计及双馈风机不同控制策略的静态等值

风电并网快速增加，风电机组如双馈感应发电机(Doubly-fed Induction Generator, DFIG)承担部分火电机组供电任务，现有静态等值算法未考虑新能源并网控制策略对静态等值影响，对静态安全分析造成威胁。因此有必要确定不同控制策略下DFIG并网潮流，建立计及DFIG控制策略的静态等值。本文首先基于DFIG内部模型，分别建立不同控制策略下DFIG并网潮模型。其次考虑DFIG有功功率、无功功率相互耦合，在求解潮流过程中判定潮流模型。最后利用内部网络对外部网络发电机无功灵敏度确定保留发电机节点，修改节点导纳矩阵保留DFIG内部结构，进行静态等值。结果表明，不同控制策略下，系统电压幅值变化幅度大于相角，本文所提等效模型比传统Ward等值具有更高的精度，验证了所提算法的可行性和有效性。

The static equivalent with different control strategies of DFIG wind farm

With the increase of the renewable energy, the doubly-fed induction generator (DFIG) replace part of thermal power units. In order to ensure the accuracy of the static equivalent, the control strategy of DFIGs must be taken into consideration. However, existing studies do not consider the discrepancies of power flow with different control strategies. In this paper, the power flow algorithm for wind power grid connection considering the control strategies of DFIGs is established based on the DFIG model, then the static equivalent is established. Considering the mutual restriction between active power and reactive power of DFIGs, the final power flow model is determined in the process of solving the power flow. The reactive power sensitivities of the internal network to the external network generators are used to determine the reserved generator buses, and the admittance matrix of the system is modified to retain the structure of the DFIG for static equivalence. The results show that with different control strategies, the variations of voltages are larger than angles, and the proposed equivalent model has higher accuracy than the traditional Ward equivalent. The simulation results validate the accuracy and effectiveness of the proposed method.