Prevention of Oil-Immersed Equipment Rupture Due to Arcing Faults Based on Metal Foam

Abstract

Oil-immersed power equipment, even when equipped with complete relay protection devices, is still exposed to a risk of rupture and explosion. During an internal arcing fault, such equipment will suffer from overpressure before the fault current is interrupted by circuit breakers. In this letter, a novel approach based on metal foam is proposed for preventing oil-filled equipment rupture. Specifically, density-layered aluminum foam sandwich panels are designed for use as sacrificial claddings to promptly mitigate arc-induced overpressure by absorbing energy through deformation. An actual arcing fault test platform with two limited closed tanks was established, and a multicharacteristic measurement system with pressure sensors and laser displacement sensors was used. Field arcing test results under various fault levels demonstrate the effectiveness of the presented method. Furthermore, the detailed morphology of metal foam, observed by a scanning electron microscope (SEM), indicates that the impact energy was partially absorbed through microscopic deformation. The proposed method provides new insight into fast overpressure mitigation and serves as a potential countermeasure to the challenging problem of equipment rupture.