United Simulation Of Hydro-electrical System Based On Detailed Models Of Conduit System And Hydro Turbine

With the building and operating of large-scale hydro power stations and pumped storage plants, the proportion of water power to power system is increasing year by year in china and the stabilization problem of hydro-electrical system is standing out, which bring forward higher requirement to the united simulation of hydro-electrical system. The transient simulation of power system uses usually simplified models of conduit system and hydro turbine. Similarly the simplified models of synchronous generator and power system are used in transient simulation of hydraulic system. The oversimplified models can not reflect the mutual effect of hydraulic system and power system, and they may cause irrational conclusions when they are used in the studies on middle or long term stability, resynchronization of hydro turbine and generator and large-disturbance surge tank system that relate closely to the mutual effect of hydraulic system and power system or the auto governing. Consequently in order to make up the faults that hydro turbine models are single and simply and models of complex conduit system are scarce, it is necessary that the detail models of hydro-electrical system be established to make crossed study of different subjects and the simulation arithmetic of the large-disturbance transient be studied.On account that models of conduit system and hydro turbine are oversimplified, first of all the detail models of complex conduit system and hydro turbine are summed up, and then the detail models of hydraulic system and power system which are fit for the large disturbance transient calculation are established, including auto modeling models of complex conduit system based on the characteristic equations, linear and nonlinear models of Francies' hydro turbine, surge tank's current model and generator's model, governor's model, excitation system's model and grids' model in the thesis. The auto modeling of complex conduit system is very important for the researchers of power system. In the thesis the conduit auto modeling models consist of the mathematic descriptions of a variety of typical units and take account of the effect of elastic hammer and mutual action of complex conduits, which can adapt to the complexity of the construction of conduit system and have high precision and efficiency. The Francies' hydro turbine models are induced, comprising of the linear model based on the model characteristic curves, the linear model based on the internal characteristics description, the nonlinear model based on four-quadrant characteristics and simply analytic nonlinear model. As a result of comparison of these models, it is believed that these models have different traits and the proper model should be selected according to the study purpose and known conditions.The equation's forms of the hydraulic system models with elastic hammer havegreat difference from power system models that hydraulic system models have partial-differential equations while the power system models all are constant-coefficient differential equations. Because directly resolving equations requires constant equation number, it is difficult that the equations corresponding to two models are directly combined together to resolve, which isn't to the good for the auto modeling of complex conduit system. In order to resolve the question, in the thesis a simulation arithmetic of hydro-electrical system is put up. The equations of hydro-electrical system are divided to two parts, one of which consists of the differential equations of conduit system, hydro turbine and generator's rotator and is solved by characteristic equation arithmetic, the other of which consists of the differential equations of generator, magnetic system and grid and is solved by longge-kuta arithmetic or covert integrated arithmetic. Through the alternative solving of the two parts, the simulation results of the large-disturbance transient could be abstained eventually. The simulation arithmetic of hydro-electrical system can meet the requirement of auto modeling of complex cond...