Study On Stable Operation Of Direct Operation Of Large Users In Lonely Net Of Hydropower Plant

General trend of power grid is to realize the power connected. But in some special occasions and situations are existing these problems which isolated net operation mode or a single power direct power supply for large customer. In order to make the power grid to be safe and stable operation, the isolated power network has important practical significance.A hydropower station in Yunnan border undertakes the power supply tasks with Yunnan grid and a mine factory in Dagong mountain in Myanmar. Due to maintenance needs,the electric power circuit in China will not supply power. At this point the hydropower station will supply power directly for the Dagong mountain loads. Power plant and load form an isolated power grid. This way of running space truss structure is weak, the running stability is relatively poor, therefore, we study the stability of the mode of the isolated net running having practical significance. The main research contents include:First,this paper established a turbine model, turbine governor model, generator model and PSS model, load model based on the influence factors of the modeling of hydroelectric units;Second,After the formation of isolated net the dynamic characteristics were analyzed.Then,according to the hydropower electrical wiring diagram and the actual requirements, Finally, we had built a hydroelectric power plant simulation model of direct power supply isolated network. Based on the construction and simulation of the model, for the stable operation of the isolated net direct power supply mode are analyzed in detail.The mainly content is that first we verified the stability of the grid when the system was running the simulation, then based on the isolated net stability simulation. Including frequency stability, voltage stability simulation. And conducted the short circuit to the effect on the stability of the isolated net running,PSS impact on investment and operational stability of solitary retreat networks, load switching effect on the stability of solitary network operation.Finally,according to the requirements of actual load degeneration model built AC electric arc furnace model, instead of a constant impedance load, forming a dynamic load model. Based on the study of electric arc furnace model of isolated net system run stably.