Study On The Nonlinear Characteristics Of Turbo-generators With Different Structure

Through theory analysis and FEM calculation, load saturated characteristics of 135MW, 300MW and 600MW turbo-generator under various operating conditions are obtained. The comparison shows that nonlinear characteristics are common phenomena of large turbo-generators.The saturated characteristics of three generators are analyzed under various conditions when the excited current, d-axis stator current, q-axis stator current separately exist and they both exist in many cases. Through comparisons of magnetic density distribution of various generators under rated voltage, the saturated degree of various area of turbo-generators are analyzed and the factors causing nonlinear phenomena are founded from the structure difference.It is found that rotor structure differences are an important factor resulting in the discrepancy of saturation degree of rotor teeth and rotor yokes which will further cause the discrepancy of saturated curves.