1. Gas in transformer oil can cause arcing, corona discharge, overheating and even explosion. It degrades the quality of transformer oil and reduces the reliability and lifetime of the transformer. There are two types of gas in transformer oil. One is gas bubble which can be seen by naked eye, the other is dissolved gas which is invisible to naked eye in transformer oil.

2. Water in transformer oil can affect the insulating strength of the oil. Upon recent research, once the water level in oil reaches 30ppm (parts per million), the dielectric strength of oil is reduced. Then, the insulating strength of oil reduced accordingly.

3. Impurity. It is obviously the impurity or other components can degrade the quality of transformer.

There are test instruments to measure gas, trace water, impurity in oil, such as transformer oil dissolved gas analyzer, water content analyzer and mechanical impurity tester.

By the way, transformer oil purification is a trend. Transformer oil purifier machine can purify and recycle transformer oil. It has functions of dehydration, degasification and impurity removing. It can remove water, gas and impurity in transformer oil quickly and efficiently. After purification, the oil becomes clean and new, and can be used again. Transformer oil purifier machine has been widely applied in power station, power sub-station, transformer factory and other enterprises.