Influence of lighting systems on power nets

1. Department of Electrical Engineering, Faculty of Mechatronics Technical University of Liberec - Czech Republic Influence of lighting systems on power nets Jan Václavík, Aleš Richter

2. Lighting systems of our interest • Small and medium size, nominal power from 1 to 100 kW • Rather high density, small area up to 104 m2 • All types of discharge lamps operated on magnetic ballasts • Offices, factory halls, commercial centers

3. Outcommings from power-net and lighting system interractions • Production of light and consumption of electrical energy  • Distortion of power-net current • Irregular instabilities – over- or undervoltage • Regular instabilities – current oscillations

4. 400 0 -10 300 -20 200 -30 100 Amplitude [dB] -40 U´FIX [V], IFIX [0,033*A], GL/GLMIN[1] 0 -50 -100 -60 -200 -70 -300 -80 -400 0 100 200 300 400 500 600 700 800 900 1000 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 Frequency [Hz] Time [s] U FIX I FIX Distortion of power-net current • Changes in conductivity of discharge GL=f(GL, IB) • Nonlinearity of ballast inductor LB=f(IB)

5. Irregular instabilities • Occurs only during some transient states, with specific parallel load and energetic balance in power-net • During startup, load variations, voltage fluctuations • Flickering • Unpredictableout of our concern

6. U 300 svit. I svit. G vyboj 200 100 0 -100 -200 -300 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 t [s] Regular instabilities • Result to prevailing or regularly repeating consequences • Predicable • Current oscillations

7. 400 Power net Lighting system U U FIX FIX I I 300 FIX FIX G /G G /G L L LMIN LMIN 200 R L N N 100 Lamp C U´FIX [V], IFIX [0,033*A], GL/GLMIN[1] 0 ~ RLC obvod -100 L -200 -300 -400 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 čas [s] Current oscillations • Oscillations of RNET-LNET-CCOMP circuit

8. Simulation and experiments • Computer model of lighting system and associated power-net • Conductivity model of discharge lamp • Non-linear model of ballast inductor • Simple model of ballast capacitor • Model of power net in form of equivalent lumped circuit parameters

9. U 300 svit. I svit. G vyboj 200 100 0 -100 -200 -300 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 t [s] Results from simulationsCCOMP=0, LNET=0

10. U 300 FIX I FIX G LAMP 200 100 0 -100 -200 -300 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 t [s] Results from simulationsCCOMP=4.5 μF, LNET= 21 mH

11. Laboratory model of lighting system • Fitting for 24 fluorescent lamp with magnetic ballasts • Allows switching between different ballast and compensation • Behavior like a real lighting system • Comfortable measurements

12. Work done • Finished measurement and analysis of current oscillations in lighting systems • Finished building of mathematical and laboratory model of lighting systems • Successfully produced the same current distortion in models as is reality • Models proves to be useful for testing hypotheses

13. Lighting system Filter Supply net L R NET NET Lamp L F ~ C C Ballast Work in progres • Precautions against current oscillations

14. Work to do… • Fine-tune parameter of the mathematical model • Suggest and test contra-measurements against rise of current oscillations • Test those contra-measurements on real lighting systems