Fuzzy Based Condition Monitoring Tool for Real-Time Analysis of Synthetic Ester Fluid as Transformer Insulant

Mridula Mridula,Shufali Ashraf Wani,R Sarathi,A J Amalanathan

doi:10.1109/access.2022.3149802

Mridula Mridula, Shufali Ashraf Wani + Show 2 more

Open Access

https://doi.org/10.1109/access.2022.3149802

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Abstract

The main aim of the present study is to explore the use of synthetic ester fluid as a transformer insulant. For this, the performance of thermally aged synthetic ester is investigated using corona inception voltage (CIV) measurement, fluorescent analysis, and dielectric spectroscopic studies. Then a fuzzy model is introduced to correlate the outcome of these studies to predict the key performance index and lifetime estimation of insulation structures. CIV tests for the thermally aged ester fluid, under AC voltage show 53.2% and 34% reduction in inception values due to ageing time and ageing temperature respectively. Furthermore, the effect of magnetic field on the performance of thermally aged ester is also studied and a drastic reduction of 54.3% and 39.4% respectively in CIV is observed. Statistical studies also indicate accelerated degradation of the insulation performance under the influence of the magnetic field, showing high scatter in CIV data indicated by decreasing beta values. Other studies such as fluorescent spectroscopy depict progressive shifts in fluorescence maxima and a decrease in emission intensity with ageing. Dielectric spectroscopy results show a manifold increase in dissipation factor due to thermal ageing. A fuzzy monitoring tool uses spectral data as input and at the output indicates the level of deterioration. The Rule-base of the model is framed using dielectric study.

Highlights

Transformers form an essential part of the power system network
One of the major problems in transformers is the discharge initiated from a weak link caused due to micro protrusion in the winding or edge of the winding, where the local electric field can enhance causing corona discharge activity
The electrical characterization of the synthetic ester is carried out using the Corona Inception Voltage (CIV) test

Summary

INTRODUCTION

Transformers form an essential part of the power system network. The information about the longevity of transformers is determined basically by the health of their insulation. A widely used traditional technique for transformer condition monitoring is Dissolved Gas Analysis (DGA) It helps in incipient fault recognition and cannot assess the ageing condition of oil. The information obtained from these sensitive optical techniques can be precisely used to predict the health of transformer insulation using an AI-based model Having known all these aspects, the following methodical experimental studies need to be carried out with thermally aged synthetic ester: (i) analysis of corona inception voltage (CIV) variation in presence of magnetic field under AC voltages ii) statistical analysis of CIV variation in presence of magnetic field (iii) fluorescent spectroscopy analysis and dissipation factor variation (iv) construction of a fuzzy model to correlate the performance analysis of thermally aged synthetic ester using these characterizations and to predict the status on the end life of the insulation

EXPERIMENTAL PROCEDURE

ELECTRICAL CHARACTERIZATION

Findings

CONCLUSIONS