What are common low frequency transformer faults and troubleshooting methods?

Common low frequency transformer Faults and Troubleshooting Methods

1. Short Circuit
Typically, this is manifested by an abnormally high current. When troubleshooting, first check for damage to the insulation between the windings or between the windings and the core. Perform local insulation repairs or replace components if necessary.
2. Bushing/Oil Tank Failure
Bushing flashover or oil tank leakage is often caused by material aging, poor sealing, or dirt accumulation. Check the bushing integrity, oil quality, and seal condition. If any problems are found, replace the bushing or clean the oil tank immediately.
3. Winding Insulation Aging
With age, the insulation layer may deteriorate, become damp, or become intruded by water, leading to breakdown. Use an insulation resistance meter or a withstand voltage tester to test the insulation of each phase winding. If any abnormality is found, immediately shut down the unit for inspection.
4. Automatic Trip and Protection Action
Transformer protection trips occur when an abnormality occurs. When troubleshooting, first confirm that the protection settings are appropriate, then check for overcurrent, overvoltage, or temperature rise abnormalities. Adjust protection parameters or replace faulty components if necessary.

How should I select a low frequency transformer to meet power and efficiency requirements?

Selecting a low frequency transformer to Meet Power and Efficiency Requirements

1. Determine Rated Power and Power Factor
Calculate the required apparent power and actual power based on system requirements. Consider the power factor and select the appropriate capacity to avoid efficiency losses caused by over- or under-sizing.
2. Select the Appropriate Core Cross-Sectional Area and Wire Diameter
The power of a transformer is positively correlated with the core cross-sectional area; higher power requires a larger cross-sectional area. Also, select the appropriate wire diameter based on the current to minimize copper losses.
3. Cooling Method and Operating Temperature
In high-temperature or humid environments, cooling methods such as oil-immersion cooling or forced oil circulation are preferred to ensure that the temperature rise is within the design range, thereby improving overall efficiency.
4. Efficiency Indicators and Loss Control
Pay attention to copper loss, iron loss, and power losses caused by magnetic leakage. Selecting high-permeability silicon steel sheets and high-quality enameled wire can significantly improve efficiency. Cross-validate no-load and loaded losses to ensure the selected model meets the expected efficiency targets.