Arteche CA Series User manual

USER MANUAL
CONTENTS
PRELIMINARY CONSIDERATIONS
INTRODUCTION
TRANSPORT AND HANDLING
INSTALLATION
INSPECTION AND MONITORING QUICK
TROUBLESHOOTING GUIDE
ANNEX I
ANNEX II
ANNEX III
HIGH VOLTAGE INSTRUMENT TRANSFORMERS
CA / UT / KA

1High Voltage Instrument Transformers | CA/UT/KA
User Manual
OBSERVATIONS/
Keep the instruction manual in a safe and accessible place to
ensure that any operation or maintenance task can be performed
quickly and easily when necessary.
For safety reasons, only qualified sta can use this equipment.
Read the instruction manual and other documentation before
the equipment’s installation, commissioning and maintenance.
Become familiar with all equipment information and safety
precautions before using the equipment and during its operation.
Always use the equipment within the guidelines indicated in the
instruction manual and other relevant documents.
In order to prevent malfunctions, carry out proper controls and
maintenance.
Do not use or handle the equipment in a manner contrary
to what is expressly stated in this manual, do not modify the
equipment with parts from other manufacturers. This behavior
can lead to damage to the equipment and/or personal injury.
ARTECHE is not liable for accidents due to causes unrelated to
our guidelines.
In the event of equipment malfunction or any other type of
problem, communicate it immediately to the corresponding
ARTECHE department, providing the following information:
› Evaluation of contents and the product’s nameplate (name,
serial number, type and date of manufacture).
› Description of the problem (as detailed as possible, including
the situation immediately before and after the problem
occurred) and supporting photos or videos.
If you have any questions, please contact ARTECHE www.arteche.com
› EMEA: [e-mail]
› APAC: [e-mail]
› NAM: [e-mail]
› LATAM: [e-mail]
PRELIMINARY CONSIDERATIONS
ENVIRONMENTAL CONSIDERATIONS/
Disposal considerations:
Disposal or recycling will be carried out in accordance with
current legislation. Oil and impregnated products shall be
disposed of through an authorized manager in authorized plants.
They can be incinerated in suitable plants, respecting local
regulations. The oil is free of PCBs and chlorinated products.
More information on the oil safety data sheet. The metals are
recyclable (copper, steel, aluminum, silver, etc.).
Measures to be taken in the event of an oil spillage:
Prevent the oil from spreading or getting into the sewage
system, ditches or rivers by using sand, absorbents or other
appropriate barriers. Collect the oil with an absorbent material
and send it to appropriate containers for disposal, in accordance
with local legislation. Oil is not easily biodegradable. It contains
components with bioaccumulation potential.
DANGER/
CAUTION
Indicates that improper use or
handling may result in physical
damage to the equipment,
serious injury or even death
SAFETY PRECAUTIONS/
For safety reasons, only qualified personnel can carry out
maintenance and commissioning or operation.
Read the instruction manual and other documents before using
the equipment. Become acquainted with every aspect of the
equipment and its safety precautions before use.
Do not use, handle or modify the equipment in a way that is not
expressly stated in these operating instructions and do not use
or modify the equipment with parts from other manufacturers.
The safety precautions used in this manual are indicated by the
following message:
Depending on the situation, mishandling can have serious
repercussions, even when “Caution” is indicated in this
instruction manual. Strictly observe all security measures.
These safety precautions are the manufacturer’s suggestions to
ensure the safety of the equipment.
Users are requested to establish security measures so as to
maintain safety and the equipment operating in accordance
with various standards and requirements
ARTECHE will not be liable for accidents caused by not carrying
out the safety measures.

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High Voltage Instrument Transformers | CA/UT/KA
User Manual
FOREWORD/
This manual describes the construction, installation, commissioning and monitoring for safe use of a high-voltage instrument
transformer with oil-paper insulation.
INTRODUCTION
SCOPE OF APPLICATION/
The manual applies to the following transformers:
›Current Transformers, CA Series, Models: CA-36..800.
›Inductive Voltage Transformers, UT Series, Models UTx-52..525.
›Combined Transformers, KA Series, Models KA-36..245.
DESIGN/
Instrument transformers have the active parts located inside
a metal enclosure located in the upper part for current
transformers and in the lower part for voltage transformers.
The insulator can be either ceramic (porcelain) or polymeric
(silicone), and is composed of a certain number of sheds.
The internal insulation consists of layers of paper impregnated
with dielectric oil, with a relatively small volume, and hermetically
sealed.
The variations in oil volume are balanced by one or more stainless
steel compensators located in the device’s upper enclosure. A
highly visible indicator at the top shows the compensator position.
At the bottom of the transformer there is a valve for oil sampling.
The secondary terminals of the windings are located in the
terminal box at the base of the transformer.
All metal parts are treated against rust and the fasteners are
made of stainless steel.
1. Cover
2. Oil volume compensator
3. Primary terminal
4. Core(s)
5. Primary winding
6. Secondary winding
7. Insulator
8. Capacitive bushing
9. Insulating oil
10. Secondary terminals
11. Tan Delta measurement tap
12. Ground terminal
13. Oil level indicator
14. Eyebolts for lifting
›CA ›KA›UTx
1
3
5
7
8
9
10
12
11
2
3
1
2
33
4
1
2
4
4 6
6
5
5
6
7
8
9
10
13
10
12 12
13
4
5
6
13
14
14 14
14
14
14 14

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User Manual
TRANSPORT/
TRANSPORT AND HANDLING
ARTECHE’s packaging guarantees a correct transport to
destination.
These transformers can be transported both horizontally and
vertically. For transport, the transformer should be properly
attached to the packaging to avoid movement.
› Load and unload the transformer slowly and avoid sudden
movements.
› It must be secured to the truck to avoid movement.
› Keep truck acceleration under 5G, and the speed under:
• Unpaved road ___________ Max. 30 km/hour
• Secondary road ___________ Max. 60 km/hour
• Highway (motorway) ___________ Max. 90 km/hour
STORAGE/
The storage area must maintain the necessary cleanliness and
safety conditions so as to avoid damage to the transformer.
Follow the safety markings on the packaging at all times.
› Storage in vertical position: The transformers can be stored
upright in their original packaging, which was designed to
this end.
› Storage in horizontal position: Transformers may only be
stored horizontally within their original packaging, designed to
this end. We recommend not keeping them in this position for
more than 12 months. Therefore, if they are to be stored for a
longer period, they should be taken out of the box and secured
in an upright position. The transformer must be in an upright
position for at least 2-3 days before start-up. After placing the
unit in an upright position, check to see if there is residual oil
in the storage area and ensure that no oil is leaking from the
transformer.
Closed or semi-closed horizontal packages can be stacked at
two heights if it is the same package and device. Closed or semi-
closed vertical packages can only be stacked at two heights for
the UTx-52..72 models. In no case can the original position of the
packaging be changed.
Wooden packaging loses its properties over time, especially
in outdoors. Therefore, transformers cannot be stored in their
packaging indefinitely. This period depends on the type of wood,
temperature, humidity, contamination, etc. It is recommended to
monitor the integrity of the packaging regularly.
After unpacking the transformers and if they are not to be
installed immediately, always store them anchored firmly to the
floor with no time restriction.
The final holder will be responsible for delivering the used
packaging or its waste for environmental management according
to the legislation in force in their country.
HANDLING/
Unpacking: Remove the top and sides of the box to allow free
handling of the unit.
Annex I, contains the following figures.
If the transformer is in a horizontal position, to place it in a
vertical position, proceed as indicated in Fig. 1:
a. A wooden wedge (C) will be placed before beginning to lift it.
b. During the lifting process, the slings must always be kept in
an upright position.
DANGER
INJURIES from falls and tipping
› Do not place the equipment upside down or on its side
› Do not transport the equipment in conditions other than those mentioned
RECEIPT/
After receipt, check the packages for signs of shock, tampering,
oil, etc. Any anomaly must be indicated on the transport
company’s receipt sheet and communicated to ARTECHE or the
equipment supplier.
Once the transformer has been unpacked, check that none of
the screws holding the insulator have become loose during
transport. If they have, tighten them according to the torque
indicated in Annex II. If any other type of anomaly appears,
inform ARTECHE or the supplier of the equipment. Include
photos of the damaged transformers with the report.
› Possible damage to the packaging: Bumps on the outside, oil
stains on the outside of the packaging, open packaging, etc.
› Possible damage to equipment: Broken or defective insulator,
oil leaks, dented metal parts, damaged secondary terminal
box, etc.
The packed units can be moved by forklift or with slings or
chains. Follow the safety markings on the packaging.
DANGER INJURIES AND/OR FIRE
› Do not use damaged equipment
DANGER
INJURIES from falls and tipping
› Do not place the equipment upside down or on its side
› Handle the transformer according to the instructions in this manual
› The slings used must be in good condition and suitable for handling the equipment
according to its weight, which is indicated on the nameplate
Under no circumstances should a transformer be manipulated by pulling on the primary terminals
This may cause damage to the equipment and void its warranty

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High Voltage Instrument Transformers | CA/UT/KA
User Manual
INSTALLATION
Model Weight* Procedure
KA, CA >1,600 kg According to Fig. 4: The movements will be made by hooking the device with four slings
through the four holes which are located at the base for this purpose. A sling must be
fixed at head height, hugging the lifting slings, to prevent the transformer from swinging,
as indicated in Fig. 4a or in Fig. 4b.
Note: The center of gravity of the CA models is very high. The center of gravity of UT
models is very low.
UTx-52..300
KA, CA <1,600 kg According to Fig. 3. The movements will be carried out by hooking the device with two
slings through the two eyebolts arranged for that purpose on both sides of the head or
intermediate body.
UTx-420..525
*The total weight of the transformer is indicated on the nameplate
Once the equipment has been placed in an upright position, a
visual inspection is suggested so as to detect possible oil leaks
or stains.
Oil stains are not necessarily the result of a leak. In most cases,
the stains are nothing more than oil residues left over from the
manufacturing process.
The stain should be cleaned with a degreaser and the equipment
should be kept under observation. If the stain reappears or
spreads, contact the manufacturer.
MOUNTING ON THE STRUCTURE OR PLATFORM/
Check the information on the nameplate to verify that the
electrical characteristics match those of the system.
Check the status of the oil compensator’s position indicator. If
the indicator is hidden, the device cannot be connected to the
network, and ARTECHE or the supplier of the equipment must
be informed (Fig. 5).
Some transformers have a mechanical protection for the
compensator that must be removed before installation (Fig. 6).
If this is the case, it shall be indicated on the equipment itself by
means of a label.
Carefully check to make sure that all four legs of the device sit
perfectly on the platform, before tightening the anchor screws.
If this is not the case, correct the defect, by wedging metal
plates or similar. Failure to do so may result in insulator breakage
or oil leakage.
When the device is in a vertical position, movements can be made as indicated at Fig. 2, Fig. 3 and Fig. 4.
DANGER
INJURY AND/OR FIRE
› Do not install the equipment without following our specifications
› Use the transformers under proper service conditions and according to specifications
› Do not loosen any screws or fastening nuts, it can cause oil leaks
ELECTRICAL DISCHARGE
› Do not wire or connect when the equipment is energized
› The delta-tangent measurement tap (if any) must always be grounded when the transformer is
in service
› The ground terminal of the apparatus must be solidly earthed by means of a connection capable
of withstanding and conducting the line’s fault current to earth
› Do not short-circuit the secondary circuit of the voltage transformer
› Do not leave the secondary circuit of the current transformer open

5High Voltage Instrument Transformers | CA/UT/KA
User Manual
ELECTRICAL CONNECTIONS/
Primary connections
The most common connector materials are copper and
aluminum. They can have a tin or silver coating with so as to
prevent galvanic pair corrosion and improve their contact.
Do not bring aluminum into contact with copper-based
materials unless special precautions are taken.
Material Finish Cleaning
Copper
Copper/Brass We recommend cleaning the contact surfaces with
a soft cloth (avoid brushing with a metal brush)
Aluminum
Aluminum
Bare
We recommended vigorously brushing the contact
surfaces with a soft metal brush (preferably
stainless steel) or sandpaper, until you see the
characteristic shine of the clean metal
Copper/Brass
Only impregnate the contact surfaces to be used with contact
grease, keeping the others clean. Remove excess grease to
avoid contamination.
Tightening must be carried out using a torque wrench, as shown
on the diagram plates and in Annex II.
Change of primary ratio (if applicable). In current transformers
(CA) and combined (KA), depending on the model, the change
of primary ratio can be done in one or both primary terminals.
The position and torque of the links is indicated on the diagram
plates next to the terminal (Fig. 7) or under the protective cover
(Fig. 8). Before commissioning the transformer, check and make
sure that the primary connection is in the ratio corresponding to
the operating current.
Secondary connections
The secondary winding(s) must be connected to earth through
one of its terminals, preferably in the secondary terminal box
itself.
In case of secondary with intermediate taps, the common
terminal must be grounded.
Check that the secondary connections are correctly tightened
and the contact surfaces are clean.
The screws of the lower cable gland cover, the block cover
and the terminals must be tightened to the torque specified in
Annex II.
In the terminal box there is a terminal block where the secondary
wires are connected.
The disposition of the terminals is indicated on the secondary
marking plate on the inside of the box cover.
A faulty contact or a bad connection can lead to rapid transformer deterioration
Current transformer (CA)
and current secondaries
of the combined
transformer (KA)
Any secondary that is not loaded must be short-circuited and grounded
The voltage between open circuit secondary terminals can reach dangerous values
and can even destroy the device
Voltage transformer (UT)
and voltage secondaries
of the combined
transformer (KA)
Any secondary that is not loaded must be left open and grounded at a single point
The current in a short-circuited secondary can reach dangerous values and can even
destroy the device
Avoid excessive torque, as the connector may suer damage such as cracks which may expand in the future and
cause it to break
An inadequate torque may cause improper contact and cause the terminals to heat up during operation
CAUTION
Do not use the secondary terminal block as a step
To make or check the primary connections, a lifting platform or a ladder should be used,
maintaining the necessary safety conditions for work at height. In no case may the
terminal block be used as support
Check the correct external wiring.

6
High Voltage Instrument Transformers | CA/UT/KA
User Manual
Grounding
The ground terminal of the transformer must be properly
connected to the ground network by a connection capable of
carrying the network’s fault current. Check that the connection
is tightened correctly and that the contact surfaces are clean.
The low voltage (neutral) terminal of the voltage primary
winding must always be grounded when the transformer is in
service (not applicable for CA). This terminal can be located
inside the secondary terminal box on the side of the box or on
the outside of the tank (Fig. 9.)
The tangent delta measurement tap(if it has one) must always
be grounded when the transformer is in service.
If it needs to be removed, the following steps must be followed
to reconnect it (only applicable for CA series):
› Check the thread conditions. If necessary, clean them and
apply contact grease.
› Tighten the connection screws on the block and the base
correctly, per the tightening torque specified in Annex II.
› Ground connection is tested with a multimeter connected
between the link and the CT base. Measurement should be
done at the lowest scale and the result must be below 0.3 ohm
(Fig. 10).
Always follow the Arteche Manual for instructions on transport,
storage, handling and installation.
ARTECHE instrument transformers do not require maintenance.
There are no moving parts and no components susceptible to
wear and tear, so no active maintenance is required.
However, some companies perform some monitoring operations
on instrument transformers as part of a general substation
maintenance program. These maintenance programs are not
intended to extend the life of the units, as the measures have no
impact on the state of the insulation or the performance of the
units. These programs serve to know the state of the isolation, so
that the user can make decisions based on the results obtained,
as well as detect situations that may be causing damage to the
unit.
We at Arteche, as manufacturers, do not establish any specific
measures, since the decision depends on:
› the resources available to each user,
› the location of the instrument transformer (can be a position
which is more or less critical),
› the environmental and electrical conditions that the unit must
withstand at each specific point,
› the history of the unit,
› the specific types or the problematic units,
› etc.
The following inspection points are only a suggestion in case
they are within the user’s maintenance policy.
1. Physical inspection:
a. Mechanical: Look for signs of impact, damage or loose
parts.
b. Electrical: Check the correct state of the electrical
connections.
c. Oil: Look for oil leaks and check the oil level.
2. Dielectric tests:
d. Electrical tests to evaluate the insulation of the equipment.
For the test procedure, see Annex III.
3. Oil tests:
e. Tests performed on oil samples. The oil tests analyze the
state of the insulating liquid and show the properties
of the system in general. The transformer oil contains
information on the status of the device. Therefore,
analysis of used oil can provide early indications of paper
deterioration, overheating points and electrical faults.
This data can be useful as a guide for corrective actions
which should be applied for the transformer. When taking
oil samples, follow Arteche’s user manual on oil sampling.
As a general rule, the transformer should be filled with
the same amount of oil as extracted. If this is not possible,
please contact with Arteche.
4. Thermographic testing:
f. Use of thermographic cameras.
INSPECTION AND MONITORING
DANGER
ELECTRIC SHOCK AND/OR INJURY
› Everything should only be carried out by personnel qualified in the maintenance and verification
of the equipment
› Do not touch live parts
DANGER The transformer must be firmly grounded. A faulty or non-existent connection may cause damage,
even destroying the device

7High Voltage Instrument Transformers | CA/UT/KA
User Manual
Type Code Test Observations
Physical inspection
A1 Packaging Look for signs of rough handling
A2 Insulator Check that is not damaged and is clean. Check that it is not loose, bent or broken
A3 Primary
Terminals Check that they are not loose, bent or broken
A4 Secondary
Terminal
Box
Check that it is not damaged and is securely fastened to the tank or transformer holder
A5 Check that no rain water enters the terminal box
Check that the ventilation openings are not blocked
A6 Metal parts Check for dents, scratches or signs of corrosion
A7 Unusual behavior Check for unusual noises, vibrations or odors
B1 Primary
connections
Check that there is good contact, that there are no signs of corrosion and that all nuts and bolts
are properly tightened. The use of conductive grease is recommended to improve contact, such as
Penetrox A13
B2
Connections
for changing
primary ratio
(if applicable)
In addition to the above, make sure that the connection matches the real primary current
B3 Secondary
circuits
Check that all screws are properly tightened, and that there are no signs of corrosion.
In the case of secondary windings with intermediate taps, check that the connection matches the real
transformer ratio
Check that unused current secondaries are short-circuited
Check that unused voltage secondaries are open-circuited
B4 Grounding Check that the grounding terminal is correctly connected to the substation grounding network, that the
screws are correctly tightened and that there are no signs of corrosion
B5
Connection
DDF (tgδ)
(if applicable)
If the unit is provided with this tap, when the transformer is energized the outlet must be properly
grounded. Open this tap only for measuring and when the transformer is not energized
Leaving it open when the transformer is energized will cause overvoltages and damage to the
transformer
B6
Voltage
transformer
neutral
connection
(if applicable)
Only UTx and KA. Check that the neutral terminal (N) of the primary winding is grounded.
Leaving it open when the transformer is energized will cause overvoltages and damage to the
transformer
B7 Readings Check that the reading values of the secondary match the values expected
C1 Oil level
indicator Check that it remains within the red areas at all times
C2 Oil stains
or leaks
Check the following areas for visible oil traces:
› Insulator flanges
› Junctures between parts of the metal enclosure
› Junctures between the secondary terminal box and the tank or base
›Primary terminals’ surrounding area
Dielectric tests
D1 PF/DDF/tgδ
The limit values of this parameter depend on the transformer’s voltage level. The recommended values
are given with the order. It is also important to control this parameter’s change over time. A change
in the value of this parameter indicates a change in the properties of insulation, but it is not definitive
proof of faulty insulation. For this reason, if the value of the delta tangent is above the recommended
value or has increased, a careful investigation should be carried out and further testing may be required.
In this case, contact Arteche for assistance.
For details on the test procedure, follow Annex III
D2
Measurement of
the Insulation
resistance
For field tests, the use of the megohmmeter (Megger) is very common, and the tests that are usually done are:
› Primary vs. secondary + Ground for current
› N/P2 against secondary and ground for voltage
› Each secondary against ground
› Among the secondaries
In the case of new equipment, the value obtained does not provide any information, unless a short circuit is
detected. Generally, values above 200 MΩshould be expected. However, the comparison of long-term values,
as in the case of tanδ, or power factor, can help determine whether a device is still in good working order.
Do not test at voltages above 3 kV AC or 1 kV DC.
Do not test for more than one minute. It is not recommended to repeat this test often as the
internal insulation could be damaged.
For details on the test procedure, follow Annex III
D3 Ratio test
The Portable Transformer Ratio Meter is commonly used to measure the ratio, excitation current and
polarity of windings. The values obtained are a sign that the transformer is in good condition and can
be energized.
They should not be compared with the results of factory tests carried out in the manufacturing plant
laboratory. Due to the high precision required for this measurement, the actual uncertainty of the test
must be taken into account when testing on site.
For details on the test procedure, follow Annex III
Oil tests
E1 Visual aspect The oil’s visual aspect may be an indication of contamination
E2 Water content This value will provide information about the contamination of the oil. Reference values according
to IEC 60599
E3 PF/DDF/tgδ
(at 90ºC)
This value will provide information about the contamination of the oil. Reference values according to
IEC 60599
E4 DGA The are several gases which may be dissolved in the transformer oil. The contents of each gas can be
related to dierent aspects. Reference values according to IEC 60599
Tests
thermo-
graphic
F1 Thermographic
analysis
Using thermographic cameras, hot spots can be detected in the operation of transformers. In most cases, hot
spots on instrument transformers occur at the primary terminals’ connection point to the line. If present, check
the integrity of the connectors, as well as their correct position and whether they are correctly tightened

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User Manual
TESTS PROGRAM/
When What
On arrival of the transformers at the warehouse or substation A1
After unpacking A2 - A3 - A4 - A6 - C2
During assembly A2 - A3 - A4 – A5 - A6 - B1 - B2 - B3 - B4 - B5 - B6 - C1 - C2 - D2 - D3
After energizing A7 - B7 - C1 - C2 - F1
Routine checks (weekly or monthly) A2 - A7 - B7 - C1 - C2
Annual check A2 - A3 - A4 - A5 - A6 - A7 - B1 - B2 - B3 - B4 - B5 - B6 - B7 - C1 - C2 - F1
Every five years Same as annual + D1
After re-connections, load changes A7 - B1 - B2 - B3 - B4 - B5 - B6 - B7 - F1
After the fault conditions, the short circuits, etc. A3 - A7 - B1 - B2 - B3 - B4 - B5 - B6 - B7 - C1 - C2 - D1
See also “Careful check of the transformer” below
After 1 year from start-up and after 5 years from start-up, if the
values are normal and there is no considerable increase, perform
an analysis after 15 years from start-up, and then every 5 years
E1 - E2 - E3 - E4
CAREFUL CHECK OF THE TRANSFORMER/
It is recommended that all regular tests be repeated after a
long period of operation (about 20 years), or if a major network
disturbance has occurred that could damage the transformer
(e.g. a short circuit with current or duration values higher
than the nominal ones, or over-voltages caused by the
malfunctioning of the switches).
QUICK TROUBLESHOOTING GUIDE
Phenomenon Cause Countermeasure
Oil stains
Oil residues from the
manufacturing process
Clean the area and keep it under
observation for 24 hours. If the stain does
not reappear, the device can function
normally. If the leak persists, contact
Arteche
Loose junctions
Tighten the screws and bolts, clean the
area and keep it under observation. If the
leak persists, contact Arteche
Cracks or damage to components Contact Arteche
Oil level indicator not visible
Level indicator is stuck Remove top cover and eliminate
mechanism blockage
Leakage or overpressure Remove service transformer and contact
Arteche
Cracks in resin parts Bumps or improper handling Contact Arteche

User Manual - Annex I High Voltage Instrument Transformers | CA/UT/KA
ANNEX I
›UTx-420..525
›CA-36..800 ›KA-36..245 ›UTx-52..300
HANDLING AND CONNECTION

2
User Manual - Annex I
High Voltage Instrument Transformers | CA/UT/KA
›Fig. 1: Lifting
›UTx-420..525
›CA-36..800
›KA-36..245
›UTx-52..300
C
C
C
C

3
User Manual - Annex I
High Voltage Instrument Transformers | CA/UT/KA
›Fig. 2: Movement not allowed
›Fig. 4: Movement
›Fig. 3: Movement
›CA-36..800 ›KA-36..245 ›UTx-52..300 ›UTx-420..525
›CA-36..800
<1,600kg
›KA-36..245
<1,600kg›UTx-420..525
›UTx-52..300›CA-362..800
>1,600kg
›KA-170..245
>1,600kg
›Fig. 4b
›Fig. 4a

4
User Manual - Annex I
High Voltage Instrument Transformers | CA/UT/KA
›Fig. 5: Level indicator ›Fig. 6: Oil Compensator Protection
›Fig. 10: Resistance measurement tgδtap connection
›Fig. 8: Primary diagram plate under the protective cover
›Fig. 7: Primary diagram plate next to the terminal
›Fig. 9: Neutral Grounding

User Manual - Annex II High Voltage Instrument Transformers | CA/UT/KA
ANNEX II
Screw type
Torque wrench setting (Nm)
Use Torque wrench setting
M12/16/20 Fixing the insulator to the base 30 Nm
M10/12 Tangent Delta measurement tap 30 Nm
M10/12 Primary reconnection taps 30/40 Nm
M8 Secondary terminals (if they are of the screw type) 12 Nm
M10 Grounding (inside secondary terminal box) 12 Nm
M6 Cable gland 12 Nm
M8 Terminal Block Cover 20 Nm
TIGHTENING TORQUES
NOTE: If a torque dierent from that indicated in this table is indicated on the drawing or plates of the equipment, the torque indicated on the
drawing or plate must be applied.

User Manual - Annex III High Voltage Instrument Transformers | CA/UT/KA
ANNEX III
ON-SITE ELECTRICAL TESTS
All ARTECHE transformers are tested at our High Voltage laboratories, under the strictest criteria of international standards and/or
under specific client standards/specifications when so requested. All of it under a thorough quality system, certified under ISO 9001.
However, it is normal for pre-operative tests to be performed in order to confirm certain important equipment values. The following
is a guide to the most common on-site tests and the proper way to perform them on ARTECHE brand transformers.
This annex applies to the following equipment:
›Current Transformers, CA Series, Models: CA-36..800.
›Inductive Voltage Transformers, UT Series, Models UTx-52..525.
›Combined Transformers, KA Series, Models KA-36..245*.
*For combined transformers, tests will be performed accordingly to the current and inductive voltage parts.

2High Voltage Instrument Transformers | CA/UT/KA
User Manual - Annex III
The purpose of this test is to assess the insulation of the HV
transformer.
The IEC 61869-1 standard labels this test as a special test,
and mentions that “the test circuit must be agreed between
the manufacturer and the customer”, and that “the dielectric
dissipation factor depends on the insulation design.” The usual
values are less than 0.5%.
There is no mention of this test in the IEEE C57.13 standard.
NOTE: Field testing of tanδmay be susceptible to dierences
in measured values from factory testing due to the following
factors:
›The type of test equipment used and the measurement voltage
level.
›Thermal conditions (high humidity, rain, pollution).
›Temperature of the test object.
›Induced voltages to the test object through other equipment.
It is recommended that the surfaces of the transformer (insulators
and others) be clean, to avoid external leakage currents.
The field measurement of tanδfor transformers that are
already equipped with capacitive test taps (tanδ tap) can be
carried out in the same manner as at the factory. In the case
of other instrument transformers without tanδtap, the base of
the instrument transformer is always grounded and cannot be
isolated. Therefore, it is possible that the measurement of tanδ
that is carried out in the factory or in the laboratory cannot be
carried out in the substation in the same manner.
Test instruments for field use are usually equipped with solutions
to compensate for external leakage current. The voltage test
for this particular equipment is typically 10 kV for high voltage
insulation and approximately 2.5 kV for low voltage insulation.
Ta n δand capacitance measurement can also be performed in
the field using other low voltage test bridges and a transportable
high voltage test set capable of measuring voltages up to the
nominal voltage. The choice and application of various test
equipment is at the discretion and experience of the user.
In addition to the measurement of tanδ, the measuring
equipment can usually also measure other parameters such as
capacitance and power factor.
MEASUREMENT OF CAPACITANCE AND DIELECTRIC DISSIPATION FACTOR (tanδ)
›Fig. 1a
POWER
SUPPLY
ELECTRODE
10 kV
MEASUREMENT
ELECTRODE
›Fig. 1b ›Fig. 2
MEASUREMENT
ELECTRODE
POWER
SUPPLY
ELECTRODE
10 kV
It is recommended that the test be carried out at a voltage of
10 kV AC.
If the device has a tanδtap, it is recommended to perform the
test through this tap.
›HV (UST) test for transformers with tanδtap (Fig. 1):
• The test must be performed in UST (Ungrounded Specimen
Test) mode.
• The power supply cable (HV) of the measuring equipment
must be connected to the primary terminals P1 and P2, which
are short-circuited with each other.
• The measurement cable must be connected to the tanδtap,
which should be previously disconnected from the ground
(Fig. 1b).
• The secondary terminals must be short-circuited and grounded.
• Warning: At the end of the test, tanδtap must be connected
to earth and its contact verified.
›HV (GST) test for transformers without tanδ tap (Fig. 2):
• The test must be performed in GST ( Ground Specimen Test)
mode.
• The power supply cable (HV) of the measuring equipment
must be connected to the primary terminals P1 and P2, which
are short-circuited with each other.
• The measuring cable of the measuring instrument must be
connected to the ground terminal, directly at the base of the
instrument.
• The secondary terminals must be short-circuited and
grounded.
CURRENT TRANSFORMERS/

3
High Voltage Instrument Transformers | CA/UT/KA
User Manual - Annex III
It is recommended that the test be carried out at a voltage of
10 kV AC.
If the device has a tanδtap, it is recommended to perform the
test through this tap.
›HV (UST) test for transformers with tanδtap (Fig. 3):
• The test must be performed in UST (Ungrounded Specimen
Test) mode.
• The (HV) power cable of the measuring equipment must be
connected to the primary terminal (A).
• The neutral connection of the primary (N*) must be
disconnected from the ground and connected to the guard
cable.
• The measurement cable must be connected to the tanδtap,
which should be previously disconnected from the ground.
• The corresponding secondary terminals at the end of each
secondary winding must be connected to each other, and to
earth.
• Warning: At the end of the test, the tanδshould be grounded
and the contact should be verified.
›HV (GST) test for transformers without tanδtap (Fig. 4):
• The test must be performed in GST ( Ground Specimen Test)
mode.
• The (HV) power cable of the measuring equipment must be
connected to the primary terminal (A).
• The neutral connection of the primary (N*) must be
disconnected from the ground and connected to the guard
cable.
• The measuring cable of the measuring instrument must be
connected to the ground terminal, directly at the base of the
instrument.
• The corresponding secondary terminals at the end of each
secondary winding must be connected to each other, and to
earth.
INDUCTIVE VOLTAGE TRANSFORMERS/
›Fig. 3
A
Ta n δ tap
LV
measuring
cable
›Fig. 4
A
* The N or P2 terminal can be located inside the secondary terminal box on the side of the box or on the outside of the tank.
N N
LV
measuring
cable
Guard
Wire - P2
Guard
Wire - P2

4High Voltage Instrument Transformers | CA/UT/KA
User Manual - Annex III
The measurement of the insulation resistance is done to check
the integrity of the transformer insulation and to ensure that it
has not been internally damaged during transportation.
This test depends largely on the design of the transformer, the
general configuration of the test, the instruments used, etc.
The values obtained may not be representative of the actual
state of the insulation.
If this test is performed, it is recommended to contact the
manufacturer.
For field tests, the use of the megohmmeter (Megger) is very
common, and the tests that are usually done are:
›Primary vs. secondary + Ground for current.
›N/P2 against secondary and ground for voltage.
›Each secondary against ground.
›Among the secondaries.
In the case of new equipment, the value obtained does not
provide any information, unless a short circuit is detected.
Generally, values above 200 MΩshould be expected. However,
the comparison of long-term values, as in the case of tanδ, or
power factor, can help determine whether a device is still in
good working order.
Do not test at voltages above 3 kV AC or 1 kV DC.
Do not test for more than one minute. It is not recommended
to repeat this test often as the internal insulation could be
damaged.
INSULATION RESISTANCE MEASUREMENT
›Fig. 5 ›Fig. 6 ›Fig. 7
Primary vs. Secondary + Ground P/S+G (Fig. 5)
›The line cable of the measuring equipment must be connected
to the P1 and P2 primary terminals, which are short-circuited
with each other.
›The ground wire of the measuring equipment must be
connected to the short-circuited secondary wires, by the
ground terminal, and directly to the base of the equipment.
›If the guard wire is used, it must be connected to the porcelain
insulator.
Secondaries vs Ground S/G (Fig. 6)
›The P1 and P2 Primary terminals must be disconnected.
›The line cable of the measuring equipment must be connected
to the short-circuited secondary terminals.
›The ground cable of the measuring equipment must be
connected to the base of the equipment.
Between secondaries S/S (Fig. 7)
›This test is only applicable to transformers having more than
1 secondary.
›The P1 and P2 Primary terminals must be disconnected.
›The secondaries to be assessed will be connected; one to
the line cable and the other(s) to the ground cable of the
measurement equipment.
›The test is repeated with each secondary.
CURRENT TRANSFORMERS/
SUPPLY
ELECTRODE
GUARD
ELECTRODE
GROUND
ELECTRODE
GROUND
ELECTRODE
GROUND
ELECTRODE
SUPPLY
ELECTRODE
GROUND
ELECTRODE
SUPPLY
ELECTRODE

5
High Voltage Instrument Transformers | CA/UT/KA
User Manual - Annex III
Primaries vs. Secondaries+ Ground N/S+G (Fig. 8)
›The line cable of the measuring equipment must be connected
to the terminals of the primary winding (A-N) that are short-
circuited with each other, and the grounding plate (N*) must
be disconnected from the primary winding.
›The ground cable of the measuring instrument must be
connected to the short-circuited secondary terminals together
with the ground terminals on the secondary terminal block as
well as the tank.
Secondaries vs Ground S/G (Fig. 9)
›Primary terminal A must be disconnected and the neutral
connection of the (N*) primary winding must be grounded.
›The line cable of the measuring equipment must be connected
to the short-circuited secondary terminals.
›The grounding cable of the measuring equipment must be
connected to the tank.
Between secondaries S/S
›This test is only applicable to transformers having more than
1 secondary.
›Primary terminal A must be disconnected and the neutral
connection of the (N*) primary winding must be grounded.
›The secondaries to be assessed will be connected; one to
the line cable and the other(s) to the ground cable of the
measuring equipment.
›The test is repeated with each secondary.
INDUCTIVE VOLTAGE TRANSFORMERS/
›Fig. 8 ›Fig. 9
* The N or P2 terminal can be located inside the secondary terminal box on the side of the box or on the outside of the tank.
NN
A A

6High Voltage Instrument Transformers | CA/UT/KA
User Manual - Annex III
The Portable Transformer Ratio Meter (TTR) is commonly used
to measure the ratio, excitation current and polarity of windings.
The values obtained are a reference that the transformer is
in good condition and can be energized. They should not be
compared with the results of factory tests carried out in the
manufacturing plant laboratory.
Due to the high precision required for this measurement, the
actual uncertainty of the test must be taken into account when
testing on site.
The TTR contains 4 terminals (this configuration may vary
depending on the manufacturer):
›H1: Black excitation terminal.
›H2: Red excitation terminal.
›X1: Black secondary terminal.
›X2: Secondary red terminal.
TRANSFORMER RATIO TEST
To carry out the test, it will be necessary to excite the transformer
on the secondary side if a TTR is used, because this is where the
highest number of turns are located.
This test verifies the transformer ratio and polarity, and displays
a “+” signal if correct, and a “-” signal if inverted. To carry out the
test, proceed as follows (Fig. 10).
›The clamps marked “X” will be connected to the transformer’s
primary terminals:
• X1 will be connected to the CT’s main terminal.
• X2 will be connected to the other primary terminal.
›The excitation terminals (the clamps marked “H”) will be
connected to the transformer’s secondary terminals:
• H1 will be connected to the positive polarity terminal of the TI.
• H2 will be connected to the negative polarity terminal of the TI.
• The remaining secondaries must be short circuited.
CURRENT TRANSFORMERS/
›Fig. 10
X2
P2
X1
P1
H1
H2