Dry-type transformers and oil-immersed transformers difference

In daily life, the common transformer is tantamount to dry-type transformers and oil-immersed transformers of the points, the two have their own characteristics, and the scope is very different, but both are superior performance, popular. From the literal point of view, dry-type transformers and oil-immersed transformer is the main difference is no "oil", as I do not know, because there is no oil, both in appearance there is a big difference.
Dry-type transformer without oil, do not shell, and can directly see the transformer coil, and 3 phase step up transformer because there is oil, there is a shell, the shell is transformer oil, oil soaked with transformer coil, from the outside Can not see the transformer coil.
Oil-immersed transformer in order to facilitate the heat, that is, to facilitate the flow of internal insulation oil cooling, the external design of the radiator, like a heat sink, and dry-type transformers but not the radiator, cooling transformer coil by the following fan, prefabricated compact transformer as a result of fire needs, generally installed in a separate transformer indoor or outdoor, and dry-type transformers must be installed indoors, under normal circumstances installed in the low-voltage distribution room, and low-voltage Power distribution cabinet installed side by side.
It can be said that the two have their own advantages and disadvantages, each with its own characteristics, no matter what kind of transformer has its scope of application, can be used within its scope to play the greatest value.

Importance of Setting Temperature Control System for Dry Type Transformer

single pole transformer itself, the safe operation is very important, its safe operation and its service life, largely depends on the transformer winding insulation is safe and reliable.
In addition, we must know that the winding temperature on the insulation of great influence, if the winding temperature exceeds the insulation temperature, it is likely to make the insulation is damaged, reducing the use of dry-type transformers, and even lead to its normal work, Therefore, the transformer operating temperature monitoring and alarm control is very important, because the power transformer 10kva structure from the inside to the outside are: core, low voltage winding and high voltage winding. While the heat source for the core and low-voltage winding, the outer surface of the high-voltage windings due to the small current and heat rarely.
Therefore, the use of ordinary axial fan blower transformer surface and air conditioning cooling effect is not good. Transformer in the manufacturing, has reserved a dedicated cooling duct, only a specially designed dry air-cooled temperature control device in order to achieve the desired results.
As the dry-type transformers are often unattended operation, in order to ensure the safety of dry-type transformers, installation of air-cooled temperature control system and the ventilation of the switchgear transformation, so that when the temperature is too high to automatically start the ventilation cooling device is very important.
Therefore, the dry-type transformer set temperature control system is necessary.

Oil-immersed transformer inspection items are as follows:

1, see the 11kv single phase transformer is not a threat to the safety of the transformer running around the hidden dangers;
2, see the gas relay is not full of oil;
3, see the side of the casing is not damaged, there is no discharge traces or other anomalies;
4, check the cooling device operation;
5, check the conventional type transformer running sound is normal;
6, check the connection head and the side of the casing pile with or without heating, discoloration;
7, to see the discoloration of respirator selenium color change has not changed;
8, see the oil pillow and oil filling casing in the oil level, oil color is normal, there is no oil leakage phenomenon;
9, see the annex and the body without leakage, oil leakage phenomenon;
10, check the upper oil temperature table indicates there is no abnormal situation;
11, check the explosion-proof tube diaphragm has no effusion, the appearance is not complete and so on.

Transformer core grounding treatment:

100kva single phase pole mounted transformer core grounding inspection is generally used to detect the steel clamp pieces and iron core insulation, if measured through the screw insulation resistance is zero, you can determine the grounding point, and then from the top down the gradual investigation. But also useful multimeter power measurement, but need to do security measures, and by experienced professionals to operate.
100kva oil transformer assembly and maintenance is the main reason for multi-point grounded core. So in the maintenance must be folded silicon steel sheet, need to be crushed when the insulation can not be crushed between the stack to keep the laminated clean, metal powder can not stay on the disc, the prominent silicon steel hammer to use flat, leak Magnetic processing to be painted, some pads and insulation washer must be replaced when crushed, loose should be fastened. Grounding plate and core to overlap firmly, do not touch other silicon steel. If you find the phenomenon of touch the core, to install the insulation board and fixed. When the bottom of the tank dirt and sludge is completed, the transformer insulation drying, the transformer after the power transformer repair inspection and observation to confirm the sound normal, all components connected well, there is no prominent phenomenon can be loaded into the fuel tank.

single transformer can be divided into three-phase transformers and single phase transformer

oil immersed distribution transformers 1000kVA and above, shall be installed outdoor thermometer type signal, and then the distant signal. 800kVA and above should be installed oil immersed distribution transformer gas relay and pressure protection device, 800kVA transformer oil-immersed according to the following requirements, in consultation with the manufacturer, but also can be equipped with gas relay. Dry-type transformers shall be specified by the manufacturer, the installation of a temperature measuring device, and more generally for the 630kVA transformer installations.
Products classified according to the number of phases to distinguish between single transformer can be divided into three-phase transformers and single phase transformer

. In a three-phase power system, the general application of the three-phase transformer, when the oversized transport conditions and subject to the  three single-phase power system can also be applied consisting of three single-phase transformer transformer group.

Description of Farady power transformer​

Using its consolidated technology and the experience it has accumulated in the construction of oil immersed power transformers, designs, builds, tests, commissions and maintains power transformers with voltages of up to 35 kV and power ratings of up to 4 MVA.Farady 50kva power transformer

 are used wherever it is necessary to connect systems for the generation, transmission, distribution and utilisation of electrical energy, which function at different voltages, in order to transfer large quantities of active and reactive energy between these systems.

Manufacturer of standard and custom oil immersed distribution transformer

Manufacturer of standard and custom oil immersed distribution transformer. Available with single phase and three phase power supply. Various features include multi-tapped, low impedance and temperature rise, optional filters and input/output breakers, integral power and remote power distribution and oil immersed power transformer. Suitable for recording studios,commercial/residential movie theatres, server rooms, diode and SCR rectifiers, inverters, frequency converters, induction heaters, voltage transformation and other applications. Commercial, education, healthcare, testing, security, telecommunications and other industries served.

Farady oil immersed transformer 1000kVA and above, shall be installed outdoor thermometer type signal, and then the distant signal

Farady oil immersed transformer 1000kVA and above, shall be installed outdoor thermometer type signal, and then the distant signal. 800kVA and above should be installed oil-immersed transformer gas relay and pressure protection device, 800kVA transformer oil-immersed according to the following requirements, in consultation with the manufacturer, but also can be equipped with gas relay. dry type transformer price shall be specified by the manufacturer, the installation of a temperature measuring device, and more generally for the 630kVA transformer installations.

Power transformer magnetic flow refers to what

The excitation current of the polemounted transformer is only the transformer side of the power supply winding connected to the differential protection circuit, the excitation current is equivalent to the internal fault of the transformer short-circuit current. Therefore, it will inevitably affect the correct work of longitudinal differential protection. Under normal circumstances, the transformer excitation current is small, usually only the substations and transformers rated current of 3% to 6% or less, so the differential protection circuit of the imbalance current is very small. In the case of external short-circuit, the excitation current will decrease due to the voltage drop of the system. Therefore, the influence of excitation current on the differential protection is often negligible in steady state. In the special case of a sudden increase in voltage, it is possible to generate a large field current which is 6 to 8 times the rated current. This transient process of the transformer excitation current is usually referred to as inrush current

Introduction of Low - voltage Outlet Method of Dry - type Power Transformer

1, low-voltage standard closed bus: If the use of closed wiring project bus (also known as plug-in bus or bus-shaped busway), the corresponding dry-type pole mounted transformer provide standard closed bus terminal to facilitate connection with the external busbar. Enclosure (IP20) products, enclosed on the top cover of the housing provide closed bus flanges; no enclosure (IP00) products, only closed busbar terminals. 2, low-voltage side of the standard side line: when the dry-type transformers and low-voltage distribution panel placed side by side, in order to facilitate the connection between the terminals, 25kva pole mounted transformer can provide low-voltage side of the outlet, usually with GGD, GCK, MNS and other low- Transformer factory and switchgear factory to sign the interface with the minutes to confirm the detailed size with the interface to ensure the smooth installation of the scene. 3, low-voltage side of the line stand side row: and the horizontal side of the outlet similar to the elected domino screen, such as the vertical layout of low-voltage power distribution screen, the transformer can provide low-voltage side row of qualifying side.

Transformer technology, voltage ratio and efficiency

For different types of transformers have the appropriate technical requirements, can be expressed with the corresponding technical parameters. Such as the main technical parameters of pole mounted transformers are: rated power, rated voltage and voltage ratio, rated frequency, operating temperature level, temperature, voltage regulation, insulation and moisture resistance for low-frequency transformer main technical parameters are: Frequency characteristics, nonlinear distortion, magnetic shielding, electrostatic shielding, efficiency and so on. Transformer voltage than the two sets of transformer coils were N1 and N2, N1 for the primary, N2 secondary. In the primary coil with an AC voltage, in the secondary coil will have induced electromotive force at both ends.When N2> N1, the induced electromotive force than the primary plus the voltage is higher, this kind of transformer called the step-up transformer: When N2 is the voltage ratio (turns ratio), when n <1, then N1> N2, U1> U2, the transformer step-down transformer.

substations and transformers business in the future development of technological progress will take the road. The traditional old products despite the market, there is production, but the profit margins have been very small, it is impossible to form a strong competitive edge, the transformer main profit point is a new generation of high-end products, passive integration technology, the rapid rise of micro- Machine products, a comprehensive upgrade for the transformer to provide a leap-forward development of the technology entry point. In recent years, the development of 10kva transformer frontier, such as power ferrite materials, soft magnetic alloy materials, amorphous crystalline magnetic materials, nano-alloy magnetic materials, piezoelectric ceramics, nano-insulating materials have achieved fruitful development, which for the electronic transformer The industry technological progress has created good conditions, the electronic transformer will miniaturization with the needs of the whole, to the high-frequency, low loss, chip-oriented direction.

How to Determine the Reasonable Capacity of Transformer

First of all to investigate the local power supply voltage, the user's actual electricity load and the conditions of the place, and then refer to the transformer nameplate marked technical data selected one by one, generally from the transformer capacity, voltage, current and environmental conditions into account, Should be based on the user's electrical equipment capacity, nature and use of time to determine the required load, in order to select the transformer capacity.
In normal operation, the oil type transformer should bear the load of the transformer rated capacity of about 75 to 90%. If the actual load of transformer is less than 50%, it should be replaced with small capacity transformer. If it is larger than the rated capacity of transformer, the transformer should be replaced immediately.
At the same time, the transformer in the choice of the power supply line to determine the polemounted transformer primary coil voltage, according to the secondary device voltage selection of electrical equipment, the best choice for low-voltage three-phase four-wire power supply system. This provides power for both electricity and lighting.
For the choice of current load should pay attention to the motor starting to meet the requirements of the motor (because the motor starting current sink operation than the large 4 to 7 times).

Transformer routine maintenance knowledge is as follows:

In recent years, with the power grid capacity, voltage level, and the advancement of power reform, power supply sector not only to ensure the reliability of power supply, but also to ensure the quality of power supply. three phase pad mounted transformer as an indispensable important power system equipment, its normal work or not directly affect the safe and stable operation of the power grid. Therefore, to ensure the reliable operation of the transformer has important practical significance. China's large transformer over 220 kV in recent years, the occurrence of multiple insulation incidents, mostly with its partial discharge. Therefore, the partial discharge of effective inspection can effectively determine the operating state of the Amorphous Core Transformers.

Drying Method of Transformer

Induction heating method
This oil immersed distribution transformer is the body on the tank, the outer winding coil through the power frequency current, the use of fuel tank wall eddy current loss of heat to dry. At this time the temperature of the wall should not exceed 115 ~ 120 ℃, body temperature should not exceed 90 ~ 95 ℃. In order to facilitate the winding coil, as much as possible so that the coil turns less or less current, the general election of 150A current, the conductor can be useful 35 ~ 50mm2 wire. The tank wall can be pad asbestos multi-root, wire around the asbestos.
Hot air drying method
This method is the body in the drying room through the hot air drying. Imported hot air temperature should be gradually increased, the maximum temperature should not exceed 95 ℃, in the hot air inlet should be equipped with filters to prevent the entry of Mars and dust. Do not blow the hot air directly to the body, as far as possible from the body below evenly blowing in all directions, so that moisture from the lid vent holes released.

Protection of dry - type transformers

According to the use of environmental characteristics and protection requirements, 3 phase step up transformer can choose a different shell. Usually IP20 protective shell, to prevent the solid foreign body greater than 12mm in diameter and rats, snakes, cats, birds and other small animals to enter, resulting in a short-circuit power failure and other malignant failure, to provide security for the live part of the barrier. If you need to install the transformer in the outdoors, you can choose IP23 protective shell, in addition to the IP20 protection, but also to prevent the vertical line into a 60 ° angle within the water droplets into. But the IP23 shell will reduce the cooling capacity of the transformer, the choice should pay attention to its operating capacity to reduce.

A thorough analysis of the cause of spontaneous combustion of power

First, the prefabricated compact transformer high and low voltage on both sides without insurance. Although some have been fitted with drop-out fuse and claw insurance, but its fuse is used more aluminum or copper wire instead, resulting in low-voltage short-circuit or overload, the fuse can not fuse and burn the transformer. Distribution transformer high and low fuse configuration properly. Transformer fuses on the widespread configuration of the phenomenon is too large, resulting in a serious overload distribution transformer when the transformer burned.
Second, the rural lighting lines are more, most of them are using single-phase power supply, coupled with the construction of the jumpers in the random and management is not in place, resulting in a partial load shifting phase of operation. Long-term use, resulting in a phase coil insulation burned the aging transformer.
Third, the tap.
1, privately adjust the tap. As the winter and summer load differences in electricity consumption, the voltage level of change. Thus some rural and corporate electrician without electric repair department to adjust the trial and adjust the tap changer privately, resulting in distribution transformer tap-changer is not in place, bad contact and burned.
2, the tap switch poor quality, irrational structure, the pressure is not enough, contact is not reliable, the external character wheel position and the actual position is not exactly the same, causing the star moving contact position is not fully contact, dislocation of the dynamic and static contact The insulation distance between the two taps becomes small and short-circuit or ground discharge occurs under the action of the potential between the two taps. The short-circuit current will soon burn the taps and even damage the whole winding.
Fourth, oil leakage is the transformer most common appearance anomalies. As the transformer body filled with oil, the connection parts are rubber beads, pads to prevent oil leakage. After a long period of operation, will make some of the rubber beads in the transformer, rubber pad aging caused by oil seepage cracks, resulting in decreased performance after damp insulation, discharge short circuit, burn the transformer.
Fifth, the single phase pole mounted transformers high and low voltage lines are mostly introduced by the overhead lines, lightning arrester is not put into operation in time or without the installation of 10kV surge arresters, resulting in lightning destroyed the transformer.
6, some of the distribution transformer is not configured a protection, or is configured with a protection, but its action, reliability is very low, and some can not even action.

Farady oil immersed power transformer is certified

The oil immersed power transformer is certified IEC and every transformer is endowed with a certification of PCB and PCT-free oil.The use of the latest manufacturing technologies such as step-lap cores and oval technology guarantees the maximization of the power/losses rate, and all this at a budget price. All our standard distribution transformers sold in the world are compliant with the new standard on no load and load losses, and tested applying a 0% tolerance to ensure very low energetic and economic losses.

Farady produce distribution transformers

Farady distribution transformers are available in full ranges of 50- 35kv. We chose to design and produce distribution transformers with high quality standard features, not only complying with Norms, but also enhancing the durability and the efficiency of the transformer. The standard C3 painting cycle applied on all oil immersed distribution transformers guarantees a + 33% of protection more than the average transformer on the market.

Farady 13.8kv single phase transformer

The kind of special pole mounted distribution transformer is can be directly step down the high voltage from 35kV to low voltage 240V ~440V. Its usefull for small load demand village or region using. No need middle transform by another high voltage, thus save the cost of the electrical investment. Farady 13.8kv single phase transformer have most competitive price will go through lots of tests carefully before dispatch: Raw material check, Winding test, Assemble test, Painting check, Nameplate check and routine tests.

Single Phase Pole Mounted Distribution Transformer

Farady pole mounted transformers are categorized by type and class. Class identifies the number of high voltage bushings, mounting positions, and lightning arresters when required. Farady Single phase pole mounted transformers are designed and manufactured in compliance with all applicable standards. Farady pole mounted transformer rated voltage during 6-35kV, oil immersed transformer are most used in power plant, power grid transmission and distribution station,industry& commerce electrical substation as the electrical equipment of power transmission.

Farady pad mounted transformer

Farady three phase pad mounted transformer, for use on underground power distribution systems, are best suited for commercial applications in public access areas and where underground service is required. These distribution transformers meet modern design requirements for flexibility and provide a visually pleasing installation. Construction allows installation in locations accessible to the general public without the need for protective fencing or vaults. These units are ideally suited for apartment buildings, schools, hospitals, shopping centers, commercial buildings, or industrial sites.

Farady offer safety oil transformer

Farady oil transformer offer an environmentally responsible, high efficiency, safer choice. The units have high-fire-point fluid, providing fire safety benefits, and a projected life well beyond that of a traditional mineral-oil transformer. These efficient and cost-effective transformers use fluid. Because of safety reason and the flammability of the oil in the oil type transformer, they are mostly used for outside applications. One of the safety features in an oil immersed power transformers is a sensor to tell if gas is accumulating inside the transformer, which is a sign of an electric arc in the winding. This prevents catastrophic burnout. Below are a list of a few areas where oil filled transformer are used.

Electric Power Transformer

Farady oil immersed transformers are suitable in case of external installations or in the most heavy industrial areas. Farady transformers are filled with mineral oil free from PCB and PCT. The tank is realized  in order to allow the oil expansion during the normal heating and cooling phases of transformer due to load cycles, or by a radiators system. It is also possible to produce transformers in the version with oil conservator or the hermetic type. This series has advantages of high reliability, low loss, low noise, low temperature rise and low part discharge.

Transformers with on load tap changer

The on load tap changer transformer is used to vary the voltage ratio with the transformer on duty providing uninterrupted regulation. The on load tap changer is activated by a motor drive. Drive shafts and bevel gear units mechanically connect the motor-drive to the on load tap changer. An electronic step voltage regulator is used for sensing the voltage variation and to operate automatically the motor drive. The OLTC installed in our power transformers are of technically advanced design.

The design of the oil immersed power transformer

The design of the oil immersed power transformer, windings can be continuous or interleaved disc, simple or multiple helix. Cooling channels are made with duly shaped rods and flow guide rings. Tappings are provided on the HV windings, controlled either by means of an off circuit switch or an on load tap changer transformer.In addition to power and distribution transformer manufacturer，power transformers either for general purposes (reducing-increasing voltage on main grid, feeding auxiliary transformers, transferring to the grid the own produced current) and for specific purposes (industrial transformers, autotransformers, insulation transformers, starting transformers, transformers for testing ..).

The farady step up transformers

The farady step up transformers are transformers used in booster transfer networks or in central outputs either unloaded or with a load graduality up to a maximum power of 4MVA, 35 kV. They are produced as either dry or oil forced types. The forced dry type power transformer are manufactured as either hermetic or with tanks. In dry types containers can be produced up to IP44 according to protection class. Casts can be manufactured in Standard or in condensed form or upon request.

Farady oil immersed transformer features

Farady can design and manufacture oil immersed transformer with voltage up to 220KV and capacity up to 100MVA according to IEC standard, This series of oil immersed transformer have following features: low loss,low temperature rise and low partial discharge, high reliability, core lifting free,no leakage. Farady oil immersed power transformer is advanced insulation temperature control technique, special insulation material are used in hot-spot of the winding and transformer body.

SCB 11 Cast Resin Dry Type Transformer

SCB 11 Cast Resin Dry Type Transformer

Farady Electric manufacture a complete range of three phase distribution transformers, including oil-immersed type & cast resin dry-type transformer, we always designed with increased margins of safety and reliablity,and meet the following standard:

IEC60076, IEEE Std, GB1094

http://www.farady-electric.com/scb-11/

The structure of Farady transformer

For distribution transformer, insulation and cooling conditions according to points, can be divided into oil immersed transformers and dry type transformers. In order to strengthen the insulation and cooling conditions, the transformer core and windings are together immersed in a tank filled with transformer oil in. In exceptional cases, such as street lights, mine illumination, but also with dry-type transformers. In addition, there are a variety of special-purpose special transformers.

Oil immersed transformer classification

Oil immersed transformers 1000kVA and above, shall be installed outdoor thermometer type signal, and then the distant signal. 800kVA and above should be installed oil-immersed transformer gas relay and pressure protection device, 800kVA transformer oil-immersed according to the following requirements, in consultation with the manufacturer, but also can be equipped with gas relay. Dry-type transformers shall be specified by the manufacturer, the installation of a temperature measuring device, and more generally for the 630kVA transformer installations. Products classified according to the number of phases to distinguish between single transformer can be divided into three-phase transformers and single phase transformer. In a three-phase power system, the general application of the three-phase transformer, when the oversized transport conditions and subject to the three-phase power system can also be applied consisting of three single-phase transformer transformer group.

Oil Immersed Transformers are mostly used for outside applications

Because of safety reason and the flammability of the oil in the oil type transformer,oil immersed transformers are mostly used for outside applications. Farady oil immersed distribution transformers are suitable in case of external installations or in the most heavy industrial areas. The transformers are filled with mineral oil free from PCB and PCT. The oil tank is realized to allow the oil expansion during the normal heating and cooling phases of transformer due to load cycles, or by a radiators system. It is also possible to produce transformers in the version with oil conservator or the hermetic type.

Farady power and distribution transformer manufacturer

We manufacture Outdoor/indoor oil immersed distribution transformer without top expansion tank upto 33kv substation system voltage. This design has a single tank. The core and windings are contained in the lower tank. The primary winding is taken through the HT insulator to be connected to the primary terminal arranged at the top of the HT insulator. The secondary windings are connected to secondary terminals placed on the lower tank.

Farady power transformer

Farady power transformer manufacturer present the largest portion of the capital investment in addition the power transformer remains oil immersed power transformer which presents a fire hazard that is particularly objectionable in urban and metropolitan environment. After careful studies of various alternatives to conventional transformer technology to produce a gas insulated power transformer with increased mega volt-ampere ratings, gas insulated power transformer has been developed with a use with non flammable gas. For changing the insulating material from oil to gas a comparative study between these types of transformers should be made. In this paper two mathematical models are suggested and simulated by computer programs to calculate the temperature of the cooling mediums and transformer windings.

Farady Amorphous oil-immersed transformer

Widely replacing the silicon steel core transformer by amorphous alloy core oil immersed transformer in outdoor power distribution system, then we can get the desirability of good energy saving effect and reduce the pollution of the atmosphere. Farady Amorphous Core Transformer commonly use sealed structure, so insulated oils and dielectric are not affected by air pollution, which can be run in a damp environment. In this case, it is ideal equipment for distribution in urban and rural general distribution network, especially suitable for low power, load fluctuations and the area which is difficult to carry out routine maintenance.

Farady distribution transformer with Conservator

Farady distribution transformer has a power range of 6.3-2500kVA, and it suits for 10KV, 50/60Hz power transmission and distribution systems. The Farady oil immersed transformer is often accepted for 6KV and 10KV power transmission and distribution systems, the high voltage auto load booster shows lowered no-load loss and reduced no-load current, thus realizing notable energy saving performance. Moreover, the noise level meets relevant requirements of environmental protection policy. So, this is an energy saving and environmental friendly product.