1. IEEE Power Engineering Society Toronto Chapter Ontario Wind Turbines – Testing of Electrical Safety Kinectrics Seminar May, 2007 Eugene Peter Dick IEEE Senior Member 49 Lynngrove Ave Toronto, Ontario epdick@ieee.org 647 438 8116

2. 1.5 MW GE Wind Turbine

3. Foundation - Elevation

4. Tower Height: 65 to 80+ m Base Flange: 5 m , circa 200 bolts (ext, interior) Sections: 3 joined by interior flanges, platforms Access: ladder with fall restraint Bus type: rigid or locomotive flexible cable Section: 500+ mm 2 (1 000+ mcm) Erection: 500 tonne crane

5. Bolt Ring – Duplicated Inside

6. 500 Tonne Crane

7. Nacelle

8. Rotor Blades Diameter: 71 m Speed: 12 – 22 rpm Gearbox: 3-step planetary spur gear, ratio 72 Power vs wind speed:kWk/hr 5014 15021 45028 90036 1 50043 cut out90

9. Generator Rating: 1.5 MW, 1.72 MVA, 575 V, stator 1 509 A Type: double fed, 3 , (induction?) synchronous Rotor via PWM drive rated 300 kW Poles: 6, - / + 20 % speed (864 to 1 440 rpm) H (inertial const): 6.55 s (gen alone 0.8 s) Xd” (subtransient reactance): 0.27 pu Protection: V over / under / unbal, f over / under Control: pf or current compensated V

10. Typical Interconnect Requirements < 88 % V trip in 2 s, < 50 % V trip in 0.16 s > 110 % V trip in 1 s, > 120 % V trip in 0.16 s < 59.8 Hz trip in 300 s, < 57 Hz trip in 0.16 s  V on synch: < 5 %, flicker IEEE Std 519, 1453 dc: < 0.5 % on I harmonics: < 4, 2, 1.5, 0.6 % (h<11, 17, 23, 35) islanding with load: trip in less than 2 s no impact on utility feeder protection

11. Stepup Transformer

12. Transformer / Collection System Xmer: 575 / 34.5 kV, Yg / , Z = 0.76 + j 5.70 % 35-kV, 67 mm 2 (AWG 2/0) concentric Neu cable several units daisy-chained to riser pole may run Neu / bond back to main substation overhead line may be 3 or 4-wire typically 4 collection lines to main station, CB each collection line may have gnding Xmer main Xmer: 34.5 / 230 kV, 100 MVA

13. Stepup Transformer Cabinet

14. Cable Run to Riser Pole

15. Collection Line to Main Substation

16. Main Substation

17. Grounding Transformers

18. 230-kV System Tie

19. Erie Shores Setting

20. Erie Shores Layout

21. Erie Shores Ground Electrode

22. Sault Ste Marie (Prince) Wilderness

23. Prince Layout

24. Prince in Autumn

25. Prince in Late Autumn

26. Prince Ground Electrode

27. Prince 1 Collection Cable

28. Grounding - Objectives limit V between touchable objects provide low Z path so protection sees fault I direct fault I, lightning away from equipment minimize interference

29. Grounding - Definitions Remote earth: soil not rising in potential on faults Bonding: to connect two objects with low Z path Grounding: to provide bonding to remote earth G System: all conductors that facilitate grounding G Current: fault current that enters a G system G Electrode: conductors that dissipate I into soil G Potential Rise: V between G system, remote soil Step Potential: foot-to-foot V during system fault Touch Potential: hand-to-foot V on system fault

30. Grounding – Tested Quantities GPR: general hazard indicator, telco pairs Step V: coord to safe body withstand (180, 1 550 V) Touch V: coord to safe body withstand (168, 663 V) Touch types: structure, mesh, fence, gate, exterior Current splits: on external connections: Neu, Ohg Soil resistivity: model all of above Surface stone resistivity: check for deterioration Conductor integrity:  measured and modelled

31. GPR = Rg Ig Ig - Vg + Telco

32. Measure Rg with Fall of Potential C1 P1 C2 P2 x c

33. Locate Probe P at 62 % of Probe C 1 2 3 4 5 6

34. When Soil Has Two Layers C1 P1 C2 P2 x c h 11 22

35. Adjust Location for P to C Ratio

36. Interconnections Affect P to C Ratio C1 P1 C2 P2 x c

37. Soil Anomalies Affect P to C Ratio low  C1 P1 C2 P2 x c high 

38. Proximity Correction: Arbitrary P, C low  C1 P1 C2 P2 x c high 

39. Running Out Leads in Fair Weather

40. Testing When Snow Flies

41. Reading the AC Milliohm Meter

42. Six Towers Left Before Nightfall

43. Network Analyzer for Current Splits low  C1 Split- Core CT c high  C2 Network Analyzer

44. Rogawski Coil for Current Splits

45. Counterpoise Current Split

46. Network Analyzer, Scope, Megger

47. Network Analyzer for Impedance low  C1 P1 P2 x c high  C2 Network Analyzer

48. Equiv Cct for Proximity Corrections XcgXgp Xcp Ic - Ic Rcg +  Ic +  Ic Rgp - Ic Rcp + + Vp - Zd Rg

49. Proximity Correction Method Zg= Zm +  Rgp +  Rcg – Rcp  = Zd / ( Zd + Rg )  =b + Rcg / ( Rcg + Zd ) measure Zm and  read Zm at several locations for P find Zg for each, average these estimates calculate standard deviation as quality check

50. Measuring Step Potential

51. Measuring Touch Potential

52. Summary When sandy soil or rock raise Rg, tests useful Fall of Pot bad with soil anomalies, interconnections Proximity Correction method has P and C opposite Multiple estimates of Zg averaged for less noise Standard deviation of Zg checked for quality Measuring current splits good with interconnections