Power Quality - 3leon.fe.uni-lj.si/media/uploads/files/KEE okt13 IPapic 3.pdf · Power Quality, Ljubljana, 2013/1419 Detuned filter • frequency impedance characteristics – voltage

1

Course

Power Quality - 3

Ljubljana, Slovenia2013/14

Prof. dr. Igor Papič[email protected]

Harmonics - design of power factor correction devices

Content

1st day 2nd day 3rd day 4th day 5th day

Session 1

Introduction to Power Quality • what is PQ • economic value • responsibilities

Harmonics – definitions • calculations • non-linear loads • harmonic

sequences

Harmonics - design of power factor correction devices • resonance points • filter design

Flicker case study • calculation of

flicker spreading in radial network

• variation of network parameters

Interruptions • definitions • reliability indices • improving

reliability

Session 2

Basic terms and definitions • voltage quality • continuity of

supply • commercial

quality

Propagation of harmonics • sources • consequences • cancellation

Flicker - basic terms • voltage variation • flicker frequency • sources • flickermeter

Voltage sags – definitions • characteristics • types • causes

Consequences of inadequate power quality • voltage quality • interruptions • costs

Session 3

PQ standards • EN 50 160 • other standards • limit values

Harmonics - resonances in network • parallel

resonance • series resonance

Flicker spreading • radial network • mashed network • simulation • examples

Propagation of voltage sags • transformer

connections • equipment

sensitivity • mitigation

Modern compensation devices • active and hybrid

compensators • series and shunt

compensators

Session 4

PQ monitoring • measurements • PQ analyzers • data analyses

Harmonics case study • calculation of

frequency impedance characteristics

Flicker mitigation • system solutions

– network enforcement

• compensation

Other voltage variations • unbalance • voltage

transients • overvoltages

Conclusions • PQ improvement

and costs • definition of

optimal solutions

Power Quality, Ljubljana, 2013/14 3

2

Design of PFC devices

• influence of impedance change– compensator impedance varies with the number of used

compensation stages (crossing of resonance points)– network impedance change has large influence on

frequency response– load impedance has minor influence on frequency

response• detuned filter

– series connection of inductor and capacitor– resonance frequency is below the characteristic harmonic

(141 Hz, 225 Hz)– good response under different operating conditions


Influence of network impedance change

• frequency impedance characteristics– data for calculation of one supply transformer 20/0,4 kV

(two transformer in previous case)– short-circuit voltage

– rated power

– rated voltage

– ratio R/X

% 13,4=scu

kV 4,0kV; 20 == LVMV UU

4/1)/( =TRXR

MVA 63,0 x 1=nS



• frequency impedance characteristics– calculation of parameters of one supply transformer

20/0,4 kV

TRTRTR

TR

TRsc

n

NNTR

TR

sc

n

LVTR

LfjRfjZXR

XRuS

UR

XRu

SUL

ππ

π

2)2(

m 54,2)/(1

)/(100

μH 4,32)/(1

1100100

2

2

2

2

+=

Ω=+

=

=+

=


3


• frequency impedance characteristics– harmonic source

is on the network side

• impedance characteristics as a function of frequency

• one supply transformer

0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1

10

100






• two supply transformers(previous case)

0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1

10

100





• impedance characteristics as a function of number of used compensation stages

• one supply transformer 0 0.2 0.4 0.6 0.8 1

0.01

0.1

1

10


4





• two supply transformers(previous case) 0 0.2 0.4 0.6 0.8 1

0.01

0.1

1

10




is on the load side



0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1




is on the load side


• two supply transformers(previous case)

0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1


5



is on the load side



0 0.2 0.4 0.6 0.8 10.01

0.1

1




is on the load side


• two supply transformers(previous case) 0 0.2 0.4 0.6 0.8 1

0.01

0.1

1


Detuned filter

• frequency impedance characteristics– equivalent circuit with detuned filter


6

Detuned filter

• frequency impedance characteristics– data for calculation of detuned filter

– rated voltage

– reactive power

– filter frequency

– ratio R/X of C

– ratio R/X of L

MVAr 40,0=fQ

kV 4,0=LVU

50/1)/( =fCXR

10/1)/( =fLXR

Hz) (225 Hz 141=rf


Detuned filter

• frequency impedance characteristics– calculation of parameters of detuned filter

• detuned filter• 141 Hz, p = 12,5 %• 225 Hz, p = 5,0 %

( )( ) ( ) 125,0Hz 252;05,0Hz 141

502 2

2

2

22

==

===

ppff

CLprr

ff πωω


Detuned filter


• detuned filter

( )

( ) ( )

( )( ) ( ) mH 066,0Hz 252;mH 183,0Hz 141

21

mF 57,7Hz 252;mF 96,6Hz 141100

1

2

2

==

=

==

−=

ff

frf

ff

LV

ff

LL

CfL

CCU

pQC

π

π


7

Detuned filter


• detuned filter

ffff

ff

fLffCf

f

CfjLfjRfjZ

RR

XRCXRC

R

πππ

ππ

212)2(

m 10)Hz 225( ;m 15)Hz 141(

)/(502)/(5021

++=

Ω=Ω=

⋅⋅⋅+⋅⋅⋅

=


Detuned filter

• frequency impedance characteristics– voltage harmonic source is on the network side


Detuned filter

• frequency impedance characteristics– harmonic source is on the network side

• impedance from the network side• series resonance

)2(Z)(Z valueabsolute

)(Z1

)(Z1

1)(Z)(Z)(Z

11

1

fjj

jj

jjj

fL

TRSC

πω

ωω

ωωω

=→

+++=


8

Detuned filter – frequency response




• filter resonance frequency is 141 Hz

0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1

10

100







0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1

10

100



0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1

10

100







9





• comparison with classical compensator

0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1

10

100


Detuned filter

• frequency impedance characteristics– current harmonic source is on the load side


Detuned filter

• frequency impedance characteristics– harmonic source is on the load side

• impedance from the load side• parallel resonance

)2(Z)(Z valueabsolute

)(Z)(Z1

)(Z1

)(Z1

1)(Z

22

2

fjj

jjjj

j

TRSCfL

πω

ωωωω

ω

=→

+++

=


10



is on the load side



0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1




is on the load side



0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1




is on the load side




0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1


11



is on the load side


• comparison with classical compensator

0 100 200 300 400 500 600 700 800 900 10001 .10 3

0.01

0.1

1


Flicker - basic terms

Content


Session 1



sequences






reliability

Session 2



quality





Session 3










compensators

Session 4






• compensation





optimal solutions


12

Flicker – basic terms

• Voltage fluctuation• What is flicker?• Flicker frequency• Causes of flicker• Flicker evaluation• Flicker meter• Compatibility and planning levels


Voltage fluctuation

• voltage fluctuation – a series of voltage changes or a cyclic variation of the voltage envelope

• voltage fluctuations (rms value) can cause perceptible (low frequency) light flicker depending on the magnitude and frequency of the variation


What is flicker?

• flicker – impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time

• the range of modulation frequency that causes noticeable flicker is in the 0.5-25 Hz band, voltage variations are less than 10 %

• the most annoying flicker occurs at the voltage fluctuation with the frequency 8.8 Hz.

• flicker represents one of the largest problems related to power quality in the power system of Slovenia


13

What is flicker?


Flicker frequency – case 1

• What is the frequency of flicker?– assume sinusoidal modulation– what signal does represent flicker with frequency 3 Hz


Flicker frequency – case 2

– or


14

What is the frequency of flicker

– case 1

– case 2

tmtVtv fωω coscos)( 0 += Hz3 Hz500 == fff

ttmVtv f 0cos)cos1()( ωω+=

⎥⎦⎤

⎢⎣⎡ −+++= tmtmtVtv ff )cos(

2)cos(

2cos)( 000 ωωωωω

Hz47 Hz53 Hz50 000 =−=+= ff fffff


Causes of flicker

– loads drawing large and highly variable currents

– arc furnaces installations

• voltage 20 kV

time (s)


Causes of flicker

– steel rolling mils– induction motors

starting

Vol

tage

(%)


15

Causes of flicker

– welding machines– motor drives with cycloconverters

• simulation results (interharmonics)

time


Causes of flicker

– wind farms in distributed production– switching of capacitor banks – households

• pumps, refrigerators, air conditioning, washing machines, drills

• devices with heavy-start motors

– …


Flicker evaluation

• flicker meter– IEC 61000-4-15: Electromagnetic compatibility (EMC) -

Part 4: Testing and measurements techniques - Section 15: Flickermeter - Functional and design specifications

– flicker severity – intensity of flicker annoyance defined by the UIE-IEC flicker measuring method and evaluated by short and long term severity


16

Flicker evaluation

• flicker meter– short term severity Pst – measured over a period of 10

minutes– long term severity Plt – calculated from a sequence of

12 Pst values over a two hour interval, according to the following expression:

3

12

1

3st

lt 12

∑== i

iPP


Flicker evaluation

– comparison between Plt and Pst


Scheme of a flicker meter

input voltage adaptor

demodulator

weighting filter

BLOCK 1 BLOCK 2 BLOCK 3 BLOCK 4 BLOCK 5

squaring and

smoothing

dB

35

0

0,05

-3

-60

Hz

range selector

∆U / U ( % )

X2

P

Pst and Plt

calculation of

Pst and

Plt

statistical evaluation

voltage

mesurement

simulation of lamp-eye-brain response

Hz 8,8

1

0


17

Scheme of a flicker meter

• Block 1 – Input voltage adaptor and calibration checking circuit– signal generator for calibration and checking– voltage adapting circuit that scales the input signal to a

reference per-unit level• Block 2 – Square law demodulator

– the input to the flicker meter is the relative voltage variation– the modulated wave must be extracted from carrier (50 or 69

Hz)– quadratic demodulator simulates the behavior of a lamp


Scheme of a flickermeter

• Block 3 and 4 – Weighting filters, squaring and smoothing– block 3 is composed of a cascade of two filters and a measuring

range selector– first filter eliminates the dc and double mains frequency ripple

components of the demodulator– second filter is weighting filter block that simulates the

frequency response of a coiled filament gas-filled lamp (60 W, 230 V) combined with a human visual system

– block 4 is composed of a squaring multiplier and a first order low-pass filter

– the human flicker sensation via lamp, eye and brain is simulated by the combined non-linear response of blocks 2, 3 and 4


Scheme of a flickermeter

• Block 5 – On-line statistical analysis– the statistical classifier models human irritability in the presence

of flicker stimulation– it provides the statistical information required to calculate short-

term flicker severity Pst (observation period is 10 minutes)

– smoothed percentil values– i.e. P0.1 – the level exceeded by only 0.1 % of the observation

period (10 minutes)

s50s10s3s11,0st 08,028,00657,00525,00314,0 PPPPPP ⋅+⋅+⋅+⋅+⋅=


18

Flicker value

• required magnitude of voltage fluctuation for sinusoidal and rectangular modulation to get the flicker vale P = 1

• the response function is based on perceptibility threshold found at each frequency by 50 % of the persons tested


Flicker value

• multiple fluctuating loads may be impacting the same network

• aggregate Pst value calculation from N loads

– m = 4 coordinated loads to avoid coincident fluctuations– m = 3 likelihood of coincident fluctuations is small– m = 2 likelihood of coincident stochastic noise is likely– m = 1 likelihood of coincident fluctuations is small

mN

i

miPP ∑

=

=1

stst


Compatibility and planning levels

• graphical representation of flicker levels– planning level is usualy less than planning level– compatibility level may be exceed 5% of the evaluation

period


19


– compatibility levels– EN 50160 gives

higher value for Plt(1.0, 95 % value)

– planning levels

quantitycompatibility levels for MV and LV networks (IEC/TR3 61000-3-7)

Pst 1.0Plt 0.8

quantityplanning levels

(IEC/TR3 61000-3-7)MV HV

Pst 0.9 0.8Plt 0.7 0.6



• required short-circuit power in the point of common coupling PCC– primarily depends on nominal power of a supply

transformer of disturbing load– Ssc = (90÷160)·Str [MVA]– empirical and statistical evaluation


Flicker spreading

20

Content


Session 1



sequences






reliability

Session 2



quality





Session 3










compensators

Session 4






• compensation





optimal solutions


Flicker spreading

• calculation of voltage variation– dynamic load

X·I

φ

θ

R·I

U1

U2

I

I

U1 U2

R, X

P, Q

ϕϕ sincoscos 21 ⋅⋅+⋅⋅+=⋅ IXIRUΘU

ϕϕ sincos21 ⋅⋅+⋅⋅=− IXIRUU

1cos ≈Θ


Flicker spreading

• relative voltage variation

22

22

2

21 sincosU

IUXIURU

UU ϕϕ ⋅⋅⋅+⋅⋅⋅=

−

2nn U

QXPRU

U ⋅+⋅=

Δ

sc2nn S

QU

QXU

U=

⋅≈

Δ


21

Flicker spreading

• relative voltage variation– active and reactive power variations of an arc furnace


Flicker spreading

• flicker level decreases in the direction from the disturbing load towards supply source

• flicker level practically does not change in a radial direction from the disturbing load where are no supply sources

• flicker reduction on transformers


Flicker spreading

• transfer coefficient of flicker in a radial network between point A and P (disturbing load)

• calculation in a mashed network is more complex – use of simulation tools

( )( )PA

st

stAP P

PTC = A P

P


22

Flicker spreading

• flicker spreading in a radial network– case A

A P

P

A P

P

ZA ZAP

( ) ( ) ( )APA

AstAPstst PPA

ZZZ

PTCPP+

⋅=⋅=


Flicker spreading

• flicker spreading in radial network– case B

A P

P

B

( ) ( ) ( ) ( )P1PPB ststBPstst PPTCPP =⋅=⋅=


Flicker spreading

• flicker spreading in radial network– case C

A B

P

P

( ) ( ) ( )BPABA

ABAstBPstst PPB

ZZZZZ

PTCPP++

+⋅=⋅=


23

Flicker spreading

• flicker spreading in radial network– case D

A P

P B

( ) ( ) ( )( ) ( ) APstAPst

BAAPstBPstst

P1PPPB

TCPTCPTCTCPTCPP

⋅=⋅⋅==⋅⋅=⋅=


Simulation of flicker spreading

• steady-state calculation– model of transmission system– switch on/off of the load– change of voltage magnitudes– injection of load current

• dynamic simulations– model of transmission system– model of arc furnace– model of flicker meter– Influence of generator voltage controllers – models of compensation devices

• calibration of simulation model wit measurements results• calculation of flicker levels for all buses


Flicker spreading

• flicker spreading in mashed network– load flow method– two states of s disturbing load (0,1)– calculation of relative voltage drops– calculation of transfer coefficients

2,1,0

,1,0

xx

xx

x

xx VV

VVVVv

+

−=

Δ=Δ

j

iij v

vkvΔΔ

=


24

Flicker spreading

• flicker spreading in mashed network– load flow method– comparison with

measurements– variation of load


Flicker spreading

• flicker spreading in mashed network– current injection method

11 1N 1

2

AAA A

N-1

N1 NN N

Y . . . . . Y0. . . .. . . .0. Y .. . . .0. . . .

Y . . . . . Y0

VV

VI

VV

⎡ ⎤⎡ ⎤⎡ ⎤⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥ = ⋅ ⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎢ ⎥⎣ ⎦ ⎣ ⎦ ⎣ ⎦

M

M

M

M )()(

j

iij V

Vkvℜℜ

=

IYV 1−=


Flicker spreading

• flicker spreading in mashed network– current injection

method– comparison with

measurements– variation of

injected current


25

Flicker spreading

• flicker spreading through transformers– in a radial direction from the disturbing load towards

lower voltage levels (first approximation is value 1)– transfer coefficient of flicker from EHV to HV level is

approximately 0.8– transfer coefficient of flicker from HV to MV level is

approximately 0.9 (worst case)– transfer coefficient of flicker from MV to LV level is

approximately 1


Example of flicker spreading analysis

• measurement campaign in Slovenian transmission network– 31 locations– analysis of measurement results

• simulation of flicker spreading– network model– calibration of the model wit measurement results– simulation of flicker spreading in all nodes– present situation– future situation (2020)– analysis of compensation measures


Flicker measurement locations


26

Flicker measurement results (SIST EN 50160)

flicker level (Plt) 95 % values location voltage

level (kV) L1 L2 L3

RTP Jeklarna Jesenice 110 7,41 7,50 7,85 RTP Železarna Ravne 110 2,87 2,80 2,68 RTP Lipa 110 1,62 1,48 1,57 RTP Okroglo 110 1,256 1,331 1,415 RTP Zlato polje 110 1,25 1,33 1,41 RTP Kleče 110 0,85 0,87 0,92 RTP Beričevo 110 0,74 0,69 0,80 RTP Lj Center 110 0,79 0,80 0,85 RTP Šiška 110 0,92 0,95 1,02 RTP Logatec 110 0,90 0,94 1,00 RTP Slovenj Gradec 110 1,47 1,44 1,33 RTP Podlog 110 0,82 0,76 0,79 RTP Pekre 110 0,60 0,62 0,56 RTP Maribor 110 0,50 0,51 0,48 RTP Ljutomer 110 0,50 0,52 0,53



flicker level (Plt) 95 % values location voltage

level (kV) L1 L2 L3

RTP Ljutomer 110 0,50 0,52 0,53 RTP Rače 110 0,60 0,52 0,51 RTP Laško 110 0,81 0,75 0,78 RTP Hudo 110 0,72 0,88 0,75 RTP Kočevje 110 0,81 1,98 0,87 RTP Divača 110 0,39 0,40 0,56 RTP Vrtojba 110 0,30 0,31 0,44 RTP Tolmin 110 0,40 0,37 0,41 RTP Koper 110 0,63 0,61 0,65 RTP Beričevo 220 0,56 0,58 0,60 RTP Podlog 220 0,34 0,35 0,41 RTP Kleče 220 0,56 0,58 0,60 RTP Beričevo 400 0,59 0,59 0,60 RTP Podlog 400 0,41 0,42 0,46 RTP Okroglo 400 0,74 0,74 0,74 RTP Krško 400 0,27 0,23 0,59



• arc furnace 40 MVA• short and long term flicker level at 110 kV


27


• arc furnace 40 MVA• long term flicker level and current at 110 kV - correlation



• network node – different configurations• cumulative flicker levels – determination of 95 % value


Measurement results at 110 kV level

voltage (kV) current (A)

time (s)time (s)


28

Measurement results at 20 kV level

voltage (kV) current (A)

time (s) time (s)


Measurement results

• arc furnace 40MVA

• voltage at 110 kV• voltage at 20 kV• current at 20 kV


Measurement results

• arc furnace 40MVA

• voltage at 110 kV• voltage at 20 kV• current at 20 kV


29

Measurement results

• arc furnace 40 MVA• correlation between the flicker level at 110 kV and 20 kV

0

1

2

3

4

5

6

0 5 10 15 20 25

Pst Jeklarna Ravne UHP 20 kV

Pst J

ekla

rna

Rav

ne 1

10 k

V


Flicker spreading simulation

• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– present situation – summation law m = 2.7

12%

17%

20%

51%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%

33%

67%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6

0%0%

29%

71%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6

110 kV 220 kV 400 kV percentage of nodes


Flicker spreading simulation in 110 kV network (m = 2.7)


30

Flicker spreading simulation for the year 2020

• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– results for the year 2020

5%

19%

27%

49%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6

0%0%0%

100%Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6

0%0%0%

100%Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6



Flicker spreading simulation in 110 kV network for the year 2020


Flicker mitigation

31

Content


Session 1



sequences






reliability

Session 2



quality





Session 3










compensators

Session 4






• compensation





optimal solutions


Flicker mitigation

• system enforcement – increased short-circuit power• electrical separation of disturbing loads – disconnected

substation busbars• compensation measures

– series reactor– Static Var Compensator – SVC– Static Compensator - StatCom

• elimination of flicker sources – power reduction of disturbing loads (if possible)

• lighting technology– fluorescent lamps are considered to be less sensitive to voltage

flicker than incandescent lamps– ban of incandescent lamps due to energy savings reasons


System enforcement

• increased short-circuit power will reduce flicker level– new parallel

lines– additional

transformers– connection to

the higher voltage level

line disconnection


32

Separation of disturbing loads

• electrical separation of disturbing loads – disconnected substation busbars

Plt = 3,03Plt = 0,47

Plt = 0,71Plt = 0,71

TR 412400/110 kV

TR 411400/110 kV

Okroglo 110 kV »ostali«

Okroglo 110 kV »sunkovit«

Okroglo 400 kV

Plt = 5,31

TR 412400/110 kV

TR 411400/110 kV

Okroglo 110 kV

Okroglo 400 kV

Plt = 1,13

Plt = 3,44

Plt = 1,13

Plt = 0,52

RTP Jeklarnasunkovit odjem

RTP Jeklarnasunkovit odjem



• electrical separation of disturbing loads – connected substation

busbars– arc furnace is supplied

by two transformers in parallel



• electrical separation of disturbing loads – disconnected substation

busbars– arc furnace is supplied

by one transformers


33

Compensation measures

• series reactor– for minor flicker level reduction

in the point of common coupling – redistribution of flicker level– influences the operation of arc

furnace

arc

seriesreactors



• Static Var Compensator – SVC– flicker and reactive power

compensation– controllable shunt connected reactance– TCR – Thyristor Controlled Reactor is

the main element– reactive compensation current is a

function of voltage– flicker reduction factor is up to 2– reliable – good operational

experiences– small operational losses



• Static Var Compensator – SVC– single-line diagram– TCR– fixed capacitors and

filters


34


• Static Var Compensator – SVC– voltage profile improvement with SVC



• Static Var Compensator – SVC– arc furnace performance improvement with SVC



• Static Var Compensator SVC– practical applications


35


• Static Compensator - StatCom– flicker and reactive power

compensation– controllable source of reactive

current – Voltage Sources Converter - VSC

is the main element– employs GTO thyristors or IGBTs– flicker reduction factor is up to 5– not a lot of operational

experiences– higher operational losses

compared to SVCPower Quality, Ljubljana, 2013/14 103


• Static Compensator -StatCom– single-line diagram– VSC– fixed capacitors

(tuned filters)



• Static Compensator – StatCom– voltage profile improvement with StatCom– increased power of arc furnace


36


• Static Compensator – StatCom– substantial flicker level reduction



• Static Compensator – StatCom– comparison of the arc furnace currents with the

compensated grid currents



• Static Compensator – StatCom– first StatCom application for flicker mitigation – Hagfors,

Sweden (ABB commercial name SVC Light)


37

Analysis of compensation measures

• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– present situation – no compensation measures

12%

17%

20%

51%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%

33%

67%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6

0%0%

29%

71%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6




• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– only arc furnace A is compensated (SVC)

6%4%

24%

66%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%0%

100%Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6

0%0%0%

100%Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt>0,6




• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– only arc furnace B is compensated (StatCom)

6%

16%

17%61%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%

33%

67%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%

29%

71%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6



38


• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– only arc furnace C is compensated (series reactor)

12%

14%

21%

53%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%

33%

67%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%

29%

71%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6




• analysis of flicker spreading in the Slovenian power system (three arc furnaces)– all three arc furnaces are compensated

1%17%

82%

Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%0%

100%Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6

0%0%0%

100%Plt>1,5 1<Plt<1,5 0,6<Plt<1 Plt<0,6



Documents

Power Quality - 3leon.fe.uni-lj.si/media/uploads/files/KEE okt13 IPapic 3.pdf · Power Quality, Ljubljana, 2013/1419 Detuned filter • frequency impedance characteristics – voltage