimpedance here

100 MVA/ 33 kV


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Tutorial 6



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Tutorial 6 Power quality issues

T1.1Open the PSCAD case Wind_rot_sample_01.psc.

The mean wind speed is modulated by a sinusoidal signal to include the tower

shadow (rotational sampling) effect. This is the turbulant effect felt by the bladeswhen they cross the turbine tower.

What is the frequency of the sinusoidal signal?

The turbine drives a 6 pole machine. The gear boc ratio is 60. What is themodulating signal frequency (approximate) if the machine operates close to itsrated speed.?

Fig 1.Implementing the rotational sampling effect

T1.2 Observe the voltage at the load bus and at the terminal of the windgenerator.

T1.3 Verify that the voltage fluctuation at the bus is influenced by the networkcharacteristics (e.g. short circuit level).

T1.4 Open the PSCAD case Wind_startup_01.psc .This case simulates thestarting process of a direct connected induction generator. The wind turbinebrings the generator to a set speed (eg. 0.7 pu) before the main generatorbreaker is closed. The machine speeds up, acting as a motor before it settles

down to its generating mode.

T1.5Observe the power flow during this process and verify the motoring action.

Observe the increased reactive power requirement and the starting currentduring the start-up process.

N

D

N/D

60.0

WmCos

Clear

1sT

*

0.05

*D

+

F

+

Vw Vw

*

3.0

A

BCompar-ator 2 Pi

Wind

Gear Ratio No. of Blades 'shadowing index' mean wind speed


19/36


T1.6The high starting current will cause prolonged voltage dips in other parts ofthe network. Discuss the soft starting technique that can be used to limit thestarting current and hence the voltage dips.

Fig 1.Thyristor based soft starting of the wind generator.

T1.7Open the PSCAD case svc_wind_01.psc .This case simulates the softstarting process of a direct connected induction generator. Observe the startingcurrents when the generator is started with and without the thyristors.

Note the timings of the thyristor breaker and the main breaker of the windgenerator.

Can a FACTS device improve the situation?

T1.8Open the PSCAD case svc_wind_02.psc .This case simulates the softstarting process with an SVC (Static VAR compensator). How do you determinethe approximate size of the required SVC (to improve the voltage profile duringstart-up)?

Verify the operation of the start-up process with the SVC in place.

T1.9Open the PSCAD case Wind_startup_01.psc .With the generatordisconnected from the system, perform a generator transformer energizationinvestigation.

Note: Inrush depends on the point on wave of switching. How do you perform abatch mode simulation to capture the worst case?

I M

W

S

TMotor

0.0

*-1.0

Twind

V

A

2.5 MVA Machine

0

Breaker

A

B

Ctrl

Ctrl = 1

TIME


20/36

Network

Data:

Equivalentsource:

345kV

Z+=35Ohms@85degrees

Z0=32Ohms@80deg

Transformer1:

50MVA,345/115kV

Impedance14%(0.14pu)

Losses(noload/cupper):0.001pu/0.002pu

Noload(ormagnetizing)current1%

Transformer

2:

10MVA,115/13.8kV

Impedance1%(0.1pu)



TLine_01

T

TLine_02

T

RL

RRL

Ea

Ia

#1 #2

45 km line

100 km line

P = 5.485Q = -3.064

V = 115.9

V

A

Bus 1

Bus 2

P+jQ

Transformer 1

Per phase load/vo

3 MW / 1 MVAR

66.4 kV/phase

'Weak system'

345 kV


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Transmissionlines:

3conductorflattower

115kVLoad:

15.316 [m]

4.724 [m]

5.486 [m] for Conductors3.81 [m] for Ground Wires

C1 C2 C3

5.0292 [m]

G1 G2

Ground_Wires: 3/8" EHSS

Conductors: Penguin

Tower: TH-10

2.438 [m]

0 [m]

Mid-Span Sag:

.378 [m]

P+jQ

Per phase load/voltage

3 MW / 1 MVAR

66.4 kV/phase


22/36

Wind

System

data:

Thissystemrepresents10 inductionmachines(woundrotor)operatinginparallel.Themachin

arerepresentedbyasingleequivalentmachine/transformer.

Machine

data:

MVA0.75MW*10=7.5

Voltage 0.69kV

Turnsratio0.2805

Inertia3.694

Mechanicaldamping 1%(0.01pu)

Resistance:(stator/rotor):0.0053[p.u.]/0.007[p.u.]

Magnetizinginductance4.0209

Leakageinductance:(stator/rotor):0.1060[p.u.]/0.1216[p.u.]

Transformer

3:

5MVA,13.8/0.69kV

Impedance1%(0.1pu)



BRK1

BRK1

TimedBreaker

LogicClosed@t

P = 3.648Q = -1.908

V = 0.6438

V

A

1.00499

TIMES

TL

I M

W

#1 #2

Tin*-1

Transformer 2


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Data:

Machinedata:

Turnsratio2

Inertia1.7

Mechanicaldamping 00.0001pu

Resistance:(stator/rotor):0.0034[p.u.]/0.00607[p.u.]

Magnetizinginductance3

Leakageinductance:(stator/rotor):0.0202[p.u.]/0.021[p.u.]

0.037 [H]

100 MVA Transformer

33/230 kV, Z = 0.1 pu 55 km line

230 kV

Wind Farm

#1 #2

V

AS

TL

I M

W

Rrotor

+

Rrotor

+

Rrotor

+

External rotorresistance

1.004

Stot

0.0

TimedBreaker

LogicOpen@t0

BRK

-0.5

Add fimpe

100 MVA/ 33 kV


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dm / Tutorial-TCR FACTS Course 1 / 7

Modeling and Application ofFACTS Devices

Tutorial

Basic operation of a Thyristor ControlledReactor

Prepared by:

Dr. Ani Gole Dr. Dharshana Muthumuni

Date: May 2007Revision:Date:


25/36


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. Basic operation of a TCR (Thyristor controlled reactor)

T1.1Create a new case by using either the Menu or Toolbar. A new case should appear in theWorkspace settings entitled noname [psc]. Right-click on this Workspace settings entry andselect 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 T_01.psc

T1.2Open the main page of your new case. Build a case to study the operation of a thyristorcontrolled reactor as shown in fig.1.

The applied voltage is 7.03 kV rms line-neutral at 60 Hz.

The reactor is rated at 33 MVAR (per phase or 100 MVAR 3 phase). What is the requiredinductance?

Fig.1 Single phase TCR circuit.

T

Ia

FP

T

FP

0.0

01[ohm]

Vas

0.00393[H]

33 MVAR (Max7.03 kV rms (l-n)


26/36


T1.3Plot the currents (Ia) and voltages (Vas) on the source side of the circuit.

Fig.2 Basic steps to create a graph with a selected signal.

T1.4The control circuit shown in Fig.3 is used to generate the thyristor firing pulses. Implementthe circuit in the PSCAD case.

Fig.3 Control circuit for firing pulse generation.

120.0

cos(th)

Vc th

sin(th)

VCO

A

B Compar-ator

Alfa

FP

*.5

Main : Controls

180

90

Alfa

120

Ia1

2.61419

Alpa_Order

Alpa_Order


27/36


28/36


T1.6 The variation of the fundamental component of the reactor current with the firing angle isgiven by the following equation.

I( ) V

w L

12

( ) 1

sin 2 ( )( )

:=

Where,

90 100, 180..:= ( ) 90( ) deg:=

Verify the PSCAD results with the calculations outlined in the accompanying MATHCADworksheet (TCR.mcd). You may use the FFT (Fast Fourier Transform) model in the Master libraryto extract different frequency components.

Fig.6. FFT component.

T1.7Discuss the reasons for any differences.

Discuss the Phase angle error due to the time step delay inherent to thesimulation.

Your instructor will explain the calculation program structure of EMTDC and the definition ofelectric and control type models.

T1.8Observe the harmonic spectrum of the source current. Note the absence of higher orderharmonics. The results shown in Fig.7 are for a firing angle of 120 deg.

Fig.7 Harmonic spectrum

Mag

Ph

dc

(7)

(7)

F F T

F = 60.0 [Hz]

Ia

1

Ia_

4.0

0.0

[1] 2.62733


29/36


Note:The harmonic content of the current is given by:

In n,( ) 4 V

L w

sin ( )( ) cos n ( )( ) n cos ( )( ) sin n ( )( )( )

n n2

1( ):=

where n 3 5, 15..:=

Fig.8 Variation of harmonic contant with firing angle

The example discussed so far uses a simplified control setup to generate the firing pulse.

T1.9 Load the case TCR_2.psc.

The firing pulses are generated based on a Phase Locked loop (PLL) based control system. Thephase locked loop generates a sinusoidal signal that is locked in phase to the system voltageVs. Understand the various blocks of the PLL.

T1.10 Observe the internal signals of the PLL.

T1.11 Verify the correct operation of the TCR under the following situations.

Sudden change in the system voltage phase angle (possible due to load changesin the system etc.)

Change in system frequency.


30/36


Appendix:

Peak current (theoretical) at different firing angles (results from Mathcad)


31/36

Tutorial

Simple Thyristor Switched Capacitor (TSC)

This tutorial highlights the operation of a TSC and show the detrimental effect of

misfiring.

There are two different types of firing modes.

Voltage crossing based firing

Forced firing

In TSC firing systems, the Voltage Crossing Based Firing is automatically selected when

the capacitor voltage is larger than the system voltage (usually due to capacitor voltage

amplification due to the series inductor). In this tutorial, we select each of them manually.

a) The TSC stage can be switched On/OFF by the buttons provided on the control

panel. With the parallel discharge resistor (R) set to 100 Ohms, implement the

capacitor On/Off operations. Observe the transients.

b) Set R = 100000 Ohms (infinite). Note that the voltage crossing based switching

will not work as the capacitor voltage is higher than the system voltage (due tovoltage amplification in the L-C circuit).

Set the switch to the forced firing position. The logic is set to fire the thyristor at a

voltage peak. In a real system, they should fire at the peak where the difference

7.0 kV (l-g)

Source

Vc

VsFp

Fp1786.43[uF]

100000.0[ohm]

12

157.5

5E-6

[H]

LC tuned to

300 Hz

33 MVA

Max

VQ

0.0

01[ohm]

V

F

Ph

2:

Misfire Sw.

0

On Switch

0

Reset

0

Forced Firing

1

0Xing Forced1

-1

Retard

0


32/36

between the capacitor and the system voltage is minimum. However the logic

does not ensure this. This gives you the opportunity to investigate what happenswhen you accidentally fire at the wrong peak.

Investigate the waveforms with forced firing at the correct as well as the

incorrect instant. Also, observe the magnitude of the voltage amplification. Does

it agree with theory?

c) A pushbutton is provided to initiate a single thyristor misfire. Investigate the over-

voltages seen by the thyristors following misfires at different instances.A metal oxide arrestor (MOV) is usually placed across the thyristor to prevent

over-voltage damage. As its protection level is set rather low, the arrestor is often

triggered following an over-voltage. It does not conduct during normal operation.

d) Place a surge arrestor across the thyristors and observe the reduced over-voltage

following the misfire.


33/36


34/36

Objective(s):

Modelinganarcfurnace

Modelingflickerduetotheoperationofarcfurnace

MitigationofflickerusingaSTATCOM.

Loadthecaseeaf_statcom.psc.

Thiscaseillustratesthestartingoperationofanarcfurnace.Arcfurnaceloadsarehighly

non linearand random innature.Thisgivesrisetofluctuatingcurrentsandresults in

voltagefluctuations.

Discuss the arc furnace model and different parameters.

Run the case and observe the currents and voltages at different points in the network.

Observe the flicker level. Discuss the flicker meter and other methods used to estimateflicker.

Loadthecasestatcom_6pls_pwm.psc.

Thiscase illustrates thebasic featuresofaSTATCOM.Discusswith the instructorand

understanddifferentcomponentsofaSTATCOManditscontrols.

RunthearcfurnacecasewiththeSTATCOMinoperationandverifythattheflickerlevel

isreduced.

Change

the

STATCOM

transformer

rating

and

determine

the

minimum

rating

required

toreducetheflickerlevels.

dm / Tutorial_05

2 / 4


35/36

Electric arc furnace model

The developed EAF model is based on the non-linear differential equations asoutlined in [1],which models the non-linear characteristics of the electric arc aspictured in Fig. 1a. The equations representing the arc voltage (v) to arc current

(i) are shown below, where r is the arc radius:

ik

krkrdt

drr

m

n 23

21 2 =+

+

iv

r

km

=+2

3

The parameters ki, r and n characterize the arc under a given operatingcondition. In reality, this V-I characteristic shows much more noise due to theunpredictable and chaotic nature of the load. Fig. 1b shows a more realistic EAFV-I characteristic.

Main : XY Plot

-1.50 -1.00 -0.50 0.00 0.50 1.00 1.50-100

-75

-50

-25

0

25

50

75

100+y

-y

-x +x

XAxis Y Axis

I2 V2

Aperture 2.5550660793Width

11.661Position0.000s 20.000s

(a) Ideal (b) Actual

Fig. 1 Ideal and actual V-I characteristic of an EAF

Arc Data Setting:Parameters k1 to k3 can be selected to obtain the EAF settings, such as activepower, reactive power and power factor close to what were measured in the

practical system. As the EAF model is sensitive to the system connected,parameters k1 tok3 may need to be re-tuned if the system configuration changes.The EAF model is designed to be able to take the inputs parameters as variablesso the optimization routines of PSCAD can be used to expedite the process.

Modulation Type setting:The randomness feature of the EAF model is simulated by adding certainsinusoidal and Gaussian noise. The magnitude/frequency of sinusoidal

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modulation and the standard deviation of Gaussian function can be specified.Each phase can be independently controlled.

It is important to note that it is impossible to get a simulation case to match the

observed results perfectly due to the nature of the problem. The important thingis to capture the essential features and the trends of a practical arc furnace.

Reference:[1] A Harmonic Domain Computational Package for Non-Linear Problems and its

Application to Electric Arcs, E. Acha, A. Semlyen, N. Rajakovic. IEEETransactions on Power Delivery,Vol 5, No.3, July 1990.

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