Scope of application

This manual is applicable to the loading and unloading, transportation, storage, installation, use and maintenance of thin insulated dry transformers with rated capacity of 31500kVA and voltage class of 35kV and below without excitation and on load voltage regulation epoxy resin casting.

Second, the characteristics of dry transformer

Dry transformer has the characteristics of low loss, low discharge, explosion-proof, flame-proof, environmental protection, no pollution, no maintenance, strong short-circuit resistance and so on.

3. Conditions of use

1. The ambient temperature is not higher than 40℃, and the altitude is not more than 1000m. If the ambient temperature is higher than 40℃ or the altitude is more than 1000m, appropriate adjustments should be made according to the relevant provisions of GB1094.11-2007.

2. The shell protection grade is IP20, IP23 and other series types.

3. There are two cooling methods: air self-cooling (AN) and forced air cooling (AF). For air self-cooling (AN) and forced air cooling (AF) transformers, it is necessary to ensure that the installation environment of the transformer has good ventilation capacity. When the transformer is installed in the basement or other environments with poor ventilation capacity, it is necessary to add heat dissipation and ventilation devices, and the ventilation volume is 4m3/min according to the 1kW loss (PO+PK).

Four, the main specifications of the product

1. For single-phase dry type transformer products, models are mainly: DC (B) 10, DC (B) 11 series.

The meaning of the model is as follows: (Take "DC (B) 10 transformer" as an example)

2. For tri-coherent transformer products, the models are mainly: SC (B) 10, SC (B) 11 and other series.

The meaning of the model is as follows: (Take "SC (B) 10 transformer" as an example)

5. Transportation and lifting

1. Product transportation

1.1 The product can be transported by train, ship, car, aircraft and other means of transportation, and the transportation of the product must be kept clean and free of pollutants.

1.2 The product shall be loaded in accordance with the requirements of the transportation regulations, and the product shall be firmly placed, and violent shaking, collision and movement are not allowed during the transportation process.

1.3 Transformer without packing box, attached parts, accessories, factory documents, etc. are packed into separate boxes and shipped together with the transformer.

1.4 Products without packing boxes are firmly fixed to the transport vehicle through holes such as carts, clips and hangers, and do not tie the wearing parts such as coil, insulation, pad, and lead to prevent damage to the product.

1.5 During the transportation of the product, the inclination shall not exceed 30°.

1.6 The product is not allowed to pile up after unloading at the terminal or terminal of the station, and the bottom should be padded with square wood, and the height of the cushion is not less than 100mm.

2. Product lifting

2.1 Lifting equipment such as crane, truck crane or forklift can be used for loading and unloading equipment.

2.2 Loading and unloading procedures shall be strictly followed.

2.3 The "Lift from here" sign is sprayed below the four corners of the main packing box (near the chamfer of the slide). When lifting, the wire rope should be suspended at the "lifting from here", as shown in Figure 1: If there is no packing box or the transformer is lifted out of the packing box, the four rings on the body should be used at the same time to lift, and the Angle between the lifting wire rope should not be greater than 60°, as shown in Figure 2 (Note: dry transformers should be strictly lifted by four-point simultaneous lifting). To lift the transformer with the shell, please use the lifting ring specified above the shell to lift, and the Angle between the lifting wire rope should not be greater than 60°, as shown in Figure 3.

Note: When hoisting the transformer with the shell, pay attention to the lifting hole on the lifting bracket in the middle of the transformer shell (the lifting bracket is composed of the lifting screw connected to the upper clamp of the transformer) to ensure the lifting strength. It is strictly forbidden to lift the four corners of the shell hoisting ring (the hoisting ring is used to hoist the shell, and its strength cannot withstand the overall weight of the transformer. Forced lifting can cause serious deformation of the transformer housing or cause the transformer to fall because the housing cannot bear the overall weight of the transformer).

2.4 The surface of the main packing box is sprayed with the center of gravity symbol. If the center of gravity is obviously deviated from the center position, the length of the wire rope should be adjusted when lifting so that the hook is facing the center of gravity of the box.

2.5 The product should be handled with care during loading and unloading.

2.6 When lifting an on-load regulator transformer, if the on-load switch is connected to the transformer, only use the transformer's suspension ring to lift the transformer.

6. Acceptance, storage and storage

1. Check and accept

After receiving the transformer, the user should immediately notify our sales staff to check the transformer on the scene.

1.1 Check whether the nameplate data of the product is consistent with the order contract, such as product model, rated capacity, rated voltage, connection group label, impedance voltage, etc.

1.2 Check whether the factory documents are complete and consistent with the order contract.

1.3 Check whether the parts and accessories in the packing case are consistent with the packing list.

1.4 Check whether there is damage during the transportation of the product, whether the product parts are damaged and displaced, whether the wiring is loose or broken, whether the insulation is damaged, whether there is dirt or foreign matter. At the same time, things such as bedding wood used in transportation must be removed.

1.5 After the product is unpacked and checked, if it does not meet the requirements, you can fill in the "Feedback Information Sheet" with our sales staff and sign it and send it back to our company, our service staff will solve it for you in a short time. In addition, if the transformer is not put into operation immediately, it should be properly stored or repackaged (good moisture, rain) to prevent damage and loss.

2. Storage and storage

2.1 The packaging of the products to be stored should not be removed. If the packaging needs to be removed for acceptance, the packaging should be restored after the acceptance.

2.2 Products requiring long-term storage must be checked and stored in the warehouse. The warehouse should be clean and dry, and active chemicals and corrosive items should not be stored at the same time.

2.3 Stacking is not allowed for all products.

2.4 Dry-type transformers should be stored indoors in principle, if the environment is limited, the products that need to be placed outdoors for a short time should not be removed from the packaging, and check whether the box (body) is damaged and take anti-rain measures, and use square wood and other padding, padding height is not less than 100mm.

2.5 The outdoor storage time should not exceed two months, and the ambient temperature should not be lower than -10℃.

Seven, product installation

1. Before installation, carefully read this manual, product nameplate and product dimensions, understand the product weight, installation methods, etc., and prepare the corresponding lifting equipment and tools.

2. When this product is installed, it is generally more than 500mm away from the wall and other obstacles, and the distance between adjacent transformers should be more than 500mm.

3. The small safety distance between the transformer live conductor and the ground should meet the national standard GB 10994.3-2003 "Power transformer Part III: insulation level, insulation test external insulation air gap", the product technical performance indicators fully meet the national standard GB 1094.11-2007 "Power transformer Part 11: Dry type transformer, technical parameters in line with the national standard GB/T 10228-2015 "Dry type power transformer technical parameters and requirements".

4. The small safe reference distance between the surface of the high voltage coil and the ground is as follows:

5. Under normal circumstances, the transformer can be placed directly in the use of the site, installation and inspection can be put into operation. For shock-proof and other special requirements, the foundation of the transformer should be installed with bolts, the position of the bolts should refer to the transformer outline diagram, so that it corresponds to the installation hole of the transformer. The small wheel of the transformer is removed during installation, and the transformer is fixed by buried bolts. (Note: transformer shock and noise reduction can be taken in the transformer car and ground joint pad rubber)

6. Transformer equipped with rollers, the direction of the rollers can be changed by 90°.

Seven. When installing a transformer with enclosure, do not apply gravity to the enclosure to avoid deformation of the enclosure.

8. Field handover test

1. Check before operation

1.1 Check whether all fasteners and connectors are loose and tighten them again.

1.2 Check whether the parts removed during transportation are properly reinstalled, and check whether there is foreign matter in the transformer. If there is excessive dust, it must be cleaned up according to Article 6.2.

1.3 Check whether the fan, temperature control equipment and other auxiliary devices can run normally. For the three-phase power fan, attention should be paid to its steering. When the fan turns normally, the wind blows upward from the bottom of the coil into the coil, otherwise it is reversed. Refer to the instructions to change the phase sequence of the power supply in time. For temperature control, temperature display and other auxiliary equipment, refer to their instructions for correct and reliable wiring (need to test the fan start and stop, overtemperature alarm and overtemperature trip and other items to ensure that the thermostat works normally).

2. Test before operation

The transformer should be tested as follows before operation:

2.1 Measure the DC resistance of the winding at all tap positions (tighten the connection bolts after testing).

2.2 Determine the polarity and measure the voltage ratio of the windings in all subsequent sections according to GB50150, and determine the connection group label.

2.3 Check whether the transformer housing and core are permanently grounded.

2.4 Coil insulation resistance test, under normal circumstances (temperature 20-30℃, humidity ≤90%) :

High-low pressure and ground ≥300MΩ instrument: 2500V megohm meter

Low-voltage ground ≥100MΩ Standard ≥ 20MΩ instrument: 2500V megohm meter

In a relatively humid environment, the insulation resistance value of the transformer will decrease. In general, if it is less than the required value or the transformer is subjected to abnormal moisture condensation phenomenon, regardless of its insulation resistance, it must be dried before it is tested for voltage resistance or put into operation.

2.5 Check whether the iron core is properly grounded, remove the ground lug, check whether the iron core is properly insulated from the ground, and reinstall the ground lug. Core insulation resistance test, under normal circumstances (temperature: 20-30℃, humidity ≤90%) :

Core - clamp and ground ≥2MΩ instrument: 500V megohm meter

Core screw - core and ground ≥24MΩ instrument: 500V megohm meter

Similarly, under relatively humid environmental conditions, this value will decrease, as long as its resistance value is > 0.1MΩ, it can be run, and it can generally be dried to meet the requirements.

2.6 For the on-load voltage regulator transformer, the necessary inspection and test should be carried out according to the operation manual of the on-load voltage regulator tap-changer before it is put into operation.

2.7 External application voltage test, the test voltage is 85% of the factory test voltage (Note: Before external application voltage test, the temperature controller sensor cable must be disconnected, so that the sensor cable and the sensor probe and high and low voltage coil to maintain a sufficient safe distance).

Nine, transformer trial operation

1. Before the transformer is put into operation, the tap plate should be adjusted to the appropriate position according to the transformer nameplate and tap indicator.

1.1 In no-load voltage regulation, connect the connection plate of the voltage regulation tap to the corresponding position according to the mark on the nameplate and tap indicator plate according to the power grid voltage.

For example, for a transformer with a voltage of 10000 + 2×2.5%V, the nameplate voltage is as follows:

2-3                        10500V

3-4                        10250V

4-5                        10000V

5-6                        9750V

6-7                        9500V

If the local power grid voltage is 10kV, the tap plate should be connected to 4-5 levels, see Figure 3. When the input voltage is high (10500V), in the case of ensuring high voltage power off, connect the connector of the tap plate upward, and the tap plate should be connected to the 2-3 stops, as shown in Figure 4; When the input voltage is low (9500V), in the case of ensuring high voltage power off, the connector of the tap plate should be connected downward, and the tap plate should be connected to 6-7 stops, as shown in Figure 5. When the input voltage needs to be fine-tuned, the tap piece is connected in gear 3-4, suitable for the input voltage of 10250V, and the tap piece is connected in gear 5-6, suitable for the input voltage of 9750V.

When the low voltage output voltage is 420V, if you want to get 400V voltage, please adjust the high pressure tap gear to 2-3, that is, the high voltage is about 10500V, when the low voltage output voltage is 380V, if you want to get 400V voltage, please adjust the high pressure tap gear to 6-7, that is, the high voltage is about 9500V. Users can adjust the tap voltage gear as required. Pay special attention to power off and discharge the transformer before adjusting, and then adjust and change the gear.

1.2 For on-load voltage regulation, please refer to the operating manual of the on-load voltage regulation tap-changer. In the case of power failure, the tap-changer can be put into operation after normal debugging.

2. When the transformer has a temperature controller, please refer to the operating instructions of the temperature controller. After the temperature control and temperature display are normal, the transformer is put into operation first, and then the thermostat is put into operation.

3. The transformer should be put into operation when no load is on, the peak value of the closing inrush current can reach 8-10 times the rated current, and the current quick-acting protection setting value of the transformer should be greater than the peak value of inrush current. Generally, the closing impact is 3 to 5 times, and according to experience, a successful closing can basically ensure the normal transformer. If the transformer is sent to multiple places together, due to the impact of overvoltage on the power grid during power transmission, the transformer sound will fluctuate, and the sound will suddenly increase, do not mistake it for a transformer problem)

Current quick acting protection setting value ≥ rated current x 10

4. After the transformer is put into no-load operation, the load should be from light to heavy, and the check product is no different, avoid blindly putting in a large load. (After 48 hours of no-load operation, the load can be put in)

5. The transformer overload operation should be in accordance with IEC60076 "Dry power transformer load Guidelines" or according to the ambient temperature and initial load state, the transformer allows short-term overload. The following table shows the allowable overload time curve at ambient temperatures of 20 ° C and 40 ° C. (for reference only)

The overload curve is allowed when the environment is 20 ° C. The overload curve is allowed when the environment is 40 ° C

6. When the ambient temperature is below the limit value, the output power of the transformer can be slightly higher than the rated value. On the contrary, when the capacity is reduced, the transformer can operate at higher ambient temperatures. See the following table:

   

7. After the transformer exits the operation, it is generally not necessary to take other measures to put it back into operation. However, if it is at high humidity and condensation has occurred in the transformer, it must be dried before the transformer can be put back into operation.

Ten, transformer maintenance

1. In general, in dry and clean places, inspections should be carried out once a year or more; in other places, such as when air may be contaminated with dust or chemical fumes enters, inspections should be carried out every three to six months.

2. When checking, if too much dust is found, it must be removed to ensure air circulation and prevent insulation breakdown, pay special attention to clean the insulator, pad and other places of the transformer, and use dry compressed air 2-5 atmospheres to blow the dust in the ventilation airway.

3. Check whether fasteners and connectors are loose, whether the cold-pressed structure part is compressed without loosening (high-voltage cable terminal part), whether the conductive parts have traces of rust and corrosion, but also observe whether the insulation surface has creepage marks and charring phenomenon, and take appropriate measures to deal with it if necessary. Check whether the conductive rod is deformed or the distance between the conductive rods is close. In order to ensure the safe operation of electrical equipment, the small safety distance between the conductive rods of the 10kV transformer should not be less than 80mm (the conductive bend pipe of the transformer is equipped with a high voltage 10kV heat shrink tube when the transformer is discharged from the factory can effectively ensure that the conductive rod is too close to cause accidents. However, for safety reasons, it is recommended to check the distance between the conductive bend and the straight pipe before powering on, and the principle is raised to large). Keep a safe distance between the incoming cable and the conductive pole. In particular, do not place the ground cable on the conductive pole. Use cable ties to bind the ground cable to the cable.

4. After the transformer has been in operation for several years (five years is recommended), the insulation resistance can be tested according to Article 10.2.4 and 10.2.5 to determine whether the transformer can continue to operate, and other tests are generally not required.

11. Safety precautions

1. Before the transformer is installed and put into operation, for the transformer without a shell, a barrier should be installed around the transformer to avoid accidents.

2. After the transformer is put into operation, do not touch the main body of the transformer to prevent accidents.

3. The test, installation and maintenance of the transformer must be undertaken by qualified professionals.