This paper presents a simulation of a nonlinear model of a hydraulic system proposed to function as a system of lubrication for the bearings of a steam turbine using the technique of Bong graph. The Bond Graph modeling takes advantage of the exchange power and the analogies between the subsystems hydraulic, mechanical and electrical, allow the description of significant nonlinearities of the components, and can be used to simulate small and large transient responses. The system can be divided into modules, examining the flow variables and effort over the course of each module and the subsystems can be gathered to simulate the system as a whole.