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Papers by Suprit Pradhan
ISAET, 2017
This paper presents an analysis with regard to
Even with availability of the modern day online insulation diagnostic tools like partial discharg... more Even with availability of the modern day online insulation diagnostic tools like partial discharge monitoring, the measurements like Dissipation Factor (tanĪ“), DC High Voltage Insulation Currents, Polarization Index (PI) and Insulation Resistance Measurements are still widely used as a diagnostic tools to assess the condition of stator insulation in hydro power plants. Diagnostic tests were performed on the stator windings of 15MVA generators of Basochhu Hydropower Plant, to evaluate the condition of the stator winding insulation in one of the generators that have been operated since 1999. This paper presents diagnostic study done on the data gathered from the measurements which were performed in 2015 and 2016 as part of regular maintenance as since its commissioning no proper aging data were maintained. Measurement results of Insulation Resistance Test, Polarization Index Test, DC High Potential Test and Dissipation Factor Test are discussed with regard to their effectiveness in assessing the ageing condition of the stator insulation. After a brief review of the theoretical background, the strengths of each diagnostic method in detecting symptoms of insulation deterioration are identified. The results observed from Basochhu Hydropower Plant is taken into consideration to conclude that Polarization Index and DC High Voltage Insulation current measurements are best suited for the detection of humidity and contamination problems and Dissipation Factor measurement is a robust indicator of long-term ageing caused by oxidative degradation.
International Journal of Electrical and Computer Engineering, 2015
Current transformers are an integral part of power system because it provides a proportional safe... more Current transformers are an integral part of power system because it provides a proportional safe amount of current for protection and measurement applications. However, when the power system experiences an abnormal situation leading to huge current flow, then this huge current is proportionally injected to the protection and metering circuit. Since the protection and metering equipment's are designed to withstand only certain amount of current with respect to time, these high currents pose a risk to man and equipment. Therefore, during such instances, the CT saturation characteristics have a huge influence on the safety of both man and equipment and on the reliability of the protection and metering system. This paper shows the effect of burden on the Accuracy Limiting factor/ Instrument security factor of current transformers and the change in saturation characteristics of the CT's. The response of the CT to varying levels of overcurrent at different connected burden will be captured using the data acquisition software LabVIEW. Analysis is done on the real time data gathered using LabVIEW. Variation of current transformer saturation characteristics with changes in burden will be discussed.
ISAET, 2017
This paper presents an analysis with regard to
Even with availability of the modern day online insulation diagnostic tools like partial discharg... more Even with availability of the modern day online insulation diagnostic tools like partial discharge monitoring, the measurements like Dissipation Factor (tanĪ“), DC High Voltage Insulation Currents, Polarization Index (PI) and Insulation Resistance Measurements are still widely used as a diagnostic tools to assess the condition of stator insulation in hydro power plants. Diagnostic tests were performed on the stator windings of 15MVA generators of Basochhu Hydropower Plant, to evaluate the condition of the stator winding insulation in one of the generators that have been operated since 1999. This paper presents diagnostic study done on the data gathered from the measurements which were performed in 2015 and 2016 as part of regular maintenance as since its commissioning no proper aging data were maintained. Measurement results of Insulation Resistance Test, Polarization Index Test, DC High Potential Test and Dissipation Factor Test are discussed with regard to their effectiveness in assessing the ageing condition of the stator insulation. After a brief review of the theoretical background, the strengths of each diagnostic method in detecting symptoms of insulation deterioration are identified. The results observed from Basochhu Hydropower Plant is taken into consideration to conclude that Polarization Index and DC High Voltage Insulation current measurements are best suited for the detection of humidity and contamination problems and Dissipation Factor measurement is a robust indicator of long-term ageing caused by oxidative degradation.
International Journal of Electrical and Computer Engineering, 2015
Current transformers are an integral part of power system because it provides a proportional safe... more Current transformers are an integral part of power system because it provides a proportional safe amount of current for protection and measurement applications. However, when the power system experiences an abnormal situation leading to huge current flow, then this huge current is proportionally injected to the protection and metering circuit. Since the protection and metering equipment's are designed to withstand only certain amount of current with respect to time, these high currents pose a risk to man and equipment. Therefore, during such instances, the CT saturation characteristics have a huge influence on the safety of both man and equipment and on the reliability of the protection and metering system. This paper shows the effect of burden on the Accuracy Limiting factor/ Instrument security factor of current transformers and the change in saturation characteristics of the CT's. The response of the CT to varying levels of overcurrent at different connected burden will be captured using the data acquisition software LabVIEW. Analysis is done on the real time data gathered using LabVIEW. Variation of current transformer saturation characteristics with changes in burden will be discussed.