SELF-CONTAINED SURGE ARRESTERS 12 - 420 kV · SELF-CONTAINED SURGE ARRESTERS 12 - 420 kV INTRODUCTION ... 5 Specification of the surge arrestors according to IEC 60099-4 -2014 2017-12-22

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SVENSKAKRAFTNÄTSWEDISH NATIONAL GRID

UNIT, BUSINESS AREA AT- Anläggningsteknik

DATE2017-12-22

CONSULTATIONS

OUR REFERENCETR01-12E

TECHNICAL GUIDELINE

REVISION5

APPROVED

SELF-CONTAINED SURGE ARRESTERS 12 - 420 kV

INTRODUCTIONThis English text is to be regarded as a translation of the Swedish guideline. The Swe- dish text and the interpretation thereof shall govern the contract and the legal relations between parties.

These guidelines are mainly based on the Swedish standard SS-EN 60099-4. The guidelines State preferred alternatives where the standard allows selections. They also include additions to and clarifications of the standard. The guidelines may as part of a contract be made compulsory for the Supplier and will in such cases specify requirements that will, in addition to the standard, be applicable for manufacture and testing of surge arresters for a.c. networks 12 - 420 kV. The guideline may in applicable parts also be used for gas insulated switchgears and HVDC installations.

These guidelines are applicable for self-contained gapless metal-oxide arresters.

TECHNICAL GUIDLINE 2017-12-22 TR01-12E rev 5

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Revision

Notes Change notes Date

B Revision 2006-11-20

3 New template. Collaboration with Vattenfall removed. Table with creep age distances have been updated, all creep age distances for both ceramic and non-ceramic insulators are now identi-cal.

2013-02-25

4 Creep age distances updated. Pollution test method withdrawn. Standards updated. Line discharge class changed for 420kv Trans-former/Reactor.

2016-11-01

5 Specification of the surge arrestors according to IEC 60099-4 -2014 2017-12-22


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Content

1 GENERAL .................................................................................................................. 5

1.1 Applicable standards ................................................................................... 5

2 DEFINITIONS ........................................................................................................... 6

3 IDENTIFICATIONS AND CLASSIFICATIONS ...................................................... 6

3.1 Identification of Surge Arresters ................................................................ 6

4 Requirements on Surge Arresters ............................................................................ 7

4.1 Rated Voltage ............................................................................................... 7

4.2 Rated Frequency ......................................................................................... 8

4.3 Nom inal Discharge Current ....................................................................... 8

4.4 Arrester Classification ................................................................................ 8

4.5 Earth-fault Factor ........................................................................................ 9

4.6 Residual Voltages ....................................................................................... 10

4.7 Short-Circuit Capability ............................................................................ 11

4.8 Operating Conditions ................................................................................ 11

4.8.1 Am bient tem peratures ................................................................ 11

4.8.2 W ind loading ............................................................................... 11

4.8.3 Pollution ....................................................................................... 11

4.9 Insulators ................................................................................................... 12

5 Design ...................................................................................................................... 13

5.1 Installation ................................................................................................. 13

5.2 Connections ................................................................................................ 13

5.2.1 Arresters for 12 – 52 kV system s ................................................ 13

5.2.2 Arresters for 82,5 – 420 kV system s .......................................... 13

5.3 Disconnecting Devices ............................................................................... 13

5.4 Mechanical strength .................................................................................. 13

5.5 Isolated footing .......................................................................................... 14

6 Testing ..................................................................................................................... 14


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6.1 Type tests .................................................................................................... 14

6.2 Routine tests and acceptance tests ........................................................... 15

7 Documentation ........................................................................................................ 15

7.1 General ....................................................................................................... 15

7.2 Docum ents required w ith tender .............................................................. 15

7.3 Docum ents subm itted at delivery ............................................................. 15

7.4 Docum entation and spares after delivery ............................................... 16

Appendix 1. Basic and guarantee data ............................................................................. 17

Appendix 2. The terminal plates and bolts sizes ............................................................. 18

Appendix 3. Component Data List ................................................................................... 19


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1 GENERAL

1.1 Applicable standards Applicable Swedish standards (SS) shall be used. When these do not exist, European

standards (EN) and international standards (IEC) are applicable. The latest version of

each standard shall be used.

If the surge arresters do not in all respects fulfil the applicable standard or any addi-

tional requirements of this document, the deviations shall be clearly presented by the

Supplier.

Applicable standards and guidelines:

SS-EN 60099-4:2014 Metal-oxide surge arresters without gaps for a.c.

systems.

SS-EN 60099-5:2013 Surge arresters-Selection and application recommen-

dations.

SS-EN 60529:2014 Degrees of protection provided by enclosures (IP-code).

SS-EN 62155:2003 Hollow pressurized and unpressurized ceramic and

glass insulators for use in electrical equipment with

rated voltages greater than 1 000 V.

SS-EN ISO 1461:2009 Hot dip galvanized coatings on fabricated iron and steel

articles -- Specifications and test methods.

SS 421 01 67:2016 Dimensionering av utomhusställverk – Vind och

islaster.

IEC/ TS 60815-3:2008 Guide for the selection of insulators in respect of

polluted conditions.

SS-EN 61462:2008 Composite insulators - Hollow insulators for use in

outdoor and indoor electrical equipment - Definitions,

test methods, acceptance criteria and design

recommendations.


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2 DEFINITIONS

See §3 of SS-EN 60099-4

3 IDENTIFICATIONS AND CLASSIFICATIONS

3.1 Identification of Surge Arresters The surge arrester is identified by the following data, which also shall be stated on the

permanent rating plate:

> Continuous operating voltage (U c)

> Rated voltage (U r )

> Nominal discharge current [kA]

> Short-circuit capacity, [kA]

> Thermal energy rating, W th [kJ / kV]

> Repetitive charge transfer rating Q rs [C]

> Arrester class classification (according to IEC60099-4:2014, &4.2)

> Name of manufacturer

> Type designation and identification of the complete surge arrester

> Identification of the position of a unit (for multi-unit arresters)

> Year of manufacture

> Serial number

> Contamination withstand level of the enclosure ( according to IEC TS 60815-1 or a

total creepage distance in mm)

The rating plate shall have Swedish text and be made of corrosion resistant material,

preferably stain-less steel.


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4 Requirements on Surge Arresters

4.1 Rated Voltage Surge arresters shall have the following rated voltages:

1) Phase arresters connected at transmission line end-points shall be selected with a higher rat-ed voltage of 360 or 390 , 210 and 132kV for 420kV, 245kV and 170kV highest system voltage respectively. A separate study is required in these cases.

Design voltage/ Highest

voltage of the system

Um / U s , [kV]

phase-phase

Minimal continuous

operating voltage

U c, [kV]

Location of surge

arrester

Rated voltage

(kV)

420 255 Phase 1)

330

245 4)

148.5 Phase 1)

192

” Neutral XX 3)

170 103 Phase 1)

120 2)

” Neutral 75 3)

145 88 Phase 1)

120

” Neutral 75 3)

82,5 50 Phase 90

” Neutral 60 5)

52 31.5 Phase 54 6)

” Neutral 33 5)

36 21 Phase 33

” Neutral 24

24 14.5 Phase 26

” Neutral 18

12 7.3 Phase 13

” Neutral 9

Table 1 Nominal voltages


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2) Due to the short duration of temporary over-voltages in solidly earthed networks, a lower rated voltage than the maximum possible temporary over-voltage has been selected for standardisation purposes.

3) The insulation level of the transformer neutral must be considered when selecting rated volt-age.

4) A small part of the Swedish 245 kV grid is operated at highest system voltage of U s=260 kV. Deviating from the definition of design voltage for equipment, phase surge arresters for 245 kV with U c=157.5kV and U c=198 kV rated voltages shall be selected for this net.

5) Neutral arresters shall be coordinated with the lower temporary over-voltages in the neutral, as well as with a possible lower insulation level of other equipment connected to the neutral.

6) In networks with a highest system voltage (U s) of 48 kV, the phase surge arresters shall have a rated voltage of 48 kV.

7) For neutral point is U c=0

4.2 Rated Frequency The rated frequency is 50 Hz.

4.3 Nominal Discharge Current Surge arresters are classified in accordance with their nominal discharge current.

Rated Voltage, U r [kV] Nominal Discharge Current [kA]

330 – 390 20

< 330 1) 10 1

Table 2 Nominal Discharge Current

1) At local distribution stations and cable connections in overhead transmission lines

of 12 and 24 kV networks, surge arresters with nominal discharge currents of ≥ 5kA

may be used. However, in case of more important substations at this level, the higher

discharge current of 10kA shall be used.

4.4 Arrester Classification Arrestor class is only required for surge arresters with design voltages ≥ 145 kV2. For

surge arresters with lower design voltage normally no class is specified.

Surge arresters shall, unless otherwise stated in the request for tender, have line dis-

charge classes in accordance with the tables below.

1 I some cases surge arrestor Ur=192/ 193kV shall be in 20kA discharge class, please see table 4.4 2 For 12 and 24kV networks a surge arrestor with nominal discharge current ≥ 5 kA (DM class) shall be used. However, for important plants a nominal discharge current of 10 kA (DH class) should be used.


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Highest voltage

of the system

U s [kV]

Arrestor classification

according to SS-EN 60099-

4:2014

Thermal energy

rating,

W th3

[kJ / kV]

Repetitive charge

transfer rating

Q rs

[C]

420 SH 13 3.6

245 SH 10 2.6

170 SM 7 1.8

145 SM 7 1.8

Table 3 Surge arrestor discharge classes for lines

Highest voltage of

the system

U s [kV]

Arrestor classification

according to SS-EN

60099-4:2014

Thermal energy

rating,

W th4

[kJ / kV]

Repetitive

charge transfer

rating

Q rs

[C]]

420 SH 10 2,6

245 SM 9 1,8

170 SL 4,5 1,2

145 SL 4,5 1,2

Table 4 Surge arrestor discharge classes for transformers and reactors

4.5 Earth-fault Factor Networks with design voltages of 145 – 420 kV are normally solidly earthed, in some

cases through a low ohmic resistance. In networks at the 145 and 245 kV levels there

are a few cases where the transformer neutrals are isolated.

Networks with design voltages 12 – 82.5 kV are normally reactance earthed. There are

networks at the 12 and 24 kV levels that have isolated neutrals.

The following values for earth-fault factors shall be taken into consideration:

3 3 Rated for Ur [kV]


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Highest voltage of the system

Us [kV]

Earth-fault factor

[p.u.]

420, 245 1.3

170, 145 1.4

82,5, 52, 48, 36, 24, 12 1.73

Table 5 Earth-fault factors

4.6 Residual Voltages The maximum residual voltage (discharge voltage) must not exceed the values given in

the tables below.

Rated voltage U r

[kVeff]

Discharge voltage [kV/ U r ]

Steep front (1/ (2 – 20)

μs) 20kA

Short (8/20 μs)

20kA

Long (30/60 μs)

2 kA

330 – 390 2.9 2.6 2.1

Table 6 Surge arresters with a nominal discharge current of 20 kA

Rated voltage U r

[kVeff]

Discharge voltage (kV/ U r )

Steep front (1/ (2 – 20) μs)

10kA

Short (8/20 μs)

10kA

Long (30/60 μs) 1

kA

192 – 210 2.8 2.5 2.1

Long 0 .5 kA

9 – 132 3.1 2.8 2.2



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Rated voltage U r

[kVeff]

Discharge voltage [kV/ U r ]

Steep front (1/ (2 – 20) μs)5kA Short (8/20 μs)

5kA

9 – 26 3.6 3.3


4.7 Short-Circuit Capability The pressure relief system of the surge arresters shall be designed to, with safe mar-

gins, pass the required type tests, using the symmetrical short-circuit currents that

appears in the networks.

82.5 – 420 kV 40 kA

12 – 52 kV 20kA

The earth-fault currents in the solidly earthed 145 – 420 kV networks are of the same

magnitude as the symmetric short-circuit currents, while the earth-fault currents in

the reactance earthed networks are limited to the 10 – 20 A level.

4.8 Operating Conditions

4.8.1 Ambient temperatures

If not otherwise specified, the lowest temperature for equipment is – 40 °C for south-

ern Sweden and – 50 °C for northern Sweden (north of Dalälven).

4.8.2 Wind loading

For normal outdoor installations, a wind pressure of 700 Pa on a cylindrical surface

shall be used. This corresponds to a wind velocity of 34 m/ s. In case equipment is in-

stalled on heights or in coastal areas a higher wind pressure might be required, in

which case load calculations shall be made using wind pressures according to SS 421

01 67.

4.8.3 Pollution

If the surge arresters are intended for installation in polluted or coastal areas, special

requirements will be stated on corrosion protection and creepage distances of insula-

tors. If the surge arresters must allow spray-washing, this will be stated separately in

the request for tender.

Co rro s io n pro te ctio n

All external details shall be made of corrosion resistant material. Steelwork shall be

either stainless or be protected by hot dip galvanizing (SS-EN ISO 1461).


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4.9 Insulators Insulators shall be of composite. Exception are washable surge arrestors that are to be

made of porcelain.

Composite insulators shall be designed and tested in accordance with applicable

standards and SS-EN 61462 and SS-EN 60099-4 §10. The external insulating material

of composite insulators shall be silicone rubber. The surge arrester shall be designed in

such way that damage on the insulator as a result of an inner over-pressure is avoided.

For some exposed locations an increased creepage distance and/ or the possibility for

insulator washing may be required. The possibility for washing shall be specified in

the tender. If the surge arrestor is washable with constrains, the constrains shall be

specified. All washable surge arrestors shall be in porcelain in class C130 according to

IEC 60672. For washable surge arrestors with constrains the manufacture shall specify

the constrain.

In a normally polluted environment a creepage distance of Site Pollution Severity

(SPS) class b is required and for polluted environment class d is required as given in

IEC 60815-1. Increased creepage distance is recommended in the west coast of Sweden

(approximately 30 km from the coast and in the valley of the river Göta älv up to the

Lake Vänern).

If not other specified the same creepage distance shall be valid for composite and ce-

ramic insulators.

The required creepage distances for insulators in normal and polluted environment are

specified in the table as follows:

Highest voltage

of the system,

U s

[kV]

Minimum creepage distance, [mm]

ceramic/ composit

Polluted environment

(class d) 5

Normal environment

(class b) 6

12 300 190

24 600 380

36 900 580

52 1300 830

82,5 2060 1320

145 3620 2320

170 4250 2730

245 6120 3930

420 10500 6740

Table 9 Minimum creepage distances

5 5 Classes in accordance to IEC 60815-2 and -3, that is 27.8mm/ kV for class b and 43.3 mm/ kV for class d , rounded to the nearest tens.


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5 Design

5.1 Installation If not specified otherwise, the surge arresters will be installed standing in a vertical

position. If they are intended for any other type of installation, e.g. hanging or at an

angle, this will be specified in the request for tender.

5.2 Connections

5.2.1 Arresters for 12 – 52 kV systems

The line and neutral connections shall preferably be made of stainless steel. In case the

connectors are made of aluminium, bolts, nuts and washers shall be made of stainless

steel and arranged to allow the connection of copper conductors.

The line connections shall allow connectors with diameters up to 15 mm. The neutral

connections shall allow 35 mm 2 copper wires.

5.2.2 Arresters for 82,5 – 420 kV systems

The line connections shall be designed either as a connection pad with four holes 40

mm apart or as a 30 mm bolt, in accordance with Appendix 2.

Earth connections shall be made of stainless or hot dip galvanized steel. With space

enough to connect a 50 mm 2 copper wire 7.

5.3 Disconnecting Devices The surge arresters shall, unless otherwise specified in the request for tender, not be

provided with any disconnecting device.

5.4 Mechanical strength In addition to the bending momentum created by a wind pressure of 700 Pa on a cy-

lindrical surface, the insulator of the surge arrester shall be dimensioned for an addi-

tional momentum from a static force applied at the top connector according to the

table below. The safety factor must not be less than 1.25.

7 This is a functional earthing and therefore requirements for conductor size of protective earthing given in TR01-13 is not applicable.


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Highest voltage of the system U s

[kV]

Specified long-term load (SLL) 8

[N]

245 – 420 1500

52 – 170 500

12 – 36 300

Table 10 Specified long-term loads

For high short circuit currents shall dynamical be taken in to account.

5.5 Isolated footing Surge arresters with rated voltages ≥ 90 kV shall be provided with isolated footing to

allow the use of surge counters, if not specified otherwise in the request for tender.

Unless otherwise specified in the request for tenders, surge counters shall not be in-

cluded in the supply.

The insulation for footing and ground wire shall be >5*l ([kV], LIWL) where l is the

length of the wire. (Normally> 15 kV). The functional grounding wire shall be insulated

between the insulated footing and a current leackage measurement loop or a surge

counter. The wire insulation level shall be sized by calculated overvoltage for particular

installation, though it should be at least Um=3.6kV according to IEC60071-1.

The isolated footing shall have at least the same maximal allowed bending forces as

the surge arrester.

6 Testing

6.1 Type tests The type of surge arrester shall have passed type tests (design test) in accordance with

the requirements given in IEC 60099-4:2014, §10. The supplier shall show that the

tests have been performed on surge arrester designs using the same components and

in the same manner as those being offered, ensuring that the characteristics will be the

same.

8 SLL Specified long-term load [N] as given in IEC 60099-4


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6.2 Routine tests and acceptance tests The routine and acceptance testing shall as a minimum include all tests required in SS-

EN 60099-4:2014 §9.

7 Documentation

7.1 General Instructions and outline drawings that are submitted in conjunction with the delivery

shall have text in Swedish.

7.2 Documents required with tender With the tender the following documents shall be provided:

> List of data, dimension drawings, instructions for erection, operation and mainte-

nance, type test certificates and also other documents needed for the technical

evaluation.

> Bases for evaluation of the need and costs for maintenance, such as:

• The interval for condition control and other measures of maintenance and the

time necessary for these works.

• Necessary spares, special tools and accessories and the costs for these.

7.3 Documents submitted at delivery If not agreed otherwise, the following documentation shall be submitted in paper and

electronic form, together with the delivery of the equipment:

A list containing the following:

> Order number

> Manufacturer

> Type and model name and/ or number

> Serial number

> Technical data list

> Type test report

> Environmental information as below (see also TR 13-01):

• The interval for condition control and other measures of maintenance and the

time necessary for these works.


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• Information about the main content of the equipment (type of material in per-

centage of weight) Information about the content of dangerous substances

(for example heavy metals, carcinogenic compounds and compounds hard to

biodegrade, xenobiotic substances).

• Handling and treating of the equipment when it has served its time.

The following will be attached to the list:

> Final outline drawings with all relevant references.

> Spare parts list

> Instructions for transport, storage, installation, maintenance, testing and condi-

tion monitoring

> Test reports from routine and acceptance tests

Component Data in accordance with Appendix 3.A document file containing all docu-

ments and test reports in accordance to 6.2 shall be delivered to the end user the latest

at the time of commissioning of the plant.

The supplier shall propose and describe a method to measure the resistive component

of the continuous leakage current of the surge arrester. The amount of the resistive

current during normal operating voltage shall be stated, as well as the highest value for

which a continued safe operation will be allowed.

7.4 Documentation and spares after delivery The manufacturer shall at request provide the purchaser with necessary service bulle-

tins and during at least ten years after delivery with for the maintenance necessary

spares. Improvements in design, or instructions which can be applied to the equip-

ment as supplied, shall be notified after delivery, preferably in the form of service bul-

letins.


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Appendix 1. Basic and guarantee data

(information given in offer)

Number of surge arrestors

Location phase/ neutral-point

Aplication Line/ Transformer/ Reactor

Position hanging / standing

Highest system voltage U s [kV] xxx

Continuous operating voltage U c [kV] xxx

Rated voltage U r [kV] xxx

Arrester class classification (HS/ MS/ LS or DS/ DM/ DL) xxx

Thermal energy rating (W th ) [kJ / kV] xx,x

Repetitive charge transfer rating (Q rs) [C] x,x

Nominal discharge current[kA] xx

Specified long-term load (SLL) [N] xxx

Specified short-term load (SSL) [N] xxx

Surge Counter: yes/ no

Insulator material composite/ porcelain

Total creepage distance[mm] xxx

Washable or not washable yes/ no


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Appendix 2. The terminal plates and bolts sizes

Bo lt Length 125 mm : Diameter : 30 , 40 , 60 mm

Plate Figure

Measure

[mm]: a b c d e

2 - 75 1 2 holes 75 17,5 40 14 10

4 - 75 2 4- holes 75 17,5 40 14 15

9 - 125 3 9- holes 125 22,5 40 14 35

12 - 165 4 12- holes 125 22,5 40 14 35

Table 11 The terminal plates and bolts sizes


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Appendix 3. Component Data List

(Swedish language is to be used)

Apparatdatalista för ventilavledare Svenska Kraftnät

Beskrivning Värde Enhet

Allmänt

Station * Ify lls av ställverksbyggaren EX Hagby,

Objekt id/ Littera * Ify lls av ställverksbyggaren EX T1-400-V

Beskrivning * Ventilavledare

Lägsta omgivningstemp oC Ex -50

Tillverkare *

Typbeteckning *

Tillverkningsnummer * num m er

Levererad * ååm m

Montagsätt * stående/ hängande

Kopplad * Fas-Fas, Fas-Jord, nollan

Högsta driftspänning Us kV EX 420kV

Kontinuerlig driftspänning Uc kV EX 255kV

Märkspänning Ur kV EX 330kV

Nominell avledningsström kA EX 20

Urladdningsenergisklass kV EX HS

Termisk energikapacitet (Wth) [kJ / kV] kV EX 13

Upprepande laddningsöverföringskapacitet (Qrs) [C] C EX 3,6

Märkkorttidsström, 1s kA EX 40

Spolbarhet * J a/ Nej/ Begränsad

Vikt per fas kg

Norm, Riktlinje * TR1-12

Standard * SS-EN 60099-4:2014

Måttskiss och sammanställningsritning * Ritningsnum m er

Montage och skötselanvisning * Ritningsnum m er

Max statisk horisontell last (SLL) N EX 10000

Max dynamiska horisontell last (SSL) N EX 20000

Apparatuttag, storlek EX 9-125 (platta), 60 (tapp)

Typ av isolator Kom posit/ Porslin

Krypsträcka isolator m m