The mathematical model of dynamic loads was developed based on an analysis of the polished rod load of beam pumps, and the variation of the dynamic loads and the computation of the minimum and maximum limits during a ...The mathematical model of dynamic loads was developed based on an analysis of the polished rod load of beam pumps, and the variation of the dynamic loads and the computation of the minimum and maximum limits during a complete pumping cycle were given out by solving the model.Field examples verify that it is necessary to take into account the inertial and vibration loads while calculating polished rod loads.During the prophase of the pumping production, the dynamic to polished rod load ratio is relatively large.Then the ratio decreases rapidly and becomes small after entering stable production.Moreover, the total deformation of rod and tubing in CBM wells is much smaller than that in oil fields, and the deformation caused by the dynamic loads is also relatively small.The result of this work is the calculation of the dynamic loads.The application of this calculation for the sucker rod pumping system in CBM wells can give the desired accuracy of polished rod load and the dynamometer cards, which provides a reasonable basis for the design and selection of beam pumps.展开更多
This paper gives an insight on the effect of transmission line temperature variations, resulting from loading and weather conditions changes, on a power system＇s steady state and dynamic performance. The impact of dy...This paper gives an insight on the effect of transmission line temperature variations, resulting from loading and weather conditions changes, on a power system＇s steady state and dynamic performance. The impact of dynamic load models on system stability is also studied. The steady-state and dynamic stability simulation results of a 39 bus system for constant line impedance （the traditional simulation practice） are compared to the results with estimated, but realistic, temperature varied line impedances using PSLF （positive sequence load flow） software. The modulated line impedances will affect the thermal loading levels and voltage profiles of buses under steady state response, while the dynamic results will show improved damping in electro-mechanical oscillations at generator buses.展开更多
基金Supported by the National Science and Technology Special Project of China(2008ZX05038-004)Shandong Province Science and Technology Development Project(2009GG10007008)
文摘The mathematical model of dynamic loads was developed based on an analysis of the polished rod load of beam pumps, and the variation of the dynamic loads and the computation of the minimum and maximum limits during a complete pumping cycle were given out by solving the model.Field examples verify that it is necessary to take into account the inertial and vibration loads while calculating polished rod loads.During the prophase of the pumping production, the dynamic to polished rod load ratio is relatively large.Then the ratio decreases rapidly and becomes small after entering stable production.Moreover, the total deformation of rod and tubing in CBM wells is much smaller than that in oil fields, and the deformation caused by the dynamic loads is also relatively small.The result of this work is the calculation of the dynamic loads.The application of this calculation for the sucker rod pumping system in CBM wells can give the desired accuracy of polished rod load and the dynamometer cards, which provides a reasonable basis for the design and selection of beam pumps.
文摘This paper gives an insight on the effect of transmission line temperature variations, resulting from loading and weather conditions changes, on a power system＇s steady state and dynamic performance. The impact of dynamic load models on system stability is also studied. The steady-state and dynamic stability simulation results of a 39 bus system for constant line impedance （the traditional simulation practice） are compared to the results with estimated, but realistic, temperature varied line impedances using PSLF （positive sequence load flow） software. The modulated line impedances will affect the thermal loading levels and voltage profiles of buses under steady state response, while the dynamic results will show improved damping in electro-mechanical oscillations at generator buses.
