Detection, Measurement, and Classification of Partial Discharge in a Power Transformer: Methods, Trends, and Future Research

Insulation degradation is one of the prime reasons for failures in power transformers. Partial discharge (PD) is considered as one of the primary causes of initiation of insulation degradation. Thus, monitoring of PD in a power transformer at a preliminary stage is the most important task to prevent any catastrophic failure. This paper presents a brief introduction of PD phenomena along with the causes and effects. Various topics of contemporary research related to PD, such as modelling, detection, measurement, and classification, are grouped under different headings with exhaustive up-to-date bibliography. The paper outlines distinctive sensors and technologies based on acoustic, ultra-high-frequency, electric, and hybrid methods. The techniques are compared, and their advantages and limitations are pointed out. The techniques of denoising of PD signal based on signal processing, artificial intelligence, and statistical analysis are summarised. The challenges and trends in future PD research are also discussed. This paper would provide immense help for the researchers, academicians, and service engineers working in the field of PD in power transformers.