This paper reports an investigation to develop a dynamic hybrid power system simulation model to maximize the renewable energy extraction and to analyze disturbances. The investigated model is based on two types of renewable power generation: wind turbine generator and photovoltaic generator, connected to a three-phase isolated grid constituted by a diesel generator. The interconnection between the renewable sources and the AC diesel generator is made by a DC-link with buffer batteries and an inverter. First, the system is sized according to the electric demand and the availability of renewable energy resources. Then, each component of the hybrid power system is dynamically modelled in order to maximize the renewable energy to total energy ratio and to analyze the disturbances that affect the correct operation.