The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Prabhakar Neti - One of the best experts on this subject based on the ideXlab platform.

  • Stator-Interturn-Fault Detection of Doubly Fed Induction Generators Using Rotor-Current and Search-Coil-Voltage Signature Analysis
    IEEE Transactions on Industry Applications, 2009
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-Coil Voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition when the DFIG is operating under imbalanced load or these methods are based on experimental results alone without any theoretical basis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator interturn faults in DFIGs. Hence, in this paper, an in-depth investigation is conducted to determine the origin of various harmonic components in rotor currents and their feasibility to detect stator interturn faults unambiguously. Detailed analysis is presented, which explains the mechanism by which the stator-interturn-fault-related harmonics are induced in the rotor circuit. The theory is verified with simulation and extensive experimental results. To confirm the feasibility of the proposed technique for detecting stator interturn faults and obtain results on speed sensitivity of fault detection, a prototype of digital-signal-processor-based fault-diagnostic system has been developed, which is capable of producing very fast trip signal in about 2 s.

  • Stator Interturn Fault Detection of Synchronous Machines Using Field Current and Rotor Search-Coil Voltage Signature Analysis
    IEEE Transactions on Industry Applications, 2009
    Co-Authors: Prabhakar Neti, Subhasis Nandi
    Abstract:

    Our recent observations suggested that harmonics in the field current are very promising to detect stator interturn faults in synchronous machines. So far, an increase in some of the even harmonics in the field current has been reported to detect such faults. However, no explanation has been provided for the cause of these harmonics. Moreover, the even harmonics can significantly increase with supply unbalance as well as time harmonics, which can lead to a serious confusion. Hence, in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the field current and their feasibility to detect stator faults. It was found that, owing to structural asymmetries of the field winding, some of these components clearly increased with stator interturn fault. The findings are helpful to detect faults involving few turns without ambiguity, in spite of the presence of supply unbalance and time harmonics. Both simulation and experimental results are presented in this paper. The diagnosis results have also been verified using a rotor-mounted search Coil, which can also be used to detect even a one-turn stator fault very effectively.

  • stator inter turn fault detection of doubly fed induction generators using rotor current and search Coil Voltage signature analysis
    IEEE Industry Applications Society Annual Meeting, 2007
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-Coil Voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition when the DFIG is operating under imbalanced load or these methods are based on experimental results alone without any theoretical basis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator interturn faults in DFIGs. Hence, in this paper, an in-depth investigation is conducted to determine the origin of various harmonic components in rotor currents and their feasibility to detect stator interturn faults unambiguously. Detailed analysis is presented, which explains the mechanism by which the stator-interturn-fault-related harmonics are induced in the rotor circuit. The theory is verified with simulation and extensive experimental results. To confirm the feasibility of the proposed technique for detecting stator interturn faults and obtain results on speed sensitivity of fault detection, a prototype of digital-signal-processor-based fault-diagnostic system has been developed, which is capable of producing very fast trip signal in about 2 s.

  • Stator Inter-Turn Fault Detection of Doubly-Fed Induction Generators Using Rotor Current and Search Coil Voltage Signature Analysis
    2007 IEEE Industry Applications Annual Meeting, 2007
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator inter-turn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search Coil Voltage. So far, fault diagnostic techniques proposed for stator inter-turn fault detection in DFIG are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because either they fail to account for condition when DFIG is operating under unbalanced load or these methods are based on experimental results alone. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator inter-turn faults in DFIGs. Hence, in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the rotor currents and their feasibility to detect inter-turn stator faults unambiguously. Detailed analysis is presented that explains the induction of stator inter-turn fault related harmonics in the rotor circuit. The theory is verified with simulation and extensive experimental results.

Subhasis Nandi - One of the best experts on this subject based on the ideXlab platform.

  • Stator-Interturn-Fault Detection of Doubly Fed Induction Generators Using Rotor-Current and Search-Coil-Voltage Signature Analysis
    IEEE Transactions on Industry Applications, 2009
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-Coil Voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition when the DFIG is operating under imbalanced load or these methods are based on experimental results alone without any theoretical basis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator interturn faults in DFIGs. Hence, in this paper, an in-depth investigation is conducted to determine the origin of various harmonic components in rotor currents and their feasibility to detect stator interturn faults unambiguously. Detailed analysis is presented, which explains the mechanism by which the stator-interturn-fault-related harmonics are induced in the rotor circuit. The theory is verified with simulation and extensive experimental results. To confirm the feasibility of the proposed technique for detecting stator interturn faults and obtain results on speed sensitivity of fault detection, a prototype of digital-signal-processor-based fault-diagnostic system has been developed, which is capable of producing very fast trip signal in about 2 s.

  • Stator Interturn Fault Detection of Synchronous Machines Using Field Current and Rotor Search-Coil Voltage Signature Analysis
    IEEE Transactions on Industry Applications, 2009
    Co-Authors: Prabhakar Neti, Subhasis Nandi
    Abstract:

    Our recent observations suggested that harmonics in the field current are very promising to detect stator interturn faults in synchronous machines. So far, an increase in some of the even harmonics in the field current has been reported to detect such faults. However, no explanation has been provided for the cause of these harmonics. Moreover, the even harmonics can significantly increase with supply unbalance as well as time harmonics, which can lead to a serious confusion. Hence, in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the field current and their feasibility to detect stator faults. It was found that, owing to structural asymmetries of the field winding, some of these components clearly increased with stator interturn fault. The findings are helpful to detect faults involving few turns without ambiguity, in spite of the presence of supply unbalance and time harmonics. Both simulation and experimental results are presented in this paper. The diagnosis results have also been verified using a rotor-mounted search Coil, which can also be used to detect even a one-turn stator fault very effectively.

  • stator inter turn fault detection of doubly fed induction generators using rotor current and search Coil Voltage signature analysis
    IEEE Industry Applications Society Annual Meeting, 2007
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-Coil Voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition when the DFIG is operating under imbalanced load or these methods are based on experimental results alone without any theoretical basis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator interturn faults in DFIGs. Hence, in this paper, an in-depth investigation is conducted to determine the origin of various harmonic components in rotor currents and their feasibility to detect stator interturn faults unambiguously. Detailed analysis is presented, which explains the mechanism by which the stator-interturn-fault-related harmonics are induced in the rotor circuit. The theory is verified with simulation and extensive experimental results. To confirm the feasibility of the proposed technique for detecting stator interturn faults and obtain results on speed sensitivity of fault detection, a prototype of digital-signal-processor-based fault-diagnostic system has been developed, which is capable of producing very fast trip signal in about 2 s.

  • Stator Inter-Turn Fault Detection of Doubly-Fed Induction Generators Using Rotor Current and Search Coil Voltage Signature Analysis
    2007 IEEE Industry Applications Annual Meeting, 2007
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator inter-turn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search Coil Voltage. So far, fault diagnostic techniques proposed for stator inter-turn fault detection in DFIG are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because either they fail to account for condition when DFIG is operating under unbalanced load or these methods are based on experimental results alone. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator inter-turn faults in DFIGs. Hence, in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the rotor currents and their feasibility to detect inter-turn stator faults unambiguously. Detailed analysis is presented that explains the induction of stator inter-turn fault related harmonics in the rotor circuit. The theory is verified with simulation and extensive experimental results.

Dhaval Shah - One of the best experts on this subject based on the ideXlab platform.

  • Stator-Interturn-Fault Detection of Doubly Fed Induction Generators Using Rotor-Current and Search-Coil-Voltage Signature Analysis
    IEEE Transactions on Industry Applications, 2009
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-Coil Voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition when the DFIG is operating under imbalanced load or these methods are based on experimental results alone without any theoretical basis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator interturn faults in DFIGs. Hence, in this paper, an in-depth investigation is conducted to determine the origin of various harmonic components in rotor currents and their feasibility to detect stator interturn faults unambiguously. Detailed analysis is presented, which explains the mechanism by which the stator-interturn-fault-related harmonics are induced in the rotor circuit. The theory is verified with simulation and extensive experimental results. To confirm the feasibility of the proposed technique for detecting stator interturn faults and obtain results on speed sensitivity of fault detection, a prototype of digital-signal-processor-based fault-diagnostic system has been developed, which is capable of producing very fast trip signal in about 2 s.

  • stator inter turn fault detection of doubly fed induction generators using rotor current and search Coil Voltage signature analysis
    IEEE Industry Applications Society Annual Meeting, 2007
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-Coil Voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition when the DFIG is operating under imbalanced load or these methods are based on experimental results alone without any theoretical basis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator interturn faults in DFIGs. Hence, in this paper, an in-depth investigation is conducted to determine the origin of various harmonic components in rotor currents and their feasibility to detect stator interturn faults unambiguously. Detailed analysis is presented, which explains the mechanism by which the stator-interturn-fault-related harmonics are induced in the rotor circuit. The theory is verified with simulation and extensive experimental results. To confirm the feasibility of the proposed technique for detecting stator interturn faults and obtain results on speed sensitivity of fault detection, a prototype of digital-signal-processor-based fault-diagnostic system has been developed, which is capable of producing very fast trip signal in about 2 s.

  • Stator Inter-Turn Fault Detection of Doubly-Fed Induction Generators Using Rotor Current and Search Coil Voltage Signature Analysis
    2007 IEEE Industry Applications Annual Meeting, 2007
    Co-Authors: Dhaval Shah, Subhasis Nandi, Prabhakar Neti
    Abstract:

    A novel technique for detecting stator inter-turn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search Coil Voltage. So far, fault diagnostic techniques proposed for stator inter-turn fault detection in DFIG are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because either they fail to account for condition when DFIG is operating under unbalanced load or these methods are based on experimental results alone. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator inter-turn faults in DFIGs. Hence, in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the rotor currents and their feasibility to detect inter-turn stator faults unambiguously. Detailed analysis is presented that explains the induction of stator inter-turn fault related harmonics in the rotor circuit. The theory is verified with simulation and extensive experimental results.

De-cheng Hong - One of the best experts on this subject based on the ideXlab platform.

  • Calculation of Tilted Coil Voltage in Cylindrically Multilayered Medium for Well-Logging Applications
    IEEE Access, 2020
    Co-Authors: Qiwei Zhan, Tao Chen, Hongnian Wang, Qiuli He, De-cheng Hong
    Abstract:

    In cylindrical multilayered medium, we develop two tool models for electromagnetic (EM) well logging: a metal mandrel winding with a co-axial (tilted) transmitter Coil and a tilted (coaxial) receiver Coil. The Voltages on receivers in those two models are proven to be the same and only zero-order harmonic of EM field need to be considered for Voltage calculation. To calculate the Voltage, two pseudo-analytical formulae are presented by using the integral of electrical field in spatial and wavenumber domain, respectively. Those two alternative pseudo-analytical formulae can be used to verify calculation accuracy of each other in some scenarios when other numerical methods do not work well. Furthermore, the reflection coefficients of EM fields, consisting of the ratios of the cylindrical functions, are introduced to avoid overflow problems in the numerical integral. Numerical examples corroborate the correctness and stability of the proposed formulae. These formulae help advance the forward modeling and inversion of logging-while-drilling (LWD) azimuthal resistivity measurements and new extra-deep azimuthal resistivity tools (EDAR).

  • Calculation of Tilted Coil Voltage in Cylindrically Multilayered Medium
    2019 IEEE International Conference on Computational Electromagnetics (ICCEM), 2019
    Co-Authors: De-cheng Hong, Na Li, Tao Chen, Jiang-tao He
    Abstract:

    In this paper, we present two approaches to calculate the Voltage of a tilted Coil in the cylindrically multilayered medium. The calculation of electromagnetic (EM) fields can be solved using a set of pseudo-analytical formulas. These formulas contribute to the forward modeling and inversion of traditional azimuthal resistivity Logging-While-Drilling (LWD) measurements or the new extra-deep azimuthal resistivity tool (EDAR). We assume the transmitter is an axial-Coil and therefore only zero-order harmonic components of electric fields need to be considered because of axial symmetry. A set of novel general reflection and transmission coefficients proposed in this paper are presented as the ratios of the modified Bessel functions, and thereby the numerical overflow problems can be obviated. Numerical examples are presented to verify the validity and the stability of the proposed formulas.

Qiwei Zhan - One of the best experts on this subject based on the ideXlab platform.

  • Calculation of Tilted Coil Voltage in Cylindrically Multilayered Medium for Well-Logging Applications
    IEEE Access, 2020
    Co-Authors: Qiwei Zhan, Tao Chen, Hongnian Wang, Qiuli He, De-cheng Hong
    Abstract:

    In cylindrical multilayered medium, we develop two tool models for electromagnetic (EM) well logging: a metal mandrel winding with a co-axial (tilted) transmitter Coil and a tilted (coaxial) receiver Coil. The Voltages on receivers in those two models are proven to be the same and only zero-order harmonic of EM field need to be considered for Voltage calculation. To calculate the Voltage, two pseudo-analytical formulae are presented by using the integral of electrical field in spatial and wavenumber domain, respectively. Those two alternative pseudo-analytical formulae can be used to verify calculation accuracy of each other in some scenarios when other numerical methods do not work well. Furthermore, the reflection coefficients of EM fields, consisting of the ratios of the cylindrical functions, are introduced to avoid overflow problems in the numerical integral. Numerical examples corroborate the correctness and stability of the proposed formulae. These formulae help advance the forward modeling and inversion of logging-while-drilling (LWD) azimuthal resistivity measurements and new extra-deep azimuthal resistivity tools (EDAR).