Transformer Oil Dielectric Strength Test Method

Transformer Oil Dielectric Strength Test Method

Transformer oil, also known as square shed oil, is a mixture of natural hydrocarbons obtained through distillation and refining of petroleum. Its main components include alkanes, alkane saturated hydrocarbons, aromatic unsaturated hydrocarbons and other chemicals. It features stable purity, low viscosity, good insulation and cooling performance. Under normal temperature and pressure, it is a pale yellow transparent liquid with a relative density of 0.895 and a freezing point < -45℃.

Experimental Purpose

In the chemical and scientific research fields, breakdown voltage determination is the core indicator to measure the insulation performance of the oil product. By measuring the breakdown voltage, the pollution degree of the oil product can be judged, and the breakdown voltage value can directly reflect the content of impurities such as moisture and suspended solids in the oil; it can inspect the oil treatment effect to ensure that the drying and filtration of the oil injected into the equipment meet the requirements; it can warn of equipment operation risks and ensure production safety.

The experiment is carried out in accordance with the GB/T 507 standard. Shengtai Instrument SH125A Oil Pressure Resistance Tester complies with this method and is selected for the experiment.

Experimental Instruments

① SH125A Oil Pressure Resistance Tester

② Auxiliary parts such as samplers, glass test rods, and cleaning reagents

Experimental Steps

1. Check the instrument and all accessories to ensure they are clean, dry and free of contamination.

2. Use a clean and dry sampler to extract the sample in accordance with the GB/T 4756 standard, mix it evenly to avoid generating bubbles.

3. Let it stand indoors to make the oil temperature close to room temperature.

4. Pour the oil sample into the oil cup, adjust the electrode spacing to the specified value (2.5mm), and let the oil sample stand to allow air bubbles in the oil to escape.

5. Apply voltage and increase it uniformly at the set speed.

6. Observe and record the voltage value at the moment the oil sample breaks down.

7. Conduct multiple experiments to ensure the accuracy of the results, and compare with the standard value to evaluate the performance of the oil sample.

Experimental Results

Through multiple experiments, the average breakdown voltage of the transformer oil is 42kV, which meets the standard.