Dec. 21, 2020
First, although dry-type transformers have strong moisture resistance, they are generally susceptible to moisture due to their open structure, Dry-type transformers should also avoid long-term outages to avoid severe moisture. When the insulation resistance value is lower than 1000/V (operating voltage), it indicates that the transformer is seriously damp, and the trial operation should be stopped.
Second, the dry-type transformers used for step-up in power stations are different from oil-immersed transformers. Open-circuit operation on the low-voltage side is prohibited to avoid overvoltage on the grid side or lightning strikes on the line, resulting in the transmission of overvoltage and insulation breakdown of dry-type transformers. In order to prevent the transmission of overvoltage hazards, a set of overvoltage protection arresters (such as Y5CS zinc oxide arresters) should be installed on the side of the dry-type transformer voltage bus.
Check whether all fasteners are loose, whether the electrical connection is correct and reliable, whether the insulation distance between the charged body and the charged body to the ground meets the regulations, there should be no foreign matter near the transformer, and the surface of the coil should be cleaned.
(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 the coils and the coil to the ground. If the insulation resistance is significantly lower than the factory measurement data, the transformer is damp. When the insulation resistance is lower than 1000Ω/V (operating voltage), the transformer must be dried.
(3) The test voltage of the withstand voltage test should meet the requirements. When doing the low voltage withstand test, the temperature sensor TP100 should be taken out. After the test is over, the sensor should be returned in time.
(4) When the transformer is equipped with a fan, the fan should be energized and run and ensure its normal operation.
The transformer can be energized for trial operation after careful inspection before putting it into operation. During the trial operation, special attention must be paid to check the following points. Whether there are abnormal sounds, noises, and vibrations. Whether there are abnormal smells such as burnt odor. Whether there is discoloration due to local overheating. Whether the ventilation is good.
1. Flame retardant, no pollution, and can be installed directly in the load center.
2. Maintenance-free, easy to install, and low operating cost.
3. The shell can have good moisture-proof performance. In normal operation, the transformer can be operated without pre-drying under 100% humidity.
4. Small loss, lightweight, small size, low noise, good heat dissipation, and can run at 150% rated load under forced air cooling.
5. Equipped with a complete temperature protection control system to provide reliable protection for the safe operation of the transformer.
6. High reliability. The inspection results of the products that have been put into production show that their reliability indicators have reached the international advanced level.
Baoding Zhongyi Electrical Material Manufacturing Co., Ltd. mainly produces oil-immersed power transformers, dry-type transformers, box-type substations, high and low voltage switchgear sets, and various special transformers. Hoisting, tooling, and testing equipment are complete. Our company has passed the ISO9001-2015 international standard quality management system certification. All performance indicators of the product have reached relevant national and international standards. If you want to get more information about good quality dry-type transformers, please contact us.
Add: Room A1109, No.483 Yulan Street, Baoding City, Hebei Province, China