How are oil-filled transformers rated?

Oil-filled transformers are rated based on several key parameters that reflect their operational capabilities and design specifications. These ratings typically include the transformer’s power rating in kilovolt-amperes (kVA), voltage ratings which indicate primary and secondary voltages, frequency in hertz (Hz), and insulation class which describes the thermal endurance of the insulating materials used. Additionally, oil-filled transformer manufacturers specify the temperature rise, which is the maximum increase in temperature the transformer can safely handle under load conditions. Other important ratings include short-circuit power ratings, impedance percent, and cooling type, such as whether it utilizes natural or forced oil circulation. Ultimately, understanding these ratings is crucial for ensuring optimal performance and longevity of the transformer within its application.