Extended Use for the Frequency Response Analysis: Switching Impulse Voltage Based Preliminary Diagnosis of Potential Sources of Partial Discharges in Transformer

Kamalaselvan Arunachalam,Hassan Haes Alhelou,Balasubramanian Madanmohan,Rajesh Rajamani,Pierluigi Siano,Natarajan Prabaharan

doi:10.3390/app10228283

Kamalaselvan Arunachalam, Hassan Haes Alhelou + Show 4 more

Open Access

https://doi.org/10.3390/app10228283

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Abstract

The Frequency Response Analysis approach (FRA) is useful in the fault diagnosis of transformers. However, its usefulness in diagnosing any potential sources of Partial Discharge (PD) in transformers has not been thoroughly investigated so far. In this work, the use of Impulse voltage-based FRA (IFRA) in diagnosing inter-turn shorts and potential sources of PD were investigated on a 315 kVA, 11 kV/433 V transformer. Inter-turn shorts and PD sources were emulated and the usefulness of IFRA in their diagnosis was investigated while using switching impulse voltage at different magnitude levels as the test signals. For emulating the inter-turn shorts and the PDs, special tappings were provided on one of the 11 kV windings through the low capacitance bushings. Low voltage impulse was successful in diagnosing the inter-turn shorts, but unsuccessful in identifying the sources of PDs. During the test condition, the test voltage was adjusted with the presence of artificially created PD sources. The frequency response of the transformer before and after the inception of PD was observed and analyzed in this article. The FRA results demonstrated that the switching impulse voltage based IFRA approach at moderate voltages could be useful in diagnosing the presence of the potential sources of PDs.

Highlights

The Frequency Response Analysis (FRA) approach has been effectively used for mechanical, electrical, and magnetic core fault diagnosis purposes, such as axial and radial displacements/deformations, loosening of clamping pressure, inter-turn shorts, grounding issues, and core saturation problems, as per standards, working group recommendations, and literature [1,2,3,4,5,6]
The usefulness of the Impulse voltage-based FRA (IFRA) in diagnosing the inter-turn shorts and potential sources of partial discharges in the transformer winding was investigated on a 315 kVA, 11 kV/433 V, Dyn 11, Oil Natural Air Natural (ONAN)
Low magnitude switching impulse was found to be effective in diagnosing the inter-turn shorts, but, due to its magnitude being insufficient in incepting the discharge, ineffective in diagnosing the potential sources of partial discharges

Summary

Introduction

The Frequency Response Analysis (FRA) approach has been effectively used for mechanical, electrical, and magnetic core fault diagnosis purposes, such as axial and radial displacements/deformations, loosening of clamping pressure, inter-turn shorts, grounding issues, and core saturation problems, as per standards, working group recommendations, and literature [1,2,3,4,5,6]. They used a broad spectrum of frequency components, contained either a sweep sinusoidal signal of constant magnitude or lightning/switching impulses [1,4]. Sci. 2020, 10, 8283 interference (EMI) and electromagnetic compatibility (EMC) of DC machines, and demonstrated the usefulness of the frequency domain analysis in performance characteristic analysis [9,10]

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