Tang Haiyan

Fault ride through characteristics of connection of large wind power island to VSC-HVDC grid

With increasing scale of wind power development, large wind power bases will, where there is no support from synchronous power source, be directly connected to the grid and therefore one of developing trends to transmit currently large-scale wind power is transmit the wind power “island” with the long distance VSC-HVDC transmission technology when it is connected to the grids. When a large-scale wind power island is connected to a VSC-HVDC grid, the wind turbines and the VSC-HVDC grid will influence each others operation and control, and in particular, in the case of fault, mutual coupling of dynamic characteristics of electrical variables at different time scales between the wind turbines and the VSC-HVDC grid cannot be ignored. The paper is focused on non-synchronous detection of disturbance, one of key problems found in connection of wind power to the VSC-HVDC grid, and studies the fault ride-through (FRT) technology for the island-connected large-scale wind power and the VSC-HVDC grid, by analyzing the impact of fault-response characteristics of the wind power and the VSC-HVDC grid at different time scales on each other.

The dynamic simulation model and parameter identification method of DFIG type wind generator for power system electro-mechanic simulation

The double-fed inductor generator (DFIG) is one important type of wind generator. Because of high percentage of wind energy, it is necessary to build accurate wind generator model and parameters for power system electro-mechanic simulation. The paper mainly presents the simulation model and parameter identification method of DFIG type wind generators. For power system transient simulation, the characteristic related to low voltage ride-through (LVRT) is most important, and the model related to LVRT is mainly presented. The parameters of the model are divided into three types and use different identification method. The identification method of important parameters is mainly presented. One actual wind generator is used as an example to explain the identification process and testify the validity of the model.