How is the dielectric strength of transformer oil measured?

The dielectric strength of transformer oil is measured using a standardized testing method, typically following ASTM D877 or ASTM D1816 protocols. In these tests, a sample of the transformer oil is placed between two electrodes, and an alternating current is applied. The voltage is gradually increased until the oil breaks down, causing a spark or arc between the electrodes. The maximum voltage applied just before breakdown occurs is recorded as the dielectric strength of the transformer oil, expressed in volts per millimeter (V/mm). This measurement is crucial for assessing the insulation properties of the oil and ensuring the safe and efficient operation of transformers. For accurate results, it’s essential to use a calibrated Globecore dielectric strength tester that adheres to industry standards.