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ELECTRICAL DEPARTMENT
1 27.4.2007 ISUUED FOR ENQUIRY KAG MZ MZ 0 27.4.2007 ISUUED FOR
ENQUIRY KAG MZ MZ
REV DATE DESCRIPTION PRPD CHKD APPRD
FACT ENGINEERING AND DESIGN ORGANISATION
1.0.0 INTRODUCTION
1.1.0 This specification covers the requirements of cathodic
protection work for the proposed LPG pipeline (total length of
3.5km ( approx)) from inside BPCL- KR premises to HPCL LPG plant
installation at Irimpanam. This document shall be read in
conjunction with engineering specifications, data sheets, drawings,
etc attached with the piping section of the tender document. The
cathodic protection for the entire length of pipelines is under the
scope of this tender.
1.2.0 The bidders should visit site and acquaint themselves with
site conditions and existing cathodic protection works carried out
in neighborhood for similar lines, before quoting. They are also
expected to contact all concerned agencies like GCDA, Cochin
Corporation, PWD, Railways, KWA, IOCL, BPCL, HPCL , State
Electricity Board, Civil Authorities, etc who are associated with
the proposed pipeline route and familiarise themselves with the
necessary formalities. Comments if any from CECRI, SCIENTIFIC &
INDUSTRIAL LIAISON EXTENSION UNIT (SILEU), Karaikudi on the
enclosed specifications for cathodic protection shall be furnished
with the bid.
1.3.0 For details like pipeline data, wrapping and coating data,
route envisaged, refer piping section of the tender document. As
the cathodic protection of the whole length of the pipeline is
covered under the scope of this tender, it is the responsibility of
the CP contractor to coordinate with both the pipe line
installation contractor(s) and install the impressed current
cathodic protection system for the whole pipeline to the
satisfaction of the client/ consultant.
1.4.0 415V, 50 Hz, TPN, AC power supply will be made available
by the Purchaser at the HPCL Irimpanam end. If power supply is
required at any other point, it shall be availed from KSEB.
Availing of the power supply in the name of HPCL shall be in the
scope of the vendor. All liaison work for the same shall be done by
the vendor. All statutory fees paid for obtaining power supply
sanction will be reimbursed by HPCL on submitting proof. Necessary
isolator with box, metering box with sealing facility, fuse and
neutral link etc, supply of cable and cabling from metering box to
isolator and isolator to T/R unit shall be provided by the vendor.
Required mounting pedestal/ frame, weatherproof enclosure for
metering box and isolator for the power receiving structure shall
also be provided. Proper earthing with required earth pits and
copper earth conductors etc. shall be done.
1.6.0 SCOPE OF WORK:
This specification together with the applicable project
specifications shall govern the design engineering, supply,
installation, testing and commissioning of a permanent impressed
current cathodic protection system to protect the external surface
of the pipeline over the entire envisaged life span (30 years) of
the project, including potential logging survey over the entire
length of the pipeline. The bidders scope shall include engaging
CECRI, SCIENTIFIC & INDUSTRIAL LIAISON EXTENSION UNIT (SILEU),
Karaikudi for site survey, soil analysis, optimum design, preparing
bill of material, providing guidelines for selection, installation,
testing and appraisal of the installation, etc. All instruments
required for soil survey shall be arranged by the bidder/
CECRI.
In case CECRI is not engaged in site survey, design /
engineering, the same shall be done by the contractor and got
verified / certified by CECRI (third party approval)
2.0.0 GENERAL (CP SYSTEM):
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
The Pipeline shall be cathodically protected by Impressed
current cathodic protection system. The cathodic protection station
shall be located at the HPCL at Irimpanam. The cathodically
protected section of the pipeline will be electrically isolated by
use of Insulating Joints, supplied and installed by the Piping
Contractor. Anode Bed shall be provided at suitable locations
depending on the site conditions. However one no. anode bed shall
be located at the HPCL Irimpanam.
The proposed LPG line is to be laid in close proximity (500mm
away) of an 24 inch naphtha line which is also cathodically
protected by impress current system. Hence effect of this 24 inch
line shall also taken into consideration while designing
/installing the cathodic protection system for the LPG line. Vendor
shall take/incorporate suitable measures in the CP system of the
LPG line to mitigate the interference and other effects from the
other lines in the route.
The transformer Rectifier units shall be the source of power for
the ICCP system. The output of T/R unit shall be automatically
varied to achieve the set pipeline to soil potential. Suitable
measures as per international practice shall be taken to mitigate
any interference current and cross currents from any source.
Special protection shall be provided at cased-crossing
(Road-crossing) (Rail crossing). etc.
Surge protection shall be provided for cathodic protection
system
Corrosion proof epoxy painting shall be provided for all support
structures
3.0.0 CODES AND STANDARDS
3.1.0 The design and the installation shall be in accordance
with the international codes and standards, and accepted
engineering practices and must also conform to the local statutory
regulations.
3.2.0 The following international codes and standards shall be
considered as minimum requirements.
Latest version of applicable publication shall be followed;
a) BS specifications and codes of practice b) ANSI
specifications c) XFPA Publications d) XACE Publications e) JEC
publications f) Indian Standards g) OISD Standards h) NACE
RP-01-69
In case of conflicting requirements amongst any of the above
standards, the publication having stringent requirement shall be
governing.
3.3.0 In case of any deviation/conflict of this specification
with the codes and standards, the provisions of this specification
shall be over-riding.
4.0.0 SURVEY:
4.1.0 Resistivity Measurement & Calculations:
To carry out the work of soil resistivity measurement winners 4
pin method shall be used.
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
Care should be taken that measurements are not influenced by
presence of overhead lines over earth shall be made at least 15m
away from underground metallic structures if any such exist along
ROW or anode ground bed locations. The depth of insertion of each
pin while measuring resistivity shall be 1/20th of the pin
spacing.
Soil resistivity shall be computed by the following
relation:
P - 2piar
Where P - Average Resistivity of soil at a depth of a metre in
ohm-metre a - Spacing between two consecutive pins in metres r -
Resistance in ohm displayed by Megger.
4.1.1 Soil Resistivity measurement along ROW
Generally the observation shall be made enclosing the soils
immediately surrounding the pipeline route between the Central
electrodes where right of way has been cleared.
At places where right of way has not yet been cleared
measurements shall be made right over the defined locations to
account for cuttings filling also. All measurements shall be taken
at right angles to ROW unless otherwise asked for by ENGINEER at
site.
Each spot shall be investigated so as to obtain average soil
resistivity upto the following depths:
0.5, 1.5, 3.0 & 6.0 Metres
All the river Creeks and other major water crossing/marshy
lands, swamps, for resistivity/observations should be so chosen so
as to obtain resistivity of the soil at river/creek beds or marsh
lands. Wherever possible depth of water table shall be determined
by available open wells when such facility is available near right
of way.
CONTRACTOR has to provide necessary facilities for such
measurements.
4.1.2 Soil Resistivity Measurement on Anode Ground Bed.
After completion of soil resistivity survey along ROW and
preparation of soil resistivity plot (Resistivity contour), based
on the resistivity values, the anode ground bed plots shall be
selected in consultation with and as directed by the ENGINEER for
the C.P. station. One no. anode ground bed shall be located at a
suitable location at the HPCL in Irimpanam/ as directed by the
Engineer in Charge.
The anode ground bed plot shall then be subdivided into three
subplots each of which shall then be investigated for resistivity
measurement at the following spacings:
1, 2, 3, 4, 5, 6 to 10 Metres.
Thus the anode ground bed subplot will have a set of seven
observations at an average with a view to determine the nature of
soil level and soil stratification and also possible water table
depth.
4.1.2.1 Soil Resistivity Survey Instrument:
Nomenclature ; Battery Powered solid state 500 volts 5 terminal
Earth Megger
Range : 0-0.1, 0-1, 0-10, 0-100 ohms.
Accuracy : Within +/- 1% of maximum value of selected range.
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
Sensitivity: Two position switch for low and high balance
sensitivity shall be prepared
Instrument should incorporate design features for max. A.C.
& D.C.ground current rejections.
Temp. Range : 0-60C fully temperature stabilized
Circuitry: Solid state suitable for rough and rugged use.
Suitable for 2,3 & 4 Pin application.
Power : Replaceable/Rechargeable battery
4.1.3 Test on SOIL Samples:
To determine the presence of anaerobic bacteria, PH of soil
samples is to be measured at selected location to be decided by
ENGINEER. If PH values indicated need further investigation, then
Redox-Probe observations may also have to be followed. Provision to
carry out both these tests are to be made by CONTRACTOR. If need be
chemical analysis of soils for determining concentration of various
cations and anions shall also be carried out. No. of locations
along ROW on which soil tests are to be made will be decided by
ENGINEER from time to time as work progresses.
4.2.0 REPORT:
Each set of observations made at spot at field shall be recorded
in metric units and shall be made into four copies. The original is
to be assigned to ENGINEER duly certified by OBSERVER.
All the resistivity observations collected thus during survey
along with ROW shall be plotted to give resistivity Contours. Each
set of observations recorded at individual spot shall be shown in
the plot. Besides marking the points of diversion of ROWs on the
plot, creek, railway, road and overhead line crossing,
topographical information shall be entered in the resistivity
contour. Such finished resistivity contour along ROW shall be
produced for ENGINEERS approval.
ln addition, the CONTRACTOR shall compile all the resistivity
observations taken along ROW and on Anode Ground bed locations and
submit to the ENGINEER for record.
5.0.0 PROTECTION CRITERIA
a) Minimum protective potential from pipe-to-soil shall be
considered as 0.95V. b) Maximum protective potential shall be shall
be considered as 1.5V. c) All these potential values mentioned in
item (a) & (b) are with respect to copper-
copper Sulphate reference cell.
d) Minimum protective potential from pipe-to-electrolyte shall
be considered 0.9V e) Maximum protective potential from
pipes-to-electrolyte shall be considered
1.10V. f) All these potential values mentioned in item (d) &
(e) are with respect to silver-
silver chloride reference cell.
g) Alternatively, a minimum potential swing of 300 mV on the
protected structure shall be the guiding criteria to establish that
subject pipeline is protected. Maximum protective potential swing
in such cases shall be decided on merits.
h) A potential swing of 20mV shall be considered the design
criteria for presence of a interaction situation requiring
investigation and incorporation of mitigation measures.
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ELECTRICAL DEPARTMENT
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FACT ENGINEERING AND DESIGN ORGANISATION
5.1.0 ELECTRICAL ISOLATION
5.1.1 Insulating joints are provided at the following point of
pipeline (see pipeline specification also)
1. At BPCL-KR 2. At HPCL IRIMPANAM
6.0.0 DESIGN GUIDELINES & C.P. SYSTEM DESCRIPTION:
6.1.0 Each cathodic protection station (C.P. Station) for
impressed Current (I.C.) System shall essentially consist of but
not limited to the following:
A very reliable D.C.Power source, anode ground bed, arrangement
for measuring pipe to soil potentials, associated anode and cathode
cabling, anode junction boxes. Installation shall be designed for
unattended operation and shall have in built provision for bonding
to other lines laid in the same ROW.
6.1.1 The carriers in the cased crossings with end seals would
be protected by Zn-sacrificial anodes if the possibility of water
accumulation exists. The anodes would in that case be in the form
of ribbon or arc shaped rod and would be welded to the carrier pipe
by thermite welding as close to the carrier pipe as practically
possible. The length of the ribbon anode would be equal to the
length of the carrier pipe inside the casing and anodes will be
mounted over the circumference in such a way that it is distributed
equally at 120 angle between them.
6.1.2 The external of casings would be coated in the same manner
like carrier pipes and also provided with zinc anodes on both sides
of the pipe. The minimum weight of zinc would be decided by
ENGINEER.
6.1.3 For providing such zinc anodes the pipe laying and
cathodic protection agency would co-ordinate with each other.
6.1.4 As part of corrosion survey full particulars regarding
secondary structure including power cables, communication lines,
electrical railway tracks etc. which would adversely influence the
system or would be influenced by the system must be collected. The
engineering of cathodic protection system would incorporate
suitable mitigation measures. In any case all the lines in common
ROW or pipelines would be bonded together through test
stations.
6.1.5 As part of cathodic protection monitoring, potential
measuring devices would be installed at all test stations. The test
station would also provide the flexibility for connecting and
disconnecting sacrificial anodes. Some of the test stations having
potential measuring terminals shall also have terminal facilities
for measuring line currents.
6.2.0 ANODES AND ANODE GROUND BED
Anode ground bed shall be located near each C.P. station and
shall be laid in low resistivity solid strata. The quantity of C.P.
station shall be decided based on actual resistivity survey.
However one no. anode bed complete with T/R unit etc. is proposed
to be located at the HPCL. The final sizing of ground bed will be
subject to ENGINEERs approval. Canistered anodes with anode lead
cables shall be laid at 1 1.5m depth in horizontal configuration.
General laying arrangement, spacing between two consecutive anodes
etc. shall conform to the respective standards. Sizing of ground
bed at each C.P. station shall be such that its total resistance to
remote earth does not exceed 0.5 ohm inclusive of anode lead cables
resistance. Each anode ground bed shall be located at a minimum
distance of 100 metres from and at right angles to the
pipelines.
6.3.0 TEST STATIONS
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ELECTRICAL DEPARTMENT
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FACT ENGINEERING AND DESIGN ORGANISATION
6.3.1 Test station along the trunk line shall be provided along
the ROW for monitoring the performance of cathodic protection
system and bonding of pipelines in common pipe trench or ROW at
intervals not exceeding 500 metres. However at backwater crossings
the test stations may be provided at the start and end points only
even if the crossing is more than 500m in length.
Some of these test stations shall have, besides pipe-to-soil
potential measurement and bonding facilities, four terminal
facilities for line current measurement.
In addition measurement station shall also be provided at
following locations:
a) At both sides of major water, road and rail cased
crossings.
b) At all insulating joints. The test station shall have
terminal facility for connection of grounding cell to pipeline.
Besides terminals shall also be provided for pipe-to-soil potential
measurement on both shoulders of joint.
c) At crossing of AC/DC electric traction system.
d) At vulnerable location with drastic change in soil
resistivity.
e) At HT overhead line crossings and selected locations where HT
line passes close to pipeline.
f) In vicinity of DC networks or grounding system where
interference problem are suspected.
g) At valve location.
h) At crossing of other foreign pipelines (bonding facility with
resistor shall be provided).
Additional test station described above, many of which shall
fall intermediate between potential test-cum-bond stations shall
have binding facilities. It is quite likely that some of these
additional test station mentioned above may coincide with those
test stations located at 500 metres interval.
Test station at location of insulating joints shall preferably
be installed independently.
Details of terminal facilities and connection schemes for
individual type of test station/current measuring
station/test-cum-bond station shall be as per relevant
standards.
6.3.2 The location of all the test station shall be marked with
their connection schemes and other relevant information on
alignment sheets as a part of detailed engineering. A test station
schedule shall also be prepared.
6.3.3 Potential test-cum-bond station provided at 500m interval
as a means to bond, monitor and control current flow in structures
laid in common ROW/trench. These potential test-cum-bond station
shall allow detection and mitigation of any interference on foreign
structures that may result from operation of this C.P. System.
6.4.0 REFERENCE ELECTRODES
6.4.1 High purity copper/copper Sulphate silver/silver chloride
reference electrodes shall be used to provide stable potential
measurement references.
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ELECTRICAL DEPARTMENT
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FACT ENGINEERING AND DESIGN ORGANISATION
6.4.2 For each automatically controlled cathodic protection
system, monitoring reference electrode shall be supervised by a
duplicate electrode in its close vicinity in an approved
location.
6.4.3 Such duplicate electrodes shall be provided to guard
against reference cell failure possibilities in an unattended
automatic system. Facilities shall be provided to reject spurious
signals during open or short circuiting of monitoring point.
Reference electrodes shall be provided to:
i) Obtain the most reliable indication of the protection and
system behavior. ii) Ascertain the effectiveness of each C.P.
station and control their output.
6.4.4 CONTRACTOR to provide 30% spare reference electrode
complete with accessories. Number and type of electrodes to be
supplied by CONTRACTOR shall be clearly indicated in his BID.
EQUIPMENT SPECIFICATIONS
7.1.0 TRANSFORMER RECTIFIER UNIT
7.1.1 Transformer The T/R unit shall be air cooled weather proof
to IP 55, with Auto /Manual control. The transformers will be the
isolation type having separate primary and secondary windings. And
electrostatic shield composed of heavy copper foil, shall be placed
between the two windings and ground bed to the rectifier. The
transformer core and windings shall be dipped in insulating
materials Thermosetting Epoxy Resin to withstand 2,000 volts (RMS
value at 50 Hz) applied for one minute between the windings and
between each winding and the transformer core. Magnet wire
insulation and transformer interlayer insulation shall be class H
type rated at no less than 180 degrees C. Actual temperature rise
shall not exceed 85 degrees C at rated conditions.
Transformer regulation will not exceed 3% from full load at
rated load. Transformer full load efficiency shall not be less than
95%. Derating factor of transformer shall be 20% excess current.
For other details refer data sheet attached.
7.1.2. Diodes/SCRs will be of silicon type and moisture
resistance giving full wave rectification. Adequate filtering
circuit shall be provided on output side to smoothen the DC output.
The input and output side shall be provided with RC circuit of
suitable capacity across each diode/SCR to protect against voltage
surges. The RC circuit shall be designed to such a manner that
voltage across the device is less than peak inverse voltage (PIV)
of diodes/SCRs at peak surge voltage. The normal output current
rating of diodes/ SCRs shall be twice the current output rating of
T/R unit and PIV shall be 1.2kV (min.). Sinks of sufficient size to
be used to prevent the core temperature from exceeding 100C at
rated ambient temperature.
7.1.3 A.C.Input Rating
The T/R Unit shall operate at 230V10%/ 415V+/-10% 50 Hz input
power.
7.1.4 D.C.Output Adjustment
7.1.4.1 Manual Mode
Suitable tappings shall be provided in the primary side of T/R
unit so that DC output voltage is obtained in voltage steps from 0
to 50V. Alternately a separate auto transformer can be provided so
that primary input voltage can be varied to achieve 0 to 50V
voltage control on D.C. output side.
7.1.4.2 Automode
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
Automatic potential control (APC) shall be accomplished by a
separate controller. The controller shall be capable of maintaining
a desired (set) structure to reference cell potential of +0.5 to
2.5V. The APC controller shall adjust the output voltage and
current to maintain protective potential on the pipeline. The
manual and automatic modes shall be capable of operating completely
independent of each other.
7.1.5 Electronic Controllers
The SCRs of the transformer rectifier shall be controlled by
commands from electronic circuit cards. These cards shall be the
plug in type printed circuit cards mounted on the front panel of
the rectifier for easy field replacement.
The printed circuit card contact pads will be gold plated to
provide easy conduction and to eliminate contact corrosion.
Completed printed circuit and controllers will be sealed with a
circuit card sealant to prevent atmospheric corrosion and fungus
contamination.
7.1.6 Reference Cell Selector Circuit and Control
A circuit shall be used which will accept three (3) reference
cell input. This circuit will automatically accept the reference
with the lowest potential above a pre-selected value higher than
the native potential of steel. This limit will minimize the
possibility of a rectifier utilizing an erroneous reference
electrode signal which could cause over protection to the pipeline.
Switches shall be provided to measure the potential of each
reference cell used and to allow manual selection of the reference
cell to be used.
7.1.7 Separate Drainage Control
Provision shall exist to individually drain each protected
structure and have both auto and manual mode available on each
drain.
7.1.8 Output Ripple The output ripple shall be less than 5% at
rated output voltage and current.
7.1.9 Input Overload Protection
Protection from overloads on the input will be provided by
moulded case, magnetic circuit breakers on the input side. These
circuit breakers will hold a 100% of rated load. They may trip
between 101% to 125% of the rated load and must trip at 125% and
above. The trip point will be unaffected by ambient temperature.
Circuit breakers will be manually reset type. The trip handles of
individual pole circuit breakers will be mechanically linked so all
lines are opened when an overload occurs. HRC fuse of suitable
rating to be provided as back-up to input breaker.
7.1.10 Output Over load Protection
Protection from overloads on the output will be provided by an
electronic current limiting feature. The transformer rectifier will
be capable of indefinitely sustaining a short circuit across the
output and will respond quickly enough to prevent damage to any
part of the circuit. This shall include any overload to T/R unit
and overprotection to pipe/structures due to reference cell
failures also.
7.1.11 Sun/Rain Shade
Sun/Rain shade to be used of 1m length using 10 SWG M.S. sheet
protruded all around of 2m protrusion 0.5m shall be at 45
angle.
7.1.12 Mounting
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ELECTRICAL DEPARTMENT
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FACT ENGINEERING AND DESIGN ORGANISATION
The T/R unit at HPCL end shall be located in substation
building. Incoming cabling to TR unit (for power supply)shall be
arranged by the purchaser.
7.1.13 Housing
T/R units shall be suitable for outdoor installation.
7.1.14 Annunciation
Arrangement shall be provided for giving visual indication of
but not limited to the followings:
i. Loss of power supply ii. Actuation of any protective device
iii. Failure of auto mode iv. Fault on cable on Primary and
Secondary circuit v. Under voltage and over voltage on supply
side.
7.1.15 Testing and Inspection
Each unit shall be inspected and tested in the manufacturers
shop. The results will be recorded and submitted. Inspection shall
include but not limited to the following:
i. Mechanical: Wiring connections, panel components, doors,
latches, hinges, finish, appearance.
ii. Electrical: Read and record A.C.volts input, DC ampere
output, dielectric strength, ripple voltage at rated output and
current limiting test. In addition, a temperature rise test on the
transformer windings and diodes/SCR and full load efficiency test
shall be conducted after the unit has been operated at full load
for 24 hours.
7.1.16 Facility shall be provided for continuous remote
monitoring of healthiness of cathodic protection system like DC
voltage (4-20mAoutput), DC current (4-20mA output), reference (PSP)
voltage (4-20mA output, and required potential free contacts for
alarm for under protection, over protection & all reference
electrode failure. The purchaser shall do required cabling from TR
unit to DCS.
7.1.17 Facility shall also be provided for current interruption
test to be conducted on the pipeline for measuring of potential.
The current interrupter test kit shall be the part of TR unit with
adjustable timers for setting ON and OFF time.
7.2.0 ANODES & ANODE BEDS
7.2.1 The contractor shall furnish the detailed specification
viz. type, material, composition, weight etc of the anodes proposed
depending on the soil survey and site conditions.
7.2.2 Sheet steel anode canisters of suitable size shall be
furnished for each anode. Anode canisters shall be filled with
tamped coke breeze having carbon content of at least 98% and
maximum resistivity 50 ohm-cm.
7.2.3 Each anode bed shall contain anodes with canisters
positioned in the soil with suitable backfill at appropriate depth
with due regard to type of configuration. Anode bed shall be
located preferably 100m (min.) or more from the pipeline/structure
under protection. Anode-bed plot limited upto ROW shall be surveyed
for topographic details. Its location and orientation shall be
reviewed by ENGINEER.
7.2.4 Layout of anodes, installation in anode-bed shall be
detailed out in a separate drawing showing anode installation
details, anode grouping, anode wiring etc. Type of layout whether
vertical installation/ horizontal installation in shallow depth to
be considered shall
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
be decided in consultation with ENGINEER on the basis of
Corrosion survey report prepared by CONTRACTOR.
7.2.5 Necessary connection of anode lead cable to anodes,
packing of anodes in canisters filled with backfill, soldering of
canisters shall be done at site. Each anode shall have lead cables
of sufficient length to reach anode junction box without in between
joints. Exact length and termination details shall be shown in
construction drawings.
7.2.6 Anode bed separation from pipeline shall be tested for
interaction.
7.2.7 At landfall points, anode land beds may be laid, if
situation demands, between low and high water line or very near low
water line. The configuration shall be horizontal in such
cases.
7.2.8 Overall resistance of the each anode bed upto its main
junction box shall not exceed 0.5 ohm unless agreed otherwise.
Potential gradient around the anode bed shall be within safety
requirements and its effective boundary shall be defined and
secured.
7.2.9 The boundary of the anode bed should be clearly marked
with the help of permanent boundary and fencing.
7.3.0 ANODE JUNCTION BOXES (AJB)
Anode junction box drawing shall be furnished by the contractor.
The height of the pedestal above ground level may require to be
greater depending on the highest flood level of the site of its
installation. Junction boxes to be mounted above ground shall have
steel enclosure which shall be dust and weather proof as per IP-55
with hinged lockable shutter. It shall have terminal block with
adequate number of terminals. Provision shall be made for
measurement of individual anode current . The AJB shall be of 10
SWG sheet steel, shunts used for current measurement of each anode
shall be 10 amps/75 mV rating. The AJB assembly shall be grouted on
concrete pedestal made of M 200 grade reinforced concrete.
7.4.0 CABLE AND CABLE LAYING
7.4.1 Anode & Cathode Header Cable
XLPE insulated and PVC sheathed armoured copper conductor
(single core) of minimum size 50mm2 to be laid by CONTRACTOR in all
types of soils (including rock) at an average depth of 1 m below
ground level.
7.4.2 Anode Lead Cable
Individual pre-packed cannistered anodes complete with minimum 6
mm2 XLPE insulated PVC sheathed unarmoured single core copper
conductor of sufficient length to reach AJB shall be supplied and
laid by CONTRACTOR in all types of soils (including rock). Length
of each lead cable should be sufficient to reach AJB without any
joint in between. Anode lead cables shall be laid in trenches at
average 1m below ground level having a 6 top cover of sand one
layer of brick soling followed by natural backfilled soil. All
anode lead cables shall be laid in PVC/PE conduits of 2.5mm minimum
wall thickness. If any road or rail crossings are encountered, they
shall be routed through 2 GI conduits instead of PVC/PE conduits at
such road/rail crossings.
7.4.3 All the Instrumentation wires shall be with PVC insulation
of 600/1100V grade and not less than 2.5 mm2 cross-section copper
conductor.
7.4.4 Cable Termination:
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
The cables shall be taken through double compression glands
inside the panels or any other electrical equipment such as T/R
unit. The individual cores shall then be dressed and taken along to
the cable ways (if provided and shall be fixed to the panels with
Nylon straps) D.C.output cable terminals shall be provided with
terminal lugs of matching current rating. Termination of other
cables shall be made of crimped lugs made with proper tools. Only
control cables of single strand may be directly terminated on the
terminals. An aluminium tag with cable number engraved on it shall
be attached to each cable at both ends. Power cables shall be
identified with red, yellow, blue PVC adhensive tapes. Where copper
to aluminum connection is made necessary, bimetallic washers shall
be used. Drilling of holes for cable glands shall be included
wherever necessary. Cables shall be neatly arranged dressed in
trenches in such a manner so that criss-crossing is avoided and
final take off to equipment is facilitated. Cable trenches in CP
room should be suitably covered by MS slabs. Detailed layout to be
prepared and furnished by CONTRACTOR for ENGINEERs approval
7.5.0 TEST STATIONS:
7.5.1 All test stations shall have weather proof enclosure with
hinged lockable front cover. Enclosure shall be made of sheet steel
of at least 3mm thickness. Enclosure shall be weather proof having
degree of protection IP-55 as defined in IEC-529 and shall be
suitable for MS post mounting.
7.5.2 Name plate should be provided inside each test station
giving the following information
a)Connection scheme diagram b)Chainage location of test station
and direction of flow.
7.6.0 INSULATING JOINT (I.J) GROUNDING CELL Grounding cell
across each insulating joint shall be provided while its connection
to pipe on both shoulders of joint shall be through test station.
Besides the above, measurement cable from pipe from both shoulders
of I.J. shall be taken out and terminated at test box.
Cables for connecting of grounding cell to pipe shall be 1C x
16mm2 (minimum), XLPE insulated PVC sheathed unarmoured copper
conductor and shall be CONTRACTORs supply.
Grounding cell for each I.J. shall consist of a pair of zinc
rods of required size and weight. The pair shall be separated by
insulation spacers and the entire assembly wrapped with PVC tapes
shall be packed in chemical backfill of Bentonite, Gypsum and
Sodium Sulphate. Each zinc rod shall be complete with 1C x 15 mm2
(minimum) XLPE insulated PVC sheathed copper cable of minimum 3m
length to reach test station.
The entire grounding cell consisting of zinc rod surrounded by
backfill with an overall dimension of 615 x 515 x 1500mm shall be
laid underground at a minimum depth equal to pipe burial depth and
adjacent to pipe.
7.7.0 EARTHING
Earthing of T/R unit shall be done as per standards. Total
resistance of each earthing grid to earth shall not exceed 1.0
ohm.
8.0.0 TRANSPORTATION, HANDLING AND STORAGE
8.1.0 All equipment/material shall be protected for inland
transport, carriage at site, outdoor storage during transit and at
site and shall be protected against corrosion, incidental damage
due to vermin, sun light, rain, high temperature, humid atmosphere
etc., for the entire period of despatch, storage and erection. The
contractor shall be responsible for any damage to the equipment
during transit due to improper and inadequate packing
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ELECTRICAL DEPARTMENT
FACT ENGINEERING AND DESIGN ORGANISATION
9.0.0 SHOP TESTING AND INSPECTION
9.1.0 All plant and equipment covered by this contract shall be
subjected to inspection and testing as defined in reference codes
and standards. The contractor shall provide all service to
establish and maintain quality of workmanship in his works and that
of sub contractors.
9.2.0 For all manufactured items inspection by HPCL at the works
is mandatory before despatch.
10.0.0 TESTING AND COMMISSIONING
10.1.0 The Contractor shall carry out all the pre commissioning
tests and commissioning procedures after installation of the system
as required and directed by the Site in Charge. Skilled labour,
personnel, tools, equipment, instruments and all consumables
required for testing and commissioning shall be provided by the
Contractor.
10.2.0 The contractor shall have necessary instruments for
carrying out the tests especially high input impedance digital
multimeter, standard Cu/ CuSO4 half cell etc. Half cell chemical is
to be changed periodically.
10.3.0 The contractor shall take readings of pipe line potential
at all the monitoring points of the cathodic protection system by
means of Cu/ CuSO4 electrode using high input impedance
voltmeter.
10.4.0 The anode currents at each of the junction boxes shall be
taken by measuring the voltage drop across the one ohm resistor
provided in the junction box with the switch kept disconnected
while taking the current measurement. After taking the measurement
the switch shall be closed.
10.5.0 The current and the potential readings shall be submitted
to the Engineer in Charge. Based on the above readings and on
review of the same by the owner and the consultant, contractor
shall carry out any modification/ rectification, installation/
replacement of anodes if required, at the rates quoted.
Final commissioning report and all final documents/ drawings
shall be furnished as per Vendor Data Requirements. All drawings
shall be submitted in soft copy also. After installation of
cathodic protection system the vendor shall impart training to
purchasers personnel on its operation and maintenance to the full
satisfaction of the purchaser. During guarantee period ,contractor
shall take periodic PSP readings.
11.0.0 AMC COMPREHENSIVE
AMC Comprehensive (including supply of spares and
consumables)shall be provided for 2 years after the guarantee
period. AMC shall cover taking periodic PSP reading for the smooth
operation of the system for the 2 years AMC period. Terms and
conditions of AMC to be followed is given elsewhere in the
document.
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