This study develops a numerical algorithm for unsteady fluid flow for short and long hydraulic systems, including various hydraulic devices in the system, through scientific searches for new ways to protect long pipeline systems from sudden pressure surges and prolonged pipeline exposure to high pressure. One of the methods is the localisation of high-pressure zones with the help of oscillating circuits. Numerical experiments show that the frequency of pressure oscillations in them increased tens of times, making it possible to dampen the energy of pressure waves more effectively with the help of pressure stabilisers of smaller volumes. The amplitude of pressure oscillations decreases rapidly due to energy loss from the friction of the liquid against the pipeline walls. Studies have been carried out for oscillatory circuits with the introduction of pipeline sections with low-pressure wave propagation velocity. These calculations reveal additional possibilities for pressure reduction.