Coordination Research Of Doubly-fed Wind Turbine Protection And System Protection

With the increase of the capacity of wind power, wind power played an importantrole for the long term sustainable development environment protection of China’senergy, but wind power development also brought a series of problems at the sametime for power system relay protection. In this thesis, wind power as a background,combined with the latest national standards "Technical rule for connecting wind farmto power system". Choose the popular double-fed wind turbine as the object of study,for the current wind generator and grid protection with the emergence of the problem,to study the wind generator protection and system protection coordination problems.The PSCAD software as the simulation platform, building double-fed inductiongenerator connecting grid simulation model. Simulating the DFIG fault characteristicsand the impact factors of the doubly-fed induction generator fault current. By thewind field of the doubly-fed induction generators, simulating the contacting line’sfault characteristics and the possible impact on the relay protection. Studying theDFIG relay protection operation action and may result in adjacent wind farms’ windgenerators the process of chain offline. From the point of view that the relayprotection of DFIG wind turbine has been unable to meet the low-voltage operatingcharacteristics. For wind machine protection and the grid protection disjointed，thepaper proposes an adaptation of DFIG voltage protection for low-voltage ride through,and gives its protection criterion. For doubly-fed induction generator rotor overcurrentand DC bus overvoltage under low voltage ride through, a double fast shortedprotection circuits put at rotor side and the DC side. Taking into account the problemsof convergence collector line protection with generator protection, a protectionscheme is proposed based on the current-voltage quantities, and overcomes difficultof the adjacent line which brings increase current and setting principles as well asaction time. It should increase the zero-sequence protection program for the collector line single-phase ground fault to rapidly removal of the single-phase ground fault.