HIGH VOLTAGE CABLE ACCESSORIES - Application, Design, Installation, Testing - Ivan Jovanovic G&W Electric Company

Size: px

Start display at page:

Download "HIGH VOLTAGE CABLE ACCESSORIES - Application, Design, Installation, Testing - Ivan Jovanovic G&W Electric Company"

Timothy Hodges
6 years ago
Views:

1 HIGH VOLTAGE CABLE ACCESSORIES - Application, Design, Installation, Testing - Ivan Jovanovic G&W Electric Company 1

2 Year 1905 First detachable porcelain pothead for 4 kv systems

3 Year 2015 Terminations and joints from 5kV up to 345 kv for all cable types

4 Chicago Toronto San Luis Potosi Delhi Shanghai Salvador

5 Application of Underground Cables Any sections of Transmission and Distribution lines may be underground

6 Examples of cable installation Directly buried or in conduits in trenches

7 Laid on trays in tunnels Examples of cable installation

8 Examples of cable installation Laid on trays under bridges

9 Examples of cable installation Laid on sea floor or river bed Submarine cables

10 Cable accessories Outdoor termination Equipment mount termination HV Power Cable Joint

11 Distribution of electrical stress in Conductor screen power cable 2 V Einsscr. = ODins ODins ln ODcondscr. Insulation screen

Cable end in accessory how does it work?

distributed Cable conductor Cable insulation Cable insulation screen Cable

insulation Stress cone ground electrode Edge of cable insulation screen

12 Cable end in accessory how does it work? High stress at conductor High stress at insulation screen Stress evenly distributed Cable conductor Cable insulation Cable insulation screen Cable conductor Cable insulation Cable conductor Cable insulation Stress cone insulation Stress cone ground electrode Edge of cable insulation screen Cable End without Insulation screen stripped back Cable End with Insulation screen stripped back Cable End inside termination

13 Extruded Cable Conductor Screen Insulation Screen Metallic Sheath Screen Wires Jacket

14 OUTDOOR TERMINATIONS GIS & Oil Immersed TERMINATIONS JOINTS

15 Use of outdoor terminations Cable terminations connects power cable to other electrical components: Overhead lines Station buses

16 Structure-mount outdoor terminations in substation Termination

17 Pole mount outdoor terminations on transmission line pole Termination

18 Typical design of outdoor termination

19 Distribution of electrical stress in the critical areas Outdoor Termination Deflector radius Interface between stress cone and cable insulation Deflector angle

20 Silicone Rubber Stress Cone Insulating Rubber Oil seal Sleeve Conductive Rubber (Deflector)

21 Use of equipment mount cable termination GIS cable termination connects the cable to the gas insulated switchgear (GIS) Oil-immersed termination connects the cable to power transformer

22 GIS Housing GIS Termination GIS terminations GIS terminations

23 Typical design of dry type GIS termination Contact pad Corona shield Connector Epoxy insulator Stress cone GIS interface plate Clamping ring Compression spring assembly Cable Entrance housing Cable support

24 Design considerations

25 Per 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.

26 Joint Design - General Joint outer screen Shield Break Cable semi-con screen HV electrode Ground electrode (deflector)

27 Electrical stress inside the joint Design - Electrical

28 Design - Electrical Magnitude of electrical stress in the critical areas Corona shield Deflector top Deflector angle

29 Use 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 protection.

30 Multiple Point Bonding Induced current in screen Load current Cable metallic screen Lower load rating of cable system Zero voltage at both cable ends (no safety hazard)

31 Single Point Bonding Induced Voltage in screen Voltage at open end (In US V Max) Cable length Induced voltage at open cable end (safety hazard) Higher load rating of cable system

32 Cross Bonding use of shield break joints Location of shield-break joints No induced voltage at open cable end (no safety hazard) Higher load rating of cable system

33 Paper Cables PIPE OIL or GAS PAPER CABLES

34 OUTDOOR TERMINATIONS EQUIPMENT TERMINATIONS Straight Joints

35 Stress in paper cables x y g Cable conductor Cable insulation Dc Di Joint insulation Stress cone (L-L profile) Formula for axial component of electrical field at the stress cone g = E x Ln Ln Ln y Dc 2 Di Dc

36 Oil-impregnated paper cable Relevant for connector design Relevant for Stress cone design

37 Retrofit of the old termination with new one

40 HV Transition Joints Definition: Device for connecting HV oilimpregnated paper cable to solid dielectric cable Typical application: To expand existing UG transmission network To replace ailing section of old oilimpregnated paper cable with new extruded cable

41 HV 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-toback Limited use and availability at 345 kv High pressure vs. Low pressure (in regard to insulating fluid at paper cable side)

42 Back-to-Back with two Insulators (CIGRE TB 415) Equipment type termination for extruded cable Equipment type termination for paper cable Gas or liquid Housing Extruded cable Paper cable Connector Corona shields

43 Back-to-Back with one Insulator Stress cone Gas or insulating liquid GIS or Transformer type termination Extruded cable Paper cable Conductor Seal Corona shield Connector Housing

44 Composite design Stress cone Epoxy insulator with built-in HV electrode Paper cable stress cone Extruded cable Paper cable Springs Connector Housing Gas or liquid

45 Single-core Transition Joint for SCFF Cable Back-to-Back with One Insulator Extruded cable Stainless steel housing Stress cone (paper roll) Tinned Cu housing Dry-Type Termination Connector clamp Paper cable Insulating fluid

46 Stress cone installation with perforated Paper Roll Paper roll (stress cone) Stress cone slope Paper is torn along factory cut perforations

47 Finalizing the stress cone Copper band Copper mesh is applied over the slope

48 Field Installation Final installation step: Oil filling of the single core 138 kv LPOF to XLPE transition joints in the field

49 Three-core Transition Joint Telescoping housing suitable for short manholes Dry-type GIS terminations 3-C Paper cable Oil breach assembly Spider assembly reinforced to prevent TMB Paper roll and crepe paper tape build-up

50 Installation of 3/C Transition Joint Bushing of the drytype termination

Design Tests per IEEE 404 138 kv HPFF Transition Joint Extruded cable in conduit HPFF transition joint Number of samples: 2 AC

51 Design Tests per IEEE kv HPFF Transition Joint Extruded cable in conduit HPFF transition joint Number of samples: 2 AC voltage: 1min and 24h Impulse voltage Ionization factor Load Cycling Pipe-type cable Accumulator HPFF transition joint Extruded cable

52 Installation of Cable Accessories

53 Excerpt from International study on worldwide 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 vulnerable part of a project involving the manufacture and installation of a new cable circuit.

Parts Heat shrinkable tubing B/M and installation instructions Joint body expended onto spiral core tube Self-fusing insulating tape Semi-con tape, 25mm wide Semi-con

55 Parts Heat shrinkable tubing B/M and installation instructions Joint body expended onto spiral core tube Self-fusing insulating tape Semi-con tape, 25mm wide Semi-con tape, 50 mm wide PVC tape Sand paper #150 to #600 grit Self-fusing Aqua-Seal tape Tinned Cu grounding mesh Connector Hot-melt tape #18AWG Cu wire String solder Gloves

56 Installation Steps 1. Cable preparation / Preparacion del cable 2. Connector crimp / Ponchado del conector 3. Connector tape fill / Encintado con cinta semicontora sobre el conector 4. Shrinking of the joint body / Contraccion del empalme 5. Taping and grounding / Encintado y Aterrizado 6. Outer joint protection / Colocacion de la manga termocontractil y (si es necesario) la cubierta de cobre

57 Cable preparation Prepare cable ends per installation instructions / Preparacion del cable de acuerdo a instruccines de instalacion

58 Connector crimp Slide the connector onto cable conductor

59 Connector crimp Butt the conductors into the connector

60 Connector crimp

61 Connector crimp

62 Shrinking of the joint body Clean cable insulation and apply grease

63 Shrinking of the joint body Position the joint and start pulling the cord

64 Shrinking of the joint body

65 Shrinking of the joint body Check the position of the joint relative to the positioning marks

66 Taping and grounding Apply semi-con tape and insulating tapes over the joint per instructions

67 Taping and grounding Apply copper mesh over the semi-con tape and solder to cable metallic sheath

68 Outer joint protection Heat shrink tube Copper housing and / or fiberglass coffin are optional

69 Outer joint protection Position heat shrink tube over the joint

70 Outer joint protection Apply heat uniformly to shrink down the tube

71 Mechanical Shrink Installation Method for Stress Cones and Joints Main drivers: for Extruded Cables Minimizes chances for field errors and damage Reduces required space, installation time and cost

72 Mechanical Shrink Installation Method for Stress Cones and Joints for Extruded Cables Scone sliding.avi GW Mechanical Shrink Accessories-live demonstration.mpg

73 SLIP- ON Cable prep: Accommodates for slip on the parking side, requires rejacketing MECHANICAL SHRINK Typically no need for additional rejacketing

74 SLIP- ON Parking: Joint body is pushed onto the cable; requires special tool and extra time and space MECHANICAL SHRINK Joint body is parked onto the cable, no tool required

mechanical stress MECHANICAL SHRINK Joint body is

75 SLIP- ON Final positioning: Joint body is pushed back the cable; requires special tool, creates mechanical stress MECHANICAL SHRINK Joint body is positioned and cord is removed, no tool is required

76 SLIP- ON MECHANICAL SHRINK

77 Process 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 variations

80 Comparison of Different Specifications for Cable Accessories and Cable Systems

81 Cable, Accessory & System Standards Governing Body ICEA IEC IEC AEIC IEEE IEEE Standard ICEA S Standard for Extruded Insulation Power Cables Rated Above 46 through 345 kv IEC Power cables with extruded insulation and their accessories for rated voltages above 30 kv (U m = 36 kv) up to 150 kv (U m = 170 kv) - Test methods and requirements IEC Power cables with extruded insulation and their accessories for rated voltages above 150 kv (U m = 170 kv) up to 500 kv (U m = 550 kv) Test methods and requirements AEIC CS9 Specification for Extruded Insulation Power Cables and Their Accessories Rated Above 46kV through 345 kv AC IEEE 48 IEEE Standard for Test Procedures and Requirements for Alternating-Current Cable Terminations Used on Shielded Cables Having Laminated Insulation Rated 2.5 kv through 765 kv or Extruded Insulation Rated 2.5 kv through 500 kv IEEE 404 IEEE Standard for Extruded and Laminated Dielectric Shielded Cable Joints Rated 2.5 kv to 500 kv Current Edition / (2013)

82 Tests Requirements for Individual Components IEC 60840, Section for cables IEC 60840, Section for cable accessories ICEA S for cables IEEE 48 (US accessory makers and users) for terminations IEEE 404 (US accessory makers and users) for Joints Tests Requirements for System IEC (International) section for cable systems IEC (International) section for cable systems AEIC CS9 (US utilities) for cable systems

83 Definitions 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. 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 system.

84 Industry 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 2.5 kv through 765 kv or Extruded Insulation Rated 2.5 kv through 500 kv Rev 2009 IEEE 404 Standard for Extruded and Laminated Dielectric Shielded Cable Joints Rated 2.5 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)

85 Industry Standards New Developments in IEEE New split combines accessories, splits voltage levels: Combine Terminations and Joints into one document Split Distribution and Transmission Two new IEEE standards Two new DGs were approved; First ICC Fall meeting 2015

86 Design and Type tests

Type test per IEEE 404 (joints) - Outdoor with composite insulator - Outdoor with porcelain insulator - Two Oil filled GIS - Two

87 LOOP #1 Initial tests per IEEE 48 (terminations) Very tough requirements, up to 4Uo LOOP #2 Type tests per IEC (system test) Type tests per AEIC (system test) Type test per ICEA (cables) Remaining type El. tests per IEEE 48 El. Type test per IEEE 404 (joints) - Outdoor with composite insulator - Outdoor with porcelain insulator - Two Oil filled GIS - Two Dry Type GIS - Two Cable types The same loop plus four joints: Two without shield break in water Two with shield break in air Total ten accessories, two cable types

88 IEEE 48 and 404 Test Loop

89 G&W HV Lab

90 G&W HV Lab

91 PQ test field

94 Conclusions HV Cable Accessories Terminations and Joints are the critical link in any modern cable system There are many different designs that can work with any modern cable designs that follow latest cable standards Oil-filled cables (OF) are still dominant technology that has been field proven over the years Transition joints are becoming increasingly important as new solid dielectric cables are being utilized Installation of is tying together cables and accessories and highly qualified jointers are a must! New developments in standardization are critical for further successful applications of cables and their accessories

TRANSMISSION ENGINEERING STANDARD TES-P , Rev. 0 TABLE OF CONTENTS 1.0 SCOPE 2.0 CABLES SPLICES

TRANSMISSION ENGINEERING STANDARD TES-P , Rev. 0 TABLE OF CONTENTS 1.0 SCOPE 2.0 CABLES SPLICES 1.0 SCOPE TABLE OF CONTENTS 2.0 CABLES SPLICES 2.1 Definitions 2.2 Scope of Specifications and Drawings 2.3 General Requirements 2.4 Routing Cables 2.5 Connectors 2.6 Conductor Connections 2.7 Heat Shrinkable