Equipment Second issue 2019

TRANSFORMERS intelligent

The alternating current passes at the primary coil,
generate varies magnetic field.
This magnetic field cut the secondary coil by that
generate electrical voltage in the secondary coil.
So the magnetic field generated by primary coil
causes to generate voltage at secondary coil by elec-
tromagnetic induction

Types of transformers when the number of turns of the primary coil “
Np” more than number of turns of the second-
Step up transformer ary coil ”Ns” it’s called step up transformer , that
means the output of the transformer more than its
Step down transformer input
when the number of turns of the secondary coil
“Ns” more than number of turns of the primary
coil ”Np” it’s called step down transformer , that
means the output of the transformer less than its
input

The efficiency of transformer

Its ratio of the maximum capacity can be pulled from the secondary coil to the prima-
ry coil capacity.

The protection of the transformer

The main component for protection circuit

Protected Circuit Breaker.
C.T. &V.T.
Protective Relay.
Direct voltage source contain from battery and Dc charger.

The main component for protection circuit

Protected Circuit Breaker.
Auxiliary Relay.
Alarms and Signaling Equipment.
ce contain from battery and Dc charger.

How to work the stages of protection

Measure the electrical quantities. Measure the electrical quantities after con-
Sense Find the fault. nect the circuit breaker which it disconnect-
Send disconnect signal to the circuit breaker ed before
and send alarm signal.
Isolate the fault.

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The characteristic of stage of protection

For an interconnected protection system, the following technical properties must be available

The speed

Must the protection device have fast response to disconnect fault part when occurred

Simplicity of installation:

The simple installation of the protection relay is a key factor in the efficiency, reliability,
and maintenance of the relay.

Reliability:

Its mean that device be ready in any
Setnimsitei.vity:

Sensitivity of the device means the accuracy
of the device in the work in terms of mea-
surement of electrical quantities and working
time , so any device have sensitivity factor =
is / io = vs. / vo.
Is, vs.: less value of volte or less value of
short circuit current.
Io, VO: less value of recent current or volte.

Selectivity:

Its mean the ability to select the fault point and select which circuit breaker must disconnect
, .when fault occurred and the relay of this zone don’t disconnected after 0.1 sec and it’s the
time of disconnected of the circuit breaker , we find the second relay do the disconnected
instead of the first circuit breaker and it have time to work instead of the first relay so it set
after 0.4 sec to disconnect the second relay , its mean there is 0.3 sec time available for the
first relay to make the disconnect .
Ex:
R1: 0.1 sec.
R2: 0.4 sec. The electrical protection:

R3: 0.7 sec. Protection of power • Differential Protection
transformer: • Overcurrent Protection
• Earth Fault Protection
• Restricted E.F Protection

Capacitor bank: • Current Balance Protection
• Over current Protection
• Earth Fault Protection
• Max. Voltage Protection
• Low Voltage Protection

• Differential Protection
Reactor protection: • Over Current Protection
• Earth Fault Protection
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Protection
of public bars:

Frame Leakage
Protection that’s at 33 KV
bars only.

Buchholz relay:

Consists of two columns, the first in the top and second in
the bottom, in case of a short circuit occurred inside the
electric transformer, the oil is boiling and the gas increases,
these gases overturn the upper columns in the Buchholz
Relay and these for alarm.
When the upper columns changes, the contact points are
closed and the alarm occurs.
In case of disconnected the electrical transformer after
alarm, the gases increased and overturn the bottom columns
and occur trip which is the process of separation for the
electric transformer.

The temperature It has limit for the temperature of oil in the transformer, when be 95
make alarm, when it 105 make trip.
And it has limit for the temperature of winding of the transformer, when
be 105 make alarm, when be 115 make trip.

Pressure: Here, in the case of delaying the operation of the Buchholze Relay and the Differen-
tial Relay, the pressure of the oil is increased by a certain value.
Pressure called Pressure Relief the oil is released from its position.

Transformer testing

The transformers should meet the conditions of the electrocution standard specifications which are re-
Egyptian standard specifications number 0136- 05/ ferred and at the expense of the manufacturer company
2006, 0136- 03/ 2005, 1886/ 2007, 6977/ 2009. according to the running rules and methods in the
And so that the following routine tests are carried most modern version or the standard specifications and
out in the factory and according to the international which are certified by the engineer

No load tests

The load is raised on the sides of the low voltage in the transformer with keeping the sides of the medium
voltage open, the following parameters are measured:

• Measuring the current at no load.
• Measuring the loss of power at no load (no load losses).
• Measuring the winding resistance and the range of their equality at the phases.
• Measuring the voltage and conversion rate (ratio) {V1/V2= N1/N2}, and this percentage is measured at each

step of the tap changer steps to make sure of the lowest value and the highest value and to compare it with
the allowed value in the technical specifications of the transformer either in the project's documents or in the
accepted tables of guarantee.
• Identifying the vector group to ensure meeting the required standard specifications.

Short circuit test

This is carried out by injecting the short circuit current (Isc), based on the transformer's voltage, on the high 135
voltage coils with making a short circuit on the low voltage coils. In this test, the following parameters are
measured:

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1. Load current.
2. Measuring the impedance voltage which is known as Z% or % of short circuit

voltage.
3. Measuring the loss of copper (Copper losses) at the complete load current.
4. These values are compared to that which allowed according to the technical spec-

ifications of the transformer and the tables of guarantee presented by the importer
with standardizing the measured values at 95 Co for the oil transformers, and 75
Co for the dry transformers.

• Other tests

(Induced over voltage withstand test) and (partial discharge test measurement).
This test is carried out at a voltage of 800 volts and a frequency of 100 hertz (a test voltage
of twice the net voltage and a frequency of three times the net frequency) is put on the sides
of the low voltage of the transformer with keeping the sides of the medium voltage open for
a minute or this test is carried out at a voltage of 800 volts and a frequency of 150 hertz for 40
seconds, and the results should be withstanding the test without collapsing of the isolation.

1. Separate – source power frequency withstand test
2. Isolation test between coils and between the coil and the earth

1. The test is carried out at a voltage of 28 K. V. (for the transformers with medium volt-
age coils 11 or 12 K. v.) and at a voltage of 50 K. v. (for the transformers with medi-
um voltage coils 22 K. v.). This is for just a one minute for the high voltage coils with
grounding the low voltage coils.

2. The low voltage coils are tested at a voltage of 2.5 K. v. for a one minute with
grounding the high voltage coils.

1. Testing the transformer's oil.
2. Observing any leakage of the oil

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• Type test

1. The test of temperature increase at the rated current using the method of short
circuit.

2. Impulse withstand test with a number of three rushing waves for each phase by
a wave 102/ 50 microsecond and with an impulse voltage according to the rated
current of the transformer and according to the standard specifications.

3. Short circuit test, the transformer is tested 9 times with a number of three
current impulse waves for each phase in a working period of 0.5 second. And
so that the impulse wave current equals 25 times the rated current. These type
tests are only carried out when seriously affirmed to be carried out in the doc-
uments of the specifications and the cost is the responsibility of the project’s
owner not the contractor, but it is often enough to submit the type test report,
which had been done before in a one of the nationally or internationally certi-
fied analysis laboratories, on the transformer which has the same capacity and
specifications.

4. Megger test for the oil transformer and dry transformer at a voltage set at 500
volts. The test is carried out at three positions:

1. On the high voltage coils while the low voltage coils and the break out point are 137
grounded.

2. On the low voltage coils while the high voltage coils as well as the break out point
are grounded.

3. Between the low voltage coils and high voltage coils

The resistance is measured in ohm directly after spending 15 seconds and after 60
seconds. The resistance value in ohms after 60 seconds should achieve the resistance
value after 15 seconds in ohms. The value is ≥ 1.3.

• Replacing the refused equipment or tools:

In case of the presence of any problems in the materials or equipment of the trans-
former during the calibration or the test, the manufacturer company is has the respon-
sibility to replace them by other appropriate and accepted materials and equipment
and the responsibility is on the manufacturer or the contractor, and so that the routine
tests are carried out another time if these materials are related to the types of these
tests.

• General

1. The transformers are evaluated, produced and tested according to the last
version of the international electrocution specifications IEC 60076, part (1) to
part (5).

2. The three phase power transformers are immersed in oil by natural cooling
and a natural cooling air (Oil immersed Natural Air Natural Cooled (ONSN)).

3. The transformers are decided whether they will be installed indoor or outdoor
and also the altitude above sea level, the ambient temperature, the relative
humidity and the air polluters of dust, sand or any other polluters are deter-
mined.

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• Technical electrical specifications

1. The following data should by determine: 800, 630, 300, 200, 100, 63, 50 k. v. a.
2. Maximum continuous output (power), which determines 3000, 2500, 2000, 1600, 1500, 1250,

1000, 800, 630, 300, 200, 50, 100 and 63 k. v. a.
3. Primary voltage: according to the available medium voltage nets
4. 3300, 6600, 10500, 11000, 20000, 22000.
5. Manual voltage changer in the side of primary voltage without a load (Off load tap changer)
6. Chooses (+) 2 x 2.5 %, zero, (-) 2 x 2.5 % (five steps) or + 2 x 2.5 %, zero, (-) 4 x 2.5 % (seven

steps).
7. Secondary voltage: 400/ 231 volt and a grounded neutral point.
8. Connection group (transformer’s coils connecting systems) (vector group): Dynl l.
9. Frequency: 50 hertz.
10. Impedance voltage, percentage impedance or the percentage of short circuit voltage: shouldn’t

be less than 4 % (and the maximum extra tolerance is determined to be 10 %)
11. Temperature rise, in the ambient temperature according to what is mentioned in the international

electrocution specifications number IEC 60076.

• Top of oil: 45 Co measured by the thermometer.
• On windings (coils): 55 Co measured through the resistance.

• Isolation level

Isolation level For a primary voltage of 24 k. v. For a primary voltage of 12 k. v.

High voltage impulse withstand 125 k. v. 75 k. v.
voltage (BIL) (regulated impulse 50 k. v. 28 k. v.
3 k. v. 3 k. v.
voltage)

Power frequency withstand volt-
age (isolation level) (direction of

medium voltage)

Low voltage power frequency
withstand voltage (secondary

voltage)

• Loss: most distribution companies demand that the transformers are of the low loss type not nor-
mal loss type.

• The neutral points in the transformers are grounded.
• The transformer should be filled with the transformers' oil according to the international electro-

cution specifications number IEC 60296. The oil should be of mixable type (NYNAS type high-
grade oil) which is classified to have a high resistance to decomposition.
• Over load to the transformer: the transformer should be able to feed the loads which reaches the
maximum regulated value for it, in addition to the ability to load the transformer with extra 10 %
beside the regulated maximum value for two hours without damaging the transformer and with-
out exceeding the temperature increase above the limits shown above either for the oil or for the
coils (windings), considering what is mentioned in the table number
• (5/ 5- 3).
• Short circuit current capacity: the transformer should be able to withstand the mechanical and
thermal stress without a damage when there is a shortage (fault) on its sides for two seconds and

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at the level of the short circuit power of voltage nets 11 k. v. (500 m. v. a.), and for voltage nets
22 k. v. (750 m. v. a.).
• Parallel operation: this should be identified in the tender documents to consider traducing these
transformers completely symmetric for this purpose to work in a complete efficiency in parallel
together in all the conditions of operating loads and the same power factor.
• Earthing or grounding: all the metal parts that don’t carry a current in the transformer – exclud-
ing the iron heart single chips- and all the nails and clamping plates should be connected to the
collecting side which will be connected- when installing- to the earth system.
• Connection ends or sides: the ends of high and low voltage should be connected to isolators made
of porcelain appropriate for the operating voltage with fixing these isolators to the tanker's cover
in a methods that makes its changing easy without opening or removing the cover.

Technical specifications of production Iron heart (core):

• the transformer's core is made of cold pulled silicon steel sheets with a thickness
not more than 0.3 mm and with a low loss.

(1) Windings (coils): high voltage windings are made of copper wires with round cross section
isolated with varnish or a rectangle cross section isolated with cellulose paper. Low voltage windings
are made of copper slices without isolation or made of wires isolated with paper. The windings should
be powerfully fixed to withstand shocks and shakings while transferring the transformer and also the
power resulting from the short circuit current.
(2) External tank: the transformer's tank should be made of winding steel plates so that the external
body is the cooling surface and the tank is provided with another tank for extending the oil, and the
tube that transfers the oil to the tank is installed on it and the Bochholz relay device may be installed to
it, the extending tank is tubes which has a hole for compensating the oil shortage (decrease) and a hole
for installing the device of absorbing moisture (silica gel) and also an indicator of the oil's level.

• Distributing transformer's accessories

• Oil conservator vessel with oil level indicator and oil filling plug.
• Thermometer of indicating the oil temperature.
• Silica gel breather: for absorbing moisture, and this material is orange, which is converted to green when

exposed to moisture, and should be free of cobalt.
• The device of changing the converting percentage while the transformer is not connected to the source

(off load tap changer).
• Bochholz relay device (magnetic liquid level gauge with alarm contacts).
• Rings (cycles) for lifting the transformer with winch (lifting tackles).
• Provision for lifting the transformer from downwards with a jack (provision for jacking).
• Provision for skidding or towering the transformer on the ground.
• Earthing or grounding terminal
• Oil drain valve.
• Oil sampling tape.
• Four wheels.
• (the transformer's indicating board) Rating and diagram plates, and also the transformer's number should

be sculpted on the its cover in clear letters if they are necessary and demanded.

• Additional attachments (if necessary to be added) 139

1. Oil temperature gauge electronic digital type for transfer signal to computer.
2. A closing diaphragm which breaks when the pressure increases inside the transformer (explosion dia-

phragm).
3. The device of protecting the transformer from the internal extra pressures if it is tight and not provided

with an expanding tank, and provided with a pressure relief device with alarm contact).
4. A dial type thermometer with an alarm contact.
5. Pressure vacuum gauge (indicator) inside the tank.

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• The transformer's data board (Name plate)

1. A data board is put in a clear and apparent place on the transformer, which
shows all the transformers details which is shown afterwards on a board in
prominent or engraved letters.

2. Manufacturer's serial number
3. Year of manufacture
4. Number of phases
5. Rated power
6. Rated frequency rated voltages
7. Rated currents
8. Vector group
9. Impedance voltage
10. Connection diagram
11. Table fiving tapping voltage & the positions
12.Total mass
13. Total mass (without tank and oil).

• Transformer oil

All the distribution transformers in this specification should be imported when they are
filled with oil, and the used oil is treated to prevent oxidation (inhibited) and free of
moisture and components of acidity and alkalinity and sulfates and achieve an electric
isolation not less than 30000 volts (minimum dielectric strength of 30000 volts) when
testing a sample with a diameter of 25 mm and a lacuna between the tests poles 2.5
mm and according to the international electrocution specifications number IEC 60296.

(1) With the tender, a type of oil displayed to use, in addition to providing the de-
tailed technical bulletin to explain the quality of the displayed oil.

(2) The cooling oil should have a high flash point and should be biodegradable and
non-bio- accumulating.

1. And should meet or be better than the following specifications:

2. Dielectric strength : 43 k. v.

3. Dielectric constant at 25 Co : 2- 38

4. Flash point : 285 Co

5. Fire point : 312 Co

6. Thermal conductivity at 25 Co : 0.00031

7. (cal/ sec. cm2c/ cm)

8. Specific gravity at 25 Co : 0.876

• b- Operation and mainte- They should be available in the two
nance booklets languages, Arabic and English.

• c- Spare parts The proposed spare parts and their
prices are displayed.

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• Approved manufacturers

It is preferred to mention some names of manufacturer companies which products meet
the acceptance of the engineer, and mentioned in the end, or approved equal quality.
The appendix number (m5/ 5- 3) shows more details about the iron heart (core), the
windings (coils), the tank, the dielectric, voltage changer, painting, windings’ saturation,
ventilation paths, the transformer’s cover or lid, degree of tightening and the penetration
isolators.
The appendix number (m5/ 5- 2) shows the guarantee tables for the oil transformers
which should be filled and completed and signed by the manufacturers (producers) and
be presented with the tender.

• General

1. The dry distribution transformer is three phase with powers up to 3 mega volt am-
pere (m. v. a.) and voltages 7.5, 11, 22 and 33 k. v./ 0.4 k. v. . it doesn’t have oil for
isolation, but this done either by cast resins or air, and the windings have different
structures and shapes and should meet the Egyptian standard specifications number
1886/ 2007 and 1888/ 2005 and the international electrocution specifications IEC
60076- 11.

2. These transformers are distinguished by a high safety coefficient, which allows
them to be used it dangerous areas and places with low ventilation and also the high
buildings load centers in which the oil transformers are not allowed for use.

3. It is recommended that dry transformers are used in the buildings' basements in
which the oil transformers are not allowed to be used, and in high buildings which
design economics require installing the distribution transformers in interior floors.

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• Transformer classification

The suitable transformer for the operating conditions is chosen in some sites such as high towers, huge malls,
hospitals and the stations installed under the ground's level and in mines and factories of chemicals. The trans-
former is classified according to all of the following considerations:

The windings covering

The transformer’s windings may not be covered with a cast resin but is surrounded by air.
The transformer’s windings may be surrounded with a cast resin

• The transformer's tank and method of ventilation

• If the transformer is not covered and is not surrounded with a protective container, then cooling the trans-
former's core and its dielectric windings is done using external air.

• If the transformer is covered and surrounded with a protective container, it should be designed so that the
transformer's windings core cooling depends on external air and in this case, it is necessary to refresh or
renew the air of the place to which the hot air is released from the transformer's core. The container's pro-
tection degree is often IP 00, IP 20, and IP 23 based on the ambient atmosphere around the transformer.

• If the transformer is covered, tighten, and surrounded with a container, this container should be provided
with interlocking margins which prevents exchanging the external ambient air or the air or gas inside it if
the transformer is of the Gas filled dry type.

• Cooling medium

1. The cooling medium around the transformer may be the natural air around the container.
2. The cooling medium may be a stable gas such as nitrogen, that’s in case of completely closed transformer

with providing the container with means to face the change of the gas volume inside the container.

• Cooling method

1. The cooling may be either:
2. Natural cooling, or
3. Natural/ forced, for the forced cooling, fans are used, which work when the transformer’s loading reaches

near the complete load.
4. Forced, by moving the cooling medium along the transformer’s continuous loading range using fans in-

stalled on the container’s surface with the presence of air inlet holes with filters

Transforming percentage Like what happens in case of oil transformers

Method of connecting the Like the oil transformers.
phases windings

The regulated (rate) power Like the oil transformers.
for the transformer

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• Arrangements of changing the loading percentages on the load

Unlike the oil transformer, the dry transformer is provided with an ends box which is connected to each of
the transformer's phases and of the medium voltage coils (windings) to change the transforming percentage.
The box should be provided with copper jumpers to make the required connections to change the transform-
ing percentage on no load.
The ends box should be provided with a tough lock to prevent tampering while loading the transformer.

Transformer’s iron core

• The silicon steel sheets should be collected in a method that lowers the loss on no load, and also reduc-
ing the noise caused by the movement of these sheets.

• The iron core should be treated after collection by some layers of paint to protect it from corrosion

Windings (coils)

• It is important to be concerned with isolating the windings at a high temperature in contrast to the oil trans-
former's windings.

• The transformers should be well fixed and flexible isolators or breaks should be used to reduce the shakes
and noise and also to withstand the stresses resulting when there is a short circuit without harming the
windings or isolating them.

• In the transformer isolated by cast solid resins, the used material's type should be chosen so that is doesn’t
crack when the operating temperature is changed and to be flame- resistant and doesn’t release any poi-
sonous or flammable gases, and also in this case, the wires used in the windings should be isolated using
dielectric paints or using a silicon material.

• In the transformers which are not isolated by cast resins, the windings should be isolated by materials of
the types: Class- A, b, E, F, G, or C, so that the windings' temperatures don’t exceed the values mentioned
in the table number (5/ 5- 6).

Penetration isolators

• Like the oil transformer.

Percentage of the transformer's impedance

••• TLTihhkeeemntuhamexoibmielrut(mr5a/nt5esfm-o6rp)mesreharto.uwres itnhceraelalsoewiendthvaelutreasnosffotremmepr.'sIncocmrepasoeneinnttshe transform-
er's components.

Table (5/ 5- 6): the maximum allowed values for the temperature increase
for the transformer's parts above the ambient temperature 40 Co

parts of the transformer Degree of the windings Temperature of the di- The maximum allowed
windings isolation electric system (Co) temp. increase (Co)

Class A 105 Co 60 Co
Class E 120 Co 75 Co
Class B 130 Co 80 Co
Class F 155 Co 100 Co
Class G 180 Co 125 Co
Class C 220 Co 150 Co

Iron core, metal parts, In any case, the temperature
and the nearby parts shouldn’t reach the extent
that may cause any damage
to the iron core or any other
part of the transformer

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Note• : windings' temperature increase is measured by the resistance (dielectric) method.

- The transformer should be provided with two groups of temp. indicators, one of them also
sends an audible or visible alarm of the temperature increase when the temp. is near the maxi-
mum allowed limit.
- The second indicator group disconnects the transformer from the feeding source when the
temperature increase continues

• The transformer’s attach- • The transformer’s data board
ments
The transformer’s data board should contain the follow-
The transformer should be provided with the following ing
attachments: The rated or the regulated power (k. v. a.)
Lifting rings or cycles The rated or regulated voltage in the side of medium
4 steel wheels which movement direction is easy to be voltage and low voltage.
changed (easy to steer). The rated frequency (hertz).
A nail in the metal body for grounding it. The method of connecting the low voltage and medium
Data board. voltage windings.
Two temperature indicators which are used also for the The connecting system and the displacement angle (for
purpose of warning (alarm) and disconnecting the trans- example Dynl l).
former from the source. The method of natural/ forced cooling by air.
Classification of the dielectric materials of the windings
(class A/ E/ B/ F/ G/ or C).
The dielectric medium surrounding the isolated wind-
ings and the iron core (resin material/ air/ a stable gas
like SF6/ C2F6/ and N2.
Transforming percentage operating device (number of
steps, percentages of transforming).
Percentage of the transformer’s impedance (4 %, 5 %, or
6.25 %).
Windings’ temperature.

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A comparison between oil Disadvantages of the dry
and dry transformers: transformers:

Advantages of dry transformer Is can’t be compared to the oil transformer
Although they dry transformer requires more maintenance in terms of maintenance or changing the
than oil transformer because the dust's accumulation of the broken windings, especially if the trans-
isolator, the maintenance cost for dry transformer is less as former is isolated by a cast solid resin.
it needs just to be cleaned, not to change the isolator or to be To avoid breaking the transformer, it is
qualified such as filtering or get rid of the moisture as in the oil necessary to remove accumulated dust on
transformers. the isolator.
The dry transformer can be installed in the load centers, which The difference is price and the payback
reduces the loss of low voltage. period of using the transformer depends
It needs a smaller area and can be installed with the connecting on each using case alone, which in turn
and breaking switches of high voltage. depends on the site’s conditions.
Lower the opportunities of firing, as there's no flammable oil. While in the dry transformer the used
The dry transformer has a less volume then the oil transformer voltage doesn’t exceed 33 k. v. in terms
of the same power and can be installed inside the buildings, of the high voltage, it is possible in the oil
cellars and higher floors of buildings in a safe method. transformer to use voltages up to 750 k. v.
The dry transformer is distinguished as it able to be continu- The loss percentage in case of load and no
ously loaded in a percentage of 100 %, while in the oil trans- load in the dry transformer is high, com-
former about 80 %. pared to the oil transformer.
The dry transformer can be loaded, and especially which is Sometimes, the price of the dry transform-
used for types of isolation by a developed technology which er may reach 1.5 times that of the oil trans-
can withstand high temperatures (up to 220 Co) as in the dry former for the same power if the trans-
transformers which use the saturated polyester material in a former is surrounded with a container. The
vacuum medium (Vacuum pressure impregnated) as a polyester dry transformers’ prices are expected to
sealant for the windings. get lower in the near future due to the huge
It is noticeable that in the oil transformer, it is not possible to expansion in their use in the electricity
increase the temperature to higher than 85 Co above the ambi- distribution nets.
ent temperature, also the paper isolators are still the most used
in this transformer.

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intelligent

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intelligent

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Egypt Distributors

CAIRO:

Eskimo for Eng. & Trade

43 Nagib El Rihani St., Cairo, Egypt
Tel: +2025906541
Fax: +2025916275
Email: [email protected]
Web: www.eskimoegypt.net

Gharib Engineering

8, Ganzoory Street, Cairo, Egypt
Tel: +202 24820605
Fax: +202 26839618
Email:[email protected]

Engineering Centre

3 Ebn Hany Elandaloss Str. From Taiaraan St.,
Cairo, Egypt
Tel: +2022620944
Fax: +2024036523

Omega Engineering & Trading

P.O.Box 2454 19, Moustafa Ragab St.
Tel: +204176211
Fax: +202916364
Email:[email protected]
Web: www.omegaeg.com

ALEXANDRIA:

Engineering Centre

20 M. Abd Elmeguid Elzayat St, Alexandria
Egypt
Tel: +2034830767
Fax: +2034831333
Email: [email protected]

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SolaHD™ Buck-Boost
Transformers

Buck-Boost Transformers provide a compact, en-
ergy efficient, low cost means for raising or low-
ering voltage by a relatively small amount – usu-
ally 5 to 27 percent. Buck-boost transformers are
typically used to power control panels, landscape
lighting and other loads with specific voltage re-
quirements that differ from the available line volt-
age. The proper buck-boost transformer can max-
imize the performance and life of the connected
equipment.

• Specifications Group 2 Group 3
120 x 240 Volt Primary, 16/32 240 x 480 Volt Primary, 24/48
Group 1 Volt Secondary. Non-Encap- Volt Secondary. Non-Encap-
120 x 240 Volt Primary, 12/24 sulated: 50/60 Hz; 0.15, 0.25 sulated: 50/60 Hz; 0.15, 0.25
Volt Secondary. Non-Encap- kVA. Encapsulated: 60 Hz; kVA. Encapsulated: 60 Hz;
sulated: 50/60 Hz; 0.05, 0.1, 0.5, 0.75, 1, 1.5, 2, 3, 5, 7.5 0.5, 0.75, 1, 1.5, 2, 3, 5, 7.5
0.15, 0.25 kVA. Encapsulated: kVA. kVA
60 Hz; 0.5, 0.75, 1, 1.5, 2, 3,
5, 7.5 kVA.

Hertz: 50/60 Hz or 60 Hz

Number of Phases: Single Phase
Windings: Aluminum

• FEATURES • Applications

• cULus Transformers are useful where the available
• Small, single phase, dry type distribution trans- voltage must be changed to accommodate the
voltage required by the load. For many elec-
former trical circuits, the National Electrical Code
• Dual voltage primary and a dual voltage second- (NEC) requires a separately derived neutral
secondary connection provided by Delta-Wye
ary connected transformers
• Transformers can be connected for a wide range
• Typical applications include:
of voltage combinations
• In compliance with NEC Article 210.9, Excep- • Hospitals
• Office Buildings
tion 1 when field connected as an autotransform- • Industrial Plants
er. They can handle loads up to 20 times the • Schools
nameplate rating • Commercial Buildings
• More efficient than equivalent isolation trans- • Shopping Centers
formers • Apartment Buildings
• When the primary and secondary windings are • High Rise Buildings
connected it becomes an autotransformer, allow-
ing it to supply a load with a much larger kVA
rating than the nameplate indicates
• Connected as an insulating transformer, the
transformer’s capacity matches the nameplate
kVA rating.

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Note: Weights and dimensions may change and should not be used for construction purposes.

Note: Weights and dimensions may change and should not be used for construction purposes. 155

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Appleton™ TRE Series Ex e Transformers

TRE Series Ex e Transformers meet ATEX and IECEx standards and are suitable for use in Zone 1
and 2 locations. These increased safety transformers are suitable for mounting inside Ex e rated enclo-
sures. They are ideal for use in OEM increased safety applications where the available voltage must be
changed to accommodate the voltage required by the load and safety voltage. They can be used when
your application require primary and secondary protection by fuses or branch circuit breaker.

Applications:

• • Equipment transformers are useful where the available
• voltage must be changed to accomodate the voltage
• required by the load and safety voltage.
• • Suitable for use in certifi ed increased safety enclosures
• and OEM increased safety applications.
• • Requires primary and secondary protection by fuses or Branch Circuit Breaker

Specifications Features

• Hertz : 50/60 Hz • ATEX, IECEx
• Number of Phases : Single Phase • Class I
• Operating Temperature: -20 °C to +80 °C • Circuit insulation voltage between: 4500 V
• Primary Voltage: 230/400 V, 240/415 V
• Secondary Voltage: 24/48 V, 2x110 V between windings; 2300 V between primary
• Windings: Coppe winding and earth; 1800 V between secondary
winding and earth
Technical Data • Ex e Terminals capacity 4 mm²
• Class F insulation

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SolaHD™ K-Factor Ventilated
Transformers

K-Factor Transformers feature conductors
capable of carrying the harmonic currents
of non-linear loads without exceeding the
temperature rating of the insulation sys-
tem. The basic design takes into account
the increase in naturally occurring “stray”
losses caused by non-linear loads that can
cause standard transformers to dramati-
cally overheat and fail prematurely. The
core and coil design manages the DC flux
caused by triplen harmonics.

Suitable Applications

• Any situation where the available voltage must be changed to accommodate the voltage
required by the specific electrical circuit or connected equipment. For many electrical circuits,
the National Electrical Code (NEC) requires a separately derived neutral secondary connec-
tion provided by Delta-Wye connected transformers.

• Distribution transformers can be located close to the load. No vaults are required for installa-
tion and no long, expensive feeder Ines are needed. Common applications include inductive
and resistive loads such as motors, lighting and heating

SPECIFICATIONS

• Group A:
• K-4 Rated 480 ∆ Primary, 208Y/120 Secondary. 15, 30, 45, 75, 112.5, 150, 225, 300, 500 kVA
• Group B:
• K-13 Rated 480 ∆ Primary, 208Y/120 Secondary. 15, 30, 45, 75, 112.5, 150, 225, 300 kVA
• Group C:
• K-20 Rated 480 ∆ Primary, 208Y/120 Secondary. 15, 30, 45, 75, 112.5, 150, 225, 300 kVA
• Hertz:
• 60 Hz
• Number of Phases:
• Three Phase
• Temperature Rise:
• +150°C
• Windings:
• Aluminum

Features

• UL
• Energy Efficient Compliant to DOE 2016. Made in the USA
• Conductors to carry harmonics of a K-rated load without exceeding insulation temperature
ratings
• UL 1561 Listed up to K-20 rated protection
• Rated temperature rise of +150°C, +220°C insulation
• Shielded for quality power
• Basic design takes “stray losses” into account and functions within safe operating temperatures
•
Core and coil design engineered to manage the zero sequence flux caused by triplen harmonics

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•
UL

• Energy Efficient Compliant to DOE 2016. Made in the USA
• Conductors to carry harmonics of a K-rated load without exceeding insulation temperature ratings
• UL 1561 Listed up to K-20 rated protection
•Rated temperature rise of +150°C, +220°C insulation
•Shielded for quality power
•Basic design takes “stray losses” into account and functions within safe operating temperatures
•Core and coil design engineered to manage the zero sequence flux caused by triplen harmonics

kVA Type 3R HxWxD Approx. ElecConn Primary Secondary SolaHD
Weather Ship Amps Amps Catalog
Shield Number
Weight
(lbs)

Single Phase: 240 x 480 Volt Primary,120/240 Secondary60 Hz, Design Style 1?

15 WS-15 28 x 16 x 16 210 1 62.5/31.3 125/62.5 ES5H15S

25 WS-15 28 x 16 x 16 245 1 104/52.1 208/104 ES5H25S

37.5 WS-17 31 x 18 x 18 340 1 156/78 313/156 ES5H37S

50 WS-17 31 x 18 x 18 415 1 208/104 416/208 ES5H50S

75 WS-09 44 x 23 x 21 610 1 313/156 625/313 ES5H75S

100 WS-09 44 x 23 x 21 705 1 417/208 833/417 ES5H100S

167 WS-16 46 x 26 x 24 980 1 695/348 1392/695 ES5H167S

Three Phase: 480 Volt Δ Primary, 208/120 Secondary60 Hz, Design Style 1

15 WS-02 23 x 18 x 14 221 5 18.1 41.7 E2H15S

30 WS-14 28 x 23 x 16 310 5 36.1 83.4 E2H30S

45 WS-14 28 x 23 x 16 387 5 54.2 125 E2H45S

75 WS-30 34 x 28 x 22 678 5 90.3 208 E2H75S

112.5 WS-30 34 x 28 x 22 794 5 135 313 E2H112S

150 WS-10 44 x 33 x 21 1006 5 181 417 E2H150S

225 WS-11 46 x 36 x 24 1368 5 271 625 E2H225S

300 WS-11 46 x 36 x 24 1479 5 361 834 E2H300S

500 WS-12 65 x 45 x 35 2457 5 602 1390 E2H500S

Three Phase: 480 Volt Δ Primary, 240 Volt Δ, Secondary with reduced capacity center tap60 Hz,
Design Style 1

15 WS-02 23 x 19 x 14 221 6 18.1 36.1 E5H30S

30 WS-14 28 x 23 x 16 322 6 36.1 72.3 E2H30S

45 WS-14 28 x 23 x 16 387 6 54.2 108 E5H45S

75 WS-30 34 x 28 x 22 678 6 90.3 181 E5H75S

112.5 WS-30 34 x 28 x 22 792 6 135 271 E5H112S

150 WS-10 44 x 33 x 21 1009 6 181 361 E5H150S

225 WS-11 46 x 36 x 24 1367 6 271 542 E5H225S

300 WS-11 46 x 36 x 24 1478 6 361 723 E5H300S

500 WS-12 65 x 45 x 35 2457 6 602 1204 E5H500S

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