Tanasescu Gabriel - Academia.edu (original) (raw)

Papers by Tanasescu Gabriel

Research paper thumbnail of Measurements using New Online Monitoring System for Power Transformers based on Absorption and Resorption Currents

This paper presents a series of results obtained by measurements on a power transformer, in servi... more This paper presents a series of results obtained by measurements on a power transformer, in service in Romania. The measured parameters are transformer loading factor, top-oil temperature, hydrogen content, oil resistivity, oil loss tangent, the water content from oil based on absorption and resorption currents method. The parameters were recorded on-line with a new monitoring and diagnosis equipment. The condition of the transformer was in depth investigated by estimating the health index based on the measured on-line condition parameters. The results are shown at different moments in time. The trend of the parameters' values was analyzed showing a slight decrease with time. Finally, knowing the current condition of the transformer based on its health index and operating temperatures profiles (top oil, winding and hot-spot), the remaining lifetime is estimated together with required maintenance solutions.

Research paper thumbnail of Health index calculation of electrical equipments using DiagConsole software

2013 8TH INTERNATIONAL SYMPOSIUM ON ADVANCED TOPICS IN ELECTRICAL ENGINEERING (ATEE), 2013

ABSTRACT During operational life, electrical equipment from the Electrical Grid is subjected to f... more ABSTRACT During operational life, electrical equipment from the Electrical Grid is subjected to failure due to external causes (lightning strikes, over voltages) and internal causes (ageing of their insulation systems). Condition assessment of this equipment, in order to avoid premature failure, is a very important topic due to reliability and investments issues. The health index is being used by many utilities due to the fact that it shows the global degradation condition of an equipment so that the beneficiary can choose between the type of maintenance or replacement operations. This paper presents a software (DiagConsole), designed to assess the condition of all the electrical equipment from the Romanian Electrical Grid by calculating their health index. The structure of DiagConsole (offline and online monitoring and diagnosis) is presented, in particular for power transformers. The final part of the paper presents a case study, done on a power transformer for which the health index is calculated using DiagConsole. Based on the health index, the condition of the transformer is evaluated.

Research paper thumbnail of The Ageing States Assessment for Electrical Machines Insulation Systems by Absorption/ Resorption Currents

Research paper thumbnail of Assessment of Power Transformers Conditions Based on Health Index

Power transformers are important assets in electrical power grids, in terms of both reliability a... more Power transformers are important assets in electrical power grids, in terms of both reliability and costs. The conditions of these assets have to be known, in order to avoid any possible outages and to choose the appropriate maintenance operation that could be done. The health index of a power transformer is one single overall indicator that represents its condition and is derived by a weighting process of all available indicators. This paper presents a case study on several power transformers from Romanian Electrical Grid, discussing the benefits of using health index and failure probability as overall diagnostic tools. Moreover, a remaining lifetime calculation based on the transformer failure probability is defined.

Research paper thumbnail of Measurements using New Online Monitoring System for Power Transformers based on Absorption and Resorption Currents

This paper presents a series of results obtained by measurements on a power transformer, in servi... more This paper presents a series of results obtained by measurements on a power transformer, in service in Romania. The measured parameters are transformer loading factor, top-oil temperature, hydrogen content, oil resistivity, oil loss tangent, the water content from oil based on absorption and resorption currents method. The parameters were recorded on-line with a new monitoring and diagnosis equipment. The condition of the transformer was in depth investigated by estimating the health index based on the measured on-line condition parameters. The results are shown at different moments in time. The trend of the parameters' values was analyzed showing a slight decrease with time. Finally, knowing the current condition of the transformer based on its health index and operating temperatures profiles (top oil, winding and hot-spot), the remaining lifetime is estimated together with required maintenance solutions.

Research paper thumbnail of Health index calculation of electrical equipments using DiagConsole software

2013 8TH INTERNATIONAL SYMPOSIUM ON ADVANCED TOPICS IN ELECTRICAL ENGINEERING (ATEE), 2013

ABSTRACT During operational life, electrical equipment from the Electrical Grid is subjected to f... more ABSTRACT During operational life, electrical equipment from the Electrical Grid is subjected to failure due to external causes (lightning strikes, over voltages) and internal causes (ageing of their insulation systems). Condition assessment of this equipment, in order to avoid premature failure, is a very important topic due to reliability and investments issues. The health index is being used by many utilities due to the fact that it shows the global degradation condition of an equipment so that the beneficiary can choose between the type of maintenance or replacement operations. This paper presents a software (DiagConsole), designed to assess the condition of all the electrical equipment from the Romanian Electrical Grid by calculating their health index. The structure of DiagConsole (offline and online monitoring and diagnosis) is presented, in particular for power transformers. The final part of the paper presents a case study, done on a power transformer for which the health index is calculated using DiagConsole. Based on the health index, the condition of the transformer is evaluated.

Research paper thumbnail of The Ageing States Assessment for Electrical Machines Insulation Systems by Absorption/ Resorption Currents

Research paper thumbnail of Assessment of Power Transformers Conditions Based on Health Index

Power transformers are important assets in electrical power grids, in terms of both reliability a... more Power transformers are important assets in electrical power grids, in terms of both reliability and costs. The conditions of these assets have to be known, in order to avoid any possible outages and to choose the appropriate maintenance operation that could be done. The health index of a power transformer is one single overall indicator that represents its condition and is derived by a weighting process of all available indicators. This paper presents a case study on several power transformers from Romanian Electrical Grid, discussing the benefits of using health index and failure probability as overall diagnostic tools. Moreover, a remaining lifetime calculation based on the transformer failure probability is defined.