CABLE DE GARDE A FIBRES OPTIQUES (OPGW) BASE SUR LE CONDUCTEUR AL-59

OPGW BASED ON AL-59

Abrégé anglais

The invention is based on manufacturing OPGW conductor by using AL-59
including wires,
tubes and every metal in the OPGW, That means the OPGW according to our
invention consists
of a conductor made of aluminum alloy type AL-59 with no other type of metals.

Revendications

Claims
I claim:
1. An OPGW comprising a plurality of wires and a tube, at least one of said
wires
manufactured solely from AL-59.
2. An OPGW comprising a plurality of wires and a tube, said tube manufactured
solely
from AL-59.
3. An OPGW comprising a plurality of wires and a tube, at least one of said
wires or said
tube manufactured solely from AL-59.

Description

CA 02735305 2012-08-07
OPGW Based on AL-59
Field of the invention
[0001] The invention is related to type of metal to be used in overhead power
electrical line
ground wires when used as optical fiber cables.
Back ground of the Invention
[0002] Conventional Optical Power Ground Wires (OPGWs)
[0003] OPGW manufactured by all companies in the past were made of aluminum
clad steel
wires with the fibers inserted in a tube made of steel and cladded with
aluminum. The tubes
are usually placed in the first or second layer. But recently such tubes are
made of
aluminum and many companies place such tubes in the center of the cable to be
far from
lightening effects which might damage the fibers inside the tube.
[0004] Problems with Aluminum and ACSR OPGW:
[0005] The problems with aluminum clad steel wires or aluminum conductor steel
reinforced
(ACSR) of OPGW are: corrosion and mechanical damage by wind-induced movement.
If the
tube is made steel or steel covered with aluminum, then its resistance is high-
In case such
overhead lines are subjected to lightening, then such high resistance will
cause the tube to
go to a very high temperature which might damage the fibers. If these tubes
are made of
aluminum, then high winds which might cause the conductors to vibrate so much
that the
aluminum tubes might get damaged.
[0006] OPGW-Dorking:
[0007] For conventional OPGW based on Dorking conductor withAluminum central
tube
andaluminum clad steel wires, then we shall get the following specifications:
[0008] Centralised aluminum tube with inner diameter- 4 mm
[0009] Outer diameter : 8 mm
[00010] With ten round wires made of steel and cladded with aluminum of 3.5
mm.
[00011] Total diameter 15.00 mm and total area of 133.9 mm2.
[00012] Weight: 671 kg/km.
[00013] Rated Tensile strength (RTS): 89.5 KN.

CA 02735305 2012-08-07
[00014] Final temperature of + 200 "C.
[00015] DC Resistance: 0.329 Ohm.km (at 20'C).
Summary of the Invention:
[00016] The type of OPGW according to the invention is based not on aluminum
norsteel
but on AL-59 Alloy according to Swedish Standard SS4240813 Wires and SS4240814
Conductor. AL-59 means that the conductivity of the aluminum alloy is equal to
59% of
copper conductivity at 25 C.
[00017] Advantages in General:
[00018] Much less susceptible to corrosion even without greasing which is
usually
used inACSR.
[00019] Lower resistance and better current rating.
[00020] Easier handling and transportation.
[00021] Higher surface hardness.
[00022] As for tensions and sags, they are limited by the towers and not by
conductors-
Brief description of the Figure:
(00023] Figure 1is a cross section of aconductor used as an OPGW according to
the
invention.
Detail description of the Invention
[00024] The invention is applicable to all sizes of conductors, but we shall
apply it to
Dorking as an example.
[00025] The conductor shown in Figure lincludes a tube with inner radius of
2.0 mm,
outer radius of 4,0 mm and 10 outer conductors each of 1.75 mm radius. The
type of metal
used in all these wires and tube is AL-59.
[00026] In all OPGWs used as earth wires in overhead electrical high voltage
transmission lines, the metal used is to be type AL-59 Alloy according to
Swedish Standard
554240813 Wires and 554240814 Conductor. The reference 59 means that the
conductivity
of this alloy is equal to 59% of the conductivity of copper at 25 C.

CA 02735305 2012-08-07
[00027] Also the IEC Committee TC7 and working group MT1 issued standard IEC
60104 based on AL-59to be used as a metal for overhead transmission line
conductors.
[00028] If our invention is used for Dorking type OPGW, then we shall have the
following specification:
[00029) Centralised tube which is made of AL-59 with inner diameter : 4 mmand
outer diameter: 8 mm.
[00030] With ten round wires each of 3. 5 mm diameter made also made of AL-59.
[00031] Total cross section area: 133.9 mm2.
[00032] Total diameter of the OPGW : approximately: 15 mm, as can be seen in
Figure
1.
[00033] Weight: 369 kg/km.
[00034] Rated Tensile Strength(RTS): 80.2 KN .