Original scientific paper

Thermal failure in a clamping bolt of a shunt reactor

Salvador Magdaleno-Adame

Abstract

This article presents the detection and analysis of a thermal failure produced in a core clamping bolt of a 5 MVAr gapped three-phase shunt reactor. Gases were detected in this shunt reactor during its operation at a substation in Mexico. Using dissolved gas analysis (DGA) and Duval’s triangle method, temperatures up to 700°C were estimated in the shunt reactor. Overheating evidence was detected in one of the core clamping bolts during an internal inspection of the shunt reactor. The author and the reactor manufacturer believe that the insulation of the clamping bolt was damaged by the loosening of the bolts produced by the vibration of the shunt reactor in conjunction with a possible low torque applied to the bolts. A short circuit between the bolt and the clamping frame was produced, generating the circulation of eddy currents in the bolt producing high temperatures and gasifying the insulating oil in the shunt reactor. Three-dimensional (3-D) finite element (FE) simulations were performed to verify the cause of the overheating issue in the clamping bolt of the shunt reactor, simulating the short circuit between the clamping bolt and the core frame. From the simulation results, the author determined that a short circuit between the bolt and the core frame generated the gases and the high temperatures in the shunt reactor. Finally, the manufacturer of the shunt reactor decided to reinforce the insulation of the clamping bolts using fiberglass to avoid future possible short circuit failures.

Keywords

shunt reactor; short circuit failure; finite element (FE) simulation; dissolved gas analysis (DGA); core clamping bolt; Duval’s triangle method

Hrčak ID:

309750

URI

https://hrcak.srce.hr/309750

Publication date:

13.11.2023.

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