The Influence of Temperature on the High-Voltage Equipment Insulation System Dielectric Response

Modern approaches to assessing the condition of high-voltage equipment are based on the measurement of insulation system parameters. In world practice, methods based on the measurement of polarization and depolarization currents in dielectrics are increasingly used to assess the dielectric insulation quality. In doing so, it is assumed that polarization processes are determined by the state of the dielectric, while the influence of external factors on the measurement results is as a rule not taken into account. The article addresses the study of the influence of external operational factors (the temperature and applied test voltage) on the polarization and depolarization currents, and the system dielectric response. As a result of the experiment, the dependences of polarization and depolarization currents on the temperature and applied test voltage were established. It has been found that the dielectric response function does not depend on the test voltage only at temperatures below 60 °C. This points to the need to adjust the methods of interpreting the high-voltage equipment diagnostic results obtained at higher temperature levels. A theoretical substantiation of the established dependences is given based on the physical processes occurring in the dielectric. The results obtained can be used to assess the condition and interpret the results obtained from diagnosing the insulation system of high-voltage electrical equipment (power transformers, electric motors, cables, etc.).