Analysis Of Sudden External Short-circuit Faults For The 1000MW Hydro-Generator

Now the power industry is developing rapidly, 1000MW hydro-generator has greater capacity than the 700MW hydro-generator put into operation in the Three Gorges Power Station. The research on 1000MW hydro-generator is still at an early stage at home and abroad, and there are many problems in its design and analysis. When a generator has been designed, analysis of sudden external short-circuit would become more important, and so is the case of 1000MW hydro-generator. In order to analysis the transient process of sudden external short-circuit of the 1000MW hydro-generator in no-load and rated-load conditions are analyzed by FEM and Simulink in this paper.Firstly, the developing background and study state at home and abroad are introduced in this paper, and the significance of research on sudden external short-circuit fault for 1000MW hydro-generator is analyzed in detail.Then, a mathematical model of operation characteristics for generator is built through electric machines and electromagnetic field theory in this paper, and the method of solving the two-dimension electromagnetic field with FEM is given. To satisfy the demand of calculation of operation characteristics, the electromagnetic field with finite element method and external circuit of generator are coupled to derived the variable curves of stator current and electromagnetic torque, when 1000MW hydro-generator is sudden external short-circuit in no-load and rated-load. At the same time, the physical process and operation model of sudden external short-circuit fault for 1000MW hydro-generator are analyzed based on Simulink, the variable curves of stator current and electromagnetic torque are derived.Finally, based on the theoretical analysis, the variable curves of stator current and electromagnetic torque is the same through analysis two kinds of simulation. But the differences are existed. Magnetic resistance is changed in the short circuit, the peaks in the sudden increase current will be the rated short-circuit current of more than 10 times, and continuing to increase with the short time.The work can provide a valuable reference for the design and performance study of the 1000MW hydro-generator in this paper, the simulation of sudden external short-circuit fault and the variable curves of stator current and electromagnetic torque will also be useful for the design and performance study of other generators.