Approval Project Manager: Ministry of Electricity (Moe) Republic of Iraq
Approval Project Manager: Ministry of Electricity (Moe) Republic of Iraq
Approval Project Manager: Ministry of Electricity (Moe) Republic of Iraq
Project manager
CONTRACTOR:
DESIGNED BY DATE
CHECKED BY DATE
TITLE:
THE PROCEDURE FOR INSPECTION AND TESTING
Florinel Petrilă November ‘17
OF THE POWER CABLES
APPROVED BY DATE
Gheorghe Ţăranu November ‘17
CHPT. 1. SCOPE.............................................................…..…………………….…..3
CHPT. 5. RESPONSIBILITIES…………...……………………………..………….……5
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1 SCOPE
This procedure establishes the provisions related to the competence of the staff which is
undertaking the tests/checks, the succession of the specific tests/checks, the required equipment,
the methods to be applied and the responsibilities of the involved persons.
2 FIELD OF APPLICATION
This procedure is applied to BLACK SEA staff for the inspection of the power cables, no
matter their manufacturing type and with a rated voltage up to and including 20 kV.
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4. REFERENCE DOCUMENTS
NOTE : The user’s responsibility is to ensure that it is using the valid editions of the
documents, by reading the reference list of the documents.
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5 RESPONSIBILITIES
Position / Competence
5.1 General Director /
5.1.1 Approval of internal documents that regulate the activity of the test&check staff.
5.1.2 Ensure the fulfilling of test&check staff independence requirements and the materialization of such
independence in the organizational structure of the organization.
5.1.3 Ensure the financial and material resources required for a proper undertaking of test&check staff’s
activity.
5.2 Production-Technical Director /
5.2.1 Approval of the test&check schedule for own works.
5.2.2 When necessary, ensure the material resources and the technical staff for the test&check
activities.
5.3 Test&Check Responsible /
5.3.1 Draw up of test&check schedule and program.
5.3.2 Maintain the connection between the client’s empowered staff or with the Manufacturing Team
Lead in order to ensure optimum conditions for undertaking the tests and checks.
5.3.3 Provide the staff and equipment reqired for undertaking the tests and checks
5.3.4 Planning the compliant training of the subordinated staff.
5.3.5 Check the performance of the occupational safety and fire fighting training.
5.3.6 Check the conformity draw up of test/check reports.
5.3.7 Approval of test/check reports.
5.4 Profile Lead /
5.4.1 Responsible for the training of operators/ technical staff in charge with the tests/checks.
5.4.2 Preparation of measuring and monitoring devices, tools and equipment required for the
performance of tests/checks.
5.4.3 Checking the corresponding operation and metrology check status of all the measuring and
monitoring devices.
5.4.4 Establishment and insurance of optimum work conditions with the site responsible, to avoid
influencing the test/check results and to ensure all the occupational security conditions.
5.4.5 Responsible for drawing up and signing the work permits and for the provision of safety and work
areas.
5.4.6 Draw up of test/check reports.
6. PROCEDURE
6.1 Type of object to be tested, checked
6.1.1 Object to be tested, checked:
a) Any type of power cables with a rated voltage up to 20 kV.
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6.3 Stabilization periods and medium
6.3.1 Power cable checking is performed only after observing the following provisions:
a) measurements performed at environment temperature;
b) the temperature corrections for 20C shall be applied;
c) the cable ends shall be prepared for tests;
d) if not otherwise provided by the technical manual, the equipment to be used shall be
at environment temperature.
6.5.2 The circuit-breakers will be in open position or disconnected, the disconnectors will
be open(perform a visual check to see that the mobile contacts are completely removed from the
stationary contacts) and the CLPs will be closed; check that there is no voltage on cable terminals
by using a voltage presence indicator compatible with the rated voltage of the related cable and
install the short-circuit devices on disconnectors’ terminals located towards the cable.
6.5.3 The work conductor and the client will determine together where the tests and checks
will start.
6.5.4 The work lead will nominate a team consisting of at least two qualified persons that
will secure the work area at the opposite end of the cable and this team will perform the works
according to the instructions of the work lead.
6.5.5 The persons nominated for the works and for guarding the work area will wear a
complete safety work outfit and have at least one remote communication device (mobile phone,
transceiver) with good operation and coverage.
6.5.6 After determining that there is no voltage, immediately untie the cable terminals from
the connection system and take actions so they cannot come into contact with each other or with
other nearby metallic parts for the whole duration of the tests and checks.
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6.5.7 Untie both ends of the metallic cable screens from the earthing installation; notify
the start of works after taking such organizational actions.
6.6.2 At the opposite end, the pair of conductors whose resistance is measured may be
successively set under short-circuit. The buzzer will sound if there aren’t any continuity faults and
the ohmmeter and megohmmeter will indicate very small values. Otherwise, the buzzer will not
sound and the measuring devices will indicate a high value or the infinite, thus showing that there
are continuity faults.
6.6.3 A phase correspondence indicator is used to identify phases on live cables but
mobile phones can be used, too.
6.6.4 After checking, the work lead will note the obtained values in a report, he will review
such values and then decide if there are or there aren’t any continuity faults; if in doubt, perform
checks from the other end of the cable; the two sets of values will be compared and reviewed by
the work lead.
6.6.5 When determining continuity faults, the client will be advised to locate the faults.
6.6.6 The work lead ensures the communication of the electrician from the other cable end
that he can perform the work for the checking of the ohmic resistance.
6.7 Ohmic resistance measuring on conductors and screens – Low voltage and
high voltage power cables.
6.7.1 The ohmic resistance for each conductor and the cable screen is determined after a
successive measuring of the resistances between two phases and between a phase and screen,
by using the resistance measuring bridge.
6.7.3 The values R1 ,R2, R3, E will be determined by mathematically solving the system
of four equations with four unknowns from the item 6.7.5.
6.7.4 The reference ohmic resistance of the conductors and screen of LEC, under the
related environment temperature conditions, is equal to the reported value of the value measured
at 1 km from LEC; Rc(1km,20C) is normalized, provided by the supplier or shown in the norms
according to the material used to manufacture the conductors (Cu sau Al).
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6.7.5 The mathematical relation between Rc and R1, 2, 3 is shown below:
R1,2,3 = Rc x L x [ 1 + 20 ( - 20)]
where:
20 temperature coefficient:
- for Cu = 3,93 X 10
- for Al = 4,03 X 10
= environment temperature measured with thermometer,
R1,2,3 = resistance determined for conductor 1,2,3,
L = cable length [km].
6.7.6 Rc is determined from the above relation and must correspond to normalized values,
according to conductor material and cross-section.
– Insulation resistance measuring and test under continuous high voltage 6.8
.over 1 kV – Low voltage and high voltage power cables
6.8.1 The checking stages are successively performed between each two phases between
each phase and the cable sheath / metallic screen, as follows:
a) the inductor / megohmmeter is successively connected to the ends of the conductors;
b) the voltage level used to check the insulation resistances shall be selected according to
the cable Un and type;
c) perform the measuring of insulation resistance after 60s (1 min) since the voltage
application with the inductor / megohmmeter;
d) write the values indicated by the device in the test/check report;
e) review the obtained results.
6.9.1 If the values obtained for the insulation resistance are smaller than the normalized
ones, determine the absorption coefficient as follows:
a) the same measuring and installation scheme is achieved as for insulation resistance
measuring ;
b) successively connect the inductor / megohmmeter at the ends of the conductors;
c) select the voltage level used to perform the checking of the insulation resistances,
according to the cable Un and type;
d) read the insulation resistance value at 15s and 60s after voltage application;
e) write the values indicated by the device in the test/check report;
6.9.2 The ratio between the insulation resistance values read at 60s and at 15s represent
the value of the absorption coefficient given in the following formula:
Ca = R60 / R15
Ca 1.3
Ca = absorption coefficient,
R60 = insulation resistance read at 60s,
R15 = insulation resistance read at 15s.
6.9.3 The obtained results are reviewed to avoid repeating the same measurements; it is
recommended to read R15 and R60 when measuring the insulation resistance and
determining Ca = R60 / R15.
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6.10 PVC or PE sheath test under high voltage - over 1 kV - Low voltage and high
voltage power cables; Determination of leakage currents.
6.10.1 PVC or PE sheath test and the determination of leakage currents is performed with the
same measuring and installation scheme as for measuring the insulation resistance, as
follows:
a) successively connect TIC 2 kit terminals to conductor ends;
b) select the voltage level used for the increased voltage test, according to cable type and Un;
c) it is recommended to apply the increased voltage under a constant speed of (2-3) kV/s until
reaching the maximum value;
d) the maximum value of the test voltage shall be applied for a time according to the valid
standard and according to the manufacturer’s technical instructions
6.10.2 After the elapse of the test time, read the value of the leakage current; it’s value will not
exceed the following limits:
a) 200 A for 3,5/6 kV si 5,8/10 kV cables ;
b) 600 A for 12/20 kV cables ;
c) 1000 A for 27/35 kV cables.
6.10.3 After the increased voltage test it is compulsory to check the insulation resistance in order
to determine the eventual weak points of the insulation.
6.12.1 After the finalization of the tests/checks, the Test&Check Responsible will ensure
the issue of corresponding test / check reports and will conclude with regard to the performed
measurements as follows :
a) If the measured values are within the limits of the applicable norm and/or the limits of the
technical specifications, the conclusion will be : „CORRESPONDING”;
b) If the measured values are not within the limits of the applicable norm and/or the limits of the
technical specifications, the conclusion will be : „NOT CORRESPONDING”;
c) in such case, the Profile Lead or the Test&Check Responsible may issue recommendations
for the remedial of the situation (re-design, technical re-evaluation of the installation, etc.).
6.12.2 The test reports are filled in by the Profile Lead, by using the provisions of this test
procedure and the requirements of the standards, norm and manufacturer’s technical sheet of the
low voltage and medium voltage cables mentioned under chapter 4. – Reference Documents.
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