Failure Analysis and Teardown Inspection of Transmission Shunt Reactor in High Impedance Complex Transmission Network Power System

As power grids age amid the energy transition, assets increasingly operate beyond their original design envelope introducing critical technical, operational, and safety risks. This paper presents a comprehensive failure analysis of a 181 MVAr, 362 kV shunt reactor at an Australian metropolitan transmission substation. After over two decades of service, the reactor suffered catastrophic B-phase winding failure within seconds after energisation. Protection systems responded correctly, clearing the fault in 63 ms. Post-failure inspection confirmed severe internal winding damage, significant oil spillage, and tank deformation.