energya cables

8/11/2019 Energya Cables

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1. 1 Introduction

1.1.1 Company Profile

Energia cables is a new contributor to the Helal El-Sewedy cables Group.

Material options are copper or aluminum conductors PVC or XLPE insulation

with protections of steal tapewire or aluminum tapewire and jackets of

PVC or HDPE.

The capability to provide lead covering allows the production of submarine

cables.

The factory is located on zone A3 of the 10th of Ramadan City and Occupies

50,000 square meter.

Energia will produce of 132 and 220 KV cables.

1.1.2 Departments List Tree

Any successful organization must have departments with desired objective and

responsibilities and I found this concept in the EGYTECH Cables Factory . . . .

And now let me tell a little a bout factory departments

Figure 1:Department list tree


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1.1.3 Departments Cycle

As we see in the previous figure (fig.1.1) the departments list tree but we must

know the most important operation named by (Departments Cycle) and that's

shown in the next figure (fig.1.2).

Fig. 1.2 Departments Cycle

Sales DepartmentCustomer

Technical Department

Planning Department

Production Department

Quality Department

Final ProductCustomer

1

2

3

4

5

6


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1.1.4Diagram Description:

1.The customer makes a discussion with sales department about the order

technical specifications.

2.Sales department told technical department about the order specificationand wait feed back as acknowledge that the specifications can

manufacture and suitable with the standard specifications.

3.Technical department after send the acknowledge repair TDS technical

data sheet for this order then repair report to the planning department

with the specification of order.

4.Planning department make analysis of the orders and the materials then

repair job order send to the production department with priority of the

jobs.

5.Production department receive the job order and start to finish it in the

desired time.

6.Quality department make a tests every section to be sure that the

product suitable with the standard values. Then the quality department

passed the product to be the final product then it be delivered to thecustomer.

1.2Cables

Power cable (a type of electrical cable) is an assembly of two or more

electrical conductors held together with, and typically covered with, an overallsheath. The conductors may be of the same or different sizes, each with their

own insulation and possibly a bare conductor. Larger single conductor

insulated cables are also called power cables in the trade. The sheath may be


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of metal, plastic, ceramic, shielded, sunlight-resistant, waterproof, oil-

resistant, fire-retardant, flat or round, and may also contain structural

supports made of high-strength materials.

1.2.1Cables Types

The two major cables types

- Over Head Transmission Lines (OHTL)

- Under Ground Cable

1.2.1.1 Over Head Transmission Lines (OHTL)

It's used for the long distance transmission lines and distribution between

the villages and towns, metals towers is used to carry the cable in the air.

O.H.T.L. is cheaper than the under ground cable.

Some kinds of O.H.T.L. :

All Aluminum Conductor (AAC)

All Aluminum Alloy Conductor (AAAC)

All Conductor Steel Reinforced (ACSR)

All Copper Conductor (ACC)


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Bare soft and hard drawn strande

Soft drawn type is used for grounding electrical systems, while hard drawn

type is used in over head distribution networks.

All aluminium conductors

used for aerial distribute lines have relatively short spans, aerial feeders and

bus bars of substations.

All aluminium alloy conductors

used for transmission and distribution networks, having relatively long spans

Conductors Comparison Between Different Types of Aluminum

(for 185 mm2 Conductor as an example)AAC AAAC ACSR

Tensile (KN) 43.66 71.55 85.12

Weight (Kg/Km) 671.1 670.3 980.1

Figure 2 copper conductors

Figure 3 A.A.C

Figure 4:A.C.S.R


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1.2.1.2 Under Ground Cable

Used in the towns because it's very safe for the customers.

It's expensive because the isolation operation and armoring operation .

Some kinds of Under Ground Cable :

Low Voltage Cable:

It's used for transmission high capacity of

power voltage; maximum conductors in

the cable are four cores and can

transmission up to 1 kV.

Medium Voltage Cable:

This cable can have single core and can

reached to three core, cable support from 1 kV

to 35 kV

High voltage Cable :

it's contain a single core and voltage range

that can the cable carry from 35 KV to 150 KV

Extra High voltage Cable :

It's support more than 150 KV

Figure 5:low voltage cable

Figure 6 :MV cable

Figure 7 :HV cable


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Cable Manufacturing process

Drawing

O.H.T.L. Stranding

Insulation

AssemblyBedding

Sheathing

Warehouses

Testing

Screening

Armoring

Delivery

Customer

M.V

L.V.

Un armoring

Cable

Armoring Cable


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2.1 Metal Section

2.1.1 Introduction:

The metal section is the area of the production factory where the first step forcables

Manufacturing is carried out, the conductor manufacturing process. This

section is divided basically in two main areas, one for the drawing process

and another for the stranding process.

Figure 8 :metal section

As we see in the fig.2.1 the sections of the metal section split to 2 sectionsnamed Drawing section and Stranding section . . . . .

We will take about the two sections but first we will take about the Row

material that can be used in the two sections . . . . . .

There are three types of metals are used in cables manufacturing:

A- Copper with diameter 8 mm and weight (3-4) ton.

B- Aluminum with diameter 9 mm and weight 1.5 ton.

C- Aluminum Alloys with diameter 9.5 mm and weight 2.5 ton


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There are three types of raw material used in the metal section:

Copper, Aluminum, and Aluminum Alloy. Copper arrives from El Sewedy UMC.

Before entering into the drawing process, a welding machine must join the

different coils, therefore in this way it becomes a non stop process. We canhave copper with all possible cross-sectional areas.

There are two types of aluminum used here to manufacture conductors: H12

used to obtain underground cables, and H14 used to obtain overhead lines.

There is just one type of aluminum alloy, the H17, used to obtain overhead

lines too.

And now we will find table show us description of Diameter, electric resistive,

tensile strength, elongation and Specific weight of the rows material.

Diameter

(mm)

Ele. Resistive

(.m2/km)

Tensile

Strength

(Kg/mm2)

Elongation Weight

(g/mm2/m)

AL. H12 9 28.264 8:10.5 20% 2.7

AL. H14 9 28.264 10.5:14 15% 2.7

AL. Alloy 9.5 32.53 17:22 3.5% 2.7

Copper 8 17.241 Max. 250 40% 8.89

Notes:

The max. Tensile strength of the copper thats mean the maximum force

that can applied over cross section area.

Not good efficiency of conductor when Elongation and CSA increasing

because the resistance will increase too.

Aluminum Alloy put additives with the alloy contains silicon and

magnesium to avoid the tensile strength increasing.


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Advantage of copper or Aluminum

CU is approx. 60% lower specific resistance than AL.

CU has small cross section area than AL for the same power.

AL has lower weight than CU for the same power.

AL is cheaper than CU.

AL is used for cables needing flexibility and copper for cables needing

high stresses.

AL mainly using for over head cables and copper mainly using for under

ground cables.

2.1.2 Drawing Section

2.1.2.1 Definition

Drawing is a mechanical process to reduce the wire diameter by tension force

between 17 to 33 % of the first diameter by passing the wire through number

of dies of certain sequence till we get the required diameter

2.1.2.2 Main Machine Component

Pay Off

Drawing Block

Final capstan Block

Annealer

Dancer

Take Up


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Pay Off

Drawing Block

The drawing block is the most important block in this machine cause it's make

the main process of the machine.

Block Component:1-Wire guide (die holder) this block is die holder and die.

2-Gear box, for rotate all capstans.

3-Final Die Holder.

4-Capstan.

5-Drawing Lubricate.

Dies Construction

Pay Off Drawing Block Final capstan Block

Dancer

Annealer

Take Up

This part is the first stage in the drawing machine, its function is

take the row material (copper or aluminum wire) to the second

stage and it can be bobbin or Basket

Figure 9:Drawing machine block diagram

Figure 10 Dies contruction


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Entrance angle: give chance for oil to pass with wire in die.

Reduction zone: reduce the diameter of wire (elongation process).

Boaring: die diameter and this zone is response of output wire.

Back relief: this zone is curvature to give smooth surface.

Reduction angle : copper (18) Aluminum(20) Alloy (14)

The length of die related to the kind of material and the desired diameter

of the wire.

The die and wire is lubricating continuously for cooling the wire and die.

Types of Dies:

Ceramic die (using as a guide not for boaring). Tungsten die (using in Stranding operation).

Note:

We use diamond in the boaring area when we care of quality of wire

surface and using in fine boaring machine.

Diamond types:

natured diamond dies (very expensive)

synthetic diamond dies (more cheep that the natured)

-Gear Box

Slip Machine: thats mean in the draw machine gear boxto rotate all the

capstans synchronies with one motor.

Non slip machine: that's mean for each capstan motor to control the motion.

-Final die holder

Driver by separate motor to give circular motion to reduce the scrap in the die.


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-Capstans

We turn the wire over the capstan by 3 turns to save the tension of the wire.

-Drawing lubricate

This soap is for: reduce the fraction between the wire and the die and to give a

smooth surface.

Change mineral oil every 6 months

Soap oil mixed with fixed amount of water 85%

Figure 11drawing lubricata cooler

-Emulsion percentage:

Heavy drawing machine: 10 14 %

Intermediate drawing machine: 8 10 %

For Annealer: 0.51 %

-Final Capstan Block

The function of the last capstan to be sure that the diameter of wire not

changed, to reduce the cut of wire and the number of turns in technical

recommendation catalog.

-Annealer

This block is exist only in copper wire , This operation is temperature process

for copper metal after drawing operation done, done by increase the heat to 50


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degree but system isolating from air to decrease the hardiness of copper again

because it's increasing in the drawing operation.

Aluminum alloy is annealed in a special oven, by putting the whole spool/coil

in it after drawing.

Annealer construction

boiler steam generator : to reduce the oxidation

Brushes transform: closed electric circuit current reach to 8000 A to heating

the wire.

Cooling zone: cooling by emulsion.

We need to decrease the hardness because the relation between the hardness

and the resistance.

RH

Where H Hardiness of metal & R Resistance of metal

Dancer

It's constructing from two capstans and pneumatic system and its function to

make synchronization speed between take up and the feed speed of drawing

block.

This part using in the start up of the machine and when the end of the

machine to avoid the wire cutting.

Figure 12Dancer diagram


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-Tae up

Take up kinds: Bobbin (400 mm up to 800 mm)

Take up kind depend on the diameter of the wire.

- Types of Drawing Machines

1.Heavy Drawing Machine

Single wire

Double wire

2. Intermediate Machine

3.Fine Machine.

- EGYTECH Drawing Machines

DO Drawing operation

DO.1 DO.2 DO.3 DO.4 DO.5

Kind of M/C Heavy

drawing M/C

Single wire

Slipping M/C

Heavy

drawing M/C

Single wire

Slipping M/C

Heavy

drawing M/C

Single wire

Slipping M/C

Intermediate

drawing M/C

8 wires

Slipping M/C

Heavy

drawing M/C

Double wire

Slipping M/C

SupportedMetal

Copper Aluminum Aluminum Copper CopperAluminum

Max. no. of

dies

13 15 11 8 X 11 2 X 16

Min. diameter

(mm)

1.2 Inlet dia. Inlet dia. 0.26 1.35

9.5 9 9.5 9

1.7 1.53 2 1.9

Max. diameter

(mm)

4.5 Inlet dia. Inlet dia. 1.35 4.5

9.5 9 9.5 9

4.5 5.2 4.5 5.2

Max. Speed

(m/s)

31.5 37.5 37.5 30.5 35


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Focusing in DO.5:

It is a copper drawing M/C.

This machine consists of 11 pair of dies (22 die).

The maximum and minimum diameters I can get from this machine are

4.5&1.4mm respectively.

This machine can draw two wires in the same time.

The wires out from this machine can be turned on pulleys or baskets

according to the stranding machine that will strand it.

The following table contains the sizes of the dies that used in the machine:

2.1.3 Stranding Section

2.3.1 Definition

The need of making the stranding operation can be explained as follows. The

current flows typically along the surface of the conductor (skin effect), so to

allow the conductor to carry more current, more wires of smaller cross-

sectional areas are used instead of using just one of larger area. In this way,

conductors are made of layers of wires.

The operation of stranding can be summarized as follows:

One wire is placed in the center of the conductor; a second layer containing 6

wires is stranded around it, then becoming the "1 + 6" conductor the center of

the next third layer, which is made of a total of twelve wires; if the conductor

needs to have another layer, the previous "1 + 6+ 12" becomes the center of

the this new fourth layer.


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The conductor of cables consists of a number of strands of wire of circular

cross section so that it may become flexible and array more current.

To avoid the bending and deformation of the cable conductor under normal

conditions.

The number of strands in cables is 7, 19, 37, 61, 127 and 169.

For example the arrangement of 7 strands cables six strands spiraled around a

central strand.

As we see in the table the formation of wires with the number of layer

Lay length:

It is the distance in mm between two consecutive ups or downs of a certain

component of the cable.

Conductor Number of layers Layers

7 wires 2 1 + 6

19 wires 3 1 + 6 + 12

37 wires 4 1 + 6 + 12 + 18

61 wires 5 1 + 6 + 12 + 18 + 24

Figure 13:formation of wires


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Calculation method of stranding conductor diameter

Calculation method of circular conductor diameter

By this equation

Dc = .Dw

Where:-

Dc The diameter of conductor of the cable

Dw The diameter of the wire.

Lay factor

3 5 7 9 11 13 15

No. of wires 7 19 37 61 91 127 169

Calculation method of core of ACSR conductor diameter

By this equation

Dc = n.Dw.DS

Where

Dc The diameter of conductor of the cable

Conductor Factor

91 wires 810

61 wires 1012

37 wires 1214

19 wires 1416

7 wires 1618


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n .. .Factor.

Dw The diameter of the wire.

DS The diameter of the steel.

n 2 4 6

No. of Layers 1 2 3

Stranding lay direction

The alternate layers have right and left spirals the arrangement of 7

strands conductor six strands spiraled around a central strand.

Te direction of spiraling of this layer (12 strands) is in the opposite

direction to the previous layer.

Stranding Cables

Sector cables (used for low voltage range 3 X 1204 X 903 X 100 +

60 )

Compact Cables (used for medium and high voltage range)

Over Head Transmission Line (O.H.T.L.)

AAC

ACC

ACSR

AAAC

Figure 14:Rotating cage


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The stranding M/Cs classification

1- Rigid stranded M/Cs.

This M/Cs consists of:

Feeding carrier.

Rotating cage contains 6 pulley carriers.




Double capstan of diameter 2m.

Receiving carrier. After each cage there are rollers used in compressed and sector

conductors.

2- Double twist M/Cs.

This M/C strands the wires by using a rotating arm which rotates fast

twisting the wires, and then the wires are reversed to be turned on the

receiving pulley which rotates around itself and that is the other twist.


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2.2. Extrusion Section

2.2.1 Introduction

The Extrusion section function is insulate the conductor from the any behind

air and insulate the conductor from the others conductors.This stage is very important stage in manifactor the cables because the ability

of using this cable mainly depend on the insulation stage.

The Extrusion section made insulation to the L.V. cables and for H.V. cables

made in the C.V. section and this will be described in other chapter.

2.2.2 Type of Material

The material is divided two main parts

1-Thermoplastic material.

2-Thermosetting material.

The difference between the two material is that the 1st can be recycled but the

other can't.

Thermoplastic such as PVC and thermosetting such as XLPE

The XLPE material consists of PE (polyethylene) with Catalyst material and by

operating condition it's converted to XLPE

Figure 15 Extrusion section


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PE + CATALYST =XLPE

There are types of materials are used in insulation section but the materials

which used to insulation the cable are

1-PVC (polyvinyl chloride)

2-XLPE (Cross Linked Polyethylene)

The material is used for insulation depend on the type of screw which used in

insulation, bedding or sheathing process

And we will find the different between the materials that we used in this table:

PVC XLPE

Cost Cheaper than XLPE More Expensive than PVC

Made in Egypt Imported

Recycling Yes No

Operating

Temperature

70C 90C

Density From 1.4 to 1.6 g/cm3 0.92 g/cm3

Cooling

trough

The conductor pass cool

water 14C in cooling system

Must be pass in hot water

60C to 10m from cooling

system

Generally materials are used in Extrosion section as follows

1-PVC (polyvinyl chloride)

2-XLPE (Cross Linked Polyethylene)

3-LDPE (Low Density polyethylene)

4-LLDPE (Low Liner Density polyethylene)

5-MDPE (Medium Density polyethylene)

6-HDPE (High Density polyethylene)


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7-LSOH (Low smoke zero halogen)

8-LSHF (Low Smoke halogen free)

The material (LLDPE, MDPE and HDPE) are used for sheathing

The material (LSHF and LSOH) are used for insulation

And the recycled PVC is used for bedding (inner covering), if wanted PE for

bedding so used MDPE.

Properties of cable insulation

1-Must have specific resistance.

2-Must be high dielectric strength (KV/mm)

3-Rigid and flexible.

4-Must non flammable.

2.2.3 Extrusion Machine Components

Figure 16: Insulation Machine block diagram

The main component of each Extrusion machine can be summarized as follow

1-Pay off this feed the machine with conductor.

Pay Off Caterpillar Extruder

Spark Tester

Cooling Trough

Take up Caterpillar


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2-Caterpillar the aim of this part to pull the conductor, there are two

caterpillars one at the beginning the machine and other at the end, the

speed of two caterpillar must be synchronized.

3-Extruder it's consists of screw, barrel and crosshead the screw part

consists of five zones which used to heat the insulation material PVC or

XLPE before going to the crosshead of the machine, the head part consists

of four heaters

4-Cooling trough it is necessary to cool it before going into the reel.

5-Spark Tester it's apart that response of the test insulation its idea that

applied DC voltage reached to 10 KV to test the insulation of the wire.

6-Take up the reel is ready to go to the assembly process.

1-Tube tooling

T1 inner diameter of tip = C1 (diameter of conductor of pay off X 1.1)

D1 inner diameter of die = T2 outer diameter of T1 X ([3 to 4] thickness of

insulation)

2-Pressure toolingT1 inner diameter of tip = C1 (diameter of conductor of pay off + [0.1 to

0.5] mm)

D1 inner diameter of die = C2 desired diameter after insulation

Figure 17:Extruaion method


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2.2.4 EGYTECH Extrusion M/Cs

Figure 19:INdulation line

NMB 80

Processes made : Insulation

Diameter of the cable from 0.5 mm2 to 10 mm2 it's better to run 10mm2 cable in the BM 100 because it is too heavy, therefore in

general it is preferred to insulate cables from 1 mm2 to 6 mm2

Materials used in this machine : PVC and XLPE

The next conductors are insulated with this machine: stranded

,flexible and solid.

Max. line speed 1000 m/min

Spark detector is installed to verify that the insulation has no faults.

Pay off: two units with reel of maximum diameter of 1000 mm and

minimum diameter of 630 mm and maximum weight of 1 Ton.

Figure 18:tooling of head method


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This machine has no caterpillars instead it is using two cabstands to

apply tension to the conductor.

Take up: two units with reel of maximum diameter of 1000 mm and

minimum diameter of 630 mm and maximum weight of 1 Ton one

units is in operation and the other one is standing by as a backup.

NMB 100

Processes made : Insulation and sheathing

Diameter of the cable:

a-Copper conductors from 10 mm2 (round) to 35 mm2 (round and

sector).

b-Aluminum with 50 mm2.


The next conductors are insulated with this machine: stranded.


Spark detector is installed to verify that the insulation has no faults in

this machine if alarm enabled the machine stop immediately.

Pay off: two units with reel of maximum diameter of 1600 mm andminimum diameter of 630 mm and maximum weight of 6 Ton.

This machine has no caterpillars instead it is using two cabstands to

apply tension to the conductor.



NMB 120

Processes made : Insulation, bedding and sheathing

Diameter of the cable: copper or aluminum conductors from 5 mm2

(round) to 57 mm2 (sector or round).


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Spark detector is installed to verify that the insulation has no faults.



This machine has two caterpillars.



NMB 150

Processes made : Insulation, bedding and sheathing

Diameter of the cable: copper or aluminum conductors from 11 mm2


Materials used in this machine: PVC and XLPE, low smoke material

etc.


Spark detector is installed to verify that the insulation has no faults. Pay off: one unit with reel of maximum diameter of 3400 mm and



Take up: one unit with reel of maximum diameter of 3400 mm and


NMB 160

Processes made : Bedding and sheathing


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Diameter of the cable : copper or aluminum conductors from 10 mm2


Materials used in this machine : PVC and recycled material (just for

bedding).








3.6 comparisons between the M/Cs

BM80 BM100 BM120 BM150 BM160

Processes

mode

Insulation Insulation and

sheathing

Insulation

bedding and

sheathing

Insulation

bedding and

sheathing

bedding and

sheathing

Size of thecable

0.5 mm2to 6 mm2

For cu 10 mm2to 35 mm2

for AL 50 mm2

5 mm2to 57 mm2

11 mm2to 115 mm2

10 mm2to 130 mm2

Materials used PVC and XLPE PVC and XLPE PVC and XLPE

and LSHF

PVC and XLPE

and LSHF

Recycled PVC

Max. linear

speed

1000 m/min 400 m/min 200 m/min 150 m/min 140 m/min

caterpillar no No two two two


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2.3 Assembly Section

2.3.1 Introduction

In fact the Rotating Machine section divided in four main tasks :

Fig. 5.1 Assembly section

The description of each section:

An Assembly, to put in one cables all phases together; and covers them

with propylene tape.

Armoringwhich covered cables by (steel or aluminum) (tape or wire), to

protect the cable against mechanical stresses like for example ground

pressure


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Leadthe cable or conductor is covered by layer of layer of lead to protect

the cable against water penetration or chemicals Reaction

Screening the cable is covered by layer of cupper (tape or wire), to earth

the cable.

Not all these steps need to be followed to manufacture a cable it depends

mainly on the customer requirements or the final conditions and situation of

the cable (marine, petroleum, etc.

2.3.2 Assembly Section

As said before the main function of this stage to put in one cables all phasestogether; and covers them with propylene tape.

During this first step all conductors are assembled together in one cable and

after that the cable is covered with polypropylene tape

Any kind of cable can be assembled in this step.

For section conductors with higher cross section areas the performing lay

length can be done during the stranding operation but for small areas this

operation is done directly during the assembly operation.

If the performing lay length was made in the stranding machines the RPM of

the pay off and take up of the assembly machine must be very high to

maintain the lay length however if the lay length is carried out in the assembly

section the RPM of pay off is fixed while the take up is rotating to be able to

apply the lay length to the complete assembled cable.

Assembly Machine Block Diagram

Figure 20:assembly machine block diagram

Pay Off Assembly Block Correct Angle

Tape or Armoring Stage

Dies Stage

Take up


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Pay off this stage is very important because

we must care about the tension between it

and the take up stage. For assembly we used

motor because we need a low tension but inarmoring case we using pneumatic system

cause we need a high tension

Assembly Block this block to assemble the phases and can assemble with it

filler.

Figure 22Assembly block

Correct angle when we perform the lay with sector cable we must to be sure

that all lays have correct angle with each other this block do this job by

determine range of angles for trying to correct the angle but if angle be larger

or less than the range the machine stopped immediately and trying to correct

the angle manually.

Die Stage this stage generally is three dies first die make the assembly function

only the second die make the assembly with compact the cable the third and

the last die used with the second die when we need segmental cable used for

installed the long die.

Figure 21pay off


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Tape or Armoring Block this in real is two block the first is tape block for put

taping to thecable and the kind of the tape is polypropylene and the second is

for armoring the cable and this stage is optional depend on the customer

requirements.

Figure 23:taping and armoring

Take up this block as we said before must its tension synchronized with the

pay off

Assembly M/Cs

Assembly 3000

Assembly 2200

Assembly 1600

Assembly 3000

This machine is used with all kind of process: Assembly armoring (steel wire

armoring SWA or steel tape armoring STA) and screening.

Figure 24take up


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Figure 25assembly 3000 pay off

Pay offs there are five pay offs one with a maximum diameter of 3000 mm used

with longbobbin and four with a maximum diameter 2200 mm. the big pay off is

used for armoring and the other four for assembling up to four conductors.

Maximum weight supported with pay off 3000 is 15 TON and for pay off 2200

is 8 TON.

Take ups one take which is rotating at low speed because in this machine the

lay length is highused for both the assembly and armoring operation.

Figure 26assembly 3000 take up and pay off


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The maximum weight of take up 3000 is 15 TON.

Max. Formation lay length from 300 to 3000 mm

Max. Number of armoring wireis 60 wires

The assembly Head contains the Screwaxis and two Die holders. The first die

has a diameter equal to the diameter of

the cable with an extra 2 or 3 mm and

it fixes the cable to avoid movement

during the entire assembly operation; the second die has a suitable diameter

with no tolerance to compact the cable, and to make it as much rounded as

possible.

Cage with propylene tape device. It is possible: (a) to put one tape with a

percentage of over lap, (b) to put two tapes at the same time, with over lap

between them to increase the speed of the machine and the production. The

speed of the assembly machine is determined by the RPM of that device. This

tape is added to separate the insulation from the bedding.

Assembly 2200

This machine is similar to Assembly 3000 in the technique and in the Block

diagram

Pay offs there are four pay offs one with a maximum diameter of 2200 mm and

the other sizes supported is 1600 and 1250 mm.

Take up

Fig. 5.9 Two tapes operationFigure 27 two tabes operation


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The maximum weight of take up 2200 is 10 TON.

This machine assembly two kinds of cables the power cable and the control

cable

The definition (n X C)

Where: n ... number of wires assembled C is thecross section area of

one wire

The sizes supported with this machines:

For control: 24 X 4 - 37 X 4 (two stages)

For power: 4 X 240

Max. Formation lay length from 150 to 1500 mm

Max. Number of armoring wire is 72 wires

Assembly 1600

Assembly machine 1600. It is used just for assembling and armoring (steel

wire). In the assembly operation, this machine is used just with round

conductors with small sizes, basically control cables, and made up to 24

phases.

The Machine description

Figure 28Assembly 1600 Machine


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Five Pay offs, one with a maximum diameter of 1600 mm used with long

bobbins and used for either assembling or armoring operations, and four with

the same maximum size but fixed used just for assembling Can support 630

too.

One Take up, which is rotating at a very high speed because the lay length in

this case is small, used for both the assembly and armoring operations; For

safety reasons because of the high speed, it is kept inside a cage.

Roller with four bases, to collect and

change the direction of the phases.

Two Guides with holes to guide the

conductors up to the head; it is possible to

decide which holes to use depending on the

number of phases to be assembled.

Max. Formation lay length from 50 to 550

mm

Max. Number of armoring wire is 50 wires

2.3.3 Armoring Section

5.3.1 Armoring Operation

The armoring stage is carried out to protect the

cable against any mechanical stresses like for

example ground pressure appeared over the

Figure 29Assembly hesd in Assmbly 1600 machine

Figure 30Armoring section


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underground cable when a big truck is passing over generating a pressure

force through the soil that may reach the cable.

When the cable is working under normal conditions, the current flowing

through the conductors generates a magnetic field which products current

circulating along the layer of armoring; therefore it needs to be grounded in

some point.

2.3.2.1 Types of Armoring

1) Steel tape armoring

Two types of steel tape armoring: Normal or galvanized; since the first one

can be corroded easily, the second type, although more expensive, is used

to protect the armoring against corrosion.

This type of armoring is carried out basically to protect the cable against

any horizontal mechanical stresses as explained before. Apart from that, it

can also carry the earthing fault current.

This type of armoring is done with two steel tapes by using an over gap

process: The second layer of tape is placed over the first one by 50 % over

gap of the tape width, the size of the tape is specified by its width and

thickness as follows

Tape width x Tape thickness

The next sizes are available: 15 x 0.2, 20 x 0.2, 30 x 0.2, 40 x 0.2, 40 x

0.5, 50 x 0.5, 60 x 0.5, 50 x 0.8, and 60 x 0.8. The tape width depends on

the diameter of the cable; its value is typically near the value of the

diameter of the cable; for example if the diameter is 25 mm the size of the


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tape chosen is 30 x 0.2. The tape thickness depends on the voltage of the

cable: (a) 0.2 and 0.5 are used in LV, (b) 0.5 and 0.8 are used in MV. The

values for widths and thicknesses must be according to the Standards

specifications.

2) Aluminum tape armoring and Aluminum wire armoring (not galvanized)

Aluminum is used with single core cables to avoid the magnetic field appeared

in the armoring layer; There is no magnetic field appeared in this material.

Aluminum does not allow carrying the earthing fault current because its

conductivity is very low.

3) Steel wire armoring (galvanized)

This type of armoring is carried out to protect the cable against strains, i.e.

horizontal tensions appeared along the cable, the same as for the steel tape

armoring, the wires can also carry the earthing fault current.

The operation is carried out by covering all the surface area of the cable

with wire; the called "Armoring Lay" (one period of wire moving around the

cable) can be determined as follows

Armoring lay = factor X diameter of the cable

The value of this factor is around 10 or 11, and it is calculated from several

formulas. It is important to differentiate the armoring lay from the

performing lay carried out during the stranding or the assembly operations.

2.3.2.2 Armoring machines

Armoring machine 3000 (maximum diameter of Pay off). It can be used for

armoring (steel wire or steel tape) and screening (copper wire).


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A very general description of the different parts of the machine is given as

follows:

- One Pay off and one Take up. The Pay off has a break to be able to apply

tension to the cable. The Take up has two movements: One straight to

accumulate the cable on the bobbin, and another one in rotation to make

the lay.

- One Guide to center the cable.

- Two Cages to put tape before armoring. It is used copper tape and / or

semi-conducting tape. Sometimes it is necessary to use just one type of

tape; therefore one of the two machines can be switched off. The same

technique used in the assembly operation is used here too to put the tapes.

- Big Caterpillar which needs to rotate due to the rotation of the Take up.

Two types of belts can be used in this caterpillar: Flat used with cables of

small diameter, and concave for bigger diameters.

- The Control of the machine is carried out by means of a computer. The

main parameters to be introduced are: (a) Rotation of the Pay off, left or

right, and maintaining always opposite directions for assembling and

armoring, specially in LV cables because of the use of sector conductors;

(b) for the cages, to specify whether the armoring or screening head will be

used or not, the armoring lay (right or left side), and the rotation speed.

Assembly 3000 and Assembly 2200 can use too in the Armoring

Assembly 3000 support up to 100 wires armoring; but in case of Assembly

2200 support up to 72 wires.


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2.3.4 Screening Section

Screening operation

LV cables carry typically three phases and one neutral. However, MV (multi

core) and HV (single core) cables carry just three phases, being necessary

to have an "extra" neutral to carry the fault current, short circuit current, etc;

this is done by means of the screening.

Customers determine the quantity of screening being used by specifying

the weight of screening per meter of cable or also by giving the cross-

sectional area of screening. As a result of this, it needs to be determined

the type of material used for screening: Copper wire or copper tape, being

necessary to specify the diameter in case of using copper wire, or the over

lapping in case of using tape.

Figure 31screening operation


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The maximum over lap is 48 % with higher percentages it is necessary to

use copper wire instead of copper tape, with the same technique as the one

used for armoring.

Two main benefits of using copper tape are: (a) possibility of deviating the

current (electric field) far away from the point where an existing insulation

problem may appear (impurities, etc); there is no surface area covered with

the copper wire to make the deviation (there is a distance between wires);

(b) possibility of having the earthing for the cable. The main benefit of

using copper wire is to earth the cable.

In the case of using copper wire, a new technique is being carried out to

avoid using copper tape: To decrease the diameter of the wire and increase

the number of wires. However, some customers still prefer to use copper

tape to ensure the connection.

Screening machines

There are two screening machines in the Production Area with 3000 mm of

maximum diameter for the Pay off. Both of them can be used with all kinds of

tape (cooper tape, blocking water tape, semi-conductor tape, etc). The main

difference between both machines lays just in the design of the cages. There

are two cages in each machine to allow using two different types of tapes if

necessary.


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2.4C.V. Line.

The Continuous or Cattenary Vulcanization Line (C.V. Line) is a special case in

insulation for the production Department.

The objective here is to assemble multi core cables

Drawing

Stranding

Insulation

Screening

Single coreTriple core

Bedding

Aluminum

wirearmoring

Sheathing Sheathing Sheathing Sheathing

Bedding

Steel

wirearmoring


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for Medium Voltage (3.6 kV - 33 kV),

High Voltage (66 kV - 132 kV),

and Extra High Voltage (132 kV - 220 kV), with insulation machine of cross-

linked polyethylene (XLPE)

INSULATION2.

Any cable manufactured in this section (MV, HV, and EHV) must have three

layers of insulation:

Inner semi-conductor, insulation, and outer semi-conductor.

Inner layer: Inner semi-conductor. This chemical composite is made of

XLPE45% used for insulation with a percentage of carbon 55%to give the

semi-conductivity property to the material. Carbon also gives the black color

to this material

Figure32splice box


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The use of this inner semi-conductor layer is very important. the Figure

shows this concept. If no semi-conductor is used, there would be two

different areas of contact between insulation and conductor, the called

"weak" and "strong" areas (the thickness of the insulation is thinner along

the "weak" area and "thicker" in the strong area, while the electric field is

smaller in the "weak" areas and higher in the "strong" areas). The addition of

this layer of semi-conductor has the objective of filling the gaps for the

"strong" areas and distributes the current properly along all inner part of the

insulation, removing all "weak" areas, and maintaining equal its thickness. If

no semi-conductor layer is used, the insulation may break after a few

years.

Figure shows Inner semi-conductor layer.

Another important function of this inner layer is to allow the voltage

decrease gradually from the conductor to the insulation, taking advantage

of the main property of a semi-conductor, it is neither total conductor nor

total insulation.

Middle layer: Insulation. As explained before, the only material used as

insulation in the C.V. Line is the XLPE. The main differences between both

PVC and XLPE as explained as follows

Figure33show inner semi _coductor layer


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- PVC is a thermoplastic material that can be recycled if necessary, while

XLPE is a thermo set material that can not be recycled because it would

burn if the material is overheated again. This is the main difference between

them.

- The maximum temperature that the PVC can reach before the insulation

breaks down is 70 C, while for XLPE is 90 C.

In the previous report, for the Insulation Section, it was explained the

curing process of XLPE (vulcanization) to cross-link its molecules. With

this process, the insulation material becomes stronger, and more difficult to

break.

In the C.V. Line, the curing process is made during the insulation

operation, instead of being done at the end by means of a sauna; coils

obtained from the insulation area are placed in a room with water (steam) at

60 C -70 C, and the time of this process depends on the thickness of the

insulation (it can be even up to 16 hours). The C.V. Line process can not

afford that long period of time for curing. The complete package of XLPE

(raw material) used here in the C.V. Line has internally small particles of

catalyst, while in the Insulation Section, the catalyst

is added apart.

In the C.V. Line, the process to cross-link the molecules of XLPE is made

just under one condition, the application of high temperature Max.(450 C).


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The duration of the curing process depends on the temperature, and the

heat must be applied gradually;

for example, if the material is maintained at 160 C the curing process can

take around 30 min, but if the temperature is increased up to 400 C it cantakes just 2 min, therefore, at higher temperatures the process is faster.

10V

400V


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Outer layer: Outer semi-conductor. The main function of this layer is to

protect the insulation from the screen of the cable. The copper screening

process is used for earthing the cabl

CONDUCTORS

Two situations are considered in the C.V. Line in order to put the insulation for

the conductors:

1)To insulate each core or phase separately, and after that to collect all of

them in the assembly machine; although previously making the copper

screening operation.

For MV the next conductor cross-sectional areas are considered: 50 mm2,

70 mm2, 95 mm2, 120 mm2, 150 mm2, 185 mm2, 240 mm2, and 300

mm2.

Figure 34twister


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2) To insulate one single core or phase without collecting all of them later.

For MV the next conductor cross-sectional areas are considered: 400 mm2,

500 mm2, 630 mm2, 800 mm2, 1000 mm2, and 1200 mm2.

For HV and EHV any scale can be considered.

The necessary thickness of the insulation comes with the Technical Data Sheet

(TDS) provided by the Technical Department.

2.4.1Types of C.V. Lines

The main factor to decide which type of C.V. Line use is the curing process.

During this operation, the cable can not touch any surface because of the high

temperature applied, the insulation is not solid at that time, it is almost melted,

therefore, if the insulation touches any part of the heating tubes there would

appear faults in the insulation & it needs min. 16 hours to restart.

There are three possible types of C.V. Lines depending on the position of thecable

vertical,

horizontal, and

catenaries.

All these three systems allow the cable to be exactly placed in the center of

the large tube. The vertical configuration is the best one, but it is very


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expensive and it is also necessary to use a very high structure to contain the

complete C.V. Line.

There is a problem with the catenaries configuration called "gravity sag effect",

which is not observed in the vertical configuration. In normal conditions the

high temperature of the insulation makes it going downwards and being

accumulated in the lower part forming the called "sag". To solve this problem,

the conductor does not begin in the center of the cable but in the bottom

position, so when the insulation is hot, the correction is done automatically by

the conductor going upwards being push by the insulation. This problem

happens above all in 220 kV cables because the thickness of the insulation is

larger. It is not a real problem for smaller insulation thicknesses.

Catenaries configuration can be made in different angles.

.

Catenaries C.V. Line

In general, the C.V. Line is the "same" machine as those ones seen in the L VInsulation Area, but with a different idea of operation. The insulation process

carried out in this section can be summarized as follows,

Figure 35shows gravite sag effect


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are two drums to carry out a nonstop process, one of themTherePAY OFF

is running and the other one is standing by until the first one finishes. At

that moment, the connection between conductors is made by means of a

join, as shown in Figure the first layer of the two conductors is removed,

the tube connecting the two parts is added, and finally hydraulic

compression is applied to make the proper joint.

Figure36shows conductors joint


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ACCUMULATOR

The accumulator has two poleis that allow rounding the conductor between

them seven times, with a total length of 210 m, with a distance of 50 m

between poleis. In this way, the conductor is running above the

accumulator while doing the joint operation between conductors below the

accumulator, and allowing in this way, a non stop process while changing

drums in the pay off. While doing the joint operation, the left pulley moves

to the right pulley allowing the accumulated cable to continue the process;

once the joint is finished, the left pulley goes back again. In general, not all

the 210 m of accumulated cable are necessary, for example, with a line

speed of 10 m/min, 20 min are necessary to finish with the 250 m of

accumulated conductor, so it means 20 min are necessary to carried out

the joint process, but in general, no more than 10 min are necessary,

although it is very important to have some extra time for possible

unexpected problems.

CATERPILLARS


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There are a 3 caterpillars a long the C.V. line. Their main function is to pull

the cable.

PRE-HEATER


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.

It is not a fundamental

machine for the process,

however, it is considered to

be as

a very important accessory. It

has two main uses:

a) To allow the semi-conductor be correctly attached to the surface of the

conductor. The inner semi-conductor is hot and the conductor is

cold, so those differences in temperature make the layer of material

not to distribute properly along the conductor, There are two possible

solutions: To decrease the line speed allowing the material having

more time to be attached properly, although in this case the

production can decrease considerably; or using a pre-heater, and

maintain the same speed.

b)The temperature of the cable after passing the cross head is not equally

distributed, higher temperatures are closer to the surface of the outer

semi-conductor, while the coldest ones are closer to the surface of

the conductor, with those lower temperatures being not enough high

to cure the XLPE. There are again two possible solutions:


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c) To decrease the line speed to allow having more time for heating and

curing, or using a pre-heater for a better distribution of the

temperature along the diameter ofthe cable, allowing the first layers

of the insulation receiving heat from the center to cure properly the

XLPE, see Figure

Figure73Inner semi -condudtor wrong attachment

Figure shows. Insulation. Distribution of temperature after the extrusion operation.

TRIPLE HEAD


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It is also called Cross head. There are three extrusions machines to place

the insulation of the cable: One for injecting the inner semi-conductor,

another one for the insulation, and the final one for the outer semi-

conductor. The head of the machine is triple because there are three

extrusions, as shows in the Figure these three extruders. The temperature

inside is around 120 C. The diameter of each one of the three layers placed

from each of the extrusion machines is controlled by an x-ray device

(Sikora 8800 num. 1). The operation of injecting the insulation is the same

as that one carried out with the insulation machines.


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TABLE OF MANUFACURING FIGURES


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ELECTRICAL TESTS

3.1 INTRODUCTION

Power cables can be divided into four categories depending on the voltage:

Low Voltage, up to 1kV (included),

Medium Voltage, from 1 kV to 36 kV (included),

High Voltage, from 36 kV to 170 kV (included),

Extra High Voltage, from 170 kV to 500 kV (included).

Transmission of energy is done at high voltages and low currents to decrease

losses. Voltage is generated in a power station, an immediately is stepped up

to higher voltages by means of a transformer. The transmission is made with

overhead lines (OHTL). The voltage then is step down with a transformer to

distribute the electricity, which is carried out at lower voltages and typically by

means of underground cables (UGC).

Each of them, OHTL and UGC, has advantages and disadvantages, for

example

UGC are costly compared to OHTL. The cost of manufacturing a cable can

be divided into two categories,fix and variable; fix cost is very high in UGC

because it includes digging the site, the insulation of the cable, etc, while

in general for OHTL the installation is not so expensive; variable cost,


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which includes basically the maintenance, is almost zero for UGC, but

expensive for OHTL because on the one hand it is necessary to take into

account the atmospheric pollution or humidity, and on the other hand

having a fault, for example due to birds, is much easier than in UGC.

Safety reasons. For example, it is not possible to use OHTL inside a town

or city, so it is necessary to install them preferably over large empty areas

like deserts.

War areas. One of the first and main objectives to be destroyed are OHTL,

with focus on cutting the electricity, whereas UGC are difficult to locate.

The tests carried out in the Electrical Tests Facility are summarized. Only one

mechanical test is made in this facility, the bending test. The rest of

mechanical and chemical tests are carry out in the Quality Control Lab.

3.2 TESTS CLASSIFICATION

A cable is considered to be made of insulated cores, and each different core is

made of a conductor with its insulation. The insulation is the most important

electrical layer when manufacturing cables, although there are other ones like

armoring or screening.

Tests are made in this facility to verify some properties of conductors and

insulations, in order to carry out a preventive maintenance of the material.

Tests can be classified in the next way:


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Destructive: Just one test is made over a sample, which finishes

unuseful after ending specific test. It isunthinkable to make this kind of

tests over the entire product. Flame retardant test is just one example of

destructive tests.

Non destructible: It is done over the entire product, which does not

suffer or is damaged. Typical electrical and mechanical tests are considered

here.

Another type of classification can be done as follows:

Sample Tests: A sample is taken from each different part of themanufacturing cable process. These kinds of tests begin at the starting

point of the production. If the product passes the specific test then it can

continue to the next stage of the process. The goal is to measure if the

product in each step accomplishes the customer requirements.

Routine Tests: They are made upon 100 % of the product. These kind of

tests always need to be done.

Type Tests: They are carried out just in special cases: When a new

material arrives, when new machines are purchased, or when a new

technology or design is introduced in the process; for that reason, these

tests are typically called "3M" (Material, Machine, Method). In all these

situations, it is necessary to compare the new stuff to the older one in

order to see the benefits. These kinds of tests are made over samples.

Two types of testing can be carried out depending on the material (sample or

product) properties: Electrical, and mechanical. In fact it is preferable to use


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the term "physical" properties instead of mechanical, because the chemical

properties are also included under this one. The function of each different

cable makes the decision over what type of test need to be done, electrical or

physical. In general, the function of power cables can be divided in three

stages depending on the operation voltage: Generation, transmission, and

distribution. For that reason, the most important parameters to be considered

in low voltage cables are different to those ones with medium or high voltages.

For example, the tensile strength is the most important property in OHTL, but

not in UGC.

3.3 ELECTRICAL TESTS

3.1. Low voltage cables

Two main requirements need to be accomplished in order to get a proper

voltage in buildings, factories, etc,

voltage stability, which depends basically on the government,

specified current, which depends on the cable.

It is very important to check two parameters with low voltage cables:

1) Dielectric strength of the material (insulation)

This test is carried out just one time, and no value is obtained, the result is

just to know whether the cable passes or not the test.


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The test is made between conductors, and it is done in order to verify the

capacitive effect of the insulation. Cables can be tested in two ways:

a) If there is a three-phase transformer available, it will allow directly to

energize the three conductors of the cable (terminal one), maintaining

open the conductors in terminal two, see Figure 1.

Figure 1. Low voltage tests. Dielectric strength measurement.

b)if there is no three-phase transformer available (just single-phase), tests

need to be carried out separately: Test made between conductor 1

(positive terminal of the transformer) and conductors 2 + 3 (negative

terminal of the transformer); test voltage depends on the operation

voltage of the cable, Table 1 shows an example; the other two tests are

made between conductor 2 (positive terminal of the transformer) andconductors 1 + 3 (negative terminal of the transformer), and between

conductor 3 (positive terminal of the transformer) and conductors 1 + 2


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(negative terminal of the transformer); metallic layers such as armoring

or lead need to be also treated as a conductor in order to be tested.

TABLE 1DIELECTRIC STRENGTH TEST.

Operation

voltage

Standard Test voltage Test Duration

450 / 750 V IEC 60502 2.5 kV 5 min

600 / 1000 V IEC 60227 3.5 kV 5 min

2) Electrical resistance of the conductor

If the value of the resistance increases, there will be also an increment in

the temperature of the cable, heating, and possibly over passing its melting

point as a consequence, therefore damaging the insulation.Following the IEC 60228 Standard, the DC resistance at 20 C is measured.

A correction factor is used if the measurement is taken in other conditions

of temperature.

The value of the resistance vary depending on the frequency of the current

flowing, mainly due to skin effect and proximity effect. Skin effect is caused

by the nonuniform distribution of the magnetic field caused by currents

flowing within the conductor; as the frequency of the current increases,

more current flows near the surface of the conductor, thus increasing the

effective resistance. Proximity effect is due to external magnetic fields


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generated from current in surrounding conductors. Skin effect dominates

the losses up to a certain frequency, above which proximity effect also

becomes apparent.

At 50 Hz, typical operation of cables: (i) value for resistance is quite close

to its DC resistance value, (ii) both skin and proximitty efects can be

neglected.

3.2. Medium voltage cables

Same two tests as those for low voltage, and a third one specific for medium

voltage: Partial discharges.

The partial discharge effect is a kind of ionization, similar to that one observed

with the corona effect. Since the insulation of a cable is not perfect, not totally

solid, it is possible to find very small bubbles or voids of air inside it. Figure 2

shows a layer of insulation, the voltage gradient from the conductor, and how

these small voids can lead to a very small spark.


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Figure 2. Medium voltage tests. Partial discharges measurement.

There are two mediums, insulation material and air (void), which affect the

creation of a discharge inside the void. These small discharges make the voids

increase in size, and with time the insulation fails.

Continue voltage operation, especially areas with high temperature or

overloads, makes the conductor to expand or contract. However, the

insulation does not have this property, it suffers with expansions and

contractions creating voids after some time, or expanding those existing ones.

The IEC Standard requires to verify the insulation and locate those voids that

can be dangerous in the future.

If the cable has a screening layer made of copper tape, it needs necessary to

verify the % of overlap.

3.3. High voltage cables

Same previous tests, and a fourth one specific for high voltages: Dielectric

loss angle (DLA), also called "tan ".

Figure 3 shows the meaning of this angle. At those so high operation

voltages, the insulation is not only described as a capacitive effect, but also

as a resistive effect; Figure 3a shows both couplings between two cores; it is

very important to notice that core 2 can be any metallic surface such as

conductor, armoring, screening, or lead; Figures 3b and 3c show how this

leakage current (I0) is divided in those two effects, resistive and capacitive.


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The ideal situation would be to have angle = 0, which means not to have

losses in the insulation.

Figure 3. High voltage tests. Dielectric loss angle measurement.

3.4. MECHANICAL TESTS

The only one mechanical test carried out in this facility is the bending test.

The test is made by coiling and uncoiling four times the cable around the

drum.

This test allows knowing if

1) the drum is appropriate,

2) the insulation separates from the conductor in some point,

3) new voids appear in the insulation.

6. CONCLUSIONS

Tests can be classified in different ways. For example, one classificationconsiders if the sample or product after testing is useful or not; these type of

tests are called destructive or non destructible. Another classification

considers if the test is done over a sample taken from each stage of the


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manufacturing process, or done upon 100 % of the product, or done just in

special occasions; these tests are called sample, routine and type,

respectively.

The function of each different type of cable makes the decision over what type

of tests need to be done, electrical or physical. The function of power cables

can be divided in three stages depending on the operation voltage:

Generation, transmission, and distribution.

Tests studied in this report appear in the next Standards: IEC 60270 (general),

IEC 60502-1 (low voltage), IEC 60502-2 (medium voltage), IEC 60840 (high

voltage), IEC 62067 (extra high voltage). Two different types of tests are

carried out in this facility for low voltage cables: Dielectric strength of the

insulation, and electrical resistance of the conductor. One more test is done

for medium voltages: Partial discharges; if the cable has a screening layer

made of copper tape, it needs necessary also to verify the % of overlap. One

more test is done for high voltage cables: Dielectric loss angle. Only one

mechanical test is carried out in this facility: Bending test.

In low voltage cables, see Table 1, the dielectric strength test can be done at

3.5 kV for 5 minutes as routine test, or at 2.4 kV for 4 hours as type test. The

measurement of the dielectric loss angle may be required for low voltage

cables in some special situations, being classified then as type test. Standard

IEC 60502-2 (page 47) give sequences of tests to be done, for example: 1)

Partial discharges, 2) Bending, 3) Partial discharges, 4) Tan , etc.

Special tests for special situations (marine, petroleum, etc) can be carried out

upon customer requiremen


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IEC

mm

diameter of wire

dw

mm

conductor diameter

dc

mmcable diameter after assemblydass

mmcable diameter after beddingdbed

mmcable diameter after armouringdarm

------cable diameter after sheathingdsh

mmcable diameter after insulaiondins

mm

cable diameter after screen copper

tape

dsc

mminsulaion thicknesst

mm

filling thickness

tfill

mmbedding thickness

tbed

------

sheathing thickness

tsh

------Sector copper cables------

------Sector Aluminum Cables------

------Round copper cables------

.------number of wiresNo

mm2cross section Area

A

------

coefficient

K

------mmstranding lay length

mm

Assembly lay length

------

gm

diameter ofter screen copper tape

Wsc

------

main phase

m.ph

------neutral phasen.ph

DRAWING PROCESS:-


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Sector copper cables

dw.m.ph. = 1.1281.1A/No. = mm

dw.n.ph. = 1.1281.05 A/No. = mm

Sector Aluminum Cables

dw.m.ph. = 1.1281.06A/No. = mm

dw.n.ph. = 1.1281.03A/No. = mm

Round copper cables

dw.m.ph. = 1.128A/No. = mm

dw.n.ph. = 1.128 A/No. = mm

Cu.annealing

1.1

0.5 : 1.1

0.15 : 0.40

dw(mm)

35 %

30 %

20 %

elongation

0.2 mm

0.5 : 0.2 mm

1 : 0.5 mm

>1 mmdwcopper

(+ - 0.004)(+ - 0.006)(+ - 0.01)(+ - 1%)tolerance

< 2.5 mm

>2.5 mm

dwAl(H12 H14 Alloy)

(+ - 0.025 )( + - 1%)Tolerance

STRANDING PROCESS:-


71/75


72/75

72

tfill= 0.02 x dass + 0.6 = mm

tbed= 0.02 x dass + 0.6 = mm

Tolerance

Thickness

PROCESS

(+ - 0.2) mm1 mmFILLING

( + - 0.2) mm

1.2 mmBEDDING

ARMOURING PROCESS:-

darm= dbed+ 4 x tarm = mm

Armour Tape Steel or AL

tarm

tbed

To (mm)

From (mm)

0.2 mm30--------

0.5 mm7030

0.8 mm

-------

70

Armour Wire AL or AL Alloy

darm

dbed

To (mm)

Form (mm)

0.8 mm15------

1.6 mm2515

2.0 mm

35

25

2.5 mm

60

35

3.15 mm-------60

SHEATHING PROCESS:-


73/75

73

tsh=0.035 x darm+ 1 = mm

dsh= darm+ 2 x tsh = mm

3 x 120 + 70

dass=1.31 A + 5t = 1 . 31 3 X 120 +70 + 5 X 1 . 6

= 35 . 16 mm.

tbed= 0.02 x dass + 0.6 = mm

= 0 . 02 X 35 . 16 + 0 . 6

= 1 . 3 mm

dbed = dass+ 2 tbed

= 35 . 16 + 2 X 1 . 3

= 37 . 77 mm

tarm = 0 . 5

darm = dbed+ 4 tarm = 37 . 77 + 4 X 0 . 5

= 39 . 77 mm

dsh = 0 . 035 darm + 1= 0 . 035 X 39 . 77 + 1

= 2 . 39 mm

dsh= darm+ 2 x tsh = mm


74/75

74

= 39 . 77 + 2 X 2 . 39

= 44 . 55 mm

Weight of Bedding

= 0 . 785 ( dbed2 dass2 )

= 0 . 785 X 1 . 35 ( 37 . 77 35 . 16 )

= 20 kg

Weight of Sheathing

= 0 . 785 ( dsh2 darm2 )= 0 . 785 X 1 . 53 X ( 44 . 55 39 . 77 )

= 480 kg


75/75

REFERENCES

TABLE OF FIGFigure 1:Department list tree ................................................................................................................ 1

Figure 2 copper conductors ................................................................................................................... 5

Figure 3 A.A.C ...................................................................................................................................... 5

Figure 4:A.C.S.R................................................................................................................................... 5

Figure 5:low voltage cable .................................................................................................................... 6

Figure 6 :MV cable ............................................................................................................................... 6

Figure 7 :HV cable ................................................................................................................................ 6

Figure 8 :metal section .......................................................................................................................... 8

Figure 9:Drawing machine block diagram ......................................................................................... 11

Figure 10 Dies contruction.................................................................................................................. 11

Figure 11drawing lubricata cooler ...................................................................................................... 13

Figure 12Dancer diagram ................................................................................................................... 14

Figure 13:formation of wires .............................................................................................................. 17

Figure 14:Rotating cage ...................................................................................................................... 19

Figure 15 Extrusion section ................................................................................................................ 21

Figure 16: Insulation Machine block diagram .................................................................................... 23

Figure 17:Extruaion method ............................................................................................................... 24

Figure 18:tooling of head method ....................................................................................................... 25

Figure 19:INdulation line .................................................................................................................... 25

Figure 20:assembly machine block diagram....................................................................................... 30

Figure 21pay off .................................................................................................................................. 31

Figure 22Assembly block ................................................................................................................... 31

Figure 23:taping and armoring............................................................................................................ 32

Figure 24take up ................................................................................................................................. 32

Figure 25assembly 3000 pay off ......................................................................................................... 33

Figure 26assembly 3000 take up and pay off ..................................................................................... 33

Figure 27 two tabes operation ............................................................................................................. 34

Figure 28Assembly 1600 Machine ..................................................................................................... 35

Figure 29Assembly hesd in Assmbly 1600 machine .......................................................................... 36

Figure 30Armoring section ................................................................................................................. 36

Figure 31screening operation .............................................................................................................. 40Figure 23 splice box ............................................................................................................................. 43

Figure 22 show inner semi _coductor layer ......................................................................................... 44

Figure 34twister .................................................................................................................................. 47

Figure 35shows gravite sag effect....................................................................................................... 49

Figure 2 shows conductors joint ........................................................................................................ 50

Figure 2 Inner semi -condudtor wrong attachment ............................................................................ 54
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