Performance and deterioration tests of Fibre Optic Transmitters

2. Performance and deterioration tests of Fibre Optic Transmitters Oliver Alsted Nielsen TE-ABT-PPE

3. Outline Document reference • Personal introductionand background • Status after Donovan’s earlier work • R&D Project introduction • Stage 1 – simple plastic optic fibre (POF) Transmitter system in air • Stage 2 – temperature regulated “container” and tests in heated air surroundings • Stage 3 – Immersion of transmitters in oil and repeat tests • Results • Next steps • Project conclusion (so far)

4. Who am I? Document reference Oliver Alsted Nielsen 5th semester Electrical Power Engineering Student Aarhus University, Denmark 6 months intern at PPE1st Feb – 31st July

5. Past School Projects Document reference Embedded systems Motor controls 3 phase power systems Energy system protection (CB’s, CT’s, RCD’s etc)

6. Continuation of DovonanLebon’s Work Chosen to test for 200+ hours to reproduce same optic power drop Document reference Investigate the cause of power losses from the POF transmitterson bias boards

7. Background: Transmitter sends an on-off pulse whose frequency is directly proportional to thyratron voltage grid #1. Used in systems MKP, MKE, and MKI. The bias board is used to check ageing of thyratron. Thyratron switch tank Bias board Heat sink Fibre optic transmitter Document reference

8. Initial thoughts on the cause of degrading Document reference overcurrent drive of the transmitter Temperature (switch tanks measured up to 70deg C near transmitter) Dielectric oilchemical deterioration of the diode (switch tanks filled with oil)

9. R&D Process Document reference • Stage 1 • Create a simple system in air to evaluate performance of 3 different POF transmitters at ambient air temperature. • Each transmitter-type tested at DC currents • 5 at each current setting, 4 settings, 3 types of transmitters = 60 transmitters up for test • Stage 2 • Develop a heating box which can contain all 60 transmitters and regulate temperature up to 70 degrees • Perform optical power measurements for all 60 transmitters in air at temperatures 50, 60 and 70degrees Celsius • Stage 3 • Fill heating box with dielectric oil and perform same measurements at same temperatures.

10. Stage 1 – baseline performance Document reference Create a simple system and evaluate performance of HFBR1505AZ, HFBR1528AZ and SFH756V transmitters in air.

11. Stage 1 setup • Cooling fan • Transmitters • Multimeter with temp sensor • Optokonpower meter Measured efficiency before any temperature increase: Document reference

12. Stage 2 – Heating system Document reference • Consist of: • Temperature controller + GUI • Datalogger+ PWM output • Temperature sensor (PT100) • Fibre optic transmitters • Heating circuit

13. Heating element Document reference • Simple MOSFET circuit driven with a PWM signalfrom keysightdatalogger • Resistor transfers heat via medium (air or oil) • Assuming no convection Losses, 65W needed to in- crease temp by 10C in 30min

14. Controller and datalogger Document reference Controller implemented as a live VBA script running in excel on PC Datalogger programmed from VBA script, and logs temperature, meanwhile outputting the control signal to the heating circuit

15. Results of the heating system A huge thanks to Tobias Stadlbauer  Document reference

16. Stage 3 – Immerse in oil Spill tray  Document reference Filled up box with same dielectric oil used in the switch tanks (Rhodorsil)

17. Results – SFH756V performance Document reference Output power very temperature dependent Lens effect of the oil might create better connection point Optic power is mostly regained once cooled down

18. Results – HFBR1505 Performance Document reference Lower power output despite higher currents Less deviation, might be because of screw connector Doesn’t perform better in oil than air

19. Results – B867 measurements Document reference Measured power output of transmitter installed in thyratron switch tank (saleve 4) Pulsed measurements much lower than expected compared to DC conditions.

20. Conclusions – so far Document reference Temperature causes optic power output of transmitters to drop roughly by a factor of 2 at 70deg Celsius The power output of the transmitters reset when cooled down. SFH756V performs better immersed in oil than air, might be due to a “lens” effect of the oil. Some ageing effects of the transmitters are seen at 70deg Celsius in air, need to compare with Donovan’s results We see a huge loss of optic power when measuring on pulsed transmitters, compared to DC conditions, uncertain whether it is the meter, or the transmitter.

21. Next steps Document reference Wait out 1 week of 60deg C oil test, and move up to 70deg Analyze the dataand compare with B867 measurements Discuss results (when they are ready) and agree on a long term solution

22. Thank you for listening  Document reference

23. Additional slides Document reference

24. HFBR1505AZ POF transmitter Document reference

25. HFBR1528AZ POF Transmitter Document reference

26. SFH756V POF Transmitter Document reference

27. Sequence of heating system Document reference

28. HFBR1528AZ performance Document reference

29. Transmitter comparison Document reference