Notes Change notes Date 1 (A) Revision of standards and new template 09 / 07 2010 2 Template changed.clause. 10.5.1.4 support clamp inserted. Clause 10.5.4.2 creepage text revised. Clause 10.6.7 Dry inserted in headline. Clause 10.6.8 Dry inserted in headline. Clause 10.9.1 locking of bolt and nut inserted. Clause 10.9.2 installation conditions inserted. Clause 10.9.3.2 placement of transposition installation sets revised. 10.8,2.5 revised. 10.8.3 added. 3 New template and change of clause numbers. Rev. clause 5.4.2, 6.1, 8.2.5, 9.2 installation requirements. Clause 9 inserted: nuts in long direction be installed on the side towards lower tower number. Inserted in clause 9.3 in vertical direction shall bolt head be installed on the upper side and nuts underneath. Inserted: Transposition sets shall not be installed at crossings with roads. 02 / 04 / 2012 27 / 06 / 2014 2/28
Content 1 References... 6 2 Scope... 7 3 Definition... 7 4 Description... 8 4.1 Suspension insulator sets... 8 4.1.1 Straight line insulator set... 8 4.1.2 Angle insulator set... 8 4.1.3 V-string insulator set... 9 4.1.4 Tension insulator set... 9 4.1.5 Transposition insulator set... 9 5 Requirements... 10 5.1 Material... 10 5.1.1 Insulators... 10 5.1.2 Insulator fittings... 10 5.1.3 Power arc protection devices... 10 5.1.4 Suspension clamps... 10 5.1.5 Tension clamps... 10 5.2 Design... 10 5.2.1 General... 10 5.2.2 Attachment to crossarms... 10 5.2.3 Counterweights... 11 5.2.4 Power arc protection devices... 11 5.3 Mechanical requirements... 11 5.4 Electrical requirements... 12 5.4.1 General... 12 5.4.2 Creepage distance... 13 5.4.3 Power frequency withstand voltage... 13 5.4.4 Corona... 13 5.4.5 Radio interference... 13 3/28
5.4.6 Lightning overvoltage... 13 5.4.7 Switching overvoltage... 13 5.4.8 Fault current... 14 6 Type test... 14 6.1 General... 14 6.2 Dimensions... 14 6.3 Mechanical strength... 14 6.4 Power frequency withstand voltage... 15 6.5 Corona... 15 6.6 Radio interference... 16 6.7 Lightning impulse withstand voltage... 16 6.8 Fault current... 16 7 Sample test... 16 7.1 General... 16 7.2 Dimensions... 17 7.3 Mechanical strength... 17 8 Delivery... 17 8.1 General... 17 8.2 Documentation... 17 8.2.1 Assembly drawing... 17 8.2.2 List of material... 18 8.2.3 Quality system... 18 8.2.4 Installation instructions... 18 8.2.5 Reports... 18 8.2.6 Transport and storing... 18 9 Installation... 18 9.1 General... 18 9.2 Installation of straight line, angle line and V-string insulator sets... 18 9.2.1 Straight line suspension insulator sets.... 18 9.2.2 Angle line suspension insulator sets... 19 4/28
9.2.3 V-string insulator sets... 19 9.3 Installation of tension and transposition insulator sets... 20 9.3.1 Tension insulator sets... 20 9.3.2 Transposition insulator sets... 20 10 Tables...22 Table 1 Withstand voltage...22 11 Figures...23 Figure 1 Straight line suspension insulator set...23 Figure 2 Angle suspension insulator set...23 5/28
1 References Note that standards, regulations etc. which are referred to in these guidelines are subject to continuous change and can be withdrawn, revised or replaced. The contractor shall immediately inform the client of such changes. C.I.S.P.R Publication 16-SER C.I.S.P.R specification for radio disturbance and im munity measuring apparatus and methods C.I.S.P.R Publication 18 2 EN 60383-1 EN 60383-2 EN ISO 9001 IEC 60815-1 IEC 60815-2 IEC 61284 IEC 61467 ISO 5455 Radio interference characteristics of overhead power lines and high-voltage equipment - Part 2: Methods of measurement and procedure for determining limits Insulators for overhead lines with a nominal voltage above 1 kv - Part 1: Ceramic or glass insulator units for a.c. systems - Definitions, test methods and acceptance criteria Insulators for overhead lines with a nominal voltage above 1 kv - Part 2: Insulator strings and insulator sets for a.c. systems - Definitions, test methods and acceptance criteria Quality management systems Requirements Selection and dimensioning of high-voltage insulators intended for use in polluted conditions - Part 1: Definitions, information and general principles Selection and dimensioning of high-voltage insulators intended for use in polluted conditions - Part 2: Ceramic and glass insulators for a.c. systems. Overhead lines - Requirements and tests for fittings Insulators for overhead lines with a nominal voltage above 1 000 V- A.C. Power Arc Tests on insulator sets Technical drawings Scales 6/28
SS 447 10 11 SS-EN 50341 SvK TR 05-04E SvK TR 05-05E SvK TR 05-06E SvK TR 05-11E SvK TR 05-12E SvK TR 08 Radio interference from high voltage alternating current overhead power lines Overhead electrical lines exceeding 45 kv AC Technical Guidelines Conductors Technical Guidelines Suspension and support clamps Technical Guidelines - Tension clamps Technical Guidelines - Insulators Technical Guidelines - Insulator set fittings Tekniska riktlinjer Dokumentation 2 Scope These guidelines are applicable to suspension, tension and transposition insulator sets which are to be used on overhead lines with alternating current and comprise design, testing and installation. The intention of the specification is to guarantee satisfactory performance of insulator sets during the lifetime of the overhead line. 3 Definition Technical terms and definitions used in these guidelines: Insulator set Device for insulating conductors either in suspension or tension. Insulator string The insulating part of the insulator set consisting of one or more insulators joined together. Highest voltage for equipment The highest value of phase-to-phase voltage for which the equipment is designed. The highest voltage for equipment is designated Um in this document. 7/28
Corona extinction voltage The voltage where no corona is visible when the voltage is reduced from a level with visible corona. Fault current The greatest short duration current which is caused by either a short-circuit (I k ) or an earth fault (3I o ). 4 Description 4.1 Suspension insulator sets 4.1.1 Straight line insulator set Insulator set for straight line and angle positions, with an angle of deviation <3 o (3,3 gon), for the suspension of single, twin or triple conductors in accordance with SvK TR 05-04, consisting of: one upper section connected to earth for the attachment to the supports one insulator string with power arc protection devices one lower live section with a suspension clamp or clamps The distance between sub-conductors shall be 450 mm up to and including a conductor diameter of 32 mm and 600 mm for conductor diameter greater than 32 mm. Twin conductors shall be arranged horizontally and triple conductors as an equilateral triangle with the apex downwards. See Figure 1. 4.1.2 Angle insulator set Insulator set for angles of deviation 3 o (3,3 gon), for the suspension of single, twin or triple conductors in accordance with SvK TR 05-04, consisting of: one upper section connected to earth for the attachment to supports or swing brackets one or two insulator strings with power arc protection devices one lower live section with a suspension clamp or clamps 8/28
The distance between sub-conductors shall be 450 mm up to and including a conductor diameter of 32 mm and 600 mm for conductor diameter greater than 32 mm. Twin conductors shall be arranged horizontally and triple conductors as an equilateral triangle with the apex downwards. See Figure 2. 4.1.3 V-string insulator set Insulator set for straight line and angle positions, with an angle of deviation <3 o (3,3 gon), for the suspension of single, twin or triple conductors in accordance with SvK TR 05-04, consisting of: two upper sections connected to earth for the attachment to supports or swing brackets two insulator strings arranged in a V-shape with power arc protection devices one lower live section with a suspension clamp or clamps The distance between sub-conductors shall be 450 mm up to and including a conductor diameter of 32 mm and 600 mm for conductor diameter greater than 32 mm. Twin conductors shall be arranged horizontally and triple conductors as an equilateral triangle with the apex downwards. See Figure 3. 4.1.4 Tension insulator set Insulator set for the termination of single, twin or triple conductors in accordance with SvK TR 05-04, consisting of: one inner section connected to earth for the attachment to supports one or two insulator strings with power arc protection devices one outer live section with a tension clamp or clamps The distance between sub-conductors shall be 450 mm up to and including a conductor diameter of 32 mm and 600 mm for conductor diameter greater than 32 mm. Twin conductors shall be arranged horizontally and triple conductors as an equilateral triangle with the apex downwards. See Figure 4. 4.1.5 Transposition insulator set Insulator set for rotating phases in lines with single, twin or triple conductors in accordance with SvK TR 05-04, consisting of: one inner live section with a tension clamp or clamps one or two insulator strings with power arc protection devices one outer live section with a tension clamp or clamps 9/28
The distance between sub-conductors shall be 450 mm up to and including a conductor diameter of 32 mm and 600 mm for conductor diameter greater than 32 mm. Twin conductors shall be arranged horizontally and triple conductors as an equilateral triangle with the apex downwards. See Figure 5. 5 Requirements 5.1 Material 5.1.1 Insulators Insulators shall conform to the requirements of SvK TR 05-11. 5.1.2 Insulator fittings Insulator fittings shall conform to the requirements of SvK TR 05-12. 5.1.3 Power arc protection devices Power arc protection devices shall conform to the requirements of SvK TR 05-12. 5.1.4 Suspension clamps Suspension clamps shall conform to the requirements of SvK TR 05-05. 5.1.5 Tension clamps Tension clamps shall conform to the requirements of SvK TR 05-06. 5.2 Design 5.2.1 General The insulator sets shall comprise as few individual components as practical to minimise the number of current transition locations. In addition the overall length of the insulator set shall be designed to be as short as possible. 5.2.2 Attachment to crossarms The attachment of suspension insulator sets to crossarms shall be designed such that the pivot point of the insulator swing is as close as possible to the lower edge of the crossarm and allows swing transverse to the direction of the line. The attachment of V-string insulator sets to crossarms shall be designed such that the upper pivot point of the insulator swing is as close as possible to the lower edge of the crossarm and allows swing longitudinally in the direction of the line. 10/28
The attachment of tension insulator sets to crossarms shall be designed such that the innermost pivot point of the insulator set is as close as possible to the crossarm and allows swing transverse to the direction of the line. 5.2.3 Counterweights Straight line and angle suspension insulator sets for the suspension of single, twin or triple conductors shall be so designed as to allow for the addition of counterweights when necessary. The transverse swing of suspension insulator sets, with counterweights fitted to suspension clamps, shall be limited to 45. See SvK TR 05-05. The attachment of counterweights for insulator swing exceeding 45 shall be subject to the approval by the client. 5.2.4 Power arc protection devices Power arc protection devices shall conform to the requirements of SvK TR 05-12. Radiated heat from power arcs shall not damage insulator sets. 5.3 Mechanical requirements Insulator sets shall conform to the mechanical requirements of Swedish Standard SS- EN 50341. When designing / dimensioning insulator fittings by means of stress calculations the following additional requirements shall be fulfilled. The combined stress (σ comb) of tension, bending and shear shall be less than the characteristic strength fuk at a load equivalent to Fk in accordance with Swedish Standard SS-EN 50341 clause 11.6.SE.1.1. The combined stress (σ comb) of tension, bending and shear shall be less than the characteristic strength fyk at a load equivalent to 1,1 times the load Rd in accordance with Swedish Standard SS-EN 50341 clause 11.6.SE.1.1. The combined stress of tension, bending and shear shall be calculated according to the formula: comb 2 3 2 x 2 y x y When testing fittings made from steel or aluminium permanent deformation due to tension, bending and shear stress may not occur at a load less than Fdef where; Fdef= Rd 1,1 11/28
Rd is the dimensioning load in the serviceability limit state in accordance with Swedish Standard SS-EN 50341 clause 11.6.SE.1.1. The breaking load (Fu) achieved during testing shall, for fittings made from steel and aluminium which have been statistically tested in accordance with EN 60383-1, exceed Fk. The breaking load (Fu1) achieved during testing shall for other fittings exceed 110% of Fuk where : Fu1= Fk 1,1 Definitions Rd = Dimensioning load in the serviceability limit state Fdef = Minimum required test deformation load Fk = Dimensioning load in the ultimate limit state Fu = Achieved test breaking load Fu1= Achieved test breaking load fuk = The characteristic ultimate tensile strength given in regulations for the material concerned. fyk = The characteristic yield stress given in regulations for the material concerned. 5.4 Electrical requirements 5.4.1 General Electrical designing/dimensioning shall, in addition to what is stated in these technical guidelines, be performed in accordance with Swedish Standard SS-EN 50341. The length of the insulator string for insulator sets intended for insulation between phase and earth shall be such that the required arcing distance to achieve the withstand voltages given in Table 1 are obtained. The length of the insulator string in insulator sets intended for insulation between phases shall be such that minimum arcing distances of 130% and 137% of that for phase to earth insulation are obtained for the highest voltages for equipment of 245 kv and 420 kv respectively. 12/28
5.4.2 Creepage distance The creepage distance, in accordance with IEC 60815-1 and 2, of an insulator divided by the maximum operating voltage across the insulator in the insulator set shall be at least: 22 mm/kv in areas where very light, or none, pollution can be expected. 28 mm/kv in areas where light pollution can be expected. 35 mm/kv in areas where medium pollution can be expected. 44 mm/kv in areas where heavy pollution can be expected. 55 mm/kv in areas where very heavy pollution can be expected. 5.4.3 Power frequency withstand voltage The power frequency withstand voltage of insulator sets, which are intended for phase to earth insulation, shall be the minimum voltage stated in Table 1 when tested in accordance with EN 60383-2. The power frequency withstand voltage of insulator sets, which are intended for phase to phase insulation, shall be a minimum of times the voltage stated in Table 1 when tested in accordance with EN 60383-2. 5.4.4 Corona The insulator set shall have no visible corona at the test voltage defined by: U m Test voltage *1,1 3 Where Um is the highest voltage for equipment stated in Table 1. 5.4.5 Radio interference The radio interference level for insulator sets shall be less than 60 db at the highest voltage for equipment with 50 Hz alternating voltage (r.m.s. value) over 1V interference voltage and 500 khz measuring frequency. The radio interference level shall conform to the requirements of Swedish Standard SS 447 10 11. 5.4.6 Lightning overvoltage The lightning impulse withstand voltage for insulator sets intended for phase to earth insulation shall be that stated in Table 1 when tested in accordance with EN 60383-2. 5.4.7 Switching overvoltage The switching impulse withstand voltage for insulator sets intended for phase to earth insulation shall be that stated in Table 1 when tested in accordance with EN 60383-2. 13/28
The switching impulse withstand voltage for insulator sets intended for insulation between phases shall be a minimum of 140% for 245 kv and 150% for 420 kv highest voltages for equipment of that stated in Table 1 when tested in accordance with EN 60383-2. 5.4.8 Fault current Insulator sets shall be thermally designed to resist the stated fault current and fault time so that the mechanical strength of fittings, which are subject to fault current, is not weakened due to the heating caused by the fault current. In addition the zinc layer of hot-dip galvanised steel fittings is not to be damaged. Welding due to power arcs between fittings included in insulator sets shall be as far as possible avoided. The attachment of the insulator sets to the supports shall be designed to resist the stated fault current and fault time so that welding does not occur between the contact surfaces. 6 Type test 6.1 General Unless otherwise agreed the type test is to be performed in accordance with clause 6.2, on one test insulator set for each type, included all components. Type test is to be performed in accordance with clauses 6.3-6.9 on request of the client and shall be performed at an agreed quantity of insulator sets. The tests shall be performed in such a way that neither the method nor the equipment affects the result. Tension insulator sets shall be horizontal installed during tests in accordance with Figure 4. 6.2 Dimensions The intention of this test is to check that the insulator set fulfils the requirements in accordance with clause 5.2 and also is in accordance with the manufacturers drawing regarding measurements. 6.3 Mechanical strength The intention of this test is to verify the mechanical strength of a complete insulator set in accordance with clause 5.3. 14/28
The insulator set, excluding insulators, arcing horn and clamp, is to be installed in a tensile testing machine and loaded to the stated failing load. Failure may not occur in any of the included fittings nor may yoke plates be deformed to such an extent that the purpose of the yoke cannot be fulfilled. 6.4 Power frequency withstand voltage The intention of this test is to establish the wet power frequency withstand voltage of a complete insulator set. Suspension insulator sets with suspension clamps and conductors are to be installed in accordance with Figure 1. V-string insulator sets with suspension clamps and conductors are to be installed in accordance with Figure 3. The insulator set is to be installed such that the clearance from live to earth given in Table 1 is obtained. The insulator set is then to be subjected to 50 Hz alternating current. This test is to be performed as a wet test in accordance with EN 60383-2. The wet power frequency withstand voltage of insulator sets, which are intended for phase to earth insulation, shall be the minimum voltage stated in Table 1. The wet power frequency withstand voltage of insulator sets, which are intended for phase to phase insulation, shall be a minimum of times the voltage stated in Table 1. 6.5 Corona The intention of this test is to establish the corona extinction voltage for a complete insulator set and is to be performed in a fully-darkened room. During the corona test the use of either field glasses with a minimum optical performance 7x50, or an image intensifier with light amplification greater than 40 000 in accordance with IEC 61284, is recommended. Suspension insulator sets are to be installed in accordance with clause 6.4. The distance from the live phase to earth shall be as stated in Table 1 and the insulator set is to be subjected to 50 Hz alternating current. The corona extinction voltage shall exceed the calculated test voltage in accordance with clause 5.4.4. The corona extinction voltage is to be recorded by colour photographs, one with visible corona and another at the corona extinction voltage level, with the voltage levels being indicated on the photographs. The test shall be performed in accordance with the applicable sections of IEC 61284. 15/28
6.6 Radio interference The intention of this test is to establish the level of radio interference for a complete insulator set. Insulator sets are to be installed in accordance with clause 6.4 with the distance from the live phase to earth being as stated in Table 1. The test shall be performed with the highest voltage for equipment, 50 Hz alternating voltage (r.m.s. value) over 1 V interference voltage and 500 khz measuring frequency. Testing is to be in accordance with C.I.S.P.R publication 16-SER and the results evaluated in accordance with C.I.S.P.R publication 18-2. The level of interference at the highest voltage for equipment shall fulfil the requirements of clause 5.4.5. 6.7 Lightning impulse withstand voltage The intention of this test is to establish the switching impulse withstand voltage for a complete insulator set. Insulator sets are to be installed in accordance with clause 6.4, with the distance from the live phase to earth being as stated in Table 1. They are then to be subjected to a switching impulse withstand voltage test in accordance with EN 60383-2. The switching impulse withstand voltage shall exceed the voltage stated in Table 1. 6.8 Fault current The intention of this test is to establish the capacity of a complete insulator set to withstand flash-over with a power arc. The suspension insulator set with clamps and conductors is to be installed and tested in accordance with IEC 61467 test series X. The insulator set shall fulfil the acceptances criteria in accordance with IEC 61467. 7 Sample test 7.1 General Sample tests are to be carried out by the manufacturer on an insulator set selected at random from the lot to be supplied. 16/28
7.2 Dimensions This test is to be performed in accordance with clause 6.2. 7.3 Mechanical strength This test is to be performed in accordance with clause 6.3 if agreed between the client and the manufacturer. 8 Delivery 8.1 General The client shall, according to these guidelines, approve insulator sets before delivery. For approval the manufacturer shall show that the insulator set conforms to the guidelines. The manufacturer shall provide documentation in accordance with clauses 8.2.1 to 8.2.5 inclusive for approval. The approval of drawings by the client does not release the manufacturer from his obligations regarding the insulator set complying with these guidelines. All documentation shall be written in Swedish or English. 8.2 Documentation A summary of documentation requirements is presented in SvK TR 08. 8.2.1 Assembly drawing The assembly drawing shall have a minimum of two views at an appropriate scale in accordance with ISO 5455. On the drawing shall be given: Type and/or catalogue number Principal dimensions Arcing distance Creepage distance Failing load Fault current Weight 17/28
List of materials 8.2.2 List of material Description of material in included parts. 8.2.3 Quality system Quality system in accordance with EN ISO 9001. 8.2.4 Installation instructions Installation instructions with required drawings. 8.2.5 Reports Reports in accordance with clause 6 Type test shall be provided for the clauses that are performed in accordance with clause 6. Reports in accordance with clause 7 Sample test. 8.2.6 Transport and storing The insulator sets shall be packed up in that way that they will not be damaged or fouled at transport, construction and storing. 9 Installation 9.1 General Installation of insulator sets shall be performed in accordance with the relevant drawings. Bolts and nuts shall be locked with two punches or other mechanical metallic locking system that is accepted by the client. 9.2 Installation of straight line, angle line and V-string insulator sets Suspension sets shall be installed vertical to the direction of the line. Maximum allowed deviation to the vertical plane at the suspension clamp is L/40, where L= length of the insulator set. 9.2.1 Straight line suspension insulator sets. Power arc protection devices on suspension insulator sets shall be installed in such a way that any power arc will have a predestined direction transverse to the direction of the line and outwards away from the insulator set and the support. With a horizontal phase arrangement power arc protection devices for the middle phase shall be installed in such a way that the power arc will have a predestined direc- 18/28
tion to the right transverse to the direction of the line when looking towards higher support numbers. The pivot bolt nut and the eye of the split pin in a socket are to be installed facing the support. For the middle phase the nut and the eye of the split pin are to be installed facing left when looking towards higher support numbers. See Figure 6a. The pivot bolt nuts in fittings between the conductors and the yoke plate are to be installed facing each other in twin bundle conductor arrangements and similarly for the upper two conductors in triple bundle conductor arrangements. See Figures 6b and 6c respectively. In longitudinal direction shall the nuts be installed facing against lower support number. 9.2.2 Angle line suspension insulator sets Power arc protection devices on angle suspension insulator sets shall be installed in such a way that any power arc will have a predestined direction upwards. In inclined suspension insulator sets the pivot bolt nut and the eyes of split pins in sockets are to be installed facing downwards. Nuts on horizontally orientated pivot bolts and the eyes of split pins in sockets are to be installed facing the support. For the middle phase the nut and the eye of the split pin are to be installed facing left when looking towards higher support numbers. The pivot bolt nuts in fittings between the conductors and the yoke plate are to be installed facing each other in twin bundle conductor arrangements and similarly for the two upper conductors in triple bundle conductor arrangements. In longitudinal direction shall the nuts be installed facing against lower support number. 9.2.3 V-string insulator sets Power arc protection devices on V-string suspension insulator sets shall be installed in such a way that any power arc will have a predestined direction upwards. For inclined insulator sets the pivot bolts nuts, the eyes of split pins in sockets and power arc protection device attachment arms, are to be installed facing downwards. Nuts in horizontally orientated pivot bolts and the eyes of split pins in sockets are to be installed facing the support. For the middle phase the nut and eyes of the split pins are to be installed facing left when looking towards higher support numbers. 19/28
The pivot bolt nuts in fittings between the conductors and the yoke plate are to be installed facing each other in twin bundle conductor arrangements and similarly for the two upper conductors in triple bundle conductor arrangements. In longitudinal direction shall the nuts be installed facing against lower support number. 9.3 Installation of tension and transposition insulator sets 9.3.1 Tension insulator sets Power arc protection devices on tension insulator sets shall be installed in such a way that any power arc will have a predestined direction upwards. Nuts on vertical orientated pivot bolts, the eyes of split pins in sockets and power arc protection device attachment arms, are to be installed facing downwards. Nuts on horizontally orientated pivot bolts and the eyes of split pins in sockets are to be installed facing the support. For the middle phase the nuts and eyes of the split pins are to be installed facing left when looking towards higher support numbers. See Figure 7a. The pivot bolt nuts on fittings between the conductors and the yoke plate are to be installed facing each other in twin bundle conductor arrangements and similarly for the upper conductors in triple bundle conductor arrangements. See Figures 7b and 7c respectively. For bolts in vertical direction shall the bolt head be on the upper side and the nut underneath. 9.3.2 Transposition insulator sets Transposition tension sets are not allowed in spans that cross traffic routes, railways and transmission lines nor in the adjacent spans. Power arc protection devices on transposition insulator sets shall be installed in such a way that any power arc will have a predestined direction upwards. Nuts on vertically orientated pivot bolts, the eyes of pins in sockets and power arc protection device attachment arms, are to be installed facing downwards. Nuts on horizontally orientated pivot bolts and the eyes of split pins in sockets are to be installed facing the support. For the middle phase the nuts and the eyes of split pins are to be installed facing left when looking towards higher support numbers. See Figure 7a. 20/28
The pivot bolts nuts on fittings between the conductors and the yoke plate are to be installed facing each other in twin bundle conductor arrangements and similarly for the two upper conductors in triple bundle conductor arrangements. See Figures 7b and 7c respectively. For bolts in vertical direction shall the bolt head be on the upper side and the nut underneath. 21/28
10 Tables Table 1 Withstand voltage Highest voltage Rated withstand voltages Distance for equipment Um Lightning impulse Switching impulse Power frequency phase to earth 1) phase-phase kv kv kv kv m 245 850 650 360 3 420 1175 950-4 1) Distances to be used for corona tests 22/28
11 Figures Figure 1 Straight line suspension insulator set Figure 2 Angle suspension insulator set Figure 2a Single string 23/28
Figure 2b Double string Figure 3 V-string suspension insulator set 24/28
Figure 4 Tension insulator set Figure 4a Single string Figure 4b Double string 25/28
Figure 5 Transposition tension insulator set Figure 5a Single string Figure 5b Double string 26/28
Figure 6 Straight line suspension insulator set bolt orientation The arrows indicate the direction bolts must face when looking towards higher support numbers. Figure 6a Straight line support Figure 6b Twin bundle conductor Figure 6c Triple bundle conductor 27/28
Figure 7 Tension insulator set bolt orientation The arrows indicate the direction bolts must face. Towards higher support numbers Figure 7a Terminal support Figure 7b Twin bundle conductors Figure 7b Triple bundle conductors 28/28