60-500 kV High Voltage full BD2 - nexans.com

1 60-500 kV High VoltageUnderground Power Cables XLPE insulated cablesLiaisons terres angl 08-2011 2_Liaisons terres angl 05/08 17/10/11 15:55 Page1 Underground8 Power8 CablesHigh8voltage8underground8power8cab les2 ADWEA 400 kV INTERCON 1 circuit 3 x 1 x 2500 mm2Cu enamellelength of the link SHANGHA 500 kV 1 circuit 3 x 1 x 2500 mm2Cu length of the link High8voltage8underground8power8cables3 RCONNECTION ABU DHABI namelled - 220/400 (420)kV XLPE Cable he link : 8600 m 0 kV SHIBO PROJECT Cu - 290/500 (550)kV XLPE Cable he link : 17150 mHigh8voltage8underground8power8cablesCA BLE Cable components6 Conductor7-8 Inner semi-conductor shield9 XLPE insulation9 Outer semi-conductor shield 9 Metallic screen9-10 Outer protective jacket11 Table of cable components12 Metallic screens earthing13 Short-circuit operating conditions14 Grounding methods14 Earth cable protection15 Earthing diagrams16-17 Laying methods18-19 Cable reels20 Permissible bending radius20 Pulling tensions 20 Fastening systems21 Cable system tests21 Technological developments22 ACCESSORIES Sealing Ends23 Components23 Outdoor sealing ends24 Synthetic type Composite type Porcelain type Indoor sealing ends24 Transformer sealing ends25 GIS sealing ends25 Joints26 The designs26 Straight ungrounded and grounded joint26 Joint with screen separation26 Transition joints26 The technologies27 Taped joint27 Premoulded joint27 Prefabricated joint27 Miscellaneous equipment28 Contentspage4

2 IIIINSTALLATION Sealing ends Erection29 Cable laying30 Protection of cable30 Type of installation Direct burial31 Laying in conduits32 Laying in duct banks33 Laying in galleries34 Joint pits35 Special civil engineering works36 Shaft sinking techniques36 Drilling methods 37 TABLES OF RATED CURRENTS Necessary information for designing a HV power line38 Impact of laying method on the allowed current39 Conductor cross-section and rated current calculation40 Correction factors40 List of tables of rated currents41 36/63 to 40/69 ( ) kV aluminium conductor42 36/63 to 40/69 ( ) kV copper conductor43 52/90 (100) kV aluminium conductor44 52/90 (100) kV copper conductor45 64/110 (123) kV aluminium conductor46 64/110 (123) kV copper conductor47 76/132 (145) kV aluminium conductor48 76/132 (145) kV copper conductor49 87/150 (170) kV aluminium conductor50 87/150 (170) kV copper conductor51 130/225 (245) kV aluminium conductor52 130/225 (245) kV copper conductor53 160/275 (300) kV aluminium conductor54 160/275 (300) kV copper conductor55 200/345 (362) kV aluminium conductor56 200/345 (362) kV copper conductor57 230/400 (420) kV aluminium conductor58 230/400 (420) kV copper conductor59 290/500 (550) kV aluminium conductor60 290/500 (550) kV copper conductor61pageHigh8voltage8underground8 power8cables5 All the data given in this brochureis communicated for information only andis not legally binding toNexansIIIIVG eneral8power8circuit8design8 This brochure deals withunderground power circuits featuringthree-phase AC Voltage insulatedcable with a rated Voltage between60 and 500 kV.

3 These lines are mainlyused in the transmission lines betweentwo units of an electricity distributiongrid, a generator unit and a distributionunit or inside a station or insulated cable circuits may alsobe used in conjunction with Voltage of a circuit isdesignated in accordance with thefollowing principles:Example:Uo/U (Um) : 130/225 (245)Phase-to-ground Voltage , designatedUo, is the effective value of thevoltage between the conductor andthe ground or the metallic Voltage , designated U, is theeffective phase-to-phase Voltage , designated Um,is the permissible highest Voltage forwhich the equipment is specified(see also standard IEC 38).A high Voltage insulatedcable circuitconsists of three single-core cablesorone three-core cable with HighVoltage sealing ends at each sealing ends are also called terminations or the length of the circuitexceeds the capacity of a cable reel,jointsare used to connect the circuit installation also includesgrounding boxes, screen earthingconnection boxesand the relatedearthing and bonding = 130 kV phase-to-ground Voltage ,U = 225 kV rated phase-to-phase Voltage ,Um = 245 kV highest permissible Voltage of the gridHigh8voltage8underground8power8cable s6 The8cableThe structure of high Voltage cablewith synthetic cross-linkedpolyethylene insulation will alwaysinvolve the following items:Conductor coreThe aluminium or copperconductor carries the electricalcurrent.

4 The conductor behaviour ischaracterized by two particularlynoteworthy phenomena: the skineffect and the proximity skin effectis the concentrationof electric current flow around theperiphery of the increases in proportion to thecross-section of conductor short distance separating thephases in the same circuitgenerates the proximity the conductor diameter isrelatively large in relation to thedistance separating the threephases, the electric current tends toconcentrate on the surfaces facingthe conductors. The wires of thefacing surfaces indeed have alower inductance than wires thatare further away (the inductance ofa circuit increases in proportion tothe surface carried by the circuit).The current tends to circulate in thewires with the lowest practice, the proximity effect isweaker than the skin effect andrapidly diminishes when the cablesare moved away from each proximity effect is negligiblewhen the distance between twocables in the same circuit or intwo adjacent circuits is at least 8times the outside diameter of thecable are two designs ofconductor, compact roundstrandedandsegmental Milliken Compact round conductors,composed of several layers ofconcentric spiral-wound round stranded compactconductors, due to the lowresistance electrical contactsbetween the wires, the skin andproximity effects are virtuallyidentical to those of solid plainconductor.

5 Conductors, alsoknown as Milliken conductors arecomposed of several segment-shaped conductors assembled together to form a cylindrical large cross-section conductor isdivided into several segment-shapedconductors. There are from 4 to 7 ofthese conductors, which are knownas segments or sectors. They areinsulated from each other by meansof semi-conductive or insulating spiral assembly of the segmentsprevents the same conductor wiresfrom constantly being opposite theother conductors in the circuit, thusreducing the proximity structure is reserved forlarge cross-sections greater than1200 mm2for aluminium and atleast 1000 mm2for Milliken type structure reducesthe highly unfavourable skin effectand proximity copper wire For copper conductors with a cross-section greater than 1600 mm2,enamelled wires (around two thirds ofthe wires) are included in the structureof the Milliken type proximity effect is almost completelyeliminated, as each conducting wirefollows a path alternating betweenareas that are far away from andareas close to the other skin effect is reduced owing tothe small cross-section of the wiresused, each insulated from the practice, a structure containingenamelled wires adds roughly awhole conductor example, a 2000 mm2enamelled copper cable is equivalentto a 2500 mm2non-enamelledcopper connection of enamelled copperconductors requires a differenttechnology, which Nexans hasrecently structureDC90resistanceCross-section (mm2)

6 Compact round strandedMilliken segmental stranded Milliken enamelled of the skin effectPre-spiralled segmentEnamelled copper wireCopper wireSeparating tapeMilliken conductor constructionTypical diagram of an enamelled wire conductorThe8cableHigh8voltage8undergrou nd8power8cables8 Semi-conductor screen prevent electric fieldconcentration, there is an interface ofultra-smooth semi-conductor XLPE between the conductor and the its name suggests, the insulationinsulates the conductor whenworking at high Voltage from thescreen working at earthing insulation must be able towithstand the electric field underrated and transient screen layer has the same function asthe conductor screen:Progressive transition from aninsulating medium, where the electricfield is non- null, to a conductivemedium (here the metal cablescreen) in which the electric field the Voltage reaches tens oreven hundreds of kV, a metallicscreen is main functionis to nullify theelectric field outside the acts as the second electrode of thecapacitor formed by the of a metallic screen implies: The need to connect it to earth atleast at one point along the route.

7 Draining the capacitive current thatpasses through the insulation. Draining the zero-sequenceshort-circuit currents, or part ofthem. This function is used todetermine the size of the metallicscreen. The circulation of the currentsinduced by the magnetic fieldsfrom other cables in the circulating currents causefurther energy loss in the cablesand have to be taken into accountwhen assessing the transmissioncapacity of a cable system. The need to electrically insulate themetallic screen from earthover thegreater part of the length of cableinstalled. The need to protect the metallicscreenfrom chemical orelectrochemical second functionof the metallicscreen is to form a radial barrier toprevent humidityfrom penetratingthe cable, particularly its synthetic insulation system shouldnot be exposed to humidity. Whenhumidity and a strong electric fieldare present together, the insulationdeteriorates by what is calledwatertreeing, which can eventuallycause the insulation to :In the case of an overhead line,the insulation is formed by the airbetween the bare conductor andthe metres between thepowered conductors and theground are required to ensureadequate electrical insulation andto prevent arcing between the highvoltage conductors and objects orliving beings on the componentsSC conductorscreen SC insulationscreenConductorInsulationMetal licsheathAnti-corrosionsheathHigh8voltag e8underground8power8cables9 The8cableDifferent types of metallicscreen Extruded lead alloy sheathAdvantages: Waterproofing guaranteed bythe manufacturing process, High electrical resistance, thereforeminimum energy loss incontinuous earthing links, Excellent corrosion.

8 Heavy and expensive, Lead is a toxic metal whose useis being restricted to a minimumfollowing European directives, Limited capacity to expelzero-sequence copper wire screenwith aluminium tape bonded to apolyethylene or PVC jacketAdvantages: Lightweight and cost effectivedesign, High short-circuit : Low resistance necessitatingspecial screen connections(earthing at one point or cross-bonding) in order to limitcirculating current screen welded longitudinally and bonded to apolyethylene jacketAdvantages: Lightweight structure High short-circuit capacity, Impervious to moisture,guaranteed by the : Low resistance necessitating specialscreen connections (earthing at onepoint or cross-bonding) in order tolimit circulating current losses. Higher Eddy Current losses thanwith the previous screen screenDry cross-linked PEinsulationAluminium conductorcoreSemi-conductorscreenSemi-co nductorscreenPVC jacketLead sheathXLPE insulationAluminiumconductor coreExtruded semi-conductorExtruded semi-conductorSemi-conductortapeSC insulationscreen SC conductorscreen PE jacketAluminium tapeapplied lengthwiseAluminium tapeapplied lengthwiseCopper spiralbinder tapeCopper conductor coreCopper wirescreenSwellable tapeSwellable tapeXLPE insulationdry curingHigh8voltage8underground8power8cab les10PE jacketCopper wire/alu sheathSmooth aluminium sheathCopper wire screen withextruded lead sheathThis is a combination of theabove designs.

9 It combines theadvantages of the lead sheathand concentric copper main drawbacks lie in its costand the lead copper wire screen is placedunder the lead sheath thusenabling it to share theanti-corrosion properties of protectivejacketThe jacket has a dual function: It insulates the metallic screenfrom ground (particularly for lineswith special screen connections) It protects the metal componentsof the screen from humidity outer jacket must also withstand themechanical stressesencountered duringinstallation and service, as well otherrisks such as termites, hydrocarbons, most suitable material for this is still used but increasingly less , one of the advantages of PVCis its fire-retardant properties, althoughthe toxic and corrosive fumes releasedare prohibited by many fire-retardant is specified inaccordance with IEC standards 332,HFFR (Halogen-Free Fire Retardant)materials will be used in preference materials however havemechanical properties that are inferiorto those of polyethylene and are morecostly.

10 They should be reserved forinstallations or parts of installationswhere fire protection is verify the integrity of the outer jacket,a semi-conducting layer is often appliedto this layer is made of semi-conductingpolymer co-extruded with the wire/lead sheathSC conductorscreen SC insulationscreen Conductor XLPE insulationdry curingSwellabletapeSwellabletapeCu wire screenPE jacketLeadsheathItemFunctionCompositionC onductorInternal semi-conductorInsulationExternal semi-conductorMetallic screenOuter protective sheathS 1000mm2 (copper) or 1200mm2 (aluminium)Compact round stranded cable with copperor aluminium wiresS 1000mm2(copper)segmentalS>1200mm2(alumin ium)segmentalXLPE semi-conducting shieldXLPE insulationThe internal and external semi-conductinglayers and the insulation are co-extrudedwithin the same semi-conducting shield Extruded lead alloy, or Copper wire screen with aluminiumbonded to a PE jacket Welded aluminium screen bondedto a PE jacket Combination of copper wires andlead sheathInsulating sheath Possibility of semi-conducting layer fordieletric tests Polyethylene jacket HFFR jacket to carry current - under normal operating conditions- under overload operating conditions- under short-circuit operating conditions to with