CENELEC - · PDF fileEUROPEAN STANDARD EN 50124-1/A1 NORME EUROPEENNE EUROPÄISCHE NORM October 2003 ICS 29.080.00; 45.020 English version Railway applications - Insulation

EUROPEAN STANDARD EN 50124-1/A1

NORME EUROPEENNE

EUROPÄISCHE NORM October 2003

ICS 29.080.00; 45.020

English version

Railway applications -Insulation coordination

Part 1: Basic requirements -Clearances and creepage distances

for all electrical and electronic equipment

Applications ferroviaires -Coordination de I'isolementPartie 1: Prescriptions fondamentales -Distances d'isolement dans I'air etlignes de fuite pour tout materielelectrique et electronique

Bahnanwendungen -Isolationskoord inationTeil 1: Grundlegende Anforderungen -Luft- und Kriechstrecken für alleelektrischen und elektronischenBetriebsmittel

This amendment A 1 modifies the European Standard EN 50124-1 :2001; it was approved by CENELECon 2003-10-01. CENELEC members are bound to comply with the CEN/CENELEC Interna I Regulationswhich stipulate the conditions for giving this amendment the status of a national standard without anyalteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained onapplication to the Central Secretariat or to any CENELEC member.

This amendment exists in three official versions (English, French, German). A version in any other languagemade by translation under the responsibility of a CENELEC member into its own language and notified to theCentral Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta,Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELECEuropean Committee for Electrotechnical Standardization

Comite Europeen de Normalisation ElectrotechniqueEuropäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B -1050 Brussels

@ 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No.EN50124-1:2001/A1:2003E

Uncontrolled copy when printed

EN 50124-1:2001/A1:2003 -2-

Foreword

This amendment to the European Standard EN 50124-1 :2001 was prepared by the TechnicalCommittee CENELEC TC 9X, Electrical and electronic applications for railways.

The text of the draft was submitted to the formal vote and was approved by CENELEC asamendmentA1 to EN 50124-1:2001 on 2003-10-01.

The following dates were fixed:

- latest date by which the amendment has to be implementedat national level by publication of an identicalnational standard or by endorsement (dop) 2004-10-01

- latest date by which the national standards conflictingwith the amendment have to be withdrawn (dow) 2006-10-01

Annexes designated "normative" are part of the body of the standard.Annexes designated "informative" are given for information only.In this standard, Annexes A, ß, C and D are normative and Annexes E, Fand G are informative.

Annex F (informative) Bibliography

Add the following documents:

EN 50123 series Railway applications - Fixed installations - D.C.switchgear

EN 50152 series Railway applications - Fixed installations - Particular requirements for a.c.switchgear

EN 50153 Railway applications - Rolling stock - Protective provisions relating toelectrical hazards

EN 61558 series Safety of power transformers, power supply units and similar devices


-3- EN 50124-1 :2001/A1 :2003

Add the following annex:

Annex G(informative)

Application guide

G.1 Introduction

The term "insulation co-ordination" explains the process for co-ordinating the constituents of anelectrical insulation, Le. solid/liquid insulation, clearances and creepage distances.

NOTE The dimensioning of insulation thicknesses perfonned by solid insulation and insulation distances perfonned by liquid insulationmaterials is not covered by this standard.

However, the use of this standard for the determination of clearances and creepages needs someadditional explanations: The values of the tables of Annex Aare based on EN 60664-1 andEN 60071-1 taking into account the severe electrical and mechanical situation of insulations inrailway systems and their expected reliability and long life time.

For example, the values for clearances are selected for inhomogeneous fields and, for locationswith typical railway pollutions are supplemented by safety margins. Thus, it is not necessary toperform a high voltage test, when clearances required by this standard are achieved.

Where product standards for railway applications specify test voltages and clearances, the use ofthese values is recommended. According to 1.1 it can be assumed that the insulation values in theproduct standards were derived in accordance with this European Standard.

G.2

G.2.1

Determination of minimum clearances and creepage distances

Sections

For practical use when determining insulation values it is necessary to consider the followingfactors when dividing into sections:

is the considered part of the circuit exposed to the same electrical climate? (working voltage,overvoltage category);

are the location criteria of the regarded part of circuit the same? (pollution degree,indoors/outdoors );

for economical reasons it may be useful to subdivide sections (e.g. for lower insulation valuesin areas with lower voltage stress);

for reliability or safety reasons it may be useful to increase insulation values in endangeredareas, Le. by introducingaseparate section.

For floating sections consideration should be given to capacitive effects for defining thedimensioning parameters of an insulation. Due to the actual or parasitic capacitances between theregarded section and adjacent sections, creepage and clearances can be stressed by continuousvoltages greater than the nominal voltage of the circuit. The correct selection of 4Jm and 4Ji shouldtake that effect into account.


EN 50124-1:2001/A1:2003 -4-

G.2.2 Use of method 1 and 2 for determining "'i

Methods 1 and 2 are considered as equivalent for dimensioning clearances because both methodslead to reliable distances.

Method 2 is a physical method to determine an insulation value taking into account the voltagestress occurring across the regarded insulation but it can only be used if the expected overvoltagesare weil known.

If the overvoltages are not known, method 1 should be used.

G.2.3 How to determine minimum clearances and creepage distances

The flowchart of Figure G.1 displays the procedure for determining the minimum clearances andcreepage distances by taking into account the relevant electrical, environmental and operatingconditions.


EJ

EJ

Division of the electrical circuit intosections which are to be handled separately.

For all points of this sectionthe same voltage stress applies

The complete circuit or only a single pointof the circuit may be defined as a section

Determination of rated insulation voltagefor the section of the circuit

tf..m

Rolling stock:Table 0.1

EJep 3

I

Selection of insulation typeAccording to 1.3.4 for the section

Product standards may state a preselectio

EJ

Insulation between conductive partsonly for properfunctioning

Functionalinsulation

Choice of pollution degreefor the section of the circuit

Table A.4 + Annex E

-5- EN 50124-1:2001/A1:2003

3

Sections 1,2,3......

For each sectionthe following steps are to be

performed

The section is powered direct by astandardised railway volta ge {.f,

Manufacturer's determinationaccording to 1.3.2.4 and Table A.1

Rated insulation voltagefor the section of the circuit

~m

The section includes live parts.The insulation provides a basic protection

against electric shock

In case of insulation failure,

the danger of an electric shock is given

Basicinsulation

Reinforced insulation

(as a single insulationsystem)

Double insulation

Basic + Suppl.

Signalling6.1

Pollution degreePD1...PD4B

Pollution degreePD1...PD4A

Rolling stock6.2

Pollution degreePD1...PD4

Fixed installation6.3

Figure G.1 - Detennination of minimum clearances and creepage distances


EN 50124-1 :2001/A 1:2003 -6-

EJ

u

Determination 01rated Impulse voltagefor this section 01circuit

Uiiand the minimum clearance In air

All overvoltagesare known by calculation

or by measurement

Method 1According to 2.2.2.1

01 this standard

Method 2 (2.2.2.2)Calculation or measurement

01working peak voltages

Determination 01Overvoltage categorie

OV1..0V42.2.2.1

and Clause 6

Calculation or measurement 01all wolking peak voltages

in this section (including transientand induced voltages)

lMm trom Step 2

The maximum 01this peakvoltages is

PD trom Step 4Table A3

Interpolation permitted

Minimum clearancelor functional Insulation

smaller values are allowedbut voltage test obligatory

according toClause 5 and Table A.8

Minimum clearance lor basic insulationdistances designed or measuredsmaller values are not allowed

Minimumclearance lor reinforced insulation according to 1,6 x Uiidistances designed or measuredsmaller values are not allowed

Determination 01

minimum creepage distancelor the section 01 the circuit

Choice ofthe material group I, 11,lila, or IIIb

according to 2.6 and 4.1

&Nmlrom Step 2

PD Irom Step 4

Table A5. A6 or A.7interpolation permitted

Minimum creepage distancelor functional insulation;

values are lor basic insulationsmaller values are not alloweddistances designed or measured

according to Annex CMinimum creepage. minimum

clearance

Minimum creepage diSfincelor basic insulation

smaller values are not alloweddistances designed or measured according to Annex C

Minimum creepage. minimum clearance

Minimum creepage distancelor reinforced Insulation according to 2x~m

smaller values are not alloweddistances designed or measured according to Annex C

Minimum creepage. minimum clearance

Figure G.1 - Detennination of minimum clearances and creepage distances (concluded)


-7- EN 50124-1 :2001/A 1:2003

G.2.4 Pollution

Table A.4 and Annex E may be used to identify the pollution degree applicable. Adefinition of apollution degree with numerical values is not practicable.

There is no direct relation between the protection level given by IP elasses of EN 60529 and thepollution to be expected. The IP elasses are related to the protection against the ingress of solidobjects ineluding dust and against the ingress of water (e. g. spraying, splashing, water jets,immersion, etc.). Protection according to IP classes cannot prevent pollution created by theequipment itself.

The pollution degree PD1 may be used in areas of fixed installations and of signalling equipmentwhere the temperature and the humidity are permanently controlled. These conditions are normallynot given in rolling stock.

Table A.3 shows that for indoor locations (PD1 to PD3A) the pollution has no additional influenceon clearances above 1,6 mm. On the contrary, for PD4 in rolling stock outdoor installations and forPD4A and PD4B in fixed installations, the pollution has a significant influence on clearancesthroughout the whole voltage range. Therefore these clearances are derived from the size of solidpartieIes and the accumulation of pollutants likely to reduce the clearances.

For outdoor fixed installations special conditions (PD4A and PD4B) apply. It is because thepollution at any particular area is always present for that particular area and may be very severe.Rolling stock may operate in areas where the levels will be different and then the average level ofpollution and time of application should be considered. Also fixed installations may be cleaned lessfrequently.

For further guidance in selecting PD4A and PD4B the following, which is based on IEC 60815,should be noted:

PD4A "heavy conditions"

Areas with high density of industries and suburbs of large cities with high density of heatingplants producing pollution;

Areas elose to the sea or in any area exposed to relatively strong winds from the sea.

PD4B "very heavy conditions"

Areas generally of moderate extent, subjected to conductive dusts and to industrial smokeproducing particular thick conductive deposits;

Areas generally of moderate extent, very elose to the coast and exposed to sea spray or tovery strong and polluting winds from the sea;

Desert areas, characterised by no rain for long periods, exposed to strong winds carrying sandand salt, and subjected to regular condensation.


EN 50124-1:2001/A1:2003 -8-

G.2.5 Creepages

For creepages, the required distances increase with voltage for all pollution degrees. Values aregiven in Tables A.5, A.6 and A.7 based on the rated insulationvoltage 4Jm.

Creepage distances cannot be validated by voltage tests because, among other reasons, theinfluence of pollution cannot be simulated. Product standards will address for tests taking intoaccount pollution, if existing. Reduction of creepage distances is not allowed for either functional orbasic insulation.

G.2.6 Insulations

G.2.6.1 Types of insulation

Figure G.2 gives an example of types of insulation.

i functional ~ surfaceof metallic

]'ation ! ~enclosu,"

l--71 ~c./ I~

insulation' InsulatJon II +: creepagerl

reinforced ~ = I

insulation I double I

i insulation - -I. I

L ~

solidinsulation

1Jthe creepage distanceis regarded assupplementary insulation

Figure G.2 - Example for types of insulation

G.2.6.2 Supplementary insulation

A supplementary insulation (see definition 1.3.4.3) is an additional independent insulation which isintended to protect users from electric shock in the case of breakdown of basic insulation. Theelectric stress of supplementary insulation in case of a failure can be different from the stress ofbasic insulation under normal operating conditions.

NOTE 1 Supplementary insulation may be performed as a layer of solid insulation.

NOTE 2 Partial discharge may occur in the case of a combination of insufficient clearance and well-dimensioned solid insulation.

Sometimes additional insulation is provided in addition to basic insulation for mechanical protectiononly, not to protect against electric shock. This additional insulation is not supplementary insulationin the sense of 1.3.4.3, e.g. in the case of the outer sheath of a cable.

Supplementary insulation can be used for increasing the reliability of an insulation.


-9- EN 50124-1:2001/A1:2003

G.2.6.3 Double insulation

An insulation system where a layer of a basic insulation is combined with a layer of asupplementary insulation is called "double insulation". However, the combination of two functionalinsulations is not a double insulation.

NOTE In braking resistors, the combination of a basic insulation with a functional insulation is sometimes termed "double insulation" butdoes not fulfil the requirements as defined in this standard.

G.2.6.4 Reinforced insulation

A reinforced insulation is equivalent to a double insulation, when it is not possible to identify thelayers of basic and supplementary.

NOTE A typical example of the use of reinforced insulation is for safety transformers in accordance with the series EN 61558.

G.2.7 Use of minimum distances for clearances and creepage distances

These distances are values wh ich experience has found to be satisfactory in normal railwayoperation with a good reliability of equipment.

All clearance and creepage distances dimensioned according to this standard are minimumdistances. The designer of an equipment is free to use larger distances.

NOTE Minimum values of clearances and creepage distances may be increased by the designer for specific requirements and serviceconditions in order to increase reliability.

G.2.8 Roof equipment for rolling stock

The roof of a vehicle is considered as a "closed electrical operating area" in accordance withEN 50153. In this special case, the insulation of the roof equipment may be considered asfunctional insulation. If agreed between purchaser and supplier, the clearances may be reducedaccordingly.

It is recommended, however, to use higher values for creepages on the roof due to the level ofpollution likely to be expected in that area.

G.2.9 Special cases of switching arrangements in fixed installations(see Table A.2, footnote 3)

Table A.2 gives values for ~i for the rated insulation voltage 52 kVa.c.

Switchgear intended to fulfil those requirements are used for example in substations where theyare connected to two phases of a three-phase network with a nominal voltage exceeding 25 kV. Insuch cases the switching device shall be dimensioned for a higher voltage. The next standardisedvalue is then 52 kV in accordance with EN 60071-1.

In all other cases the relevant value of ~m is either 27,5 kV or 36 kV for a {Inof 25 kV.

G.2.10 Insulation conditions in fixed installations (see 6.3.1.1)

Switching devices intended to isolate discrete sections of the contact line from the power sourceare provided with an increased value for the rated impulse voltage ~i (up to 25 %).

Detailed values for rated impulse voltages across isolating distances of switching devices arespecified in the relevant product standards; for d.c. switching devices in the series EN 50123, fora.c. switching devices in the series EN 50152.


EN 50124-1:2001/A1:2003 -10-

G.3 Examples

Figure G.3 gives an example for sections. The diagram shows a monitoring circuit for the supplyvoltage of a locomotive.

I Section 2 r

P1

~:..

.

~.=~

..

~~r~Soctioo 1 I

~_..O:IHm pi - -{111r- Roof

12.' Section 3 I

2,5~F

;;~!C ::.::.-~- -

GAP

to dc contraldevice

-=

Figure G.3 - Monitoring circuit showing examples of sections

Figure GA shows a drawing of a monitoring device used as an example for determining clearanceand creepage distances related to the monitoring circuit of Figure G.3.


-11 - EN 50124-1:2001/A1:2003

ceramic insulator

mineral oil +

silica

--,~r1-~1lJTF1

Roof

Cap

\Metallic box

Figure G.4 - Drawing of monitoring device

Device located on the locomotive roof supplied at two supply voltages:

.. 25 kVa.c.

.. 1,5kVd.c.

Determination of minimum clearances and creepage distances of the stepdown transformer TF1.

Figure G.5 - Example for the determination of clearances and creepage distances

Step1 Seetion 1 Section 2 Seetion 3(see diagram)

Step 2 Directlyconnected to the contact Not directlyconnectedto the Not directly connectedto theline contact line contact line

Calculationwith primaryvoltage Calculationwith primaryvoltage1,5 kV d.c. 25 kVa.c.

lf..m= 27,5 kV lf..m= 1,74 kV lf..m= 0,11 kV

Step 3 Basic insulation Functionalinsulation Functionalinsulation

Step 4 Pollutiondegree PD4 Pollutiondegree PD2 Pollutiondegree PD2

Step 5 Method 1 Method 1 Method 1TableÄ.2- OV4(nosurgediverter) Table Ä.2 - OV2 Table Ä.1 - OV3

lf..1= 170 kV lf..J=10kV lf..1=2,5kVTable Ä.3 Table Ä.3 Table A.3Minimum clearance =310 mm Minimum clearance =11 mm Minimumclearance =1,5 mm

Step 6 Materialgroup I Material group 11 Material group 111Table A.7. 25 mm/kV Table Ä.7. 7,1 mm/kV Table Ä.6 - 0Nm= 125 V - PD2

Minimum creepage distance = Minimum creepage distance = Minimum creepage distance =687 mm 12,4 mm 1,5mm


EN 50124-1:2001/A1:2003 -12-

G.4 Tests

G.4.1 Measuring

To demonstrate the compliance of the equipment with the insulation requirements, it is necessaryto measure the clearance and creepage distances.

In order to limit the amount of measurements, it is recommended to identify where the minimumclearances and creepage distances occur. If measurement is difficult on the complete item, it isrecommended to do this on a relevant subassembly.

If the measurement of clearances is not possible, a voltage test is performed in accordance with5.3, 5.4 or 5.5 on a subassembly to avoid overstressing of the equipment.

If the clearances for functional insulation are smaller than those specified in Table A.3, a voltagetest is mandatory.

For measuring of creepage distances refer to Annex C.

G.4.2 Testing

Two kinds of voltage tests are given in this standard:

a) Tests for verification of clearances (see Clause 5 and Table A.B)

This test is a type test. Where a relevant product standard specifies requirements for such atest, the test should be performed in accordance with the product standard. In all other casesClause 5 applies.

In the case of functional insulation when the clearance has been reduced, the voltage test iscarried out at the value for the unreduced cIearance. When carrying out the test to verifyclearances, it is good practice to test only the parts under consideration. It is acceptable to usea representative subassembly.

b) Dielectric test voltages for equipment (see Annex B, Table B.1)

This routine test is only valid for items of equipment when there is no relevant productstandard.

The test voltages for dielectric testing are based on the rated impulse voltage 4Ji taking intoaccount the overvoltage categories. Test voltages in most product standards, however, areconventionally based on the nominal voltage or the rated insulation voltage of the equipment.

The test voltages of Table B.1 are not used for checking clearances.


Documents

CENELEC - · PDF fileEUROPEAN STANDARD EN 50124-1/A1 NORME EUROPEENNE EUROPÄISCHE NORM October 2003 ICS 29.080.00; 45.020 English version Railway applications - Insulation