7. Traditional Electrical Diagnostic Methods

As in Chap. 6, the titles of paragraphs in this chapter reflect a large arsenal of methods and tools used to diagnose high-voltage equipment, only in this case—electrical. Seven of them are discussed in this chapter, the eighth most modern (defectography method) is discussed in more detail in Chap. 8.

The sensitivity of many electrical methods is higher than that of non-electric ones, so they are more widely used at present. For example, they allow one to detect the largest number of PD characteristics and use them to estimate the condition of transformers and some other high voltage devices. Most electrical methods do not need the object under analysis to be supplied by electrical voltage being much higher than the rated operating values, so they are gentle on the insulation of electrical equipment. However, many of these diagnostic methods require the measuring instruments to be in contact with the object being diagnosed, which does not contribute to simplicity and convenience. Due to the high sensitivity of the methods, it is necessary to take a series of measures and use special equipment for debugging induced interference.