Subrat Sahoo

Subrat Sahoo
ABB | ABB · Power Grids Research

Ph.D.

About

22
Publications
12,467
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201
Citations
Introduction
Subrat Sahoo currently works at the Power Technology, ABB. Subrat does research in Electrical Engineering, Electronic Engineering and Instrumentation Engineering. Their current project is 'Electrical machine diagnostics'.

Publications

Publications (22)
Conference Paper
Full-text available
The paper presents the modern-day challenges of the utilities in dealing with several monitoring solutions available in the market without a clear direction of how to interpret this data coming out of different constituent assets. A unified framework is thus proposed, where the operational behavior, performance, life cycle and usability of individu...
Article
A novel technique to improve the fault detection sensitivity in three-phase transformer using tank current method is reported. Tank current method was first published by the first-author in recent past for single isolated transformer winding. A fault in a single isolated transformer winding was uniquely identified employing the typical resonance be...
Conference Paper
Full-text available
A Damper winding performs an important function of protecting the Synchronous Motors (SMs) during transient operations. They also happen to be one source of concern for failure of SMs, which are otherwise quite reliable. The situation aggravates when the motors are fed by variable frequency drives, which brings additional stress on the damper bars....
Article
Full-text available
Early detection and diagnosis of faults in synchronous machine (SM) are crucial since they drive critical applications. In this paper, the authors exploited the combined information from numerical simulation and experimental validation to evaluate the merits of certain fault indicators, for detecting machine faults. A specially designed SM was chos...
Patent
Full-text available
A method for preventing at least one frequency component of a voltage from occurring in an electrical machine (10) comprises the steps of: obtaining, either by measuring a voltage signal or a current signal from the electrical machine (10) in time domain and transforming the measured signal into frequency domain, by simulating the electrical machin...
Article
This work presents a method for the robust detection, classification and possible compensation of harmonics in electric drives during real-time operation, with the aim of providing a framework for monitoring and diagnostic without the need of additional hardware. The detection is performed with a sparse fast Fourier transform algorithm, for its low...
Patent
Full-text available
The present disclosure relates to a method of determining an electro-mechanical fault condition in a synchronous machine having a stator and a rotor, and an exciter. The method comprises a) obtaining an exciter current signal which is a measurement of an exciter current through stationary windings of the exciter, b) transforming the exciter current...
Patent
The present disclosure relates to a method for determining an undesired condition in an electrical drive system comprising an electrical machine and an electrical drive, wherein the method comprises a) obtaining a measured signal of an electrical or mechanical parameter concerning the electrical drive system, b) obtaining a frequency spectrum of th...
Conference Paper
Full-text available
Electrical machines are subjected to numerous vibration forces. The forces generated from the radial magnetic pull on the stator core are considered in this study to understand their influence in the end-winding region. These forces exhibit distinct and noticeable impact that is separable in terms of different frequency components, when electro-mec...
Conference Paper
Full-text available
Often encountered driving critical applications, synchronous machines (SM) require reliable condition monitoring systems. In this paper, the advantages of using the field winding current of a synchronous motor as an early indicator of machine faults are demonstrated. Analysis is carried out, both through simulation, via the use of finite element me...
Conference Paper
Full-text available
Fault indicators signifying major failures in Synchronous machines (SM) are highlighted. A 15 megawatt (MW) SM was chosen in which, electro-mechanical faults were made by suitably altering physical disposition of machine parts. Finite element simulation of the motor model helped build signature for ideal and fault conditions in time and frequency d...
Conference Paper
Full-text available
-- Ideal condition of a synchronous machine (SM) and subsequent fault models representing rotor eccentricity of different types as well as inter-turn short circuits in stator and rotor are created with finite element method (FEM) simulation for a specially designed SM. This machine has provisions of recreating the same faults made in the simulation...
Patent
A coolant flow reduction monitoring system for a rotary electric machine having stator coils within a plurality of slots of a stator thereof is provided. The stator coils are cooled by a coolant flowing in a plurality of passages provided in the stator coils. The system includes an outlet temperature sensor for measuring a coolant outlet temperatur...
Article
Full-text available
Based on terminal measurements on a single, continuous-disc winding of a transformer, it is demonstrated how faults introduced at different positions along the winding could be localized with reasonable accuracy. Fault in the present context represents a discrete change, e.g. short-circuiting a few turns within a disc (i.e. predominantly an inducti...
Article
A systematic procedure is evolved that enables identification of the type-of-changes introduced in the model winding of a transformer, based on a comparison of measured neutral or line current and transfer-function with those corresponding to the reference case. Further, it was also possible to ascertain, whether the pertinent circuit element viz....
Article
Full-text available
The transfer function (TF) of a transformer winding (or its natural frequencies) is known to be dependent on many factors, like the type of winding excited, terminal configuration and type of secondary winding, arrangement of windings, clearances, tap and its positions, phase position, etc. Further, it was well established about half a century ago...

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