Computational Fluid Dynamics Study of High Energy Incidents Inside and Above Buried Underground Vaults
When a transmission cable joint in an underground vault undergoes an electrical failure this event can result in a high energy event and trigger a shock wave. Rapid and extreme pressure build up inside a manhole can cause a 200kg vault cover launching out as a dangerous projectile, which is referred as manhole incidents. The safety and reliability evaluation of the power cable joint in an underground vault has always been challenging with quite complex electromagnetic-thermal-mechanical coupling field. In this case, accurate representation of material properties is one of the most important issues in modeling the behavior of the cable joint-underground vault-vault cover system. Computational fluid dynamics (CFD) will be used to establish a 3-D parametric model considering the coupling field in this project. Based on the FE model, the pressure versus time curves in transmission vaults will be analyzed and computed considering different triggers and varying model geometry. Sensitivity analysis will be conducted to analyze the effect of parametric changes on the pressure versus time curves, such as ambient temperatures, number of vault covers, extent of venting, and input trigger energy and time profiles. The effects of the explosion of power cable joints on surrounding structures will be evaluated.