1

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 tape wire or aluminum tape wire 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
2



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 Department

Customer

Technical Department
Planning Department

Production Department
Quality Department
Final Product
Customer
1
2
3
4
5
6
3



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 specification
and 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 the
customer.

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 overall
sheath. 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
4



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)

5



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
6



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
7



Cable Manufacturing process









































Drawing
O.H.T.L. Stranding
Insulation
Assembly Bedding
Sheathing
Warehouses
Testing
Screening
Armoring
Delivery
Customer
M.V
.
L.V.
Un armoring
Cable
Armoring Cable
8



2.1 Metal Section


2.1.1 Introduction:

The metal section is the area of the production factory where the first step for
cables
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 sections
named 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
9



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 can
have 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
(.m
2
/km)
Tensile
Strength
(Kg/mm
2
)
Elongation Weight
(g/mm
2
/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.

10



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 box to 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.

13



-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: 0.5 1 %

-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
14



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.
R H
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
15



-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
Supported
Metal
Copper Aluminum Aluminum Copper Copper
Aluminum
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
16



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.
17



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
18











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 8 10
61 wires 10 12
37 wires 12 14
19 wires 14 16
7 wires 16 18
19



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 120 4 X 90 3 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
20




The stranding M/Cs classification
1- Rigid stranded M/Cs.
This M/Cs consists of:
Feeding carrier.
Rotating cage contains 6 pulley carriers.
Rotating cage contains 12 pulley carriers.
Rotating cage contains 18 pulley carriers.
Rotating cage contains 24 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
22



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/cm
3
0.92 g/cm
3
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)
23



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

24



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 tooling
T1 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
25
















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 10
mm2 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
26



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.
Materials used in this machine : PVC and XLPE
The next conductors are insulated with this machine: stranded.
Max. line speed 400 m/min
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 and
minimum 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.
Take up: two units with reel of maximum diameter of 1600 mm and
minimum diameter of 800 mm and maximum weight of 6 Ton.

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).
27



Materials used in this machine : PVC and XLPE
The next conductors are insulated with this machine: stranded.
Max. line speed 200 m/min
Spark detector is installed to verify that the insulation has no faults.
Pay off: two units with reel of maximum diameter of 2200 mm and
minimum diameter of 1000 mm and maximum weight of 10 Ton.
This machine has two caterpillars.
Take up: two units with reel of maximum diameter of 2200 mm and
minimum diameter of 1000 mm and maximum weight of 10 Ton.

NMB 150

Processes made : Insulation, bedding and sheathing
Diameter of the cable: copper or aluminum conductors from 11 mm2
(round) to 115 mm2 (sector or round).
Materials used in this machine: PVC and XLPE, low smoke material
etc.
Max. line speed 150 m/min
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
minimum diameter of 1400 mm and maximum weight of 15 Ton.
This machine has two caterpillars.
Take up: one unit with reel of maximum diameter of 3400 mm and
minimum diameter of 1400 mm and maximum weight of 15 Ton.

NMB 160

Processes made : Bedding and sheathing
28



Diameter of the cable : copper or aluminum conductors from 10 mm2
(round) to 130 mm2 (sector or round).
Materials used in this machine : PVC and recycled material (just for
bedding).
The next conductors are insulated with this machine: stranded.
Max. line speed 140 m/min
Pay off: two units with reel of maximum diameter of 3400 mm and
minimum diameter of 1200 mm and maximum weight of 15 Ton.
This machine has two caterpillars.
Take up: two units with reel of maximum diameter of 3400 mm and
minimum diameter of 1200 mm and maximum weight of 15 Ton.

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 the
cable
0.5 mm2
to 6 mm2
For cu 10 mm2
to 35 mm2
for AL 50 mm2
5 mm2
to 57 mm2
11 mm2
to 115 mm2
10 mm2
to 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




29



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.
Armoring which covered cables by (steel or aluminum) (tape or wire), to
protect the cable against mechanical stresses like for example ground
pressure
30



Lead the 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 phases
together; 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
31




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 in
armoring 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
32




Tape or Armoring Block this in real is two block the first is tape block for put
taping to the cable 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
33




Figure 25assembly 3000 pay off















Pay offs there are five pay offs one with a maximum diameter of 3000 mm used
with long bobbin 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 high used for both the assembly and armoring operation.
Figure 26assembly 3000 take up and pay off
34



The maximum weight of take up 3000 is 15 TON.
Max. Formation lay length from 300 to 3000 mm
Max. Number of armoring wire is 60 wires

The assembly Head contains the Screw
axis 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 operation
Figure 27 two tabes operation
35



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 the cross 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


36




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
37



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
38



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).
39



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.


40



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
41



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.




42



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 core
Triple core
Bedding
Aluminum
wire
armoring
Sheathing Sheathing Sheathing Sheathing

Bedding
Steel
wire
armoring
43



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)
INSULATION 2.
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

Figure 32 splice box
44



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
Figure 33 show inner semi _coductor layer
45




- 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).
46



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 can
takes just 2 min, therefore, at higher temperatures the process is faster.








I
I






10V
400V



















47



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
48




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 the
cable

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
49



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 V
Insulation 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
50



are two drums to carry out a nonstop process, one of them There PAY 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.



Figure 36 shows conductors joint


51



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









52




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

























53



.


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:

54



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 of the cable, allowing the first layers
of the insulation receiving heat from the center to cure properly the
XLPE, see Figure

Figure 73 Inner semi -condudtor wrong attachment








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

TRIPLE HEAD





55



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.


















56



TABLE OF MANUFACURING FIGURES









































57











58




59



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,
60



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:
61



Destructive: Just one test is made over a sample, which finishes
unuseful after ending specific test. It is unthinkable 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 the
manufacturing 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
62



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.
63



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) and
conductors 1 + 3 (negative terminal of the transformer), and between
conductor 3 (positive terminal of the transformer) and conductors 1 + 2
64



(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 1 DIELECTRIC 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
65



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.







66





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.
67



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 classification
considers 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
68



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
69



IEC



mm diameter of wire d
w
mm conductor diameter d
c
mm cable diameter after assembly d
ass
mm cable diameter after bedding d
bed
mm cable diameter after armouring d
arm
------ cable diameter after sheathing d
sh
mm cable diameter after insulaion d
ins
mm cable diameter after screen copper
tape
d
sc
mm insulaion thickness t
mm filling thickness t
fill
mm bedding thickness t
bed
------ sheathing thickness t
sh
------ Sector copper cables ------
------ Sector Aluminum Cables ------
------ Round copper cables ------
------ number of wires No.
mm
2
cross section Area A
------ coefficient K
mm stranding lay length ------
mm Assembly lay length ------
gm diameter ofter screen copper tape W
sc
------ main phase m.ph
------ neutral phase n.ph

DRAWING PROCESS:-
70



Sector copper cables

d
w.m.ph.
= 1.1281.1A/No. = mm
d
w.n.ph.
= 1.1281.05 A/No. = mm

Sector Aluminum Cables

d
w.m.ph.
= 1.1281.06A/No. = mm
d
w.n.ph.
= 1.1281.03A/No. = mm

Round copper cables

d
w.m.ph.
= 1.128 A/No. = mm
d
w.n.ph.
= 1.128 A/No. = mm

Cu.annealing

1.1 0.5 : 1.1 0.15 : 0.40 d
w
(mm)
35 % 30 % 20 % elongation

0.2 mm 0.5 : 0.2 mm 1 : 0.5 mm >1 mm d
w
copper
(+ - 0.004) (+ - 0.006) (+ - 0.01) (+ - 1%) tolerance

< 2.5 mm >2.5 mm d
w
Al(H12 H14 Alloy)
(+ - 0.025 ) ( + - 1%) Tolerance






STRANDING PROCESS:-
71



d
c
= K x d
w
= mm

61 37 19 7 No.
9 7 5 3 K

Stranding lay length for sector cables
AL = 28 : 30 x d
ass
= mm
CU = 30 : 35 x d
ass
= mm

Stranding lay length for round cables

= 18 : 20 x d
ass
= mm
ASSEMBLY PROCESS:-

Diameter of Round cables d
ass
= K x d
c
= mm

Diameter of Sector cables d
ass
=1.31 A + 5t = mm

ASSEMBLY lay length for Round cables =
18 :20 x d
ass
= mm

ASSEMBLY lay length for Sector (AL) cables =
28 :30 x d
ass
= mm

ASSEMBLY lay length for Sector (CU) cables =
30 :35 x d
ass
= mm

SCREENNING PROCESS:-
d
sc
= d
ins
+ 4 t
sc
= mm

w
sc
= (2.8 x d
c
) / (1 over lap %) = gm / mt

FILLING AND BEDDING PROCESS:-
72




t
fill
= 0.02 x d
ass
+ 0.6 = mm

t
bed
= 0.02 x d
ass
+ 0.6 = mm

Tolerance Thickness PROCESS
(+ - 0.2) mm 1 mm FILLING
( + - 0.2) mm 1.2 mm BEDDING


ARMOURING PROCESS:-

d
arm
= d
bed
+ 4 x t
arm
= mm

Armour Tape Steel or AL

t
arm
t
bed

To (mm) From (mm)
0.2 mm 30 --------
0.5 mm 70 30
0.8 mm ------- 70

Armour Wire AL or AL Alloy

d
arm
d
bed
To (mm) Form (mm)
0.8 mm 15 ------
1.6 mm 25 15
2.0 mm 35 25
2.5 mm 60 35
3.15 mm ------- 60

SHEATHING PROCESS:-
73




t
sh
=0.035 x d
arm
+ 1 = mm

d
sh
= d
arm
+ 2 x t
sh
= mm


3 x 120 + 70

d
ass
=1.31 A + 5t
= 1 . 31 3 X 120 +70 + 5 X 1 . 6
= 35 . 16 mm.

t
bed
= 0.02 x d
ass
+ 0.6 = mm

= 0 . 02 X 35 . 16 + 0 . 6
= 1 . 3 mm

d
bed
= d
ass
+ 2 t
bed


= 35 . 16 + 2 X 1 . 3
= 37 . 77 mm

t
arm
= 0 . 5


d
arm
= d
bed
+ 4 t
arm

= 37 . 77 + 4 X 0 . 5
= 39 . 77 mm


d
sh
= 0 . 035 d
arm
+ 1
= 0 . 035 X 39 . 77 + 1
= 2 . 39 mm
d
sh
= d
arm
+ 2 x t
sh
= mm
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



REFERENCES
TABLE OF FIG
Figure 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 .............................................................................................................. 40
Figure 23 splice box ............................................................................................................................. 43
Figure 22 show inner semi _coductor layer ......................................................................................... 44
Figure 34twister .................................................................................................................................. 47
Figure 35shows gravite sag effect....................................................................................................... 49
Figure 23 shows conductors joint ........................................................................................................ 50
Figure 23 Inner semi -condudtor wrong attachment ............................................................................ 54

REFERENCES
ENERGYA CABLES