HIGH VOLTAGE CABLE ACCESSORIES - Application, …

1 1 HIGH VOLTAGE CABLE ACCESSORIES - Application, design , installation , testing -Ivan JovanovicG&W Electric CompanyFirst detachable porcelain pothead for 4 kV systemsYear 1905 Terminations and joints from 5kV up to 345 kV for all CABLE typesYear 2015 ShanghaiDelhiTorontoSan Luis PotosiChicagoSalvadorAny sections of Transmission and Distribution lines may be undergroundApplication of Underground CablesExamples of CABLE installationDirectly buried or in conduits in trenchesExamples of CABLE installationLaid on trays in tunnels Examples of CABLE installationLaid on trays under bridges Examples of CABLE installationLaid on sea floor or river bed Submarine cablesCable accessoriesHV Power CableOutdoor terminationEquipment mount terminationJointDistribution of electrical stress in power cableConductor Conductor screenscreenInsulation screenInsulation = CABLE Endinside terminationCable conductorCable insulationCable end in accessory how does it work?

2 CABLE conductorCable insulationCable insulation screenCable End withoutInsulation screen stripped backStress cone ground electrodeHigh stress at conductorHigh stress at insulation screenStress evenly distributedCable End withInsulation screen stripped backCable conductorCable insulationStress cone insulationEdge of CABLE insulation screenExtruded CableConductorScreenInsulationMetallicSh eathScreenWiresJacketScreenOUTDOOR TERMINATIONSGIS & Oil Immersed TERMINATIONSJOINTSUse of outdoor terminations CABLE terminations connects power CABLE to other electrical components: Overhead lines Station busesStructure-mount outdoor terminations in substationTerminationPole mount outdoor terminations on transmission Pole mount outdoor terminations on transmission line poleline poleTerminationTypical design of outdoor terminationDistribution of electrical stress in the critical areasDeflector radiusDeflector angleInterface between stress cone and CABLE insulationOutdoor TerminationSilicone Rubber Stress ConeInsulating RubberConductive Rubber (Deflector)Oil sealSleeveUse of equipment mount CABLE termination GIS CABLE termination connects the CABLE to the gas insulated switchgear (GIS)

3 Oil-immersed termination connects the CABLE to power transformerGIS terminationsGIS terminationsGIS HousingGIS TerminationTypical design of dry type GIS terminationCable supportCompression spring assemblyClamping ringStress coneEpoxy insulatorConnectorCorona shieldCableContact padEntrance housingGIS interface plateDesign considerationsPer international and domestic standards it is required that terminations and GIS gear are interchangeable regardless of who made them. G&W GIS terminations meet that requirement. Joint design -GeneralHV electrodeJoint outer screenGround electrode (deflector)Shield BreakCable semi-con screenDesign -ElectricalElectrical stress inside the jointDesign -ElectricalMagnitude of electrical stress in the critical areasDeflector angleDeflector topCorona shieldUse of Joint in CABLE Bonding CABLE bonding functions: Limit CABLE metallic screen voltages Reduce or eliminate the screen losses Maintain a continuous ground path to permit fault-current return and adequate lightning and switching surge Point Bonding Lower load rating of CABLE system Zero VOLTAGE at both CABLE ends (no safety hazard)Induced current in screenInduced current in screenLoad currentLoad currentCable metallic CABLE metallic screenscreenSingle Point Bonding Induced VOLTAGE at open CABLE end (safety hazard) Higher load rating of CABLE systemInduced VoltageInduced Voltagein screenin screenCable lengthCable lengthVoltage at open end VOLTAGE at open end (In US 100(In US 100--200V Max)200V Max)Cross Bonding use of shield break joints No induced VOLTAGE at open CABLE end (no safety hazard)

4 Higher load rating of CABLE systemLocation of shieldLocation of shield--break jointsbreak jointsPaper Cables PIPEOIL orGASPAPER CABLESOUTDOOR TERMINATIONSEQUIPMENT TERMINATIONSS traight JointsStress in paper cables =DcDiLnDcyLnLnxEg2xygDcCable conductorCable insulationJoint insulationStress cone(L-L profile)Formula for axial component of electrical field at the stress coneDiOil-impregnated paper CABLE Relevant forconnector designRelevant forStress cone design Retrofit of the old termination with new oneHV Transition Joints Definition: Device for connecting HV oil-impregnated paper CABLE to solid dielectric CABLE Typical application: To expand existing UG transmission network To replace ailing section of old oil-impregnated paper CABLE with new extruded cableHV Transition Joints Relatively small usage, expected to grow significantly Up to 161 kV class, many different designs in operation At 230 kV most designs are back-to-back Limited use and availability at 345 kV High pressure vs.

5 Low pressure (in regard to insulating fluid at paper CABLE side)Back-to-Back with two Insulators(CIGRE TB 415)Equipment type terminationfor paper cableGas or liquidConnectorCorona shieldsHousingExtruded cablePaper cableEquipment type terminationfor extruded cableBack-to-Back with one InsulatorGIS or Transformertype terminationGas or insulating liquidConnectorCorona shieldHousingConductor SealStress coneExtruded cablePaper cableComposite designEpoxy insulator with built-in HV electrodePaper cableStress conePaper CABLE stress coneHousingGas or liquidSpringsConnectorExtruded cableTinned Cu housingStainless steel housingExtruded cablePaper cableConnector clampStress cone(paper roll)Insulating fluidDry-Type TerminationSingle-core Transition Joint for SCFF CableBack-to-Back with One InsulatorStress cone installation with perforated Paper Roll Paper is torn along factory cut perforationsStress cone slopePaper roll(stress cone)Finalizing the stress coneCopper mesh is applied over the slopeCopper bandField InstallationFinal installation step.

6 Oil filling of the single core 138 kV LPOF to XLPE transition joints in the fieldThree-core Transition JointTelescoping housing suitable for short manholesOil breach assembly3-C Paper cableSpider assemblyreinforced to prevent TMBP aper roll and crepe paper tape build-upDry-type GIS terminationsInstallation of 3/C Transition JointBushing of the dry-type terminationDesign Tests per IEEE 404138 kV HPFF Transition JointPipe-type cableExtruded CABLE in conduitHPFF transition jointHPFF transition jointAccumulatorExtruded cableNumber of samples: 2AC VOLTAGE :1min and 24hImpulse voltageIonization factorLoad CyclingInstallation of CABLE AccessoriesExcerpt from International study on world-wide usage of HV CABLE systems(CIGRE TB 177, Section 3 Worldwide Usage of ACCESSORIES for HV Extruded Cables , Page 29) The assembly of the ACCESSORIES is the most vulnerablepart of a project involving the manufacture and installation of a new CABLE circuit.

7 PartsHot-melt tapeConnectorSemi-con tape, 25mm wideSelf-fusing Aqua-Seal tapeSelf-fusing insulating tapeTinned Cu grounding meshSemi-con tape, 50 mm wideSand paper #150 to #600 gritString solder#18 AWG Cu wireJoint body expended onto spiral core tubeGlovesB/M and installation instructionsHeat shrinkable tubingPVC tapeInstallation Steps1. CABLE preparation / Preparacion del cable2. Connector crimp / Ponchado del conector3. Connector tape fill / Encintado con cinta semicontora sobre el conector4. Shrinking of the joint body / Contraccion del empalme5. Taping and grounding / Encintado y Aterrizado6. Outer joint protection / Colocacion de la manga termocontractil y (si es necesario) la cubierta de cobreCable preparation Prepare CABLE ends per installation instructions / Preparacion del CABLE de acuerdo a instruccines de instalacionConnector crimp Slide the connector onto CABLE conductorConnector crimp Butt the conductors into the connectorConnector crimpConnector crimpShrinking of the joint body Clean CABLE insulation and apply greaseShrinking of the joint body Position the joint and start pulling the cordShrinking of the joint bodyShrinking of the joint body Check the position of the joint relative to the positioning marksTaping and grounding Apply semi-con tape and insulating tapes over the joint per instructionsTaping and grounding Apply copper mesh over the semi-con tape and solder to CABLE metallic sheathOuter joint protection Heat shrink tube Copper housing and / or fiberglass coffin are optionalOuter joint protection Position heat

8 Shrink tube over the jointOuter joint protection Apply heat uniformly to shrink down the tubeMechanical Shrink installation Method for Stress Cones and Joints for Extruded Cables Main drivers: Minimizes chances for field errors and damage Reduces required space, installation time and costMechanical Shrink installation Method for Stress Cones and Joints for Extruded CablesScone Mechanical Shrink ACCESSORIES -live prep: Accommodates for slip on the parking side, requires re-jacketingTypically no need for additional re-jacketingSLIP-ONMECHANICAL SHRINKP arking: Joint body is pushed onto the CABLE ; requires special tool and extra time and spaceJoint body is parked onto the CABLE , no tool requiredMECHANICAL SHRINKSLIP-ONFinal positioning: Joint body is pushed back the CABLE ; requires special tool, creates mechanical stressJoint body is positioned and cord is removed, no tool is requiredSLIP-ONMECHANICAL SHRINKSLIP-ONMECHANICAL SHRINKP rocess and Tooling design Molding process Parameters Flow rate Temperature Pressure Molding process Variations Material (properties, quality issues) Operators (degree of process automation, skill set, training) Equipment variations Need to build process robust enough to compensate for the variationsComparison ofDifferent Specifications for CABLE ACCESSORIES and CABLE Systems CABLE , Accessory & System StandardsGoverning BodyStandardCurrent EditionICEAICEA S-108-720 Standard for Extruded Insulation Power Cables Rated Above 46 through 345 kV2012 IECIEC 60840 Power cables with extruded insulation and their ACCESSORIES for rated voltages above 30 kV (Um= 36 kV) up to 150 kV (Um= 170 kV)

9 - Test methods and requirements2011 IECIEC 62067 Power cables with extruded insulation and their ACCESSORIES for rated voltages above 150 kV (Um= 170 kV) up to 500 kV (Um= 550 kV) Test methods and requirements2011 AEICAEIC CS9 Specification for Extruded Insulation Power Cables and Their ACCESSORIES Rated Above 46kV through 345 kV AC2006 /(2013)IEEEIEEE 48 IEEE Standard for Test Procedures and Requirements for Alternating-Current CABLE Terminations Used on Shielded Cables Having Laminated Insulation Rated kV through 765 kV or Extruded Insulation Rated kV through 500 kV2009 IEEEIEEE 404 IEEE Standard for Extruded and Laminated Dielectric Shielded CABLE Joints Rated kV to 500 kV2012 Tests Requirements for Individual ComponentsIEC 60840, Section for cablesIEC 60840, Section for CABLE accessoriesICEA S-108-720 for cablesIEEE 48 (US accessory makers and users) for terminationsIEEE 404 (US accessory makers and users) for JointsTests Requirements for System IEC 60840 (International) section for CABLE systemsIEC 62067 (International) section for CABLE systemsAEIC CS9 (US utilities) for CABLE systemsDefinitions design Test Used in IEEE 48 and 404 to describe test sequences to qualify termination or joint for use on any CABLE with same or lower size / stress level.

10 Equivalent to Type tests in IEC. Type Test Used in IEC standards for a component test ( CABLE , termination or joint) or CABLE system test in order to qualify component or a system. Qualification Test on Complete CABLE System Used in AEIC specification to describe a Type Test (as described in IEC). Prequalification Test Used in IEC and AEIC standards for a long term CABLE system test including different installation conditions (flexible and rigid, direct burial, tunnel and conduit) to demonstrate performance of a Standards New Developments in IEEE IEEE 48 Standard for Test Procedures and Requirements for AC CABLE Terminations Used on Shielded Cables Having Laminated Insulation Rated kV through 765 kV or Extruded Insulation Rated kV through 500 kV Rev 2009 IEEE 404 Standard for Extruded and Laminated Dielectric Shielded CABLE Joints Rated kV to 500 kV Rev 2012 IEEE 48 and 404 will be combined: IEEE 48/404 for Distribution (up to 46 kV) IEEE 48/404 for Transmission (69 kV and up)Industry Standards New Developments in IEEE New split combines ACCESSORIES , splits VOLTAGE levels.