Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 15382-4 (2003): Insulation Coordination for Equipmentwithin Low-Voltage Systems, Part 4: Considerations ofHigh-Frequency Voltage Stress [ETD 19: High VoltageEngineering]

IS 15382 (Part 4) :2003IEC 60664-4 (1997)(Superseding SP 39: 1987)

mm

R+kea-T * + Wtwii“w ragat?$iT1—TmFf

Indian Standard

INSULATION COORDINATION FOR EQUIPMENTWITHIN LOW-VOLTAGE SYSTEMS

PART 4 CONSIDERATIONS OF HIGH-FREQUENCY VOLTAGE STRESS

ICS 29.080.30

@ BIS 2003

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

September 2003 Price Group 10

High Voltage Engineering Sectional Committee, ET 19

NATIONAL FOREWORD

This Indian Standard (Part 4) which is identical with IEC 60664-4 (1997) ‘Insulation coordination forequipment within low-voltage systems — Part 4: Considerations of high-frequency voltage stress’issued by the International Electrotechnical Commission (lEC) was adopted by the Bureau of IndianStandards on the recommendations of the High Voltage Engineering Sectional Committee and approvalof the Electrotechnical Division Council.

This standard was first published in 1987 as SP 39 ‘Special publication — Guide for insulationcoordination within low voltage systems’. The revision of this special publication was felt with a view toalign our standard with international practices.

This standard consists of the following parts under the general title ‘Insulation coordination for equipmentwithin low voltage systems’:

Part 1 Principles, requirements and tests

Part 2 Application guide, Section 1 Dimensioning procedure worksheets and dimensioningexamples

Part 3 Use”of coatings to achieve insulation coordination of printed board assemblies

Part 4 Consideration of high frequency voltage-stress

This standard is to be read in conduction with Part 1 of this standard.

The text of the IEC Standard has been approved as suitable for publication as an Indian Standardwithout deviations. Certain conventions are, however, not identical to those used in Indian Standards.Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should beread as ‘Indian Standard’; and

b) Comma (,) has been used as a decimal marker, while in Indian Standards the current practiceis to use a point (.) as the decimal marker.

With the publication of this standard SP 39 shall be withdrawn.

Only the English text of the International Standard has been retained while adopting it as an IndianStandard.

CROSS REFERENCES

In this adopted standard, references appear to certain International Standards for which Indian Standardsalso exist. The corresponding Indian Standards, which are to be substituted in their respective placesare listed below along with their degree of equivalence for the editions indicated:

International Standard Indian Standard Degree ofEquivalence

IEC 60112 (1979) Method for IS 2824: 1975 Method for determining Technicallydetermining the comparative and the the comparative tracking index of solid equivalentproof tracking indices of solid insulating insulating materials under moistmaterials under moist conditions conditions (first revision)

lEC 60664-1 (2002) Insulation IS 15382 (Part 1) : 2003/lEC 60664-1 Identicalcoordination for equipment within low (2002) Insulation coordination forvoltage systems — Part 1: Principles, equipment within low-voltage systems:requirements and tests Part 1 Principles, requirements and

tests

(Continued on third cover)

/ndian

IS 15382 (Part4) :2003IEC 60664-4 (1997)

Standard

INSULATION COORDINATION FOR EQUIPMENTWITHIN LOW-VOLTAGE SYSTEMS

PART 4 CONSIDERATIONS OF HIGH-FREQUENCY VOLTAGE STRESS

1 Scope

This report deals with insulation subjected to high-frequency voltage stress withinequipment. Steady-state voltages with frequencies up to 100 MHz are considered.

NOTE – High-frequency stress due to transient voltages is not considered.

2 Reference documents

low-voltage

IEC 60112:1979, Method for determining the comparative and the proof tracking indices of so/idinsulating rnateria/s under moist conditions

IEC 60664-1:1992, /nsu/ation coordination for equipment within low-voltage systems - Part 1:Principles, requirements and tests

3 Clearances

Breakdown of clearances usually occurs in less than one submicrosecond. With respect to thattime scale, an a;c. voltage of power frequency has an essentially constant amplitude. Forinstance at 50 Hz, the amplitude remains within 99 YO of its peak value for 1 ms, Therefore,during the development leading to breakdown, the peak value of the voltage is effective. Thisnormally results in identical a.c. (peak) and d.c. breakdown voltages.

At much higher frequencies, a reduction of the voltage from its peak value and even polarityreversal have to be taken into account during the development of breakdown. This effect willresult in an increase of the breakdown voltage.

Up to now, the effect of the ions (which are usually positive) which are generated duringinception of breakdown has not been considered. These ions are generated at the crest of thesine-wave and there is usually enough time for them to travel to the electrodes during theremaining part of that half wave. However, in large clearances or at high frequency, the polaritymay be reversed before the ions have been extracted from the clearance. This will result in adistortion of the electrostatic field and will reduce the breakdown voltage. The average velocityof the ions is approximately 6 x 102 mls [1]*. At 50 Hz, the time interval between the crest andthe zero crossing of the sine-wave is 5 ms, resulting in the ions moving approximately 300 cm.Therefore, at power frequency, this aspect will only be relevant for very large clearances.However, if the frequency is increased to the kHz range, this phenomenon will atso be relevantfor small clearances.

● The figures in square brackets refer to annex A (Bibliography)

1

IS 15382 (Part 4) :2003

IEC 60664-4 (1997)

The superposition of both effects results in typical curves which exhibit a minimum breakdownvoltage for a certain frequency. For clearances with homogeneous and approximately homo-geneous field distribution, data is shown in figures 1 and 2 [2]. At 25 MHz, the breakdownvoltage is nearly the same as at 50 Hz. Figure 2 shows that the clearance is a very importantparameter with respect to this behaviour.

With respect to the frequencies presently used, the range with the initial decrease ofbreakdown voltage with increasing frequency is of greater interest. This frequency range, beingup to several MHz, is described in more detail hereafter.

For small clearances in N2 at atmospheric pressure, which has similar breakdown characteristics

as air, the reduction of the breakdown voltage may only be 10 Y., as shown in figure 3 [3].However, for frequencies exceeding 1 MHz, the reduction also becomes effective for very smallclearances less than 0,5 mm. For larger clearances there is a greater reduction in thebreakdown voltage, as-shown in figure 4 [4].

As a conclusion, for homogeneous and approximately homogeneous conditions, the maximumreduction of the breakdown voltage with frequency is about 20 %. The critical frequency atwhich the reduction of the breakdown voltage occurs is approximately:

where

f~~i~ is the critical frequency at which the reduction of the breakdown voltage occurs, inmegahertz;

d is the clearance in millimetres.

The insulating characteristics of homogeneous and approximately homogeneous clearances inair at atmospheric pressure with respect to frequency can be summarized by the followingstatements.

– Above /Crit, the breakdown voltage becomes lower with increasing frequency. The reductionin breakdown voltage may be up to 20 O/O.

– The breakdown voltage has its minimum at frequencies between 1 MHz and 5 MHz. Withhigher frequencies, the breakdown voltage becomes higher and may exceed the value atpower frequency.

For inhomogeneous field conditions, fCrit is still obtained approximately from the equation given.

Above fcrit, the influence of frequency on the breakdown voltage is much more significant. This

can be seen from figure 5 [5] for comparatively large clearances and a 30° point electrode incombination with a plane electrode of 15 cm diameter. The reduction of the breakdown voltagewith respect to that at 50 Hz can be more than 50 ?40. The results are strongly influenced by theelectrode configuration. The lowest breakdown voltages were measured with the planeelectrode earthed. As a general rule, it is essential to have approximately homogeneous fieldconditions if there is high-frequency voltage stress.

I

2

IS 15382 (Part 4) :2003IEC 60664-4 (1997)

4 Creepage distances

In IEC 60664-1, tracking is the only phenomenon taken into account for dimensioning ofcreepage distances. However, recent research [6] provides evidence that this does onlyapply for very severe environ.mental conditions, and if the materials used are not resistantto tracking (see EC 601 12). Under more favorable environmental conditions, tracking doesnot seem to be relevant for dimensioning. In this case, the flashover voltage across the surfaceof the insulating material is reduced by pollution and has to be taken into account fordimensioning [7].

It is not known whether tracking is influenced by the frequency of-the voltage. However, underconditions of severe pollution, or for materials having a low comparative tracking index, smalldimensions are not possible, and a safety margin has to be provided. This safety margin mayalso al~ow for a possible influence of frequency on the withstand capability.

For less pollution, the flashover voltage across the surface of the insulation seems to berelevant for dimensioning and a possible influence of frequency has to be considered.However, this influence may already be covered by the frequency dependence of thebreakdown voltage of the associated clearance according to clause 3.

Long-term influence of humidity is likely to change this situation. A significant reduction of thebreakdown voltage -across insulation surfaces, especially for higher frequencies, occurs undersuch conditions. This is mainly a problem caused by water absorption within solid insulation,and this phenomenon is considered in clause 5.

5 Solid insulation

Two failure mechanisms of solid insulation are normally relevant. One failure mechanismresults from dielectric loss at high electric stress. Increased heating will occur, which may leadto thermal instability and thermal breakdown. This usually takes place within a few minutes andcan be easily verified. Additionally, solid insulation can include gas gaps or voids, either causedby different layers of insulation, interfaces between insulating parts and conductive parts, or byimperfect manufacturing of the insulation material. In such small gaps, partial discharges arelikely to cause eventual failure of solid insulation even if the dielectric stress is sufficiently lowso as not to cause thermal breakdown.

For solid insulation, the frequency of the voltage is a very important influencing factor. Thedielectric loss for a given frequency is obtained from the following equation:

Pv. tan6x27cfx@x C

where

P“ is the power dissipation;

tan 6 is the loss factor;

f is the frequency;

u is the voltage across the solid insulation;

c is the capacitance cd the insulation arrangement.

3

IS 15382 (Part 4) :2003

IEC 60664-4 (1997)

Due to the dependence of the loss factor tan d on frequency, the influence of frequency on thedielectric loss may be lower or higher than can be expected from the apparent lineardependency. This results in a higher probability of thermal breakdown and a reduction of theshort-time dielectric withstand capability. This phenomenon has been investigated on differentinsulating materials [8]. The most important results are shown in figure 6. For a frequency of1 MHz, the short-time breakdown field strength may only be 10 ?!. of the power frequency value.The breakdown field strength does not seem to reach a lower limit even at frequencies as highas 100 MHz.

The dielectric strength of solid insulation in general, and especially at high-frequency voltage,is further reduced by the influence of humidity and temperature.

The influence of long-time storage on the breakdown field strength of solid insulation at high-frequency voltage under high humidity is shown in figure 7 [9]. The reduction of the breakdownfield strength of mica-filled phenolic is extraordinarily high. This is a significant problem atpower frequency, but is further aggravated with increasing frequency. The poor performance ofmica-filled phenolic is caused by its comparatively high water absorption, which was found tobe in the order of 1 7. by weight under such conditions. Under the same conditions, the waterabsorption of glass-silicone laminate was only 0,3 Y. by weight.

The breakdown field strength of solid insulation is a function of the thickness of the material,and very thin films may have a breakdown field strength one order of magnitude higher thanthat of the 0,75 mm test specimen. This is shown in figure 8 [10]. With increasing frequency,there is a significant reduction of the values. At 1 MHz only approximately 10 ?’. of the 50 Hzvalues were found. At such high frequencies, the behaviour of thin films seems to be similar tothat of specimens having approximately 1 mm thickness. The influence of the thickness of thefilm on the breakdown voltage can be seen in more detail in figure 9 [10]. There is someindication that the breakdown voltage of very thin films is slightly less affected by frequency,but even for 0,01 mm film, there is still a significant reduction.

Figure 10 [11] shows that the breakdown field strength of solid insulation at all frequencies isadditionally reduced with increasing temperature. The influence of increased temperature onthe breakdown voltage of thin films is shown in figure 11 [10], which shows that the reduction ofbreakdown voltage with increasing temperature is aggravated with increasing frequency.

So far, only short-time stress and thermal breakdown have been considered. For long-timestress, partial discharges have also to be taken into account [12]. Experience shows that, inparticular, thin insulation used in low-voltage equipment cannot withstand these discharges forlong periods. Therefore, partial discharges should not be maintained under steady-stateconditions. Partial discharges are to be expected at a dielectric stress significantly lower thanthat causing thermal breakdown.

Detailed results concerning the partial discharge characteristics at high-frequency voltage areonly available for frequencies up to a few kHz [13, 14]. In that range, it has been establishedthat the time to failure caused by partial discharges is inversely proportional to frequency. Thisrelationship has been used for accelerated testing. Therefore, especially at higher frequencies,a reasonable lifetime cannot be expected when partial discharges occur.

Detailed measurements have been made on - coated printed circuit boards. One of the testboards is shown in figure 12. A typical plot of thr partial discharge intensity (apparent charge q)is shown in figure 13 [15].

4

IS 15382 (Part 4):2003IEC 60664-4 (1997)

For this type of test specimen, an increase of the apparent charge with increasing frequency ismore likely to occur than a decrease. It has been established that at high frequency, the time tofailure may only be in the order of minutes. Therefore, partial discharge testing at highfrequency for such periods may be destructive.

Additionally, the partial discharge inception voltage Ui and the partial discharge extinction

voltage LJe may be influenced by frequency. As shown in figure 14 [15], some reduction of the

partial discharge voltages with increasing frequency is to be expected for coated printed circuitboards. However, this characteristic seems to depend on the type of test specimen. As shownin figure 15 [15], the partial discharge voltages of optocouplers do not seem to be influenced byfrequency. At high frequency, there seems to be even some tendency of a decrease of theapparent charge q. However, the combined effect of frequency and apparent charge as thesource of failure is more onerous than at power frequency.

6 High-frequency testing

The following tests are relevant with regard to frequency:

verification of the short-time dielectric strength for clearances and, in particular, for solidinsulation by an a.c. voltage test at high frequency;

with regard to long-time electric stress, verification that no partial discharges are maintainedunder steady-state conditions.

the present time, high-frequency test equipment is only available with limited power output,so that only components and small subassemblies can be tested.

6.1 High-frequency breakdown test

This test is similar to the high-voltage test at power frequency. At present, no standard high-power HF test voltage scwrces are available.

6.1.1 Test method

It has been -obsemed that the high-frequency withstand is influenced by equipment temperatureand environmental conditions. The test should be performed under the most onerousconditions that may be encountered in service, including the temperature rise caused bynormal operation of the equipment.

6.1.2 Test equipment

For frequencies up to a few MHz, one way to generate the test voltage is by using a high-poweroscillator in combination with an air-core transformer. An appropriate circuit is shown infigure 16 [10]. With this circuit, fixed frequencies from 100 kHz up to 10 MHz can be adjustedwith an output power of 1,5 kW. Due to the high capacitive loading, both frequency and outputvoltage are influenced by the test specimen.

In order to cover the whole frequency range from a few kHz to 1 Ml+z, a test circuit consistingof a high-power amplifier and an HF resonance transformer can be used. The circuit is shownin figure 17 [15], together with a partial discharge detection circuit. The frequency range forresonance transformers dependent on the number of secondary turns is shown in figure 18.High-frequency operation requires a low number of secondary turns. In order to cover thewhole frequency range, several resonance transformers are required.

5

IS 15382 (Part 4) :2003IEC 60664-4 (1997)

6.2 High-frequency partial discharge test

6.2.1 Test method

Due to the high risk of deterioration of the test specimen at high frequencies, the rate ofvoltage rise should be as high as possible without causing overshoot. In general, the noiselevel during high frequency partial discharge testing will be significantly higher than thatoccurring during power-frequency testing.

The preliminary results obtained for optocouplers give some indication that the partialdischarge voltages are not significantly influenced by frequency. if this could be verified on amore representative basis, a partial discharge test with power-frequency voltage could besufficient to give enough information about the partial discha-rge characteristics of optocouplersat high frequency. For coated printed circuit boards, this is different, because both the partialdischarge voltages and the partial discharge intensity are influenced by frequency. Theseaspects need furthe-r investigation with other test specimens.

6.2.2 Test equipment

The measurement of partial discharges is more difficult, because both the test voltage sourceand the partial discharge measuring equipment are not readily available.

However, this difficulty’ ‘may be overcomefigure 17. The partial discharge detectionstorage oscilloscope of high sampling rate.to 15 were Qbtained.

by employing laboratory apparatus as shown inis performed by digital integration with a digitalWith this test circuit, the data shown in figures 13

IS 15382 (Part4) :2003IEC 60664-4 (1997)

16

14

12

4

2

0 I I I I 1 I 1 I I

0“

I

I I I I I I I I I I 1 I I I I I I I

o 1 2d/mm~

Figure 1- Breakdownat high frequency in air,

r

+ 50 Hz- + -0,88 MH;

– + – 2,5 MHz

—X— 12 MHz+K -25 MHz

I I I I I I I I 1

3 4

homogeneous field [2]

IS 15382 (Part 4):2003IEC 60664-4 (1997)

x.

-@- 0,5 mmLJ ‘ 1,5 mmAv 2,5 mm

— — .3,5 mm_

b

,

a,

-.- 1,0 mm

+ 2,0 mm+ 3,0 mm~4,0 mm_

>

0 1 1 111111 I i111111 I I1111 I I 111111 t 1 111111 1 I 111111 I I

10-2Illlu

10-1 10° 101 102 103 104 105f/kHz+

Figure 2- Broekdownat high frequency in air, homogeneous field [2]

8

IS 15382 (Part 4) :2003

IEC 60664-4 ( 1997)

11 I I

f

J I I I

-1-——

I I 1 I I 1 I I J 1 I I J I I 1

1-o-c- + -2,4 MHz– X- -4,2 MHz+ 6,6 MHz

L0.0 0.1 0.2 0.3 0.4 0,5 05 07 08. . .

d/mm~

Figure 3- Breekdown at high frequency in nitrogen, homogeneous field [3]

9

IS 15382 (Part 4):2003IEC 60664-4 (1997)

18

16

4

2

I-0- 0,5 mm -1,0 mm-U- 1,5 mm -2,0 mm+ 2,5 mm A

m 3,0 mm--0- 3,5 mm -4,0 mm—-X— 4;5 mm w

5,0 mm

o -x

A

t

t n

0 1 I I 11111 1 I 111111 I I 111111 i I 111111 I I 111111 i I Illlu

10-2 10-1 1(Y 101 102 103 104f/kHz~

Figure 4- Breakdown et high frequency in air, homogeneous field [4]

IS 15382 (Part 4) :2003IEC 60664-4 ( 1997)

1 I I* 50 Hz; point earthed—)(— 75 kHz; point earthed

+ 50 Hz; plane earthed

~ 75 kHz; ‘plane earthed

,x

1 I 1 I I I I i 1 I I I I Io 20 40 60 80 100 120 140 160 180 200 220

d/mm -

Figure 5- Breakdown et high frequency in air, inhomogeneous field [5]

11

IS 15382 (Part 4):2003IEC 60664-4 (1997)

1008060

40

20

n

Ui.

Lw

4

2

10.80.6

0.4

0.2

U mica-filled phenolic, mould~fi---- polytetrafluorethyleneU polyethylene+ polystyrene )+ forsterite ceramic.+ dry-process porcelain--0- glass-bonded mica+’ glass—X— glass-silicone laminate+ glass-melamine laminate+ paper-phenolic laminate

.0-2 10-1 10° 101 102 103 104 105f/kHz~

d= 0,75 mm

Figure 6- Breakdownat high frequency, solid insulation [8]

12

IS 15382 (Part 4) :2003IEC 60664-4 (1997)

60

40

20

1086

0.10.6

0.4

0.2

0.10.080.06

0.04

0.02

0.01~

x

>(

A

+ mi~-filled phenolic; d = 0,75 mm; new+ rni~-filled Phenok d = 0,75 mm; 180d/50% r.h.+ mi~~filled phenoliq d = 0,75 mm; 180cY100% r.h.~ 91ass-siliCOnelaminate; d = 1,5 mm; new—)(— glass-silicone laminate; d = 1,5 mm; 180d/50% r.h.+ 91ass-silicone laminate; d = 1,5 mm; 180d/100% r.h.

I 1 1111II 1 I111111 I I111111 I I111111I I 111111I I 11111I I I 1111~.0-2 1o-1 1.OO 101 102 103 104 105

f/kHz+

Figure 7- Breekdown et high frequency, eolid ineuletion; conditioning at 50 “C [9]

13

IS 15382 (Pm-t 4) :2003IEC 60664-4 (1997)

108

6

4

2

t~1~ o.8

; o-b5

0.4

0.2

0.1

-4

I I

\. I II 1

cellulose-acetobutyr

polycarbonate; 0,03M

cellutose-triacetate; 0,03 mm i- Cellulose-acetobutyrate; 0,06 mm—)(— polycarbonate; 0,06 mm

+ cellulose-triacetate; 0,06 mm

I I I 11111I I 111111I 1111111I I 111111I I 1111111 I 1111/10-1 10° 101 102 103 104

f/kHz~

Figure 8- Breakdownat high frequency, insulating films [1O]

14

IS 15382 (Part 4):2003IEC 60664-4 (1997)

40

20

1086

0.4

0.2

0.1

t

Au ‘ 0,01 mmAm 0,02 mm

x. . Av ‘ 0,05 mm_Av ~ 0,08mm

—x— 0,10mm

I I II I I I xl \\’

10-z 10-1 10° 101 102 103f/kHz~

Figure 9- Breekdownet high frequency, polystyrenefilm et 20 “C [10]

104

15

IS 15382 (Part 4) :2003IEC 60664-4 (1 997)

10080

60

40

~

20

+~ 10:8

~6sxiD4

2

-4=x-

W

I I llllJ#

I I I I I

I I 111111 I i 1111111 I 111111I I 111.1.jJ

+ -’5°c+ 20°c—X— 60”C+ loo”c

I I 111111 I I IIIIJ1

104 10-3 10-2 10-i 10° 101 102 103f/kHz+

Figure 10- Breakdown at high frequency, paper laminate(pertinax); temperature[11]

16

i-o8

6

4

t

2

0.4

0.2

0.1

+ polystyrene; 0,08 mm; 25 “C

+ polystyrene; 0,08 mm; 50 ‘C-0- polystyrene; 0,08 mm; 80 “C.+ polyethylene; 0,05 mm; 25 ‘C _

—X— polyethylene; 0,05 mm; 50 “C

IS 15382 (Part 4) :2003IEC 60664-4 (1997)

102 103 104f/kHz~

Figure 11- Breakdown at high frequency, insulating films; temperature

17

IS 15382 (Part 4) :2003IEC 60664-4 (1997)

& 1

1- through holes (interconnecting of layers)

2- conductors 45°

3- conductors 90°

The distance values aremeasured,

the smallest ones between adjacent

Figure 12- Layout of the test board

0,12 mm

0,19 mrn

0,3-1 mm

0,57 mm 1

0,12 mm

0,19 mm1

0,30 mm ‘

10,57 mm

0,13 mm

0,22 rrtm 1

J

0,30 mm

0,55 mm

0,14 mm 70,19

0.31

0,56

mm

mm

1mm

1

2

3

actually being

18

105

104

103

Ig

\u- 102

101

+-

//

/

/

+/

/ ‘/ /

x /

/

/

/

/

/

~‘/

JLwuL_W10-2 10-1 10°

f/kHz+

d= 0,3 mm

IS 153S2 (Part 4) :2003IEC 60664-4 (1 997)

A/ \\

\

\

\

~ conductors; 90°

–x-- conductors; 45°

* through-holesI

101 102

Plgure 13- Pertial diecherge et high frequency, coeted printed circuit board [15]

19

IS 15382 (Part 4):2003IEC 60664-4 (1 997)

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

-\\.

1

I

0.010-2

1 I I I 11111 I I 1I 111~

d= 0,2 mm

Figure 14- Pertiai

10-1

,\w/’ \

L+ mndu~ms; 90°; Ui+ mnductors; 90°; Ue+ @nduaors; 45°; Ui- + - conductors; 45”; Ue—)(— through-holes; l..Ji

- X - through-holes; Ue

II I I 1 1111 I 1 1

10° 101f/kHz~

diecharga et high frequancy, coatedprintad circuit board [15]

102

IS 15382 (Part 4):2003IEC 60664-4 (1 997)

n

1.8

1.6

1.4

1.2

Lo

0.8

0.6

0.4

0.2

0.0

L

-“ /I

\Lx– --–––––- ._.)(_ _+

I

I\\

I

I\\

I\\

II

+ u,d/

–X--ue*q —

I I I

10-2

Figure 15- Partiel

10°

—1 700

42--600

500tu

400~u-

300

1-lI 200

+

100

~()101 102

f/kHz~

diecherge et high frequency, optocoupier_[15]

IS 15382 (Part 4):2003IEC 60664-4 (1 997)

22

Figure 16- Baaic circuit of a HF power oscillator (colpitt circuit)

IS 15382 (Part 4) :2003JEC 60664-4 (1997)

3

/

42

—

/

5

/

6

kEE

4BB

Bus-EIlf2

I. —

p--(

mF

—

/11

1- HF generator and power amplifier, f= 2 kHz – 500 kHz2- HF resonance transformer

3 – test specimen

4 – coupling impedance

5- HF high-voltage probe

6- screened cage7- digital storage oscilloscope

8- impulse amplifier

9- conventional partial discharge detector

10 – digital voltmeter

11 – analogue oscilloscope

12- control computer

Figure 17- HF partial discharge teat circuit

23

IS 15382 (Part 4) :2003IEC 60664-4 (1 997)

8

7

4

3

2

1

0

-.. . . . . . .

,.. .

.--”

,.. .

,--”

!.. .

. . . . . . . . . . . . .

., .-. . . . . . . . . .

---- . -.---”,- --

.. . . . . . . . . . . . .

-! --’-”,” --- ;--

. .

. .

. .

-.

. .

. .

. .

200 250 300 350 400 450 500 550 600 650 700 750

f/kHz —F

Number of primary turns A/l = 20;

Number of secondary turns A12: ■ - 210, +-280, ~ -350, ❑ -420, X- 560

Figure 18- Output voltage of HF resonance traneformere.

24

IS 15382 (Part 4) :2003IEC 60664-4 (1997)

Annex A

Bibliography

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[1o]

[11]

[12]

[13]

[14]

[15]

B. Ganger, E/ecfrica/ breakdown of gases (in German), Springer Verlag, Berlin/Gottingen/Heidelberg 1953, pp. 422-450.

F. Muller, E/ecfrica/ breakdown of air at very high frequency (in German), Archiv furElektrotechnik, vol. 28, pp. 341-348, 1934.

A.W. Bright in Meek, Craggs, E/ectrica/ breakdown of gases, John Wiley & Sons,Chichester/New York/Brisbane/Toronto 1978, Chapter 8, pp. 696.

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J. Kampschulte, Breakdown of air for a.c. voltage of 50 to 100000 I-/z (in German), Archivfur Elektrotechnik, vol. 24, pp. 525-552, 1930.

28A/1 08A/CDV: Amendment to IEC 60664-1 – Revision of po//ution degrees andcreepage distance requirements.

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(Continued from second cover)

For the purpose of deciding whether a particular requirement of this standard is complied with, the finalvalue, observed or calculated, expressing the result of a test, shall be rounded off in accordance withIS 2:1960 ‘Rules for rounding of numerical values (revised)’. The number of significant places retainedin the rounded off value should be the same as that of the specified value in this standard.

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of /rtdian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in anyform without the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designa-tions. Enquiries relating to copyright be addressed to the Director (Publications), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards arealso reviewed periodically; a standard along with amendments is reaffirmed when such review indi-cates that no changes a~ needed; if the review indicates that changes are needed, it is taken up forrevision. Users of Indian Standards should ascertain that they are in possession of the latest amend-ments or edition by referring to the latest issue of ‘BIS Catalogue’ and ‘Standards: Monthly Additions’.

This Indian Standard has been developed from Doc : No. ET 19 (5344).

Amendments issued S-ince Publication

Amend No. Date of Issue Text Affected

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