Installation specification for dry-type transformer

2022-09-09 13:33:46

1次

Do you know the installation specifications of dry-type transformer?
1. Unpacking inspection before installation
Check whether the package is in good condition. After unpacking the transformer, check whether the nameplate data of the transformer meets the design requirements, whether the factory documents are complete, whether the transformer is in good condition, whether there are signs of external damage, whether the parts are displaced and damaged, whether the electrical supports or connecting wires are damaged, and finally check whether the spare parts are damaged and short.

2. Transformer installation
First, check whether the embedded steel plate of the transformer foundation is horizontal. There should be no cavity under the steel plate to ensure that the transformer foundation has good seismic and sound absorption performance. Otherwise, the noise of the transformer after installation will increase.
Then, move the transformer to the installation position with a roller bar, remove the roller bar, accurately adjust the transformer to the design position, and ensure that the installation levelness error meets the design requirements. Finally, four short channel steels are welded on the four corners close to the transformer base, that is, the embedded steel plate, so that the transformer will not move during use.

3. Transformer wiring
During wiring, the minimum distance between the charged bodies and between the charged bodies and the ground shall be ensured, especially the distance from the cable to the high-voltage coil. The high current low-voltage bus shall be supported separately, and shall not be directly crimped on the transformer terminal, which will cause excessive mechanical tension and torque.
When the current is greater than 1000A (for example, 2000a low-voltage bus is used in this project), there must be a soft connection between the bus and the transformer terminal to compensate for the thermal expansion and contraction of the conductor and isolate the vibration of the bus and transformer.

4. Transformer grounding
The grounding point of the transformer is on the base of the low-voltage side, and a special grounding bolt is led out, which is marked with the grounding center. The grounding of the transformer must be reliably connected to the protective grounding system through this point.
If the transformer has a shell, the shell shall be reliably connected to the grounding system. If the low-voltage side adopts the three-phase four wire system, the neutral wire shall be reliably connected to the grounding system.

5. Inspection before transformer operation
Check whether all fasteners are loose, whether the electrical connection is correct and reliable, whether the insulation distance between live bodies and between live bodies and the ground meets the requirements, whether there are foreign matters near the transformer, and whether the coil surface should be cleaned.

6. Commissioning of transformer before operation
(1) Check the transformation ratio and connection group of the transformer, measure the DC resistance of the high and low voltage windings, and compare the results with the factory test data provided by the manufacturer.
(2) Check the insulation resistance between coils and to the ground. If the insulation resistance is significantly lower than the factory measurement data of the equipment, it indicates that the transformer is damp. When the insulation resistance is lower than 1000 Ω / V (operating voltage), the transformer must be dried.
(3) The test voltage of the withstand voltage test shall meet the requirements. When conducting the low-voltage withstand voltage test, the temperature sensor tp100 shall be taken out. After the test, the sensor shall be returned to its original position in time.
(4) When the transformer is equipped with a fan, the fan shall be powered on and run normally.

7. Commissioning
After careful inspection before putting the transformer into operation, it can be powered on for trial operation. During the test run, special attention must be paid to the following points. Check for abnormal sound, noise and vibration. Whether there is abnormal smell such as burnt odor. Whether there is discoloration caused by local overheating. Whether the ventilation is good.

In addition, the following points should also be noted.
First, although the dry-type transformer has strong moisture resistance, it is prone to moisture because of its open structure, especially the dry-type transformer produced in China has a low insulation level (lower insulation grade).
Therefore, the dry-type transformer can achieve high reliability only when the relative humidity is below 70%. The dry-type transformer shall also avoid long-term shutdown to avoid serious dampness. When the insulation resistance value is lower than 1000 / V (operating voltage), it indicates that the transformer is seriously damp, and the test run should be stopped.
Second, the dry-type transformer used for boosting the power station is different from the oil immersed transformer. It is prohibited to operate in an open circuit on the low-voltage side, so as to avoid transmission overvoltage and insulation breakdown of the dry-type transformer due to Overvoltage on the grid side or lightning strike on the line.
In order to prevent the transmission of overvoltage hazards, a group of overvoltage protection lightning arresters (such as y5cs zinc oxide lightning arresters) shall be installed at the voltage bus side of dry-type transformer.

HENGFENGSHUAI ELECTRIC, is an electrical enterprise with transmission and distribution industry as its main business, integrating product research and development, manufacturing and trade. Designated suppliers for the world's top 500 enterprises .Its main products include power transformers, medium and low voltage switchgear, distribution panel ,circuit breakers, transmission tower ,Cable and other power distribution equipment .The group has five department: Transformer department, Panel department, power transmission tower department, cable department and electrical engineering department. HENGFENGSHUAI ELECTRIC, has been working hard to provide the best transmission, distribution solutions for users all over the world.【WhatsApp：+86158 5325 2696（Jack） +86158 5326 5269（Alisa）hfs@hengfengshuai.com https://www.hengfengshuai.com 】

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