1. Everything you always should know about high frequency Stefan Fassbinder Deutsches Kupferinstitut Am Bonneshof 5 D-40474 Düsseldorf Tel.: +49 211 4796-323 Fax: +49 211 4796-310 sfassbinder@kupferinstitut.de www.kupferinstitut.de
16. What really is that,E = 1 V/m? The fieldstrength bet-ween any twoelectrodesat a spacing of d = 1 m,between whicha voltage of U = 1 Vis applied
17. What really is that,H = 1 A/m? I = 1 A A field line with a length of 1m around a conductor through which a 1A current is passing At a distance ofthere is a field strength of 1A/m
18. What really is a magnetic flux density of B = 1 T = 1 Vs/m² ? Iron length: E. g. 300 mm mean,µR = 300 Corresponds to 600 mm iron altogether or2 mm air Field strengthwithin the core: within the gap: within the entire field, whereas: Air gap: E. g. 1 mm, µR = 1
20. I I IL IC U U UL UC Complementaryelements Inductance: Current leads voltage by 90° or voltage lags behind current by 90°, respectively Capacitance: Current leads voltage by 90° or voltage lags by 90° behind current, respectively
21. Z R XC+ XL XCRXL Complementaryelements Result: 180° Phase shift between voltages across or currents in L and C, respectively, so: Inductive und capacitive Reactances subtract linearly!Vectoral: Linear:
27. Serial resonant filters (acceptorcircuits) UR R U let the resonance frequency f0 pass without any reactance vectoral description L UL UC C
28. Attention: From outside you don't seewhat's going on inside! UR R U L UL UC Say:L and C do not limit the current! C I
29. Parallel resonant filters (rejectioncircuits) I≈0 U block currents of the resonant frequency f0 (vectoral description) C L R≈0
30. Attention: From outside you don't seewhat's going on inside! I≈0 U There is practically no current flowing through the resonant circuit, but possibly a lot within the resonant circuit! C L R≈0
31. There are many LC pairs yielding the same resonant frequency, LF or HF… Reactor reactance Capacitor reactance Serial impedance Phase angle
32. …but L by C defines the behaviourin the rest of the frequency range! Reactor reactance Capacitor reactance Serial impedance Phase angle
33. …but L by C defines the behaviourin the rest of the frequency range! Reactor reactance Capacitor reactance Serial impedance Phase angle
34. The total energy stored within the resonant circuit remains the same
35. 2.Characteristicimpedance is calculated from the specific line dimensions: Longitundinal inductance L‘ and transversal capacitance C‘ per unit of length. Model of an electric transmission line:
37. Line with small charac-teristic impedance Speed of propagation: 299.792,5 km/s
38. Line with great charac-teristic impedance Speed of propagation: 299.792,5 km/s
39. By the way, how fast does current really flow? 1 copper atom has 29 electrons. One of them is mobile. 1 mole of copper (63.546 g equalling 7.108 cm³) contains 6.02*1022 atoms (Avogadro's Constant). 1 g of copper thereby contains 9.47345*1021 electrons. So per gram 3.26671*1020 of them are mobile, this is 3.654*1019 per cubic centimetre. A current of 1 A means that at any point of the conductor 6.25*1018 electrons come flowing by (for each electron carries a charge of e = 1.9*10-19 As with it). With 16 A flowing in a 1.5 mm² residential installation cable this yields 0.8 mm/s. In case of short circuit it may be up to 50 mm/s!
40. Vital for assessing im-pulse waves reflections, e. g. at the interfaces between overhead and underground lines
41. Important in order to avoid reflections: Terminating resistor, e. g. inside an antenna socket designed as a pass-through outlet but then used as a terminating outlet. The amplitude of the terminating resistor has to equal the characteristic impedance, in this case e. g. 75 Ω:
42. Only applicable in information technology, of course! Or… Specific values of a 380 kV overhead line: Values of a 380 kV underground cable: VPE Oil
51. Direct voltage; low frequency: Electrical fields Direct current; low frequency: Magnetic fields High frequency (above ≈30 kHz):Electro-magnetic fields
63. This is how to imagine this! These fields radiate andmay beused for transmittinginformation over shortand longdistances
64. …or they may disturb said transmissions! Well, if you don't apply any filters…
65. Thisbatteryoperatedthermometerlocated ≈30 cm off a fluorescentlampdiditsjobfairly well until displayedtheroomtemperaturefairly well until… …thelighthadbeenswitched a fewtimes – thenthedisplaysuddenlyturnedkryptic!
66. There are three types of coupling mechanisms Galvanic: Electrically conductive connection ê Electrons flow »personally« from source to sink. Sort of disturbance:PEN conductor, TN-C system Inductive: current ê magnetic field ê induction Capacitive: voltage ê electrical field ê influence NFNF HF Electro-magnetic fields,radiation / susceptibility (HF)
67. 1.Galvaniccoupling What does this gentleman want to show you here? The leading example of galvanic coupling: Multiple connections between N and PE, i. e. between energy and information technique (operational earth)
68. U 2. Inductive coupling With operating currents: di/dt≈ 50 A/ms Signal level Cat. 3 data lines: 1 V Signal level Cat. 5 data lines: 500 mV Signal level 10Gbit/s beginning: 130 mV Signal level 10Gbit/s end: 600 µV! With short-circuit currents: di/dt≈ 1 kA/ms With switching transients: di/dt≈ 10 kA/ms In inverterdrives: di/dt≈ 50 kA/ms With lightning currents: di/dt≈ 50 kA/µs! l d ~ I
72. There are three of all evils: Coupling mechanisms in practice Inductive coupling: N against PE Capacitive coupling: MV against PE? Galvaniccoupling: »Second CEP« Only here it shall be è
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