Overhead transmission lines Spacers

Transcription

1 = SVENSKA KRAFTNÄT SWEDISH NATIONAL GRID UNIT, BUSINESS AREA AEL, Asset Management Lines OUR REFERENCE TR05-08E DATE CONSU12TATIONS TECHNICAL GUIDELINE REVISION 3 APPROVED Overhead transmission lines Spacers Introduction These guidelines describe the requirements on spacers for aluminium conductors steel reinforced and aluminium alloy conductors in accordance with TR 05-04E for overhead transmission lines and cover design and inspection. The guidelines intend to guarantee satisfactory performance of spacers during the lifetime of the overhead line and shall be used at purchasing of spacers. This English text is to be regarded as a translation of the Swedish guideline. The Swedish text and the interpretation thereof shall govern the contract and the legal relations between parties. utg 3 1 (20)

2 Notes Change notes Date 1 (A) Template changed 09 / 07 / Template changed. Revised chapter 8.4 Description. Clause locking of bolts and nut, punches added. Clause revised. Clause added Tables, terrain factor 0,8 deleted. 3 New template clause numbers changed. Clause 7.1 sample size changed. 02 / 04 / / 06 / (20)

3 Content 1 References Scope Definitions Description Requirements General Material Included parts Clamps Bolts and nuts Washers Threaded inserts Design Spacer Clamp Conductor groove Bolts and nuts Washers Hot-dip galvanising Welding Marking Mechanical requirements Spacers Clamp Electrical requirements Corona Radio interference Type test General (20)

4 6.2 Dimensions Thickness of zinc coating Clamp slip test Conductor damage Tightening Flexibility Tensile load Compressive load Corona Sample test General Dimensions Thickness of zinc coating Tightening Flexibility Delivery General Documentation Assembly drawing List of material Manufacturing process Quality system Installation instructions Reports Transport and storing Installation General Installation Twin bundle conductors Triple bundle conductors Tables Figures (20)

5 Figure 1 Placing, twin bundle conductors Figure 2 Placing, triple bundle conductors (20)

6 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 which are referred to in these guidelines are subject to continuous change and can be withdrawn, revised or replaced. It is the obligation that the contractor immediately will inform the client of such changes. Cigré TB 277 SS 2173 SS-EN SS-EN SS-EN SS-EN ISO 1461 SS-EN ISO SS-EN ISO SS-EN ISO 9001 SS-EN ISO SS-ISO 272 SS-ISO State of the art survey on spacers and spacer dampers, Cigré 277 Diameters of spot facings, counterbores and countersinks - Screws and nuts with ISO metric screw threads and tapping screws Overhead lines Requirements and tests for fittings Overhead lines - Requirements and tests for spacers Mechanical properties of fasteners - Part 2: Nuts with specified proof load values - Coarse thread Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods Mechanical properties of corrosion-resistant stainlesssteel fasteners - Part 1: Bolts, screws and studs Mechanical properties of corrosion-resistant stainlesssteel fasteners -- Part 2: Nuts Quality management systems - Requirements Fasteners Hot dip galvanized coatings (ISO 10684:2004) Fasteners -- Hexagon products -- Widths across flats Mechanical properties of fasteners - Part 2: Nuts with specified proof load values - Coarse thread SS-ISO 2178 Non-magnetic coatings on magnetic substrates - Measurement of coating thickness - Magnetic method SS-ISO 5455 SS-ISO 7091 Technical drawings - Scales Plain washers - Normal series - Product grade C 6 (20)

7 SvK TR 05-04E SvK TR 05-09E SvK TR 08E Technical guidelines- Conductors Technical guidelines Vibration dampers Technical guidelines - Documentation 2 Scope These guidelines are applicable to spacers that are to be used on aluminium conductors steel reinforced and aluminium alloy conductors according to SvK TR 05-04E for overhead lines and comprise design, testing and installation. The intention of the specification is to guarantee satisfactory performance of the spacers during the lifetime of the overhead line. In connection to the revision of the Technical Guideline for spacers have SS-EN Overhead lines - Requirements and tests for spacers been taken into consideration. To introduce any of the in this standard given requirements and tests have not turn out to improve the spacer in questions function and quality. 3 Definitions Technical terms and definitions used in these guidelines: Clamp That part of the spacer which attaches and secures the spacer to the respective conductor. Highest voltage for equipment The highest phase-to-phase voltage for which the equipment is designed. Highest voltage for equipment is designated Um in this document. Corona extinction voltage The voltage where no corona is visible when the voltage is reduced from a level with visible corona. 7 (20)

8 4 Description The spacer is to be used with multi-conductor bundles within the same phase for both twin and triple arrangements. Spacers for triple arrangements shall be arranged in a group consisting of three loose spacers. Spacers comprise a clamp for each conductor and a connecting bar. 5 Requirements 5.1 General Spacers shall be able to withstand the mechanical stresses which can occur during transport, handling and installation at temperatures as low as 40 C, in addition to the mechanical stresses which can occur during the lifetime of the overhead line at temperatures from -50 C to +100 C. 5.2 Material Included parts All parts of the spacer shall be manufactured of metal. Parts which are not of stainless steel shall be hot-dip galvanised according to SS-EN ISO The thickness of the zinc layer shall meet the requirements of SS-EN ISO 1461 Table 2 and Clamps The clamps shall be manufactured of aluminium alloy containing a maximum of 0,10 % Cu. The alloy shall be resistant to inter-crystalline, layer and stress corrosion Bolts and nuts Bolts and nuts shall be made of hot-dip galvanised steel or stainless steel. Hot-dip galvanised steel shall comply with the requirements according to SS-EN ISO Stainless steel shall comply with the requirements of quality A2-80 according to SS- ISO The mechanical properties shall be in accordance with SS-ISO and SS-EN Washers Washers shall be made of hot-dip galvanised steel or stainless steel and shall comply with the requirement of clause Threaded inserts To provide sufficient resistance to corrosion threaded inserts shall be made from stainless steel with a minimum quality equivalent to A2 of SS-ISO The required mechanical properties shall be equivalent to those given for bolts and nuts in clause (20)

9 5.3 Design Spacer Spacers shall be so designed that it is possible, with hot line tools, to install and remove them from live conductors without completely dismantling the parts of the spacer. Spacers shall be designed to avoid accumulation of water. Holes for drainage, if any, shall have a minimum diameter of 6 mm. Spacers shall be designed for use on twin and triple bundle conductors. 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. The spacing is chosen in accordance with the recommendations in Cigré Technical Brochure Clamp The clamp attachment to the bar shall be articulated and allow an angular displacement of ± 12 in the direction of the conductor groove and ± 2 in a direction perpendicular to the direction of the conductor groove Conductor groove The conductor groove of the clamp shall fit the conductor diameter in accordance with SvK TR 05-04E and be free from irregularities and sharp edges. The conductor groove shall not contain non-metallic materials Bolts and nuts Bolts and nuts shall have M16 metric threads with 24 mm width across flats according to SS ISO 272. For conductors with a diameter of less than 30 mm bolts and nuts with M12 metric threads and 18 mm width across flats are acceptable. Bolts shall be long enough to protrude outside the thread of the nut. Counter-bores and countersinks shall be made in accordance with SS Bolts and nuts shall be designed so that they can be mechanically locked after installation with two punches if not the manufacturer specify other mechanical metallic locking Washers The clamp to the conductor shall be equipped with a washer under the bolt head and/or under the nut. The washer shall be designed so as to avoid damage to the clamp under the washer. Washers shall be manufactured in accordance with SS-ISO Hot-dip galvanising Hot-dip galvanising shall be performed after all fabrication has been completed. 9 (20)

10 5.3.7 Welding Welding is not permitted Marking The spacer shall be marked with raised or indented / stamped characters with a minimum height of 3 mm as follows: Trademark of the manufacturer Type or catalogue number Conductor diameter Bolts and nuts to be marked in accordance with SS-ISO 3506 Year of manufacture. 5.4 Mechanical requirements Spacers The spacer shall, without showing signs of permanent deformation, withstand an axial tensile force of 8 kn. The spacer shall, without rupture, withstand an axial tensile force of 14 kn. The spacer shall, without showing signs of permanent deformation, withstand an axial compressive force of 7 kn. The spacer shall, without rupture, withstand an axial compressive force of 10 kn Clamp It shall be possible to tighten the clamp so that the force obtained between the conductor and the clamp is sufficient to secure the position of the spacer on the conductor without damaging the conductor or causing fatigue damage under the clamp. No slippage shall take place when a load of 4 kn is applied to the clamp in line with the conductor. The clamp shall without showing signs of permanent deformation, withstand the clamping forces from the bolts. The clamp shall withstand 180 % of the installation torque specified by the manufacturer without resulting in breakage. 5.5 Electrical requirements Corona Spacers shall show no visible corona at the test voltage calculated as follows: 10 (20)

11 U Test voltage = m 3 * 11, Where Um is 245 kv or 420 kv respectively Radio interference The spacer shall be conductive to avoid radio interference. 6 Type test 6.1 General Unless otherwise agreed tests shall be performed in accordance with clauses on three test samples. Type tests shall be performed in such a way that neither the method nor the equipment affects the result. 6.2 Dimensions The intention of this test is to check that the spacer conforms to the requirements of clause 5.3 and also that it is in accordance with the manufacturers drawing regarding measurements. 6.3 Thickness of zinc coating This test shall be performed in accordance with SS-ISO Each sample shall be subject to, depending on size, 3 to 10 measurements. The points of measurement shall be evenly and randomly distributed over the entire sample surface. The minimum and average layer thickness requirements in accordance with shall be fulfilled. 6.4 Clamp slip test The intention of this test is to verify that slippage does not occur between the clamp of the spacer and the conductor. The clamp of the spacer shall be installed on an ACSR conductor with a diameter compatible with the clamp. The tightening torque shall be that specified by the manufacturer. A load in line with the conductor shall be applied to the clamp. No slippage shall occur at a minimum applied load of 4 kn. 11 (20)

12 6.5 Conductor damage The intention of this test is to verify that no damage is caused to the conductor by the spacer clamp. The spacer clamp shall be installed on the same type of conductor as when testing is performed in accordance with clause 6.4. The tightening torque shall be 130 % of that specified by the manufacturer. To check that the conductor is not damaged or deformed in such a way that fatigue damages could occur prematurely the conductor shall, after the clamp has been opened, be visually examined 6.6 Tightening The intention of this test is to verify that the strength of the spacer clamp is sufficient. The clamp shall be installed on a steel or aluminium rod with the same diameter as the conductor for which the clamp is designed. The tightening torque shall be in accordance with clause Rupture shall not occur in any of the parts of the clamp and the bolt shall be easily turned by hand. 6.7 Flexibility The intention of this test is to verify that the spacer conforms to the requirements of flexibility in accordance with clause Both spacer clamps shall be installed on a steel or aluminium rod with the same diameter as the conductor for which the clamp is designed. The spacer shall be placed on a plane surface in such a way that the spacer rod is parallel with the underlying surface. One of the clamps is to be fixed to the underlying surface. The clamp not fixed to the underlying surface shall be moved along the conductor rod, with both conductor rods maintained in parallel, until it can be moved no further. The angle between the conductor groove and the spacer bar is then to be measured. The clamp not fixed to the underlying surface shall be moved vertically until it can be moved no further. During the movement of the clamp the angle between the spacer bar and the conductor rod shall be 90 with both conductor rods maintained in parallel. The angle between the underlying surface and the spacer rod shall then be measured. 6.8 Tensile load The intention of this test is to verify the capacity of the spacer to withstand tensile load. 12 (20)

13 Both spacer clamps shall be installed on a steel or aluminium rod with the same diameter as the conductor for which the clamp is designed. The tightening torque shall be that specified by the manufacturer. A tensile load in line with the spacer bar shall be applied to the spacer through the conductor rods. Neither deformation nor rupture may appear in the spacer at loads in accordance with clause Compressive load The intention of this test is to verify the capacity of the spacer to withstand compressive load. Both spacer clamps shall be installed on a steel or aluminium rod with the same diameter as the conductor for which the clamp is designed. The tightening torque shall be that specified by the manufacturer. A compressive load in line with the axis of the spacer bar shall be applied to the spacer by means of the conductor rods. Neither deformation nor rupture may appear in the spacer at loads in accordance with clause Corona The intention of this test is to establish the corona extinction voltage and is to be performed in a fully darkened room. During the corona test the use of either field-glass with a minimum optical performance of 7x50 or an image intensifier with light amplification greater than in accordance with SS-EN is recommended. Spacers shall be installed on conductors in accordance with Figure 1. A minimum clearance of 4 metres from live objects to earth shall be maintained. The spacer shall be subjected to an alternating current with a frequency of 50 Hz. The corona extinction voltage shall exceed the test voltage of clause It should be recorded by colour photographs, one with visible corona and one at the corona extinction voltage level. The voltage levels should be indicated on the photographs. The test shall be performed in accordance with SS-EN where applicable. 13 (20)

14 7 Sample test 7.1 General Sample tests shall be carried out by the manufacturer on spacers selected at random from the lot to be supplied. Test samples shall be supplied by the manufacturer free of charge to the client and shall not be included in the lot to be supplied. The sizes of the test sample are indicated in the table below. Lot size Sample size N subject to agreement 300 < N < N < N The samples shall be subject to testing in accordance with clauses Spacers which have been submitted to test shall be discarded. The manufacturer shall inform the client when sample tests are to be performed. Records from the sample tests shall be filed by the manufacturer and be shown to the client on request. In the case where any component does not comply with the requirements, re-testing shall be performed as below. If only one spacer or part thereof, fails to comply with the sample test requirement, a new sample equal to twice the quantity originally submitted for that test shall be subject to re-testing. The re-testing shall comprise the test or tests in which failure occurred. If two or more spacers, or parts thereof, fail to comply with any of the sample tests, or if any failure occurs during re-testing, the complete lot shall be considered not to comply with the requirements. Provided that the cause of the failure can be clearly identified, the manufacturer may sort the lot to eliminate all the spacers with this defect. The sorted lot shall then be resubmitted for sample testing. The number then selected shall be three times the first quantity chosen for the test. The re-testing shall comprise the test or tests in which failure occurred in the original test. If any spacer, or part thereof of the sorted lot, fails during this re-testing, the complete lot shall be considered as not complying with the requirements. 14 (20)

15 7.2 Dimensions This test is to be performed in accordance with clause Thickness of zinc coating This test is to be performed in accordance with clause Tightening This test is to be performed in accordance with clause Flexibility This test is to be performed in accordance with clause Delivery 8.1 General The client shall, according to these guidelines, approve the spacer before delivery. For approval the manufacturer shall show that the spacer conforms to these guidelines. The manufacturer shall provide documentation in accordance with clauses inclusive for approval. The approval of drawings by the client does not release the manufacturer from his obligations regarding the spacer complying with these guidelines. All documentation shall be written in Swedish or English. 8.2 Documentation General requirements for documentation see SvK TR 08E Assembly drawing The assembly drawing shall have a minimum of two views at an appropriate scale in accordance with SS-ISO On the drawing shall be given: Type and/or Catalogue number Principal dimensions The dimensions of the conductor groove with tolerances Maximum and minimum conductor diameter for the spacer clamp The width across the flats of the bolts and nuts Installation torque 15 (20)

16 All marking. Weight. List of materials List of material Description of material in included parts Manufacturing process Description of the manufacturing process Quality system Quality system in accordance with SS-EN ISO Installation instructions Installation instructions in Swedish or English with the required figures Reports Reports in accordance with clause 6 Type test report and 7 Sample test report 8.3 Transport and storing The spacers 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 on the conductors shall be performed in accordance with the installation instructions. For spacers installed on triple bundle conductors the relative distance between the spacers, within a group of spacers, shall be 5 metres. The spacers are to be installed perpendicular to the conductors. After assembly shall the bolts nuts be metallically locked with two punches or other mechanically metallic locking system that is accepted by the client. Vibration dampers in accordance with SvK TR 05-09E shall be installed in all spans fitted with spacers. Spacers according to these guidelines shall be used for all new line construction and also for those lines to be reinforced or reconstructed. 9.2 Installation Maximum deviation of the spacer clamps in the line direction is 5 cm. 16 (20)

17 9.2.1 Twin bundle conductors Within any span the spacers are to be placed in accordance with Figure 1 with distances from the supports as given in Table 1. The distances are to be measured along the ground or with a suitable measuring wheel on the conductor. The distances are valid for normal sagging tensions after clamping in Triple bundle conductors Within any span the spacers are to be placed in groups of three in accordance with Figure 2. The distances from each support to the first spacer in each group are given in Table 2. The distances are to be measured along the ground or with a suitable measuring wheel on the conductor. The distances are valid for normal sagging tensions after clamping in. The first spacer of each group shall connect the upper left conductor with the lower conductor. The second spacer shall connect the upper two conductors and the third spacer shall connect the upper right conductor with the lower conductor. The relative distances between spacers in a group shall be 5 metres. The distances are valid for normal sagging tensions after clamping in. 17 (20)

18 10 Tables Table 1 Placing, twin bundle conductors, terrain factor 1,0 Span length No s Distance form support to the respectively spacer over up to of L1 L2 L3 L4 L5 L6 L7 m m groups m m m m m m m ,44 S To be determined at each case This table is calculated for a maximum sub-span of 85 m 18 (20)

19 Table 2 Placing, triple bundle conductors, terrain factor 1,0 Span length No s Distance form support to the respectively spacer over up to of L1 L2 L3 L4 L5 L6 m m groups m m m m m m ,40 S To be determined at each case This table is calculated for a maximum sub-span of 85 m L7 m 19 (20)

20 11 Figures Figure 1 Placing, twin bundle conductors 0 L1 L2 L3 L4 L5 L6 L7 Towards higher support number Figure 2 Placing, triple bundle conductors L 5m 5m 0 L1 L2 L3 L4 L5 L6 L7 Towards higher support number 20 (20)