Open Access

ARTICLE

Electromagnetic Coupling and Diagnostic Test Analysis of Power Transformer Turn-to-Turn Short Circuit

Tao Tong^1,*, Peng Wang¹, Xiaolin Zhao², Zhigang Zhao², Ke Wang², Chen Cao³, Xincai Ming⁴
1 State Grid Jiangxi Electric Power Company Research Institute, Nanchang, China
2 China Electric Power Research Institute, Beijing, China
3 School of Electrical Engineering, Shenyang University of Technology, Shenyang, China
4 Jiangxi People’s Power Transmission and Transformation Co., Ltd., Nanchang, China
* Corresponding Author: Tao Tong. Email:
(This article belongs to the Special Issue: Advanced Analytics on Energy Systems)

Energy Engineering https://doi.org/10.32604/ee.2026.078218

Received 26 December 2025; Accepted 09 March 2026; Published online 09 April 2026

Abstract

The power transformer serves as a critical hub equipment in the electric power industry, performing the core functions of voltage transformation and power transmission in power grids. Among various potential hazards, through-fault short-circuit impacts are particularly destructive, capable of inducing severe deformation of the transformer windings and even triggering internal faults, thereby posing a major threat to grid stability. Consequently, accurate diagnosis of transformer damage after short-circuit impacts and scientific formulation of targeted overhaul strategies are of vital practical significance for ensuring safe and reliable power supply. In this paper, a comprehensive diagnostic analysis method for transformer turn-to-turn short circuits is proposed, based on the electromagnetic coupling principle of the leakage circuit. To verify the method’s effectiveness, two typical tripping events of 220 kV transformers caused by internal winding turn-to-turn short circuit faults are investigated as case studies. During on-site diagnostic tests, it is found that individual test items yield inconsistent fault indications, making it impossible to accurately locate the fault location and root cause relying on a single testing approach. Therefore, by integrating fault recording file analysis and multi-dimensional diagnostic test data, combined with in-depth research on the transformer’s electrical and magnetic circuit fault mechanisms, this study successfully identifies turn-to-turn short circuit faults occurring in different windings of the transformers and determines their exact positions. The validity and feasibility of the proposed comprehensive diagnostic analysis method are fully confirmed by the results of subsequent on-site dismantling inspections.

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Keywords

Transformer; diagnostic electrical test; turn-to-turn short circuit; winding deformation; electromagnetic coupling

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