Influence of lighting systems on power nets

Influence of lighting systems on power nets

Jan Václavík, Aleš Richter

Department of Electrical Engineering, Faculty of Mechatronics Technical University of Liberec - Czech Republic

Lighting systems of our interest

Small and medium size, nominal power from 1 to 100 kWRather high density, small area up to 104 m2

All types of discharge lamps operated on magnetic ballastsOffices, factory halls, commercial centers

Outcommings from power-net and lighting system interractions

Production of light and consumption of electrical energy Distortion of power-net currentIrregular instabilities – over- or undervoltageRegular instabilities – current oscillations

Distortion of power-net current

Changes in conductivity of discharge GL=f(GL, IB)

Nonlinearity of ballast inductor LB=f(IB)

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04-400

-300

-200

-100

0

100

200

300

400

Time [s]

U´F

IX [

V],

IF

IX

[0,0

33

*A],

G

L/G

LMIN

[1

]

UFIX

IFIX

0 100 200 300 400 500 600 700 800 900 1000

-80

-70

-60

-50

-40

-30

-20

-10

0

Frequency [Hz]

Am

plit

ud

e [

dB

]

Irregular instabilities

Occurs only during some transient states, with specific parallel load and energetic balance in power-netDuring startup, load variations, voltage fluctuationsFlickeringUnpredictable out of our concern

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

-300

-200

-100

0

100

200

300

t [s]

Usvit.

Isvit.G

vyboj

Regular instabilities

Result to prevailing or regularly repeating consequencesPredicableCurrent oscillations

Current oscillations

Oscillations of RNET-LNET-CCOMP circuit

~

RN

RLC obvod

LN

C

L

Lamp

Power net Lighting system

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04-400

-300

-200

-100

0

100

200

300

400

čas [s]

U´F

IX [

V],

I FIX

[0,0

33

*A],

G

L/G

LMIN

[1

]

UFIX

IFIX

GL/GLMIN

UFIX

IFIX

GL/GLMIN

Simulation and experiments

Computer model of lighting system and associated power-netConductivity model of discharge lampNon-linear model of ballast inductorSimple model of ballast capacitorModel of power net in form of equivalent lumped circuit parameters

Results from simulationsCCOMP=0, LNET=0

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

-300

-200

-100

0

100

200

300

t [s]

Usvit.

Isvit.G

vyboj

Results from simulationsCCOMP=4.5 μF, LNET= 21 mH

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

-300

-200

-100

0

100

200

300

t [s]

UFIX

IFIX

GLAMP

Laboratory model of lighting system

Fitting for 24 fluorescent lamp with magnetic ballastsAllows switching between different ballast and compensationBehavior like a real lighting systemComfortable measurements

Work done

Finished measurement and analysis of current oscillations in lighting systemsFinished building of mathematical and laboratory model of lighting systems Successfully produced the same current distortion in models as is realityModels proves to be useful for testing hypotheses

Work in progres

Precautions against current oscillations

~

RNET

LNET

CC Ballast

Lamp

Supply net Lighting system

LF

Filter

Work to do…

Fine-tune parameter of the mathematical modelSuggest and test contra-measurements against rise of current oscillationsTest those contra-measurements on real lighting systems