Power Research

Pritesh Bhoniya ¹, Prasanta Kundu ¹

Affiliations
1 Department of Electrical Engineering, S V National Institute of Technology, Surat - 395 007, IN

Abstract

With the appearance of deregulation, distribution transformer predictive maintenance is becoming more important for utilities to prevent forced outages with the consequential costs. To detect and diagnose a transformer internal fault requires a transformer model to simulate these faults This Paper presents here an approach has been shown for transformer fault analysis. A transformer model was designed for a 10 MVA, 132/66 kV three phase system. Data for all the parameters essential for designing a transformer were calculated, after studying machine designing. The next task was to calculate the inductance and capacitance (lumped values) which is later on used to make the ladder network which represents the transformer as inductance capacitance model. After dividing the total inductance and capacitance into segments the ladder network is ready to be used for short circuit fault analysis. Artifi cial faults were created by shorting a few segments at a time and the output voltage corresponding to input voltage under different faulty conditions were noted down. These values were used to create a frequency response curve which was compared with the response under normal condition and further analysis was done.

Keywords

Deregulation, Distribution transformer, Transformer model and Frequency response curve.

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Pritesh Bhoniya ¹, Prasanta Kundu ¹

Affiliations
1 Department of Electrical Engineering, S V National Institute of Technology, Surat - 395 007, IN

Abstract

A common failure mode for power transformers is consequent to mechanical deformation of the core or windings. Core damage is more likely as a result of transportation, while winding damage is more likely to be caused by short circuit type forces. Sweep Frequency Response Analysis (SFRA) is an effective low-voltage, off-line diagnostic tool used for fi nding out any possible winding displacement or mechanical deterioration inside the Transformer, due to large electromechanical forces occurring from the fault currents or due to Transformer transportation and relocation. This paper describe through case studies that SFRA test is more sensitive to detect faults compare to conventional testing method.

Keywords

Common failure mode, Sweep frequency response analysis (SFRA) and Frequency response analysis (FRA).

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