汽轮发电机计及双因素非线性影响的功角特性

Power angle characteristic of turbine generator considering two factors affecting nonlinear characteristics

为研究磁路饱和与磁场畸变双因素非线对汽轮发电机功角特性的影响,利用有限元方法获得发电机的有功和无功功角曲线,揭示计及双因素非线性的电抗随功角变化的规律,然后将分运行区间的饱和电抗用于功角特性解析法计算。研究结果表明,汽轮发电机计及双因素非线性后,极限功角小于90°,极限功率下降,无功功率减小;随着功角的增大,直轴电抗先增大后减小,交轴电抗变化不大,两者差值可达到14%;与直接用有限元方法计算的功角特性进行对比,用分运行区间电抗的计算结果非常吻合,而用空载特性修正的饱和电抗的计算结果相差较大。研究结果可为同步发电机静态稳定极限的确定和暂态稳定的判断提供参考。

To study power angle characteristic of turbine generator considering two factors of iron satura-tion and magnetic field distortion affecting nonlinear characteristics, active and reactive power angle curves were obtained by the finite element method. The variation laws of saturated reactances considering two factors nonlinearity were revealed and these saturated reactances divided into different operating re- gions were used to analytical expressions of power angle curve. The research results show that power anglelimit of turbine generator considering two factors is less than 90 degree and active power limit and reactive power are reduced. The direct reactance increases at first and then decreases with increase of power an- gles and quadrature reactance changes smaller and their differences are up to 14%. Comparing with power angle curves by finite element method （FEM）, calculation results with saturated reactances in differentoperating regions are in good agreement and values with reactances based on no-load characteristic are very different. The research results can provide references for analyses of steady-state stability limit and transient stability.