IG168-009
LIB
transforma.dis
Distribution transformers immersed in
dielectric liquid up to 3150 kVA
General instructions
IG-168-EN, version 05, 17/04/2020
In view of the constant evolution in standards and design, the characteristics of the elements contained in this manual are subject
to change without prior notice. These characteristics, as well as the availability of components, are subject to confirmation by
Ormazabal.
CAUTION!
When medium-voltage equipment is operating, certain components are live, other parts may be in movement and some may
reach high temperatures. Therefore, the use of this equipment poses electrical, mechanical and thermal risks.
In order to ensure an acceptable level of protection for people and property, and in compliance with applicable environmental
recommendations, Ormazabal designs and manufactures its products according to the principle of integrated safety, based on
the following criteria:
• Elimination of hazards wherever possible.
• Where elimination of hazards is neither technically nor economically feasible, appropriate protection functions are
incorporated in the equipment.
• Communication about remaining risks to facilitate the design of operating procedures which prevent such risks,
training for the personnel in charge of the equipment, and the use of suitable personal protective equipment.
• Use of recyclable materials and establishment of procedures for the disposal of equipment and components so
that once the end of their service lives is reached, they are duly processed in accordance, as far as possible, with the
environmental restrictions established by the competent authorities.
Consequently, the equipment to which the present manual refers complies with the requirements of section 11.2 of Standard
IEC 62271-1. It must therefore only be operated by appropriately qualified and supervised personnel, in accordance with the
requirements of standard EN 50110-1 on the safety of electrical installations and standard EN 50110-2 on activities in or near
electrical installations. Personnel must be fully familiar with the instructions and warnings contained in this manual and in other
recommendations of a more general nature which are applicable to the situation according to current legislation[1].
The above must be carefully observed, as the correct and safe operation of this equipment depends not only on its design but also
on general circumstances which are in general beyond the control and responsibility of the manufacturer. More specifically:
• The equipment must be handled and transported appropriately from the factory to the place of installation.
• All intermediate storage should occur in conditions which do not alter or damage the characteristics of the equipment
or its essential components.
• Service conditions must be compatible with the equipment rating.
• The equipment must be operated strictly in accordance with the instructions given in the manual, and the applicable
operating and safety principles must be clearly understood.
• Maintenance should be performed properly, taking into account the actual service and environmental conditions in
the place of installation.
The manufacturer declines all liability for any significant indirect damages resulting from violation of the guarantee, under any
jurisdiction, including loss of income, stoppages and costs resulting from repair or replacement of parts.
Warranty
The manufacturer guarantees this product against any defect in materials and operation during the contractual period. In the
event that defects are detected, the manufacturer may opt either to repair or replace the equipment. Improper handling of this
equipment and its repair by the user shall constitute a violation of the guarantee.
Registered Trademarks and Copyrights
All registered trademarks cited in this document are the property of their respective owners. The intellectual property of this manual
belongs to Ormazabal.
[1] For example, in Spain the “Regulation on technical conditions and guarantees for safety in high-voltage electrical installations” – Royal Decree
337/2014 is obligatory.
IG-168-EN version 05; 17/04/2020 3
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Table of Contents
In view of the constant evolution in standards and design, the characteristics of the elements contained in this manual are subject
to change without prior notice. These characteristics, as well as the availability of components, are subject to confirmation by
Ormazabal.
CAUTION!
When medium-voltage equipment is operating, certain components are live, other parts may be in movement and some may
reach high temperatures. Therefore, the use of this equipment poses electrical, mechanical and thermal risks.
In order to ensure an acceptable level of protection for people and property, and in compliance with applicable environmental
recommendations, Ormazabal designs and manufactures its products according to the principle of integrated safety, based on
the following criteria:
• Elimination of hazards wherever possible.
• Where elimination of hazards is neither technically nor economically feasible, appropriate protection functions are
incorporated in the equipment.
• Communication about remaining risks to facilitate the design of operating procedures which prevent such risks,
training for the personnel in charge of the equipment, and the use of suitable personal protective equipment.
• Use of recyclable materials and establishment of procedures for the disposal of equipment and components so
that once the end of their service lives is reached, they are duly processed in accordance, as far as possible, with the
environmental restrictions established by the competent authorities.
Consequently, the equipment to which the present manual refers complies with the requirements of section 11.2 of Standard
IEC 62271-1. It must therefore only be operated by appropriately qualified and supervised personnel, in accordance with the
requirements of standard EN 50110-1 on the safety of electrical installations and standard EN 50110-2 on activities in or near
electrical installations. Personnel must be fully familiar with the instructions and warnings contained in this manual and in other
recommendations of a more general nature which are applicable to the situation according to current legislation[1].
The above must be carefully observed, as the correct and safe operation of this equipment depends not only on its design but also
on general circumstances which are in general beyond the control and responsibility of the manufacturer. More specifically:
• The equipment must be handled and transported appropriately from the factory to the place of installation.
• All intermediate storage should occur in conditions which do not alter or damage the characteristics of the equipment
or its essential components.
• Service conditions must be compatible with the equipment rating.
• The equipment must be operated strictly in accordance with the instructions given in the manual, and the applicable
operating and safety principles must be clearly understood.
• Maintenance should be performed properly, taking into account the actual service and environmental conditions in
the place of installation.
The manufacturer declines all liability for any significant indirect damages resulting from violation of the guarantee, under any
jurisdiction, including loss of income, stoppages and costs resulting from repair or replacement of parts.
Warranty
The manufacturer guarantees this product against any defect in materials and operation during the contractual period. In the
event that defects are detected, the manufacturer may opt either to repair or replace the equipment. Improper handling of this
equipment and its repair by the user shall constitute a violation of the guarantee.
Registered Trademarks and Copyrights
All registered trademarks cited in this document are the property of their respective owners. The intellectual property of this manual
belongs to Ormazabal.
[1] For example, in Spain the “Regulation on technical conditions and guarantees for safety in high-voltage electrical installations” – Royal Decree
337/2014 is obligatory.
Table of Contents
1. Description and main characteristics .......................4
1.1. Design, manufacturing and testing ...........4
1.1.1. Individual or routine tests ....................5
1.1.2. Test protocol.................................5
2. Lifting, moving and handling ...................................6
2.1. Lifting and moving with a forklift truck .......6
2.2. Lifting and moving by crane..................7
2.3. Moving on wheels ..........................12
3. Transport ..................................................................13
3.1. Preparing the load for transport .............13
3.2. Transport agents............................15
3.3. Selecting the route for road transport .......15
3.4. Checking impact detectors..................16
3.5. Responsibility...............................16
4. Storage ......................................................................17
5. Installation ...............................................................18
5.1. Receiving the transformer...................18
5.2. Transformer site.............................19
5.3. Transformer electrical connections ..........19
5.3.1. Standard procedure.........................19
5.3.2. Special transformers with electrostatic screen
between primary and secondary ............21
5.3.3. Low electromagnetic emission transformers .21
6. Commissioning ........................................................25
6.1. Checking the transformer before
commissioning .............................25
6.1.1. Mineral oil insulated transformers ...........25
6.1.2. Natural ester transformers...................26
7. Maintenance .............................................................27
7.1. Access for maintenance operations ..........27
7.2. Checking the transformer ...................27
7.2.1. Transformer temperature....................27
7.2.2. Inspecting oil volume .......................28
7.2.3. Noise .......................................28
7.2.4. Tightening bolts and threaded pieces .......28
7.2.5. Oil leaks ....................................28
7.2.6. Paint........................................28
7.3. Regularity of maintenance ..................30
7.4. Repairs .....................................31
8. Additional information ............................................32
8.1. Reliability ...................................32
8.2. Company registration certificate.............32
9. Final annex ...............................................................33
IG-168-EN version 05; 17/04/2020
4
Description and main characteristics
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
1. Description and main characteristics
1.1. Design, manufacturing and testing
Medium-voltage electrotechnical regulations applicable when the transformer was manufactured.
Ormazabal's transformers have been designed and
constructed in accordance with mandatory standards, and
meet all testing requirements in current medium-voltage
electrotechnical regulations[2], as well as particular customer
specications.
More specically, apart from the mineral oil-immersed
transformers, the organic transformer range is characterised
by its use of natural biodegradable ester as a dielectric
liquid, with the following general characteristics:
• Excellent dielectric properties, with a high water
saturation point, which allows it to maintain high
dielectric strength values with a high water content.
• High re resistance: natural dielectric ester is classied
as a K class liquid (re point above 300°C) according to
Standard IEC 61100.
This classication oers the possibility of avoiding having to
install xed re extinguishing systems, according to many
of medium-voltage electrotechnical regulations of dierent
countries.
• High biodegradability in ground and water due to its
natural composition.
• It is not ecotoxic.
• Recyclable and reusable in other favourable environ-
mental products at the end of its service life.
IG168-002
1
2
3
4
5
6
7
8
9
1Medium-voltage (MV) bushings
2Pocket for thermometer installation
3Bracing eye bolts
4Ferromagnetic core
5Medium-voltage (MV) and low-voltage (LV) windings
6Enclosure and dielectric liquid
7Pulling eye bolts
8Low-voltage (LV) bushings
9Lifting eye bolts
Figure 1.1. transforma elements detail
IG-168-EN version 05; 17/04/2020 5
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Description and main characteristics
1.1.1. Individual or routine tests
The transformers are subjected to routine tests, which
guarantee compliance with the following standards:
UNE-EN 60076-1, IEC-60076-1 Winding resistance measurement
UNE-EN 60076-1, IEC 60076-1 Transformation ratio measurement and check up of vector group
UNE-EN 60076-1, IEC 60076-1 Measurement of load losses and short-circuit voltage at main tapping
UNE-EN 60076-1, IEC 60076-1 Losses and no-load current measurement
UNE-EN 60076-3, IEC-60076-3 Power frequency voltage test
UNE-EN 60076-3, IEC-60076-3 Induced voltage test
Table 1.1. Standards
1.1.2. Test protocol
All the information regarding the transformer tests
is recorded in the "Test Protocol" enclosed with the
transformer documentation.
IG-168-EN version 05; 17/04/2020
6
Lifting, moving and handling
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
2. Lifting, moving and handling
The lifting elements must be selected based on the
transformer's total weight, as shown on the name
plate.
To enable lifting and transport, each transformer is tted
with fastening and lifting elements on the top side of the
tank or on the tank cover.
There are attachment points and boreholes in the bottom
of the transformer (guide shoes and back) in order to secure
it during transport.
NEVER force the cooling elements (ns, radiators, etc.)
when lifting, moving or xing the transformer to the
transport base. The xing, moving and lifting elements
(bracing, etc.) must be able to withstand the entire
force of these operations.
Transformers must always be lifted, transported and
handled using suitable, ocially approved equipment.
All lifting, transport and handling equipment must be duly
selected and used by the handler in accordance with the
characteristics of the machine.
Ormazabal shall not be liable for any improper choice or
use.
2.1. Lifting and moving with a forklift truck
In this case, the transformer must only be lifted and moved
when tted and fastened to a pallet adequate to handle
its weight and size, making sure the cooling elements are
protected against any damage caused by the forks.
Figure 2.1. Transport using a forklift truck
IG-168-EN version 05; 17/04/2020 7
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Lifting, moving and handling
2.2. Lifting and moving by crane
When lifting and moving the transformer with a crane, it
must be remembered that the lifting elements allow the
transformer to be completely suspended. These elements
are the lifting rings, which are tted in the cover or in the
top part of the sides of the tank (depending on the weight
of the transformer) and identied for this purpose (e.g.
painted yellow). The following indications must be taken
into account when lifting the transformer:
• Use the eye bolts in the cover or top of the sides of the
transformer tank to lift the transformer with a crane,
maintaining a horizontal position at all times.
• Use proper hooks to achieve perfect vertical elevation.
• The slings on the eye bolts must form a minimum angle
of 60º with the transformer’s horizontal.
• The slings must not rub or damage the bushings or
other accessories.
Risk of death by crushing and damage to the
transformer or to the installation.
• NEVER use transformer cooling elements such as ns
or radiators as lifting elements. RISK of severe injury
and damage to the transformer.
Figure 2.2. Preparing the crane hook in the eye bolts
Figure 2.3. Lifting a transformer using a crane
IG-168-EN version 05; 17/04/2020
8
Lifting, moving and handling
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
The following indications must be taken into account when
lifting the transformer:
• Transformers with eye bolts in the sides of the tank
- The lifting elements are used via the central hole
(Figure 2.4).
Figure 2.4. Lifting element
- The transformer has four lifting elements positioned
at the top of the sides for transformers with eye bolts
in the tank (Figure 2.5).
Figure 2.5. Position of the lifting elements
- ALWAYS lift the transformer using the four lifting
elements (identied in yellow) at the same time.
NEVER lift the transformer without any of these four
elements.
IG-168-EN version 05; 17/04/2020 9
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Lifting, moving and handling
- NEVER lift the transformer using the outside holes
(Figure 2.6).
Figure 2.6. Position not permitted for lifting
- DO NOT use the transformer cover lifting elements
in transformers with eye bolts in the tank. These
elements are invalidated to prevent any use other
than to remove the transformer from the tank if this
is tted with lifting elements (see Figure 2.7).
Figure 2.7. Position of the lifting elements
IG-168-EN version 05; 17/04/2020
10
Lifting, moving and handling
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
- NEVER lift the transformer using the connecting rod
of the cooling elements (Figure 2.8)
Figure 2.8. Position not permitted for lifting
• Transformers with eye bolts in the tank cover only
Whenever the lifting eye bolts are placed on the cover,
because the weight of the transformer so allows, and
they are identied in yellow (Figure 2.9).
Figure 2.9. Rings in the tank lid
IG-168-EN version 05; 17/04/2020 11
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Lifting, moving and handling
For lighter transformers, two or four eye bolts are
optionally tted in the cover.
In the case of transformers with four eye bolts, four
lifting hooks must be used at the same time.
In the case of transformers with two eye bolts, the two
hooks must be used with appropriate equipment.
Figure 2.10. Position of the four eye bolts in the cover
Figure 2.11. Position of the two eye bolts in the cover
IG-168-EN version 05; 17/04/2020
12
Lifting, moving and handling
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
The slings or lifting chains in the eye bolts must also
form an angle equal to or above 60º with the horizontal
of the transformer, and must allow fully vertical lifting
at all times.
- The slings must not rub or damage the bushings or
other accessories.
- ALWAYS lift the transformer using the lifting
elements, as identied for this purpose. NEVER lift
the transformer without any of these elements.
- Using the connecting rods for the n panels as
lifting points for the transformer is NOT ALLOWED
(Figure 2.12).
Figure 2.12. Forbidden lifting points
2.3. Moving on wheels
Risk of machinery breakage:
Do not use the cooling elements as a support point
(ns, radiators, etc.).
Support a lever against the transformer carriage in order to
move it on its wheels.
IG-168-EN version 05; 17/04/2020 13
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Transport
3. Transport
Despite the robust design and construction of the
transformers manufactured by Ormazabal, their integrity
depends critically on the safety and protection measures
taken during transport and unloading. The transformer
may be severely damaged in these operations if any bangs,
vibrations, impacts or shocks above normal for goods with
such dimensions and weight occur.
3.1. Preparing the load for transport
The transformer must be xed using slings, chains and
other elements suitable for the weight of the transformer,
as shown on its name plate.
The protection tools and equipment provided or
recommended by Ormazabal (according to the agreement
with the customer), such as anti-vibration brackets and
elements for pulling (bracing) or securing the load, must be
used for transport.
The transformer has specially designed lashing/fastening
elements to secure it during transport/handling operations.
• Top fastening elements: if tted, there are normally
four of them, and they are located in the same structure
as the lifting elements (Figure 3.1). It is essential that
chains, hooks and pulling or lashing elements NEVER
interfere, collide or exert force on cooling ns or
radiators. For this reason, they must be mounted at
such an angle as to prevent the described collisions or
interference.
Figure 3.1. Top fastening elements
IG-168-EN version 05; 17/04/2020
14
Transport
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
• Bottom fastening elements: are located at the base
of the transformer, and are used for bracing or lashing
during transport (Figure 3.2).
Figure 3.2. Bottom fastening elements
• When securing the transformer, be sure that the lashing
or fastening chains do not interfere with any of the
transformer's accessories or cooling elements.
• The fastening straps are attached to the container's
fastening elements on both sides of the transformer,
producing a symmetrical tension which is oset on both
sides.
• The connecting rods of the cooling elements must not
be used as lashing points for transport, or for any other
similar function (see Figure 3.3).
Figure 3.3. NEVER use cooling elements as fastenings for transport
IG-168-EN version 05; 17/04/2020 15
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Transport
3.2. Transport agents
All agents, companies and personnel involved in
transporting and handling the transformer must
demonstrate preparation, training, procedures and
experience in the transport of heavy equipment and
equipment susceptible to damage due to violent transport
conditions, and must count on suitable accreditations and
certicates in order to drive the means of transport used.
3.3. Selecting the route for road transport
The route chosen for road haulage must be the one with
the best conditions for transporting heavy loads which are
sensitive to damage from impacts, bangs, vibrations and
accelerations.
Routes that reduce the eects of accelerations, vibrations,
impacts and bangs caused by winding roads, changes of
gradient and the cant of the road should take precedence
over shortest distance.
As far as possible, priority should be given to the highest
category of motorways with minimum slope, maximum
linearity and best road surface condition.
The transformers are prepared for transport on at, paved
roads without signicant potholes.
As a general rule, a "pothole" is understood as any deciency
in the terrain greater than 200 mm, whenever the terrain
has angles of attack of less than 30° (i.e. no abrupt changes).
On uneven road sections, transport speed should be
reduced in order to ensure the load does not suer sudden
acceleration and deceleration.
Trac and transport rules in the corresponding
country must be respected in all cases.
If transport for the transformer is to include road
surfaces that are not asphalted, the customer must
indicate this circumstance in the order sent to
Ormazabal. Following this communication, the best
solution for transport will be decided between the
customer and Ormazabal.
IG-168-EN version 05; 17/04/2020
16
Transport
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
3.4. Checking impact detectors
Ormazabal reserves the right to t impact detectors (or ask
for them to be tted) in its transformers in order to provide
evidence of events that may cause damage to the machine
during transport.
In accordance with Standard IEC 60076-1, section 5.7.4.2
Acceleration during transport, the transformers referred
to in this manual are designed and built to withstand
accelerations of at least 1 g in all directions (apart from
gravity acceleration in vertical direction) without any
damage.
If transport is not managed by Ormazabal, or is not carried
out under its responsibility, and accelerations in excess
of 1 g are expected during transport, all accelerations
and frequencies must be dened in the order, and the
transformer must be designed in accordance with these
values.
Ormazabal shall not be liable for any damage during
transport whenever there is evidence of transport
conditions that exceed the values dened in the standard
or those specied when requesting the oer and/or order
for the product.
3.5. Responsibility
Whenever the conditions described in this document are
not met, Ormazabal reserves the right to reject liability for
any damage caused to its product while transporting and
handling.
IG-168-EN version 05; 17/04/2020 17
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Storage
4. Storage
If commissioning is not immediate, transformers must be
stored following the recommendations below:
• Store the transformer in a place that is dry and clean.
• If the transformer is equipped with plug-in terminals,
make sure the conical protector or cap provided for
keeping the connection terminals clean and intact is in
place.
Due to the particular characteristics of natural esters
at low temperatures, it is best to avoid storing these
transformers at temperatures below -5°C. It is therefore
recommended to store indoors.
IG-168-EN version 05; 17/04/2020
18
Installation
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
5. Installation
Ormazabal is not responsible for transformer insta-
llation, which must be carried out in accordance with
applicable legislation.
5.1. Receiving the transformer
The transformer is supplied ready for connection to the grid.
Some elements, such as the rollers and/or the thermometer,
may be supplied unassembled for shipping.
When the transformer is received (at the customer's
warehouse or at the transformer’s nal location), it must
be carefully inspected, paying special attention to the
following aspects:
• The transformer ratings, as indicated on its name plate,
must match those in the "Test Protocol", and these, in
turn, must match those specied in the associated order.
• Check the general state of the transformer and ensure
the absence of any bangs, in particular in the cooling
equipment and in the insulators or terminals. If the
transformer has paint defects, it must be corrected in
accordance with the procedure set out in section “7.2.
Checking the transformer” - “7.2.6. Paint”.
• Verify that the transformer has all of its accessories
(rollers, thermometer, etc.), ensuring they are not
damaged.
Notify the transport agent and Ormazabal imme-
diately if any accessory is missing or damaged.
• The transformer seals must be unbroken and untouched.
Figure 5.1. Transformer seal detail
Tampering with or breaking a seal voids the transformer
warranty as well as Ormazabal's liability.
Notify Ormazabal immediately if any anomaly is
detected upon the receipt of the transformer. If, after
a 15 day period, the manufacturer has not received
a report of anomalies or defects found, it is assumed
that the transformer arrived in a perfect condition
and Ormazabal will not be responsible for any future
anomalies or their consequences.
IG-168-EN version 05; 17/04/2020 19
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
Installation
5.2. Transformer site
The transformer site for both indoor and outdoor
installations must allow adequate cooling.
Poor ventilation of the transformer may cause it to
overheat.
Both the technical conditions and the personal and property
safety requirements of the transformer's design and site are
dened in the applicable legislation and standards at the
place of installation.
If the transformer is installed indoors, prepare a horizontal
base that supports the transformer. Take into account the
total weight of the transformer, which is shown on its name
plate.
Lock the rollers to prevent the transformer from moving
during operation.
Natural esters have higher freezing points than those
of mineral oil. The liquid could therefore freeze during
prolonged exposure to temperatures below -10°C. In
these cases, the transformer can be powered without
aecting its physical-chemical properties. However,
the transformer should be protected from low
temperatures during prolonged storage periods.
5.3. Transformer electrical connections
5.3.1. Standard procedure
Risk of death by electric shock and of irreversible
damage to the transformer or to the electrical
installation.
• The transformer's electrical connections can only be
made by qualied personnel while always observing
proper electrical safety measures.
The steps to follow to complete the electrical transformer
connection are as follows:
1. Check that the electrical power supply to the
transformer matches the service values shown on the
transformer’s name plate.
Risk of causing irreversible damage to the
transformer or to the electrical installation.
• Verify that the electric power supply to the transformer
meets the service values shown on the transformer’s
name plate.
2. Open all the electrical power sources and interlock or
block the necessary breaking devices to prevent any
power supply.
3. Check that electrical voltage is not present.
4. Earth and short-circuit all the electrical power sources.
5. Delimit and mark the work area properly.
IG-168-EN version 05; 17/04/2020
20
Installation
General instructions
transforma.dis: Distribution transformers immersed
in dielectric liquid up to 3150 kVA
6. Check for correct dielectric liquid level.
Contact Ormazabal in the event of dielectric liquid
leaks.
Start the electrical connection by earthing the
transformer tank.
7. Earth the transformer tank using round connecting
points for a standard cross-section earthing cable, as
well as an M12 bolt (M10 on demand) and two 14 mm
washers (12 mm for M10), applying 40-60 Nm of torque
for M12 (25-35 Nm for M10).
Tools:
• Standard cross-section earthing cable.
• Round terminals of suitable diameter.
• One M12 (M10) bolt.
• Two 14 mm (12 mm for M10) washers (one for each
side of the connection terminal).
8. Connect the transformer to the medium-voltage
circuit. To avoid any leaks, use exible connections that
do not place any strain on the transformer bushings,
suciently sized to prevent excessive overheating
and, at the same time, allow heat expansion without
damaging the transformer.
The tightening torques must guarantee the proper
electric contact of the connections.
9. Connect the transformer to the secondary circuit using
exible connections which do not place any strain on
the transformer bushings, suciently sized to prevent
excessive overheating and, at the same time, allow
the expansion caused by heat without damaging the
transformer.
The tightening torques must guarantee the proper
electric contact of the connections.
10. Connect the transformer’s neutral to the electrical
installation’s neutral (where appropriate).
11. Check that the tap changer position is correct; and,
in the case of a multi-voltage transformer, ensure the
medium-voltage or primary circuit is connected to the
electrical voltage that is going to be used as service
voltage.
Figure 5.2. Transformer earth connection detail
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
Page is loading ...
/