Frankfurt (Germany), 6-9 June 2011

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limits

simple assessment procedure for 3-phase Systems

practical approach for measurements practical experiences

Andreas AbartEnergie AG Oberoesterreich also lecturer at TU GrazAsset managementPower Quality & EMCandreas.abart@netzgmbh.atPhone: +43 5 9070 2107

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limits

Frankfurt (Germany), 6-9 June 2011

1st. Step of Assessment:simple Estimation (magnetic field: 1 mT/kA at 0.2 m distance)

No further Assessment in case occupational Exposure: • Electric fields at rated voltage < 250 kV• generators and transformers• Any wire at maximum current < 1 kA (50 Hz)

Compliance demonstrated? – Yes => End of Assessment

2nd. Step of Assesment:regarding given compensation effects from parallel wires.

Compliance demonstrated? – Yes => End of Assessment

3rd. Step of Assesment (expert job):Measurements including all shielding effects

Frankfurt (Germany), 6-9 June 2011

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limits

magnetic flux density B=f(a,d)

Frankfurt (Germany), 6-9 June 2011

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limitsAbart, 15.01.2007, Seite 4

EMF-Exposure

Magnetic Flux Density Exposure of 3-Phase Electrical Power Systems (3 x 1 kA)

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

1,E+05

0,01 0,1 1 10 100

d Distance m

Ma

gn

eti

c F

lux

De

ns

ity

µT

/kA

approximation limits for non insulated wires

500 Action Value

U <

1kV

U <

30kV

U <

110k

V

U <

220k

VU

>22

0kV

0,5

1,5 2 3 4

d

a a

IL1 Il2 Il3

harmrms

harmrms

kdHzI

kdHzI

7500)3216(

5000)50(

1

1k

dkAI

µTB

22

kd

a

kAI

µTB

factors[]..., resbetween wi distance]...[

reclosest wi theand fieldpointbetween distance]...[

current...densityfluxmagnetic....

21 kkma

md

kAIµTB

Frankfurt (Germany), 6-9 June 2011

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limits

harmrms

harmrms

kdHzI

kdHzI

7500)3216(

5000)50(

harmrms

harmrms

kdHzI

kdHzI

1500)3216(

1000)50(

200

1

dkAI

µTB 350

2

d

a

kAI

µTB

240

2

d

a

kAI

µTB

occupational exposure (1000µT)

General public/office(200µT)

83,057,0 d

a

d

a 83,057,0

d

a

d

a

harmHzrms ka

dkAI

2

)50(

86,2 harmHzrms k

a

dkAI

2

)50(

17,4

harmHzrmsk

a

dkAI

2

)3216(

29,4 harmHzrms

ka

dkAI

2

)3216(

25,6

harmHzrms ka

dkAI

2

)50(

57,0 harmHzrms k

a

dkAI

2

)50(

84,0

harmHzrmsk

a

dkAI

2

)3216(

86,0 harmHzrms

ka

dkAI

2

)3216(

25,1

Frankfurt (Germany), 6-9 June 2011

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limits

ASSESSMENT: Estimation, Calculation Measurement Calculation

& Measurement

Messwerte der magnetischen Flussdichte KOPS I M3 Ausleitung + Schiene 102 MVA + Trafo 12,5/220 kV

0

200

400

600

800

1000

1200

1400

11:47:37 11:50:38 11:53:40 11:56:41 11:59:43 12:02:44

Flu

ss

dic

hte

µT EFD

EFD IN

GW

30 cm Distanzschale

Trafo 12,5/220 kV 102

Trafo 12,5 KV Generatorausleitung (Bremstrenner)

Stromschienengang

Trafozuleitung

Frankfurt (Germany), 6-9 June 2011

Abart-AT-RT.2c

RT 2c: EMF – Revision of magnetic field limits

Measurements in Practice applying summation Formula according to ICNIRP

Guidelines => Exp=Sum of Signal + Sum of noise

following Jokelas approach 2003 (regarding phase of each spectral component) is helpful but complicating processing of measurement data.

regarding spectral components > X% of limits like standards for welding equipement suggest.

RMS of spectral components weighted on limits following the EN 50366 approach (household appliances)