Research on Influences Factors of Electromagnetic Interferences for Partial Discharge Detection in Substations

Electromagnetic interference is a most important cause for wrong alarming and failing to alarm of on-line PD detection in substation. The characteristics of electromagnetic interferences are dynamic change under the influence of many factors, thus the difficulty of its identification and suppression is increased. Therefore, typical substations in geographical position and voltage level was selected as the object of research, the data of electromagnetic interferences were obtained by field testing, the relationship between their characteristics and the operating environment (geographical location, temperature, humidity) and operating conditions (voltage level and load) of the substations was studied by means of data comparison and grey correlation analysis. The results show that the geographical location and voltage level affect the type and amplitude of electromagnetic interference indirectly; according to the results of correlation analysis, it is found that the average value of the relativity between temperature and the characteristics of electromagnetic interferences is above 0.9, the humidity is the second, and the load is the smallest.