An early fault diagnosis method for inter-turn short circuits in dry-type air-core reactors considering harmonic voltages

Abstract

In response to challenges such as the subtle early fault indications and the fluctuating harmonic content in power systems affecting diagnostic accuracy， this paper presents a novel method for analyzing and diagnosing inter-turn short circuit faults in dry-type air-core reactors， taking into consideration the influence of harmonic voltages. Addressing three distinct operating conditions such as normal reactor operation， early-stage arc-type inter-turn short circuits， and mid-to-late-stage metal fusion-type inter-turn short circuits， the paper analyzes the operational characteristics of both series and parallel reactors under fault conditions to identify specific early fault indicators for inter-turn short circuits in each configuration. Additionally， the paper establishes a simulation model for inter-turn short circuit faults in reactors that accounts for harmonic voltage effects and analyzes the variation in electrical characteristics of series and parallel reactors under various operating conditions. Subsequently， it proposes a diagnostic method based on the current harmonic ratio for series reactor faults and another method based on the active power ratio for parallel reactor faults. To validate the effectiveness of the proposed method， the paper constructs an experimental test platform for inter-turn faults in series and parallel reactors and conducts experiments to confirm its correctness and efficacy.

Keywords

• dry-type air-core reactor
• harmonic voltage
• inter-turn fault
• fault diagnosis