Power System Transient Stability Analysis And Control With Wind Power Based On Energy Function

Currently the capacity of wind turbine has increased, and the wind farm coupled with increasingly higher voltage level.The wind power connected to the power transmission network has changed the dynamic characteristic of the whole power system. While the wind turbine and synchronous generator have different characteristics of steady state and transient state, the stability of power system will be altered accordingly, when wind power has been integrated. So there are some new requirements for traditional stabilizing methods in transient state of power system.Among various methods of transient stability analysis online, the method of the transient energy function can carry out the quantitative measurement of degree of stability, then it has attracted a lot of attention because it meets the demands of sensitivity analysis. In this essay some frontier problems of applied science and technology have been deeply explored, based on the mathematical model function with transient energy in the power system with wind power. The main research results are as follows:1)Based on the classical model of the transient energy function in power system, a mathematical model function of transient energy, in power system with wind power, has been established. Then the transient potential energy in each branch and transient energy distributed in wind driven generator can be calculated quantitatively.According to this model, the distribution characteristics and conversion between kinetic and potential energy, of transient energy in the network, with wind power in power grid, have been studied. In addition, the relations between the distribution of transient energy in the network and the system stability have been revealed to lay the foundation for transient analysis in the power system with wind power.2)Based on the mathematical model function, with energy in the power system with wind power, proposed in this essay, the power angle stability has been analyzed theoretically when wind turbines are integrated into a power system.Therefore the distribution characteristics, with sudden changes of wind speed disturbing the system transient energy, have been revealed. Then the necessary condition for running power system with wind power stably have been proposed and the stability criterion for power system disturbed by wind speed has been built.3) The continuous control strategy of TSCS has been proposed, based on the transient energy function in the power system with wind power. While this strategy fully utilizes the attributes of continuous regulation, transient stability can be greatly improved with a small amount of measurement. Besides, it only needs insitu signals in the installation branch and doesn’t need any remote measurement. A new feasible method is provided to solve the contradiction between the discreteness in the energy function control strategy and the continuous regulation of control equipments. Eventually the prediction technique applied in continuous strategy is effectively implemented. 4) The energy function models which is established in this paper, is applied to a actual power grid in the northeast of China. Energy distribution has been calculated while devices of TCSC are installed in simulation system for the actual power grid. And control strategy, mentioned in the essay, has improved its stability.Transient stability has been analyzed quantitatively by applying improved Stability index in the actual power grid.