Research
Our research group broadly focuses on:
- Transformer Diagnostics and Condition Monitoring
- Online FRA measurement and diagnostic techniques for transformer
- Computational Electromagnetics and Modeling of Power Apparatus
- Insulation Coordination for Grid-integrated Wind and Solar Farms
- Impulse Aging of Metal Oxide Surge Arrestor (MOSA)
- High Frequency High Voltage Transformer Design for Power Converter Applications
Transformer Diagnostics and Condition Monitoring:
This research focuses on developing innovative methods to extract and interpret information embedded in the frequency- and time-domain responses of transformer windings. By integrating classical approaches with AI/ML-based techniques, it aims to enable advanced diagnostic capabilities and improve the condition assessment of high-voltage power transformers.This work also includes developing online FRA testing and diagnostic techniques for transformers.
Computational Electromagnetics and Modeling of Power Apparatus::
This work involves finite element method (FEM)-based modeling and simulation for the design, analysis, and performance optimization of high-voltage high-frequency transformers, high voltage reactors, and high-voltage polymeric insulators.
Insulation Coordination for Grid-integrated Wind and Solar Farms:
This research investigates surge and transient phenomena in renewable energy systems, focusing on the effects of switching and lightning interactions and their propagation along transmission lines with multiple reflections. The studies aim to understand the resulting overvoltage and overcurrent stresses on transformers, generators, and power electronic systems, and to develop effective mitigation strategies to ensure reliable and resilient system operation.
Impulse Ageing of Metal Oxide Surge Arresters (MOSA):
This research focuses on the experimental investigation of the health status of MOSA under impulse ageing by measuring leakage current, polarization–depolarization current, frequency domain spectroscopy (FDS), and/or partial discharge characteristics before and after impulse application. It aims to understand degradation behaviour and develop models for impulse ageing, thereby supporting improved reliability and condition assessment under lightning and switching stresses.
Major Research Contributions
- Establishment of an indirect method to measure the series capacitance of transformer winding from time-domain and frequency response measurement
- Physical representation of a transformer winding by a coupled ladder network model constructed from its measured frequency response
- Enhancing physical resolution of constructed ladder network model for an interleaved transformer winding
- Introducing tank current to enhance the FRA sensitivity to detect mechanical fault in actual transformer
- Developing a Parametric Evaluation Method Using FRA for Comprehensive Fault Analysis in Three-Phase Transformers
- Advancing Reference-Free Fault Detection using Innovative Line and Tank Current Measurements
- Development of FRAMAT & FRAPYT: MATLAB & Python Based App Development for Fully Automated Frequency Response Measurement of Transformer Tank Current
- Developing a COMSOL-based simulation tool to compute the model parameters of a medium-voltage, medium-frequency transformer used for induction furnace applications
- Developed an FRA-based algorithm for simplified reduced-order transformer modeling to reproduce transient responses such as impulse behavior
- Designed a portable 40 kV DC Hi-Pot tester, currently under manufacturing, through collaborative research with colleagues
Research Facilities in the Laboratory
- 3 MVA, 33/11 kV Dyn11 Transformer
- 1 MVA, 33/11 kV Yyn0 Transformer
- N4L PSM-1735 Impedance Analyzer with LCR Active Head
- Digital Storage Oscilloscopes (DSO), Arbitrary Function Generators (AFG), and Current/Voltage Probes
- High-Voltage Impulse Generator (600 kV, 18 kJ)
- High Impulse Current Generator (15 kA, 8/20 µs)
- High-Voltage Testing Transformer (300 kV)
- High-Voltage DC Generation Facility (up to 40 kV)
- Pulse Power Generator using Rotating-Sphere-Gap
Research Gallery
Will be updated soon...