PhD Supervisor

गुरू ब्रह्मा गुरू विष्णु, गुरु देवो महेश्वरा गुरु साक्षात परब्रह्म, तस्मै श्री गुरुवे नमः

Prof. Sisir Kumar Nayak
Professor
Department of EEE
IIT Guwahati, North Guwahati
Assam, India, 781039
Phone: +91-361-2582530 (O)
Fax: +91-361-2582542
Email: sknayak@iitg.ac.in

PhD Thesis title

A Non-intrusive and Non-destructive Technique for Condition Assessment of Transformer Liquid Insulation

Fig 1. 33/11 kV 5 MVA Transformers in parallel operation

Output
Indian patent filed: 202231013474. Date of filing: 11/03/2022
Journal: Link

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Substation in IIT Guwahati

Research Progress

Transformer is a costly and important equipment in the Power System. The transformer's proper functioning is necessary for reliable power supply. The maintenance and condition monitoring of the transformer help in avoiding its outage/sudden failure. Condition monitoring transformer abuts monitoring the insulation strength of solid and liquid dielectrics used in transformer.

The transformer is monitored for

1. The gases generated due to various faults (thermal, electrical)

2. Breakdown strength of insulation with time

3. Physical, Electrical and Chemical properties and their changes with aging

Preventive actions are taken accordingly.

Objective I

The condition monitoring of transformer is crucial in avoiding failure of transformer. There are multiple ways of condition monitoring

1. Monitoring the degradation of solid insulation

2. Monitoring the degradation of liquid insulation

The following are a few equipment which are mostly used in condition monitoring:

All the above condition assessment devices are costly and bulky which every substation or a small power utility may not afford. In addition, these devices are not portable and detect one parameter each. My objective is to develop a compact, economical, portable, non-destructive and reliable condition monitoring device which can detect at least two properties of the transformer oil. An EMI free non-intrusive and non-destructive technique is developed to detect the moisture and acid content in mineral oil.

The mineral oil is non-biodegradable, fire hazard, and exhaustible. Researchers over time have come up with vegetable oils as an alternative to mineral oil. These vegetable oils are fire safe up to higher temperatures, biodegradable and renewable. These vegetable oils are proven to be superior in many electrical aspects compared to mineral oil. The usage of vegetable oils in transformers also slows the rate of degradation of solid insulation. The electrical and thermal properties of mineral and vegetable oil improve with the addition of nanoparticles to mineral and vegetable oils. My objectives are focussed on the applicability of these alternative oils in power transformer.

Extended Work:

The transformer insulation consists of:

Fig 2. Transformer winding terminals and solid insulation

Fig 3. Insulation used in transformer

Fig 5. Breakdown voltage tester for liquid insulation

Fig 6. Dielectric constant, resistivity measurement unit

Fig 7. Moisture Analyzer

Fig 8. Flash point Measurement

Fig 9. High Voltage Generator

Fig 4. Nanofluids with various w/v% CuO nanoparticles for transformer insulation

a

b

c

d

Fig 10. a. Fresh FR3 Vegetable Oil

b. Thermally aged FR3 (500 hours)

c. Open beaker aged FR3 (500 hours)

d. Thermally aged FR3 for 500, 1000, 1500, 2000 hours

Fig 11. Surface profile of kraft paper with aging

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Technical equipment proficiency

Projects associated

Courses taught during PhD* (PMRF Deliverables)