emc

Everything you always should know about high frequency

Stefan FassbinderDeutsches KupferinstitutAm Bonneshof 5D-40474 DüsseldorfTel.: +49 211 4796-323Fax: +49 211 [email protected]

The German Copper Institute, DKI, is the central information and advisory service dealing with all uses of copper and copper alloys. We offer our services to:

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We can be contacted by: post phone fax e-mail internet online database, or personally

Complementary elements:Inductances and capacitances

i

tuL

2

2iL

W 2

2u

CW

u

tiC

fLX L 2fC

XC 21

dt

diLuL

dt

duCiC

L

udtiL

C

idtuC

The fieldstrength bet-ween any twoelectrodesat a spacing of d = 1 m,between whicha voltage of U = 1 Vis applied

What really is that,E = 1 V/m?

What really is that,H = 1 A/m?

I = 1 A

mmm

r 1572

1

A field line with a length of 1m around a conductor through which a 1A current is passing

At a distance of

there is a field strength of 1A/m

What really is a magnetic flux density of B = 1 T = 1 Vs/m² ?

HHB R 0

Iron length: E. g. 300 mm mean,µR = 300

Air gap: E. g. 1 mm, µR = 1

Am

Vs60 10*1,26

Corresponds to 600 mm iron altogether or2 mm air

Field strengthwithin the core:

within the gap:

within the entire field, whereas: 0300

BH

0B

H

-150%

-100%

-50%

0%

50%

100%

150%

0ms 5ms 10ms 15ms 20ms

t

u/û

-150%

-100%

-50%

0%

50%

100%

150%

i/î

SinusspannungL-Strom bei SinusspannungC-Strom bei Sinusspannung

-150%

-100%

-50%

0%

50%

100%

150%


t

u/û

-150%

-100%

-50%

0%

50%

100%

150%

i/î

Sine voltageL current with sine voltageC current with sine voltage

t)sin(*û)( tu t)cos(*î)( tiL

t)cos(*î)( tiC

Complementary elements: Inductances and capacitances

Complementary elements

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

UIC

IL

U

UC

UL

I

I

Complementary elements

Result:

180° Phase shift between voltages across or currents in L and C, respectively, so: Inductive und capacitive Reactances subtract linearly!

Vectoral:

Linear:

XC R XL RXC+ XL

Z

22 RXXZ CL

RXXZ CL

R

XX CLarctan

Let us clarify some terms

1. Resonance

LCf

21

0

XC R XL

CL XX

fCfL

2

12

-150%

-100%

-50%

0%

50%

100%

150%


t

u/U

; i/I

u / U

i / I

How to imagine this?

i


-150%

-100%

-50%

0%

50%

100%

150%


t

u/U

; i/I

u / U

i / I

iiiiii

Serial resonant filters (acceptor circuits)

U

UC

UL

UR

let the resonance frequency f0 pass without any reactance

vectoral descriptionCLR UUUU

R

L

C

Attention: From outside you don't seewhat's going on inside!

U

UC

UL

UR

Say: L and C do not limit the current!

I

RIUR *

LL XIU *

CC XIU *

22 )( CLR UUUU

CLCL UUXX

RUU

R

UI

R

L

C

I≈0

R≈0

LC

Parallel resonant filters (rejection circuits)

block currents of the resonant frequency f0

(vectoral description)

CL III

U

LC

I≈0

R≈0

Attention: From outside you don't seewhat's going on inside!

There is practically no current flowing through the resonant circuit, but possibly a lot within the resonant circuit!

U

There are many LC pairs yielding the same resonant frequency, LF or HF…

R Cu = 10 W

L = 160 µHC = 7 nF

0Ω

50Ω

100Ω

150Ω

200Ω

250Ω

300Ω

350Ω

400Ω

450Ω

500Ω

0kHz 100kHz 200kHz 300kHz 400kHz 500kHz 600kHz

f

Z

-90°-75°-60°-45°-30°-15°0°15°30°45°60°75°90°

φ

Reaktanz DrosselReaktanz KondensatorImpedanz ReihenschaltungPhasenwinkel

Reactor reactanceCapacitor reactanceSerial impedancePhase angle

0Ω

50Ω

100Ω

150Ω

200Ω

250Ω

300Ω

350Ω

400Ω

450Ω

500Ω


f

Z

-90°-75°-60°-45°-30°-15°0°15°30°45°60°75°90°

φ


…but L by C defines the behaviourin the rest of the frequency range!

R Cu = 10 W

L = 16 µHC = 70 nF


0Ω

5Ω

10Ω

15Ω

20Ω

25Ω

30Ω

35Ω

40Ω

45Ω

50Ω


f

Z

-90°-75°-60°-45°-30°-15°0°15°30°45°60°75°90°

φ


…but L by C defines the behaviourin the rest of the frequency range!

R Cu = 1 W

L = 16 µHC = 70 nF


0%

25%

50%

75%

100%

125%

150%

175%

200%


t

W Energie im Kondensator

Energie in der SpuleGesamt-Energie

0%

25%

50%

75%

100%

125%

150%

175%

200%


t

W Capacitor energy content

Reactor energy contentTotal energy content

The total energy stored within the resonant circuit remains the same

consttiL

tuC

tW )(2

)(2

)( 22

is calculated from the specific line dimensions:

Longitundinal inductance L‘ and transversal capacitance C‘ per unit of length.

Model of an electric transmission line:

2. Characteristic impedance

'

'

C

LZW

Line with great

characteristic impedance:

Line with low characteristic impedance:

'

'

C

LZW

Line with small charac-teristic impedance '

'

C

LZW

Speed of propagation:

299.792,5 km/s0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

0ns 1ns 2ns 3ns 4ns 5ns 6ns 7ns 8ns 9ns 10ns

u/û

t

Line with great charac-teristic impedance '

'

C

LZW

Speed of propagation:

299.792,5 km/s

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

0ns 1ns 2ns 3ns 4ns 5ns 6ns 7ns 8ns 9ns 10ns

u/û

t

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!

Vital for assessing im-pulse waves reflections, e. g. at the interfaces between overhead and underground lines

0%

10%

20%30%

40%

50%

60%

70%

80%90%

100%

110%

0µs 1µs 2µs 3µs 4µs 5µs 6µs 7µs 8µs 9µs 10µs

t

u/û

0%

10%

20%30%

40%

50%

60%

70%

80%90%

100%

110%

0µs 1µs 2µs 3µs 4µs 5µs 6µs 7µs 8µs 9µs 10µs

t

u/û

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:

Only applicable in information technology, of course! Or…

Specific values of a 380 kV overhead line:

Values of a 380 kV underground cable:

VPE

Oilkm

mHL 8,0'

km

nFC 14' W 239

'

'

C

LZW

km

mHL 7,0'

km

nFC 280' W 50

'

'

C

LZW

km

mHL 49,0'

km

nFC 204' W 49

'

'

C

LZW

This would result in a »natural power« of…

For heaven's sake!

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable

Conductor material Al/St Al Al/St Cu Al/St Cu Cu

Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

20kV 110kV 380kV

Over-head

Under-ground

Over-head

Under-ground

Over-head

VPE cable

Oil cable


Cross section mm² 120/20 240 265/35 630 4*265/35 2000 2000

S N MVA 14.00 14.00 130.00 124.00 1800.00 900.00 900.00

R ' (20°C) mΩ/km 240.00 125.00 109.00 29.00 28.00 10.00 10.00

L ' mH/km 1.14 0.31 1.21 0.41 0.80 0.70 0.49

C ' nF/km 10.00 290.00 9.50 180.00 14.00 280.00 204.00

Z W Ω 337.64 32.70 356.89 47.73 239.05 50.00 49.01

P nat=P RA MW 1.18 12.23 33.90 253.53 604.07 2888.00 2946.35

3. Limit frequencies,4. Bandwidth and hence5. the quality

of a reactor,

of a capacitor,

a resonant circuit

0Ω

10Ω

20Ω

30Ω

40Ω

50Ω

60Ω

70Ω

80Ω

90Ω

100Ω


f

Z

-90°-75°-60°-45°-30°-15°0°15°30°45°60°75°90°

φ


3. Limit frequencies f1 and f2

4. Bandwidth B

f1

f0

f2

R Cu = 10 W

L = 16 µHC = 70 nF

B

12 ffB


3. Limit frequencies f1 and f2

4. Bandwidth B

f1 è

f0 è

f2

R Cu = 1 W

L = 16 µHC = 70 nF

B

12 ffB

0Ω

10Ω

20Ω

30Ω

40Ω

50Ω

60Ω

70Ω

80Ω

90Ω

100Ω


f

Z

-90°-75°-60°-45°-30°-15°0°15°30°45°60°75°90°

φ



0Ω

25Ω

50Ω

75Ω

100Ω

125Ω

150Ω

175Ω

200Ω

225Ω


f

Z

-90°-75°-60°-45°-30°-15°0°15°30°45°60°75°90°

φ

ReaktanzDrosselReaktanzKondensatorImpedanzParallelschaltungPhasenwinkel

R Cu = 1 W

L = 16 µHC = 70 nF

Rejection circuits

Reactor reactanceCapacitor reactanceSerialimpedancePhase angle

5. Quality is an issue,described by thequality factor Q

What matters is the ratio of the reactive by the active share of the impedance, for active load means active power, and active power means

12

00

ff

f

B

fQ

•power loss•attenuation

Between line and high frequency: Sound frequency

Which one is the right cable

to carry the sound to the speaker?

6. Interference

-280%

-210%

-140%

-70%

0%

70%

140%

210%

280%

0ms 100ms 200ms 300ms 400ms 500ms 600ms 700ms

t

u/U

, i/

I, p

/P

u1/Uu2/U(u1+u2)/U

Adding twovoltages of

50 Hz and 51 Hzand equal peak values

High frequency (above ≈30 kHz):Electro-magnetic fields

Direct voltage; low frequency:

Electrical fields

Direct current; low frequency:

Magnetic fields


LCf

21

0

This is how to imagine this!

These fields radiate andmay beused for transmittinginformation

over shortand long

distances

…or they may disturb said transmissions!

Well, if you don't apply any filters…

displayed the room temperature fairly well until……the light had been switched a few times – then the display suddenly turned kryptic!

This battery operated thermometer located ≈30 cm off a fluorescent lamp did its job fairly well until

NF NF

HF

There are three types of coupling mechanisms

Galvanic:Electrically conductive connection

êElectrons flow

»personally« from source to sink.

Sort of disturbance:

PEN conductor, TN-C system

Inductive:current

êmagnetic field

êinduction

Capacitive:voltage

êelectrical field

êinfluence

Electro-magnetic fields,radiation / susceptibility (HF)

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)

1. Galvanic coupling

With operating currents: di/dt ≈ 50 A/msWith short-circuit currents: di/dt ≈ 1 kA/msWith switching transients: di/dt ≈ 10 kA/msIn inverter drives: di/dt ≈ 50 kA/msWith lightning currents: di/dt ≈ 50 kA/µs!

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!

2. Inductive coupling

I

dt

di

d

lctu )(~

d

l

U

3. Capacitive coupling

UI

I


UI

I


UI

There are three of all evils: Coupling mechanisms in practice

Only here it

shall be

Galvanic coupling:

»Second CEP«

Inductive coupling:

N against PE

Capacitive coupling:MV against PE?

è

Therefore:Mind the coupling mechanisms!

• Galvanic coupling:Once and only once (CEP)

• Capacitive coupling:A very thin electricallyconductive layer suffices – if earthed!

• Inductive coupling:Thick magneticallyconductive layers required!

• Z. B. IEC 60364-4-44

• (DIN EN 50174-2 / VDE 0800-174-2)

And: Mind the references to cable ducts in the standards!

• Z. B. IEC 60364-4-44

• (DIN EN 50174-2 / VDE 0800-174-2)

And: Note the references re-garding the cable positioning!

Do not confuse:Analogue and digital cables

Analogue cables have a screen.

Digital cables have some-thing that looks like a screen.

How to deal with coupling mechanisms?

By just dodging them!

Common mode:

Saves copper

Differential mode:

Saves trouble

Spicing things up with a pinch of HF: A piece of cake when using an electronic transformer

Any sort of radiation:Decorative HF reactors

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