1. 1
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
OBJECTIVES
Live Line Work is nowadays considered a
valuable tool that makes possible to improve the
reliability in power systems avoiding production
losses associated with power interruptions, in
this paper the procedure developed for the
redesign of underground road-crossing between
33 kV towers in Wafra Oil Field, Kuwait, through
the installation of temporary overhead by-passes
working live with rubber gloves method is
presented, as clear example of the Live Line
Work benefits.
IMCO COMPANY PROFILE
Established in 1970, IMCO is a pioneer company
in the industrial Electrical & Instrumentation
fields in Kuwait. Today, it is one of the leading
engineering and construction companies in the
Oil & Gas, Petrochemical, Water & Electricity
sectors. IMCO services cover project
management, engineering, design, construction,
maintenance and project support services.
Locally some of the main clients and end users
are: Kuwait Gulf Oil Company (KGOC), Kuwait
National Petroleum Company (KNPC),
Petroleum Industries Company (PIC), Saudi
Arabian Chevron (SAC), Equate, Ministry of
Electricity and Water (MEW), plus many others.
Globally, it has proudly collaborated with Bechtel
(USA), Technip (Italy), Foster Wheeler (UK),
Black & Veatch (USA), GE (USA), Hyundai
Engineering Co. (S. Korea), plus many others.
IMCO has 15 sites, offices and service centers in
Kuwait and branches in Qatar, UAE and Irak. At
the present time it has around 3500 employees
across Arabian Gulf. It was the first local
company to take up Live Line Maintenance and
Washing Works in Kuwait and Middle East, and
it has capabilities that include:
33 kV TOWERLINE ROAD-CROSSING DESIGN MODIFICATION
Author/s: ENG. PABLO M. JURADO – ENG. JALAL MOHESEN
Company: IMCO Engineering & Construction Co.
Position: Senior Live Line Engineer – Project Manager
COMPANY INFORMATION
Address: P.O. Box 9309 Ahmadi, Kuwait
Zip Cod: 61004
Telephone: (965) 2398 1661
Fax: (965) 2398 4708
E-Mail: pjurado@imcokw.com
jmohsen@imcokw.com
KEY-WORDS: redesign - coordination –
uninterrupted production – temporary
overhead by-pass
COMPANY: IMCO Engineering & Construction Co.
COUNTRY: Kuwait
Type: Technical Paper
Kuwait, April 17th
of 2011.

2. 2
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
 Barehand Method
 Distance Method
 Rubber Gloves Method
 Washing & Cleaning
Working in Distribution and Transmission.
DEVELOPMENT
One of the main Live Line services provided by
IMCO, among several others, it is the Operation,
Maintenance and Construction of Overhead
Lines in Joint Operations (constituted by Kuwait
Gulf Oil Company and Saudi Arabian Chevron
for the operation of Wafra Oil Field, located in
the Partitioned Neutral Zone at the border
between Kuwait and Saudi Arabia).
Within the scope of this contract, IMCO
maintains 80 km of 11 and 13,8 kV networks,
400 km of 33 and 34,5 kV networks and 36 km of
115 kV transmission lines. Since Live Line Work
for maintenance and construction jobs in the oil
field was implemented, the level of production
losses, which are reflected as differed oil, due to
overhead lines failures have dramatically
decreased, nevertheless the failures in
underground cable terminations kept a high rate,
which all the way affected the reliability of the
network due to its direct link with the overhead
lines because of the type of design of the 33 kV
system.
There are in the oil field 8 main circuits en 33 kV,
which supplies 68 MW to the oil Wells that are
distributed around the field, which layout is made
of a main steel tower-line with double circuit,
from where the branch lines supported on
wooden poles are connected. These branches
are the ones that reach to the oil wells to give
them supply.
At every intersection between these main tower-
lines and the roads used for rig transportation
called “rig-roads”, the overhead line is
discontinued and there is an underground road-
crossing in place, which is made of 3 triple core
cables of 240 mm² Cu that were rigidly
connected to a busbar at the tower at each side
of the road and from these busbar the jumpers to
the overhead line were connected.
South Umm Gudair
Wafra
Humma
South Fuwaris
Mina Saud
(SAT Camp)
0 25 50 KM.
ADMINISTRATIVE
DIVISION LINE
S A U D I
A R A B I A
I R A N
I R A Q
S A U D I
A R A B I A
I R A N
I R A Q
S A U D I
A R A B I A
I R A N
I R A Q
SAUDI
ARABIA
KUWAIT
Partitioned Neutral Zone (PNZ)

3. 3
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
This configuration presented some important
difficulties like:
 Due to the rigid link, a failure in the
cables caused the shutdown of the
whole line.
 Despite there were 3 cables in each
road-crossing, the power couldn’t be
restored until the failed cable were
disconnected from the busbar, which
sometimes took several ours due to the
occurrence of the failure at unpredicted
time (during night time for example).
 Re-connection of the cables after
repairing or any other maintenance job
by means of Live Line Techniques was
complicated, because of space limitation
and lack of versatility of the structure
what hadn’t been designed considering
Live Line job.
 Application of Off-line diagnostic
techniques to determine the healthiness
of the underground cables was also
complicated.
In the presence of this situation it was decided to
implement a redesign and modification of the
underground road-crossing that allows:
 To avoid the complete shutdown
whenever a cable failure happened.
 To reduce the downtimes by doing
possible the disconnection of the cables
through the installation of switches.
 To reduce the rate of underground cable
failures by allowing performing off-line
cable testing to evaluate the condition of
the insulation.
 To ease the Live Maintenance on the
installations.
Droppers
UGC
Rigid link

4. 4
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
New design drawings
Implementation of the project using the Live
Line approach
The redesign should be implemented in 9 road-
crossings of the 4 main tower-lines, and the
challenge was to develop a procedure that
allows the modification of the system without
power interruption.
The installation of a double overhead by-pass
between the towers at each side of the road-
crossings that allowed the disconnection of the
existing cables, the construction of the structures
of the new design and latter the connection of
them to the towers, was planned.
This type of by-pass was done as a regular
procedure every time that a hot spot in the
connection point of an underground road-
crossing should be fixed, but in much lower pole
lines with road-crossings shorter than those in
the tower-lines. Previously only in one occasion
it had been performed in a tower-line, and that
experience was used as background to develop
the procedure.
Temporary by-pass between poles

5. 5
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
Some important tips to be considered were:
 Temporary road interruption and by-
pass installed indication. While
working on the installation of the
temporary span, a diversion for the
transit that were properly indicated has
to be provided, since these road-
crossings were located on heavy traffic
main roads of the oil field. In addition,
once the by-pass was installed, safe
height indicators before and after the
road-crossing had to remain installed, as
a clear indication that the maximum
height for the vehicles in that road had
been limited.
 Working height, since the upper face in
these towers is located to 21,6 m from
ground, it was necessary to use 24 m
insulated lifts.
 Task coordination, as it was decided to
employ two Live Line crews each one
working in a tower at each side of the
road-crossing, under the coordination of
one engineer who communicated with
the crew supervisors in each tower.
Then the supervisors communicated
with the linemen that worked at heights
by means of walkie-talkies.
Once addressed these issues and defined the
Live Line procedure to be used, a general
procedure for the execution of the Works in
every road-crossing was established, which
included the following main stages:
ACTIVITY IN CHARGE OF
DURATION
[Days]
Safe Height Indicators
installation
IMCO
Construction
1
Temporary overhead by-
pass installation and
removal of droppers
IMCO Live Line 4
Gantries construction
according to new design
IMCO
Construction
18
Re-installation of droppers
and temporary by-pass
removal
IMCO Live Line 4
Safe Height Indicators
removal
IMCO
Construction
1
28
That meant that the maximum height for
circulating vehicles was going to be limited
during 28 days approximately in each road-
crossing, so in order to not affect the rig
movements, the main plan for the whole project
execution was coordinate with Production
Division.
Construction of New Road Crossings in Tower Lines
Execution Schedule
Road Crossing Road
24/01/2010
31/01/2010
07/02/2010
14/02/2010
21/02/2010
28/02/2010
07/03/2010
14/03/2010
21/03/2010
28/03/2010
04/04/2010
11/04/2010
18/04/2010
25/04/2010
02/05/2010
09/05/2010
16/05/2010
23/05/2010
30/05/2010
06/06/2010
13/06/2010
20/06/2010
27/06/2010
04/07/2010
11/07/2010
18/07/2010
25/07/2010
01/08/2010
08/08/2010
15/08/2010
L3A&B/9 & 10 SAC Road 7
L2A&B/8 & 9 L2A&B/8 & 9
L5A&B/9 & 10 SAC Road 7
L1A&B/4 & 5 Road 4
L2A&B/4 & 5 Road 4
L5A&B/22 & 23 SC 13 Road
L5A&B/37 & 38 South Fawares Road 9
L5A&B/59 & 60 SC 14 Road
L2A&B/23 & 24 SC 3 Road
We consider that LL Crews will start installing the following temporary by-pass one week before Construction Crews finish their current job.
Live Line Work
Cold Construction Work
June 10 July 10 August 10Jan 10 February 10 March 10 April 10 May-10
Live Line Procedure for the Installation and
Removal of Temporary Overhead By-Pass
Once the Safe Height Indicators are installed,
the road transit is interrupted and the circulation
is diverted to the previously established
alternative way.

6. 6
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
An insulated lift is positioned in each tower at
both sides of the underground road-crossing and
the necessary hardware and insulators for
hanging the conductors of the temporary span
are installed.
Starting from the upper phase the conductor for
the temporary span is strung, and this operation
is repeated in the middle and lower phases.
Then this procedure is repeated for the
remaining circuit.
One of the crews installs an insulated jumper
between the permanent line conductor and the
temporary by-pass conductor and the other crew
checks the phase concordance before closing
the circuit by installing another insulating jumper.
After that, this last crew checks the circulation of
current by means of an amp-meter.
This procedure is repeated in both remaining
phases, after that the temporary overhead by-
pass remains closed and the droppers of the
road-crossing can be disconnected.
Insulated jumpers installed to energize
the temporary by-pass

7. 7
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
Then the existing jumpers between the main
conductor and the droppers are disconnected
one by one starting from the lower phase and
continuing towards the upper one, in order to
allow the removal of the droppers.
Once the underground road-crossing is dead,
the droppers are removed.
This operations are repeated in the opposite
circuit, after that the overhead by-pass remains
carrying out the total current of the lines and the
Live Line crews leave the site to the construction
team, which is in charge of performing the
modification Works according to the new design.
Remodeling Works in charge of construction
team
Dropper disconnection
Dropper removal

8. 8
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
Remodeling Works in charge of construction
team
Once the remodeling job is concluded, the Live
Line crews come back to the site to proceed with
the connection of the new installations and
removal of temporary by-pass.
With one crew at each side of the tower, the
droppers from the tower to the new gantries are
installed.
The droppers are connected to the gantries
busbar, having previously controlled that all
switches are open, and then the droppers are
connected to the main line.
Later one of the switches at one side of the road-
crossing is closed, and the phase concordance
is checked before closing the corresponding
switch on the other side. Then the remaining two
cables are energized in the same way.
The circulation of current through the main circuit
is checked, then the two crews working in
coordinated way in each tower, remove the
insulated jumpers to each side of the temporary
by-pass.
These steps are repeated in the remaining
circuit.
Now the conductors of the temporary by-pass
can be removed.

9. 9
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
Additional precautions must be taken for the
removal of the temporary span because of the
existence of the new gantry structures already
energized at the bottom of each tower. A rope
guided through pulleys is used for this operation
and the groundmen work using insulating gloves
to minimize the risks of any accidental contact,
when lowering the conductors of the temporary
span, with the energized equipment.
The conductors of the temporary road-crossing
are removed starting from the lower phase and
continuing towards the upper one.
Once the task is completed, the Safe Height
Indicators are removed and the road is open to
the transit again.
Especial Cases
The before described procedure was used in
most of the cases, although as previously
mentioned, the whole Project included the
remodeling of 9 road-crossings, executed along
9 months time during which different difficulties
had to be sorted by adapting the procedure to
each especial situation.
Such was the case of the road-crossings of
Lines 1 and 2 between towers 4 and 5 (L1/T4&5
– L2/T4&5), where an 11 kV line supported on
10 m poles run parallel to the road over which
the temporary span should be strung.
In this case a third insulated lift that was
positioned besides the 11 kV line to be crossed
was used. This lift was used as additional
support to avoid that the conductors of the
temporary overhead by-pass being installed
would touch the 11 kV line during the stringing.
At the same time, an insulated rope was installed
to be used as a messenger for the stringing of
the bare conductors of the temporary by-pass to
avoid that they fall over the 11 kV line.
Identical procedure was followed for the removal
of the temporary by-pass once the construction
job was finalized.
Another especial case was found at the road-
crossing in Line 2 between towers 4 and 5
(L2/T4&5) where one of the towers of the road-
crossing, the number 5, was situated at 90˚ of
the road-crossing direction, which prevented to
install the temporary by-pass for each circuit
parallel to the other as it had been done in the
general cases.
Job completed
Job completed

10. 10
COMISIÓN DE INTEGRACIÓN ENERGÉTICA REGIONAL
Then the idea arose of using the conductors of
the temporary by-pass installed before for the
road-crossing of Line 1 between towers 4 and 5,
which run along in parallel way at 10 m distance
of Line 2 according to the following drawing:
That is mean in this case, once the job in the
adjacent road-crossing was finished, the
conductors of the temporary span remained
installed and three short conductors were strung
between both towers 4 of Lines 1 and 2, and
both towers 5 of Lines 1 and 2 to build the by-
pass.
RESULTS
The Project was executed during 9 months
without any safety incidents, with a efficiency
standard and in which some troubles had to be
sorted like delays in the execution plan produced
by environmental factors, as for instance windy
days or sand storms, which are frequent in the
area in the period between April and July during
which the Works has to be stopped following the
safety recommendations, or like some changes
in the rig movement plan that required to
expedite the removal of the temporary by-pass.
Once the Project was concluded and the new
installations were on service, the reliability of
distribution system was substantially increased
due to:
 A failure in a cable terminal that before
caused a shutdown of the whole line,
with the new system working, it only
affected to the failed cable itself, keeping
the two remaining cables the power
supply to the main line (L3/T10 cable 3
case).
 In another occasion although the short-
circuit level produced the complete
shutdown of the line, the restoration time
was only 45 minutes while before it took
an average of 6 hours (L1B/T4 cable 1
case).
 A plan for condition monitoring of
underground cables by measuring
Partial Discharges and doing VLF (Very
Low Frequency) tests Off-Line could be
implemented.
The application of Live Line Work approach
for the execution of this Project, provided the
uninterrupted production of 300,000 BOPD,
which represented approximately u$s 24
million in losses for the client if they had to
shut down the lines for the execution of the
Works.
CONCLUSIONS
This technical paper shows a clear sample of
how Live Line Work can contribute to avoid
important economical losses, keeping at the
same time a high safety grade and motivating to
the people to work as a team for the
development of new procedures.