High Voltage Motor Stator Windings Research Articles

Changes in Insulation Characteristics of High-Voltage Motor Stator Windings with Temperature and Moisture

This research shows that all of the insulation characteristics (insulation resistance, partial discharge, dissipation factor, and alternating leakage current) of HV motor become worse at high temperature. It is also shows that partial discharge and insulation resistance are reduced at moisture absorption. Therefore, to accurately analyze the insulation degradation trend, it is necessary that those tests always be conducted under the same conditions (temperature and moisture content).

Analysis of Correlationship between Partial Discharge and Ozone Emission in High Voltage Motor Stator Windings as the Index of the Insulation Diagnosis

In this study, it turned out that the magnitude of Partial Discharges(PD) and the emission of Ozone(O3) were in a strong positive relation by performing insulation diagnostic tests on artificially defect high voltage motor statorwindings. In this sense, the O3 measurements can be a powerful index of the insulation deterioration during normal operation especially in case of surface PD activity.

Analysis of Correlation Among Partial Discharges, Ozone Emission, and Ultraviolet Radiation in High Voltage Motor Stator Windings

In this research, a normal winding and simulated defective winding were created to examine the correlation between partial discharges, ozone concentration, and ultraviolet radiation in high-voltage motor stator windings. In the simulated defective winding, the semiconductor layer was removed so that discharges could occur easily between the winding surface and the iron core. A high voltage was applied to both normal and defective windings to measure the partial discharge magnitude, ozone concentration, and ultraviolet radiation. Subsequently, the results were compared and analyzed. The electrical partial discharge magnitude, ozone emission, and ultraviolet radiation measurement methods and properties were explained, and all test results and correlations were analyzed.

Fuzzy Theory-Based Partial Discharge Technique for Operating State Diagnosis of High-Voltage Motor

This study developed an operating state diagnostic system based on partial discharge detection for analyzing faults in high-voltage motor stator windings. First, the partial discharge signal of the stator windings is measured with a high-frequency current sensor, and then phase-resolved partial discharge technology is used to convert it into three-dimensional graphics. A systematic analysis process involving the use of fractal theory architecture for fault extraction from the signal characteristics was designed for identifying faults and obtaining the fractal dimension and the lacunarity of the characteristic parameters. Similarity function defined extension theory was used for building a failure signature database for each fault. Finally, to design and build fuzzy membership function and inference systems for analyzing the operation status of the motor, the partial discharge energy value and fault type were used as indicators in fuzzy algorithms. The experimental results prove that the fuzzy diagnostic system proposed in this paper is combined with the important information of fault type and discharge quantity, where fault type is successfully recognized, and a more reliable high-voltage motor operating state monitoring technique is created. The findings are expected to monitor the operating state of high-voltage motor more effectively, thus, reducing additional maintenance costs resulted from heavy accidents.

Analysis of Off-Line and On-Line Partial Discharge in High Voltage Motor Stator Windings

The off-line and on-line partial discharge (PD) in the stator winding of three high-voltage (HV) motors (1,400 HP, 6.6 kV) is measured and analyzed in this paper. The off-line PD is measured at high values between 24,300 ~ 36,100 pC after 18 years of motor operation. Spare replacement motors were not available for testing the degree of deterioration of the stator windings in standstill status. Therefore, on-line periodic analysis was conducted to monitor the trend of PD after installing a ceramic sensor (110 pF, 6.6 kV) in the terminal box for each phase of each motor. In the stator winding of the No.1 and No.2 HV motors, which showed high magnitudes of off-line PD and low magnitudes of on-line PD, defects are expected to appear in the neutral end of the winding. On the contrary, in the stator windings of the No.3 HV motor, which exhibits high off-line and on-line PD magnitude, defects are expected to appear in the terminal end of the winding where a voltage close to the phase voltage is applied.