Summary: Basing on the results of industrial experiments, carried out on the real pipeline, the patterns of flowrate changes during unsteady processes, caused by a changing the number of working units at oil pumping stations, were established. The method of determining mean oil flowrate against time and length was developed, which allows to specify the flow capacity of the oil pipeline during unsteady processes in operation.

Keywords: unsteady hydrodynamic process, oil flowrate, flow capacity, pumping units start.

Summary: The possible range of adjustment and energy efficiency for the application of regulated drives for pumps were studied based on the example of operational main oil pipeline segment, which has significant part load. Cases using pumps with regulated drives on one and on all as well oil pumping stations of oil pipeline were investigated.

Keywords: oil pumping station (OPS), pumping unit, regulated drive, flow capacity, specific power consumption, energy efficiency.

Summary: The method of mathematical modeling characteristics of pumping units for oil pipelines rotary frequency was improved. For recalculation were used graphic characteristics of pumps, obtained experimentally for the nominal value of rotational frequency. The method is based on the application of similarity theory of centrifugal machines.

Keywords: centrifugal pump, centrifugal machines similarity theory, nominal mode, energy efficiency.