supplyFerroalloy furnace transformer

a. The transformer itself has good energy-saving characteristics: no-load loss, no-load current, load loss. As low as possible, the percentage of impedance voltage is suitable for the commonly used capacity, the use of existing high-quality raw materials, the use of small oil gap and other advanced technologies, so that the transformer really becomes energy-saving, the performance level of the international developed country products in the mid-1990s.

b. Transformer has a very stable reliability and long service life, the new structure of the product design technology to go through the test of operation and type test verification, design life is not less than 30 years.

c. Require a certain overload capacity to ensure that the user in the case of exceeding the capacity of 20% of the load, the operation indicators meet the requirements of national standards.

d. Reduce the user's maintenance workload, so that the user no longer lifts the core in long-term use, and the design maintenance-free time is not less than ten years. Free of major repairs for 20 years.

Transformer material, structure and process selection:

A complete ferroalloy furnace transformer is mainly divided into the following six parts:

Namely: iron core, winding, body, fuel tank, assembly, accessories. The following are respectively introduced

(1) Iron core: In terms of materials, we have selected 30Q130 silicon steel sheet made by Wisco or 30Z130 silicon steel sheet made by Nippon Steel Co., LTD., Japan, which is basically the same as the materials used in international developed countries.

In the structure of the use of full oblique joint plate type, the upper and lower clamp connection of low magnetic steel plate tensile plate structure, changed the previous square iron structure, so that there is no hole on the iron chip, the magnetic flux density of each section of the iron core is consistent, no distortion, in the shearing process using German imported Georg shear line, control shear burr <0.02mm (standard <0.05mm qualified products), The length tolerance per meter is less than 0.02mm, which increases the laminates coefficient and reduces the gap between seams, avoids local overheating of the core, reduces product noise and no-load loss and no-load current.

(2) Winding: From the material, the use of oxygen-free copper electromagnetic wire, mainly control its ρ20℃<0.017241, and mainly control the material and tightness of its paper insulation, while other insulation materials have been greatly improved, the main purpose is to try to make the coil has a better shaft and radial stability, overload capacity, thermal stability capacity has been improved. Wear and tear has also fallen.

(3) The body: all the wood parts of the body are changed to laminated wood, which improves the rigidity of the lead frame. The upper and lower pressing plates are made of cardboard or epoxy resin forming parts, which increases the insulation distance of the electrical conductor to the ground compared with the iron pressing plate, and can reduce the size of "window height". The primary and secondary main insulation adopts imported cardboard, which increases the strength of the main insulation. Multi-coil integrated package, improve the reliability of the product. The body is dried by Norwegian vapor phase drying equipment, drying thoroughly and without damaging the insulation, and has the role of washing the body.

(4) Oil tank: The oil tank adopts folding plate. Minimize the weld, increase the strength and make positive and negative pressure tests to ensure the reliability of the product seal.

(5) Final assembly: After the body is dry, the winding is relaxed and pressed by hydraulic equipment to achieve good results. The vacuum oil injection reduces the bubbles in the winding, reduces the partial discharge, and increases the life of the product. The use of new anti-aging sealing materials, so that the original leakage problem can be improved.

(6) Accessories: The main accessory water cooler uses YS1 oil-water cooler, so that it has a descaling meter, rather than choosing water quality, or dispersed installation, or directly fixed on the transformer host (can reduce installation work and floor area). The cooler is equipped with control box, oil flow and water flow relay, oil water differential pressure relay. On-load tap-changer selection of domestic switch, equipped with remote gear display.

The transformer oil is the naphthenic anti-aging transformer oil produced in Karamay, and the protection of the oil is a fully closed structure (that is, the pressure relief valve with the diaphragm oil storage tank structure).

About Transformer Maintenance

It is necessary for the core to be transported for a long distance after the arrival of the product, mainly to solve the fastener loosening during transportation and the user's acceptance of the manufacturer's products. However, as for the routine overhaul, we believe that it is necessary to check and replace those mechanical wear parts according to the original overhaul cycle. Such as pumps and other moving parts, but the relatively stationary transformer can be long-term without lifting the core, only monitoring the quality changes such as gas chromatography of oil is enough to grasp the situation of the body, so as to save maintenance costs, reduce the core of the body and oil pollution.

Features in terms of appearance

In the design, the product structure is compact, all kinds of transformer control lines are connected to the unified junction box and the purpose is explained, so that the appearance is beautiful and the operation is convenient.

This manual is applicable to the three-dimensional coil core power transformer with a voltage of 35KV and below.

1. Rated operating conditions:

1.1 Ambient Temperature:

High temperature: +40℃

High average daily temperature: +30℃

High average annual temperature: +20℃

Low temperature: -25℃ (for outdoor transformers) (-40℃ for 40# transformer oil)

-5℃ (for indoor transformer)

1.2 The elevation of the transformer installation site shall not exceed 1000m, and the temperature rise limit shall be corrected when the altitude exceeds 1000m.

1.3 The installation site should be free of gas, steam, chemical sedimentary dust, dirt and other explosive and etchable substances that seriously affect the insulation of the transformer.

1.4 There is no serious vibration in the installation site.

2. Transportation:

2.1 Transformers that do not need to be removed during transportation must be filled with oil for transportation; For transformers that need to remove accessories (such as oil storage tanks, heat sinks, etc.) during transportation, the space distance between the oil level in the tank and the box cover must be 100 ~ 150mm. All parts of the transformer must be sealed well to ensure that the transformer will not be affected by moisture during transportation.

2.2 All accessories of the transformer should be protected from damage during transportation.

2.3 When lifting the transformer, all the hanging mix on the box wall should be used at the same time, and the hanging ring (or lifting plate) on the box cover is strictly prohibited. When lifting, the Angle between the wire rope and the vertical line should not be greater than 30°. If this requirement cannot be met, the beam type spreader should be used to lift the transformer.

2.4 There should be no serious vibration, turbulence and shock during transportation, and the tilt of the transformer should not be greater than 15°.

3. Acceptance inspection:

3.1 After receiving the transformer, the user shall immediately check whether the model and specifications of all the received products are consistent with the order contract according to the nameplate, check whether the transformer has oil leakage and oil seepage, and whether the products and parts are damaged.

3.2 For transformers transported after removal of accessories, after arriving at the installation site, regardless of whether it is put into operation, all accessories removed during transportation (oil storage tank, moisture absorber, gas relay, etc.) should be installed immediately, and qualified transformer oil should be injected to the oil level above the oil level of the current air temperature. To ensure that there is a normal oil pressure protection transformer in the tank (for gas relays, the white cloth tape in the oil path should be cut and removed before installation).

4. Equip:

4.1 Remove the transported transformer, after the core inspection, must first install the oil storage tank, radiator, etc. When installing the thermometer (mercury thermometer, signal thermometer, resistance thermometer), the thermometer base should be filled with transformer oil, while installing the humidifier, the lower part of the humidifier should be filled with transformer oil.

4.2 After assembling other parts, oil can be injected.

4.3 For transformers equipped with radiators, gas relays and upper end with vent plug sleeve, after filling with oil, in order to completely discharge the air, the butterfly valve at the lower part of the radiator should be opened first, and then the upper butterfly valve should be opened, and then the vent plug of these components should be opened successively to release the air stored in the upper part. The vent action is rapid, only need to gently unscrew the vent plug. When the oil emerges, tighten the gas release plug immediately.

4.4 After injecting transformer oil, seal the bleed plug of radiator, gas relay, bushing, etc., and check all sealing surfaces. After 24 hours of parking, check whether there is leakage of oil, and release the gas in the gas relay again, when filling the transformer oil, pay attention to the type of oil or oil base.

4.5 Take transformer oil sample and make test for laboratory analysis.

4.6 If the transformer is equipped with a gas relay, the white cloth tape in the oil channel of the gas relay should be cut off before installation, and then the end of the oil tank with an oil storage tank should be padded 10 ~ 15mm to facilitate the gas relay collection (for a fully sealed transformer without an oil storage tank, it does not need to be padded).

5. Pre-operation test:

5.1 Measure the insulation resistance

5.2 Measure the voltage ratio and DC resistance at each tap position.

5.3 External construction frequency withstand voltage test, withstand voltage according to the factory test standard 80%, lasting one minute.

5.4 For a voltage of 35KV and a capacity of 4000kVA and above, the absorption ratio "R60 / R15" should be measured.

6. Post-test inspection:

After passing the previous tests, the transformer should be inspected as follows:

6.1 Setting and testing of protective devices, such as gas relay operation.

6.2 When checking the oil level of the oil storage tank, the butterfly valve between the oil storage tank and the oil tank should be opened.

6.3 Check whether the reading of the thermometer is correct and whether the control temperature of the temperature controller is appropriate (or according to the instructions).

6.4 Check whether the fuel tank is properly grounded.

6.5 Check whether the fastener of the pressure relief valve is removed (or whether the pressure gauge position is zero).

6.6 Transformer equipped with gas relay, when the test is put into operation, first connect the signal contact of the gas relay to the power supply trip circuit of the transformer power supply. The overcurrent protection time limit is set to instantaneous action, and then the transformer is put into the rated voltage, for 30 minutes to listen to the transformer sound, if conditions permit, the voltage of the transformer access should gradually rise from zero, so as to detect the fault early.

6.7 After the test is completed, cut off the power supply, readjust the overcurrent protection setting, connect the gas relay signal contact to the alarm circuit, and connect the trip contact to the trip circuit of the relay protection, and then make the transformer close 3 ~ 5 times under the rated voltage, so as to test the operation of the relay protection device under the shock of the excitation current.

6.8 If the transformer access voltage test results are good, it can be put into operation.

7. Transformer maintenance and storage:

Transformer response 3Check the transformer at least once a month to check whether there is oil leakage and whether the oil level is normal (If the oil level is too low, add more oil )There is no rust on the surface, whether the moisture absorber silica gel is discolored, should be every 6Check the insulation strength of the oil once a month.