The development of the new generation ground wire for lightning protectionof overhead transmission lines

Motivation of new product creation Market demand in production, close to lifetime to the core elements of the overhead transmission lines, both current and prospective without substantial rise in price products. Provision of ground wires life duration not less than 40 years, guarantee period on overhead transmission lines not less than 4 years. Provision of ground wires operability under the condition of its factual exploitation: operations of all spectrum of the main types of loads.

1 STAGEThe estimation of the basic technical features of steel-wire robes according to the GOST 3062-3064, which were used on the overhead transmission lines as ground wires. Methods Weather exposure test of lightning stroke Aging testEstimation of consumers requestsEstimation of strength characteristicsEngineering Centre FGC UES,ORGRES, Production and Commercial Firm Eletroservice, MPEI and other organizations. To realize all system researches, were involved:

Testing technique of lightning stroke Researches were conducted on the bench tester Current generator of lightning quaternary(GTM-4), which is certified by the High voltage electrical equipment test center of the State unitary enterprise (accreditation certificate ROSS RU.0001.21MB07 - 09.06.1999 ). Certificate 7-03-07 - 15.03.2007. Generator GTM-4 is capable of generating 4 current components with the following parameters: Component (current impulse of the first back discharge)height to 200 10 % ,with action integral (2dt) - 210620%2 and exposure time to 500 MKS. Component (transitory amperage) with average amplitude 2 10% width to 5 and transferred charge 10 10% C.Component (DC current) amplitude from 200 to 800 width from 0,25 to1c and with transferred charge to 200 20% C.Component D (recharge current)with amplitude 100 10% , action integral 0,2510620%2 and exposure time to 500 MKS.Description of the generator component corresponds to the IEC 60794-4-1:1999 requisitions, appendix F.Measure of the impulse signal were certified and tested according to the repetitive metrological testing: shunt -1 002 C.t. 1,5, R = 1,16 , attack time no more than 200 ns,was checked 22.05.2007.,digital-readout oscilloscope Tektronix TDS-2012,accuracy class. 2,0, was checked 30.05.2007.Registration of testing results were made by digital camera (comes with a CD supplement).

Tests results of ground wire 1 JSC BMK production.Discharge1,charge 55CDischarge 2,charge 55CDischarge3,charge 55CDischarge 4,charge 70CDischarge 5,charge70CDischarge 6,charge 70C

Discharge 7,charge85CDischarge8,charge 85CDischarge9,charge 85CDischarge10,charge 110CDischarge11,charge110C

Tests results of ground wire 2,JSC Silur productionDischarge1,charge 55CDischarge2,charge 55CDischarge3,charge 55CDischarge4,charge 70CDischarge5,charge70CDischarge6,charge70C

Discharge13,charge130CTests results of ground wires 2, CoLtd VolgoMetiz productionDischarge 1,charge55CDischarge 2,charge55CDischarge3,charge55CDischarge 4,charge 70C

Discharge11,charge 110C

General regimes of aging tests, equipment set and run time within one cyclic process (Testing laboratory Khotkovo-Test,25.05.2006.).

Aging tests results (Testing laboratory Khotkovo-Test,25.05.2006.)

Basic conclusions about the study of steel ropes according to GOST 3062 -3064The increase of working time in the process of galvanization (JSC Sevestal-metiz technology).The increase of lightning stroke durability in the process of the increase of preformation degree (JSC Severstal-Metiztechnology).Total loss of service outage in the process of cumulative effect of discharge within the range 40-85 C. The reduction of the aggregate breaking tension after the lightning exposure of all represented steel ropes.

The development of ground wires for overhead transmission lines according to the STO (Standards of organization) 71915393TU (Specifications) 0622008Development peculiarityNovelty design of the ground wire according to 71915393TU (Specifications) 0622008(ground wire)for the electric power transmission protection from direct lightning strokes consists in the lay consolidation technology, provision of line contact wires and line contact of wires provision, use of the wires outer layer of the plastic straining to enlarge contact area between outer and inner armor wires. This construction provides the reduction of linear extension (confirmation patent of the R.F.). Galvanical method application of coating to a tolerance of +5% prevents zinc layer at increases current and elevated temperature (short circuit), (it increases service life, this product is different from the previous one).Utilize technology of the lay has no parallel in the Russian Federation, the technology of application of zinc coating is comparable to the technique, which is used by Volgograd plant - JSC Severstal-Metiz in a process of production cable and wire bridges. Constructive result 40 years of service life and 20 years of exploitation under the influence of all types of loads. 2 Stage

CherepovetsplantThe plant was found in 1965. It produces more than 26000 types of production. Orel plantThe plant was found in 1967. it produces more than 11000 types of production. Volgograd plantThe plant was found in 1954. It produces more than 1500 types of steel ropes and wires. Producer Severstal-Metiz (Russia) Authorized provider and developer of the rope and wire production: Co Ltd Energoservice.

Basic conclusions about the researches of lightning stroke. )Conclusion The ground wires patterns are stable to lightning stroke (with transferred charge 55C and 110C) and also have high stable to a lightning current effect (with transferred charge 147 C),which has total occurrence probability 1,2 %, in negative and positive lightning. It ought to be noted, that such a high lightning resistance of the proved ground wires is connected with its improved construction, which is different from the ground wires construction and is used today in overhead transmission lines. There is no strength reduction after stoke.

Charge, C (Coulomb) Tension reduction, kgf (kilogram-force)Result of effect110noSurface fusion in the discharge zone in zone in area ~ 1015 mm147noSurface fusion in the discharge zone in zone in area ~ 1015 mm55noElectrode touched the surface of pattern during the process of discharge 55noSurface fusion in the discharge zone in zone in area ~ 1010 mm

Basic results of the ground wires approval tests according to STO (Standards of organizations) 71915393TU (Specifications) 0622008 for the overhead transmission lines.

List of testing: full testing:lightning stroke, mechanical (disruption, after the lightning stroke) eolian vibration ,an attack of wind load, and stableness to short-circuit current. New ground wires construction was developed especially for the protection of overhead transmission lines from lightning strokes, it was made with the use of current rope technologies and it has following peculiarities: Total resistance to lightning stroke in the load range 98,8%. High corrosion resistance at the expense of galvanic coating with +5% tolerance and reduction of the total contact area of the ground wires surface with environment. Increased breaking strength (against ropes) - (180kg/mm2 200kg/mm2), it provides reliability growth, it is especially important for the anchor poles and during the glaze formation. Extended service life almost in 2 and 5 times is a guaranteed service, in comparison with the standard rope. Applied technology, in the process of production of the ground wires lay according to the STO (Standards of organization) 71915393TU (Specifications) provides reduction of the extension strain, which decreases sagging in the process of exploitation.There is no strength reduction, no disruptions or melting wires to base metal, after lightning strokes 147 C (coulomb). .

Main points of specifications to the ground wire --O- -* STO (Standards of organization) 71915393-TU (Specifications) 062-2008, which realization is guaranteed by plant JSC Severstal-MetizGround wires should be up to quality of the standard and STO (Standards of organization) 56947007-29.060.50.015-2008 Technical requirements JSC FGC UES.Ground wires ( marking groups 1770n/mm2 (180kgf/mm2), 1870n/mm2 (190kgf/mm2), 1970n/mm2 (200kgf/mm2)) are made from galvanized wire, according to the GOST 7372-79, gauge of zinc covering should correspond to the (extra hard) group with the positive tolerance 5%. Ground wires are made length at least 500 meters. Ground wire should be resistant to impulse of the lightning discharge, which size (in Coulombs) is defined by the ground wire suspension, according to the consumer requirements and is installed by manufacturer (if it has an appendix tensile load, according to the STO (Standards of organization) 56947007-29.060.50.015-2008 Technical requirements JSC FGC UES , at least 85C.Ground wire should be resistant to the thermal influence of short circuit current,appearing in the process of the ground wires exploitation with single and double phase to earth fault, which size and time is installed by manufacturer according to the STO (Standards of organization) 56947007-29.060.50.015-2008 Technical requirements JSC FGC UES.(Lightning protection premium quality extra hard nonspinning straighten)*

Ground wire should be resistant to the eolian vibration at least 100 million cycles, which frequency should correspond to resonating frequency with wind speed from 4 to 8 ms (Frequency = 830/diameter of the ground wire in mm 10 Hz),with appendix of the tension load, which is installed by manufacturer, according to the STO (Standards of organization) 56947007-29.060.50.015-2008 Technical requirements JSC FGC UES.Ground wire should be resistant to the pitching (eolian vibration), in the process of its exploitation and under the influence of crosscut wind flow, alternate aerodynamic lift is appeared, which can create self-sustained oscillations, with the correlation of parallel and torsion motions of rope, STO (Standards of organization) 56947007-29.060.50.015-2008 Technical requirements JSC FGC UES. All others technical requirements should correspond to the GOST requirements 3241-91 and STO (Standards of organization) 56947007-29.060.50.015-2008 Technical requirements JSC FGC UES.In accordance with article13.2, Technical requirements JSC FGC UES guarantee service life of the ground wires should form at least 20 years, from the moment of commencement of operation.

Overhead transmission lines Ground wires (Lightning protection),which were made in accordance with the technical requirements STO (Standards of organization) 71915393-TU (Specifications) 062-2008, are meant for the overhead transmission lines protection from lightning strokes, diameters of which from 8 to 22,5mm and resistance from 1770 n/mm2 to 1970 n/mm2, are galvanized according to the (extra hard) group with a tolerance of +5%. The advantages of lightning protection (except high density and better corrosive resistance) is a heightened sturdiness to the lightning pulse influence from 85C and higher. Lightning protection (in contrast to steel ropes) survive even in the zones with heightened probability value of lightning discharges, during the guaranteed service life 20 years. Sole manufacturer and patent holder : JSC Severstal-Metiz.Dealer and developer : Co Ltd Energoservice. Sign of implementation : Lightning protection.Agency output: minimum 350 tons monthly.Standard-size spectrum: 8,0-22,5mm

Ground wires for the overhead transmission lines and lightning strokes protection STO (Standards of organization) 71915393 TU (Specifications) 062-2008 Construction 1 36 (1+ 7 + 7/7 + 14)

Severstal-Metiz and Energoservice express gratitude for kind attention! We are always glad to cooperate!

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