Insulation

1. Prof. Dr.-Ing. Volker Hinrichsen M.Sc. Mohammad Hossein Nazemi Winter Term 2010/2011FachgebietHochspannungstechnik High-Voltage Technology / Chapter 1 -1-

2. Introduction of High-Voltage Laboratories Office area Workshop area, Small Test Hall, Seminar Rooms Large Test Hall Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -2-

3. Introduction of High-Voltage Laboratories Accredited test lab for Um = 800 kV 1.2-MV transformer cascade 3.2-MV impulse voltage generator Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -3-

4. Introduction of High-Voltage Laboratories Our Technical Assistants (Wissenschaftliche Mitarbeiter; WiMi) .... Sébastien Blatt Katarina Samuelsson Thomas Wietoska Jan Debus Thomas Rettenmaier Mohammad Hossein Nazemi Michael Tenzer Max TuczekPatrick Halbach Karsten Golde Masi Koochack-Zadeh Sebastian Suchanek Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -4-

5. Introduction of High-Voltage Laboratories Frau Hasenei Frau Brunner Our secretary ........ Our book-keeper ........ Our workshop …… Herr Veith Herr Homa Herr Ullrich Herr Noll Herr Graulich Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -5-

6. High-Voltage Technology I: Subjects 1 Objectives, applications, selection of voltage level 2 Generating high alternating voltages 3 Generating high direct voltages 4 Generating high impulse voltages 5 Measuring high voltages - alternating- - direct- - impulse 12 Traveling waves on lines 6 Electrical fields Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -6-

7. High-Voltage Technology II: Subjects 7 Layered dielectrics 8 Control of electrical field stress and potential distribution 9 Dielectric breakdown of gases (air, sulphur hexafluoride) 10 Surface discharges, pollution flashover 11 Lightning discharges and lightning protection 13 Dielectric breakdown of solids, fluids and in vacuum Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -7-

8. High-Voltage Technology I: Recommended Books Download of the slides (English and German) and the lecture notes (German only): www.hst.tu-darmstadt.de UN: student PW: vorlesungCan be lent out from us (please contact Mrs. Koochack-Zadeh) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -8-

9. High-Voltage Technology I: Recommended BooksCan be lent out from us (please contact Mrs. Koochack-Zadeh) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 -9-

10. High-Voltage Technology I: Recommended BooksFurther recommendations: Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 10 -

11. High-Voltage Technology I: Time Schedule 1 21.10.2010 Chapter 1 Introduction 2 Excursions: 2 28.10.2010 Chapter 1 Introduction - Siemens 3 04.11.2010 Chapter 2 Generating high alternating voltages Schaltanlagenwerk 4 11.11.2010 Chapter 2 Generating high alternating voltages Frankfurt 5 18.11.2010 Chapter 3 Generating high direct voltages - ABB GIS-Fertigung 6 25.11.2010 Chapter 3 Generating high direct voltages Großauheim 7 02.12.2010 Chapter 4 Generating high impulse voltages Thursdays; starting 09:30; 8 09.12.2010 Chapter 4 Generating high impulse voltages until 16:00 16.12.2010 Cancelled two auxiliary dates needed 23.12.2010 Christmas holidays 30.12.2010 Christmas holidays 06.01.2011 Christmas holidays 9 13.01.2011 Chapter 5 Measuring high voltages 10 20.01.2011 Chapter 5 Measuring high voltages 11 27.01.2011 Chapter 5 Measuring high voltages 12 03.02.2011 Chapter 6 Electrical fields 13 10.02.2011 Chapter 6 Electrical fields 14 17.02.2011 Miscellaneous Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 11 -

12. High-Voltage Technology I: ExaminationExercises:• 2 Mini-Tests during lecture time• each test up to 10 points max. 20 pointsLecture:• only oral examination• max. 80 pointsin sum max. 100 points Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 12 -

13. Objectives of High-Voltage Technology High-voltage engineering or technology deals with • physical phenomena • technical problems, which arise with • natural presence • generation • application • measurement of high voltages. High-voltage engineering has gained most of its importance for electrical power systems. The permanent supply of electric energy, at any time, at virtually any location, economical and of high quality and reliability, could not be realized without the use and nearly perfect control of high voltages as it is fact today. Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 13 -

14. Presence of "high voltage" In technical systems ...... as continuous operating voltage ..... a.c. systems 50 Hz or 60 Hz up to Us = 1200 kV Actual (since 2008) PR of China: Us = 1100 kV India (under construction): Us = 1200 kV Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 14 -

15. Presence of "high voltage" In technical systems ...... as continuous operating voltage ..... HVDC transmission up to ± 800 kV Actual in PR of China: ± 800 kV (since 2009) (Plans for ± 1000 kV) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 15 -

16. Presence of "high voltage" In technical systems ...... as overvoltages ..... of power frequency ... • due to earth faults • „Ferranti effect“ = voltage increase at the end of a long, unloaded transmission line (or after load rejection) due to voltage drop across the inductances caused by capacitive charge currents Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 16 -

17. Presence of "high voltage" In technical systems ...... as overvoltages ..... transient ... • due to intentional or unintentional switching operations Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 17 -

18. Presence of "high voltage" In technical systems ...... as test voltage ..... alternating voltage up to 2 MV Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 18 -

19. Presence of "high voltage" In technical systems ...... as test voltage ..... direct voltage up to several MV Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 19 -

20. Presence of "high voltage" In technical systems ...... as test voltage ..... impulse voltages up to 6 MV (lightning, switching impulse voltage) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 20 -

21. Presence of "high voltage" In technical systems ...... further applications ..... high frequency alternating voltages for long wave transmitters (aerial voltages up to several 10 kV) direct voltages: charge carrier accelerators up to several 106 eV dust filters, enamel spraying systems up to 100 kV ultra-vacuum electron tubes up to several 100 kV pulse power technology in physical research Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 21 -

22. Presence of "high voltage" In nature ...... as direct voltage ...... lightning electricity: cloud voltages up to 100 MV electrostatic charges: charge separation up to several kV as impulse voltage ...... overvoltages by lightning strokes Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 22 -

23. Definition „High-Voltage“ In general, a power system is termed a "high-voltage" system if operated at alternating phase-to-phase voltages above 1 kV (rms value) or at direct voltages above 1.5 kV.Furthermore, for power systems the terms medium voltage, highvoltage and extra high voltage (even ultra high voltage) have beenestablished, depending on the "Highest voltage for equipment Um" of asystem. Voltage "Medium voltage (MV)" 1 kV < Um <= 52 kV "High voltage (HV)" 72.5 kV <= Um < 420 kV "Extra high voltage (EHV)" 420 kV <= Um <= 800 kV "Ultra high voltage (UHV)" Um > 800 kV Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 23 -

24. Goals of High-Voltage Technology Basic goal of high-voltage technology in power systems and related equipment: insulation of components at high potential from each other and from ground. The insulation must be able to reliably withstand all • electrical • mechanical • climatic • other stresses during the scheduled lifetime of equipment of up to 50 years. At the same time the construction and design must be economical and optimized in terms of cost, meaning that materials are utilized to their technical and physical limits. Safety margins are usually not paid for and would be on the manufacturers cost. Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 24 -

25. Goals of High-Voltage Technology - Issues to determine the voltage stress during service in terms of type, amplitude, time duration and frequency of occurence to understand the physical phenomena, which lead to dielectric breakdown of the insulation (gaseous, liquid or solid), and to derive design rules for the construction of high-voltage equipment to optimally utilize insulation by well founded knowledge of material properties (with particular focus on longevity) and their permanent development and improvement, as well as by reasonable shaping of electrodes and insulation arrangements to develop well-suited test methods and diagnostic tools and to standardize them in internationally accepted standards (e.g. IEC) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 25 -

26. Goals of High-Voltage Technology - Issues Insulation coordination and overvoltage protection Generating and measuring high alternating, direct or impulse voltages (and currents) in the laboratory and on-site to perform design, type, acceptance and routine tests on individual equipment or complete switchgear Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 26 -

27. High-Voltage Technology – Involved Disciplines Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 27 -

28. Transmission Voltage LevelsIn order to transport electric power over wide distances the transmissionvoltage has to be chosen high.Power in the three-phase system: P power (VA)P = 3 ⋅ ULE ⋅ I = 3 ⋅ U Δ / 3 ⋅ I = 3 ⋅ U Δ ⋅ I ULE line-to-earth voltage (V) UΔ phase-to-phase voltage (V) I current through conductor(A) Increase of power by increase of voltage or increase of current Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 28 -

29. Transmission Voltage LevelsThe power losses of transmission are basically proportional tothe power of two of the current: PV = I ⋅ R 2 PV power loss per phase (VA) I current through conductor (A) R resistance of conductor (Ω) Go for high transmission voltage! Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 29 -

30. What are the cost of transmission losses?Example calculation: costs of 1% transmission lossesThe power of the nuclear power plant Biblis (both units)shall be transmitted: P = 2 400 MW = 2.4 · 109 WThereof 1% losses: Pv = 24 MWFull load operation 24 h per day: daily working lossesWv = Pv ·T = 24 MW · 24 h = 576 MWh = 576 000 kWhAssumption: 1 kWh 1.5 cent daily cost of losses Kv,d = 8 500 €/dOperation of the plant about 330 days per year Annual cost of losses "Biblis" Kv,a ≈ 2.8 Mio. €/a Annual cost of losses "Biblis" Kv,a ≈ 2.8 Mio. €/aFor all Germany: 1% of 600 TWh = 6 TWh losses Annual cost of losses “Germany" Kv,a ≈ 90 Mio. €/a Annual cost of losses “Germany" Kv,a ≈ 90 Mio. €/a Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 30 -

31. Limitation of Short-circuit PowerYet another reason for a high-voltage system:Formation of sub-grids by an overlaid transmission voltagebackbone limits the short-circuit power of a system. 110 kV 110 kV 110 kV 380 kV 110 kV 110 kVShort-circuit currents that can be handled nowadays: 80 kA Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 31 -

32. Transmission Voltage LevelsThe transmission voltage cannot arbitrarily be increased as theeffort of insulation also increases with voltage. An optimal transmission voltage can be defined.The optimal transmission voltage results from cost considerations.The cost of a long distance power transmission is made up from • operating cost • cost of equipment • cost of overhead line conductors • cost of insulation Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 32 -

33. Transmission Voltage LevelsDetails given in the exercise P s 1 2 Assumptions: • Power transmission from „1“ to „2“ • Distance s = const. • Transmitted power P = const. • Operating cost KV ~ 1/U • Cost of equipment • Line conductor KL ~ 1/U • Insulation Kis ~ U Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 33 -

34. Transmission Voltage Levels U • Operating cost KV ~ 1/U • Cost of equipment • Line conductors KL ~ 1/U • Insulation Kis ~ U Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 34 -

35. Transmission Voltage Levels Rules of thumb for optimal transmission voltage: a) Uopt = f(P): Uopt (kV) = 15 ... 20 ⋅ P (MVA) U2 Coincidental consistance with natural load of a line: Pnat = Z Z = Surge impedance of the line L Z = 250 Ω (420 kV, four-bundle conductors) Z= C Z = 400 Ω (123 kV, single conductors) U = Z ⋅ Pnat = 16...20 ⋅ Pnat Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 35 -

36. Transmission Voltage Levels Rules of thumb for optimal transmission voltage: b) Uopt = f(s): Uopt (kV) = s(km) Not applicable for short distances as in that case the cost of transformers have considerable additional impact on cost. Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 36 -

37. Transmission Voltage LevelsGuidance values for transmission voltage, transmittable powerand transmission distances: Transmission Power Distance voltage 30 MVA Um = 123 kV (≈ demand of a 100-200 km 30 000-people town) 125 MVA Um = 245 kV (small unit of 200-400 km a power plant) 600 MVA Um = 420 kV (large unit of 400-800 km a power plant) 2000 MVA Um = 800 kV (nuclear power plant, 1000 km two units) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 37 -

38. Development of Transmission Voltages Year Voltage (kV) Place Kittler 1891 15 Lauffen-Frankfurt / D 1907 50 Stadtwerke München / D 1911 110 Lauchhammer-Riesa / D 1929 220 RWE RhIntroduction / D 1932 287 Boulder Dam / USA 1952 380 Hårspranget-Hallsberg / S 1959 525 UdSSR 1965 736 Manicouagan-Montréal / CA 1985 1200 Ekibastuz - Kokchetav/UdSSR*) Field test: 2000 km long transmission line; half of it was operated at 1200 kV for several years. Another field test in Japan: 1100 kV for more than 10 years. Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 38 -

39. Standardized Transmision Voltages (IEC 60071-1)IEC standard 60071-1 specifies standardized values of Um or Us: 72.5 kV 123 kV 145 kV 170 kV 245 kV 300 kV 362 kV 420 kV 550 kV 800 kV 1100 kV 1200 kV Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 39 -

40. International Highest Transmission Voltages Country Voltage (kV) in service planned or in test phase) Indien: 1200 kV (under constr.) China: 1100 kV (since 2008) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 40 -

41. System Voltages in Germany Planned for the future 7.2 kV 420 kV 123 kV 12 kV 0.4 kV 24 kV 245 kV 36 kV 72 kVGrids and facilities of other voltage levels are actually in use in high amountbut will not be expanded. Different philosophies for existing installations: "downrating" or "uprating". Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 41 -

42. The German InterconnectedPower System Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 42 -

43. Largest German Transmission System Operators (2005) As per Oktober 2010: 1 EnBW Transportnetze AG 2 transpower stromübertragungs gmbh (TenneT) 3 Amprion GmbH 4 50Hertz Transmission GmbH Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 43 -

44. Interconnected Electrical Power SystemsInterconnection - Pros ....Location of power plants to be chosen independentfrom load centers.Particular characteristics of different types of power plants (basic-,intermediate-, peak load-) can better be taken into consideration.Less spare power installation requiredLess impact of system faults and occasional loss ofpower plants to the userHigher overall quality of power supply (voltage- and frequency control)In Germany: f = 50 Hz +/- 50 mHz!!!! Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 44 -

45. Interconnected Electrical Power SystemsInterconnection - Pros ....Timewise (daily, yearly) and geografical (North-South, East-West)load levellingFree choice of power supplyer independent from location Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 45 -

46. The European Interconnected Power System – entsoe 2010Head Organization ENTSO-E(European Network of Transmission System Operators for Electricity)5 Regional Groups (RG) ="Synchronous Areas" or"Synchronous Zones"RG Continental Europe (former UCTE)= largest interconnected system in Europe> 600 GW installed> 400 GW assuredRegulation Zone Germany =4 TSO (Transmission System Operators) Source: entsoe Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 46 -

47. Equipment in High-Voltage Power SystemsFrom the supplier to the user .... For transmission of 1000 MW: I ≈ 20 000 A I ≈ 1 500 A 10 kV ... 27 kV 72.5 kV ... 550 kV 12 kV ... 36 kV 0.2 kV ... 0.4kV "High and Extra High Voltage" "Medium Voltage" “Low Voltage" Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 47 -

48. Equipment in High-Voltage Power SystemsTypical single line circuit diagram of a transformer substation220/66 kV (245/72.5 kV) Overhead lines Earthing switch Disconnector Circuit breaker Double bus bar 220 kV Transformers 220/66/11 kV To 0.4-kV station service system Double bus bar 66 kV Overhead lines or cables Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 48 -

49. Equipment in High-Voltage Power SystemsSide view of a typical 420-kV open air substation Distances in [m] 420-kV substation with overhead tubular double busbars in diagonal arrangement 1 ... Bus bar system I 2 ... Bus bar system II 3 ... Busbar disconnector 4 ... Circuit breaker 5 ... Current transformer 6 ... Line disconnector 7 ... Line trap 8 ... Capacitive voltage transformer T ... Bay width T1 ... Width of incoming bay T2 ... Width of outgoing bay Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 49 -

50. Equipment in High-Voltage Power Systems420-kV gas insulated switchgear (GIS) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 50 -

51. Equipment in High-Voltage Power SystemsGeneratorsTransformersCircuit breakersDisconnectors and earthing switchesSurge arrestersVoltage and current transformers, combined instrument transformersPost insulators (station posts)Line insulatorsCable, cable terminations, cable joints Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 51 -

52. FACTSFlexible AC Transmission SystemsInstallations for power flow control between two AC sub-gridsby control of voltage, phase angle and impedance jX 1 2 U1, α1 U2, α2Increased use of power electronics, e.g.: Thyristors with off-state voltages up to 8 (10) kV LTT‘s = Light Triggered Thyristors IGBT‘s = Integrated Gate Bipolar Transistors Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 52 -

53. High-Voltage DC Transmission (HVDC)Fields of application: Interconnection of asynchronous grids: 50- and 60-Hz-systems or systems of different frequency control characteristics Extremely long transmission distances (> 1000 km), which else would require high efforts of compensation measures (such as FACTS) for reactive power control and stability Sea cable links of more than 40 km, which would have a too high demand of reactive power in case of AC operation (charging power of cable capacitance!) Grid extensions in load centers, which else would lead to an intolerable increase of short-circuit power (which cannot be handled by the equipment, e.g. circuit brakers) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 53 -

54. High-Voltage DC Transmission (HVDC)System voltages: Overhead lines: usually +/- 500 kV (up to +/- 800 kV) Sea cable links: +/- 400 kV ... +/- 450 kV Modes of operation: "Back-to-back" Long distance transmission Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 54 -

55. High-Voltage DC Transmission (HVDC) Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 55 -

56. Voltage Stress in Power Systems 5 Possible voltages without arrestersMagnitude of (over-)voltage / p.u. 4 Withstand voltage of equipment 3 2 1 Voltages limited by arresters 0 Lightning overvoltages Switching overvoltages Temporary overvoltages Highest system voltage (Microseconds) (Milliseconds) (Seconds) (Continuously) Duration of (over-)voltage Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 56 -

57. Voltage Stress in Power SystemsClasses and shapes of stressing voltages and overvoltages acc. toIEC 60071-1 "Insulation co-ordination", Table 1 Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 57 -

58. Voltage Stress in Power Systems• IEC 60071-1 specifies Standard Insulation Levels for equipment.• The standard insulation level is defined by a set of two different types of Standard Voltages.• Two different Voltage Ranges are distinguished: Range I: Um = 1 kV up to and including Um = 245 kV (Distribution and transmission systems) ⇒ Standard short-duration power-frequency withstand voltage ⇒ Standard lightning impulse withstand voltage *) Range II: Um above 245 kV (Transmission systems) ⇒ Standard switching impulse withstand voltage **) ⇒ Standard lightning impulse withstand voltage *) *) "BIL" acc. to IEEE Std. 1313.1 **) "SIL" acc. to IEEE Std. 1313.1 Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 58 -

59. Standard Insulation Levels acc. to IEC 60071-1 Range I: Um = 1 kV up to and including Um = 245 kV The standard voltage values are all the same for • Phase-to-earth-, • Phase-to-phase-, • Longitudinal insulation! Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 59 -

60. Standard Insulation Levels acc. to IEC 60071-1 Range II: Um above 245 kV Different standard voltage values for • Phase-to-earth-, • Phase-to-phase-, • Longitudinal UHV: insulation! Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 60 -

61. What is an Impulse Voltage in High-Voltage Technology? Shape of a lightning impulse voltage Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 61 -

62. What is the meaning of Un, Us and Um ?Definition acc. to IEC 60071-1 („Insulation co-ordination“) = Un acc. to 28/169/CDV (Draft IEC 60071-1 Ed. 8) = Us acc. to 28/169/CDV (Draft IEC 60071-1 Ed. 8) R Voltage phasor diagram Example: German e.h.v. system „Phase-to-phase voltage“ Un = 380 kV „Delta voltage“ Us = 420 kV Um = 420 kV (usually!) Line-to-earth voltage: U = U / 3 = 242 kV LE s S T Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 62 -

63. What is the meaning of Un, Us and Um ?Definition acc. to IEC 60071-1 („Insulation co-ordination“) R Voltage phasor diagram Example: German e.h.v. system „Phase-to-phase voltage“ Un = 380 kV „Delta voltage“ Us = 420 kV Um = 420 kV (usually!) Line-to-earth voltage: U = U / 3 = 242 kV LE s S T Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 63 -

64. Design of Electrodes and Insulators Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 64 -

65. Insulation coordination Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 65 -

66. 24-hour load cycle Peak load Intermediate load Daily maximum demand Base load Daily minimum demand Day time Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 66 -

67. Climatic Stress Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 67 -

68. Sonstige Beanspruchungen …. Growth of algea, moss ..... Growth of algea, moss ..... Vandalism .... Vandalism .... Animal attack ... Animal attack ...Transportation ....Transportation .... Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 68 -

69. Other Stress …. Algae and moss ..... Earthquakes .... Transportation .... Vandalism .... Animal attack ... Short-circuit current forces .... Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 69 -

70. Equipment: Transformers Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 70 -

71. Equipment: Circuit Breakers Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 71 -

72. Equipment: Disconnectors, Earthing Switches Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 72 -

73. Equipment: Surge Arresters Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 73 -

74. Equipment: Instrument Transformers Optical current transformer (making use of electro-optical "Faraday effect") Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 74 -

75. Equipment: Line Insulators Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 75 -

76. Equipment: Cables, Cable Terminations, Cable Joints Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 76 -

77. Thyristors with Off-State Voltages up to 8 (10) kV Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 77 -

78. Light Triggered Thyristors "Reliable Power Supply for California" Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 78 -

79. First AC Power Transmission Lauffen - Frankfurt 1891 Später: 15.000 V 1000 Lamps + 1 artificial waterfall !! oil filled! Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 79 -

80. Erasmus Kittler Professor Dr. Erasmus Kittler Very first faculty of electrical engineering worldwide, 1882 Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 80 -

81. Erasmus Kittler Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 81 -

82. Enamel Spraying System operated at 100 kV Quelle: Phoenix Contact März/April 2003 Fachgebiet Hochspannungstechnik High-Voltage Technology / Chapter 1 - 82 -

Insulation

Atul Pathak

Insulation