How to judge transformer fault casting by Transformer Oil Test

Transformer oil tests can provide valuable insights into the condition of a transformer and help identify potential faults. Here are some common transformer oil tests and how they can be used to judge transformer fault casting:

1. Dissolved Gas Analysis (DGA): DGA is one of the most important tests for evaluating transformer condition. It analyzes the concentration and types of gases dissolved in the transformer oil. Certain fault conditions, such as overheating, electrical discharges, or insulation degradation, can lead to the formation of specific gases. Elevated levels of gases like hydrogen, methane, ethane, ethylene, and acetylene can indicate potential faults like overheating, arcing, or insulation breakdown.

2. Furan Analysis: Furan analysis measures the concentration of furanic compounds in the transformer oil. These compounds are formed due to the breakdown of cellulose insulation. Elevated furan levels indicate the degree of insulation aging and can help identify potential faults related to insulation degradation.

3. Interfacial Tension (IFT) Test: The IFT test evaluates the oil's ability to resist emulsification, which can occur due to the presence of water or other contaminants. A decrease in IFT may indicate the presence of water or excessive oxidation, which can lead to insulation breakdown or electrical faults.

4. Dielectric Breakdown Voltage (BDV) Test: The BDV test measures the electrical strength of the transformer oil. A decrease in BDV value may indicate contamination, degradation, or the presence of conducting particles in the oil, which can lead to insulation breakdown and potential faults.

5. Acidity Test: The acidity test determines the acid content in the oil, which can be an indication of oil degradation or the presence of contaminants. High acidity levels can lead to insulation degradation, corrosion, and potential faults.

6. Water Content Test: Water content in transformer oil should be kept within acceptable limits. Excessive water can reduce the dielectric strength of the oil, promote insulation aging, and increase the risk of electrical faults.

It's important to note that interpreting the results of transformer oil tests requires expertise and knowledge of transformer operation and maintenance. Comparing the test results with established guidelines, industry standards, or consulting with experienced professionals can help determine the presence of specific faults or potential issues in the transformer.