The remarkable advance in hydraulic and electrohydraulic power systems resulted in producing control valves of very short settling time. The rapid closure of hydraulic transmission lines leads to severe pressure surge. Thattached Simulink file is developed to evaluate the applicability of oleo-pneumatic accumulators for the protection against this phenomenon. A lumped parameter model was developed for the transmission line, assuming four lumps, considering the effect of line resistance, inertia and capacitance.