Electromagnetic Parameters Calculation Under Different Conditions Of Large Hydro-generator

Generator voltage change rate, static stability and generators running in parallel with the grid active and reactive power regulation have a close relationship with generator synchronous reactance which directly relate to the reliability of generator operation.Currently domestic manufacturers follow the traditional formula contains some of empirical coefficient,which is difficult to consider structural changes, saturation and other factors, so it is necessary to adopt the method of field calculation of reactance parameters. Especially when the motor magnetic saturation is more serious with the growing capacity of the motor.In the request of Motor parameters, the air gap permeance method does not take the nonlinear core reluctance and the tooth harmonic factors into account,so parameters obtained always error.The calculation of motor parameters on the accuracy are increasingly demanded with the increasing expansion of generating unit capacity. The current design formulas that are not properly consider the impact of magnetic saturation can no longer meet modern design and operational requirements. Therefore, the use of the method to calculate the saturation parameters of large hydro is very mcaningful.In this paper, the no-load EMF of the rotating armature hydro-generator model in different pole arc coefficient was analyzed and compared by using ANSYS, and measured waveforms were compared with the model machine. Magnetic leakage method was compared with the energy flux method under the 10KW model to calculate the rotor inductance, rotor mutual inductance between phases and the stator and rotor mutualinductance changes with time.The two methods were compared with theoretical analysis. By comparing we know that the application of ANSYS software to calculate coefficients of electromagnetic field is effective. Through the simulation model based on the machine,stator inductance,mutual inductance of stator rotor mutual inductance,mutual inductance parameters of the rotor phase of a 1000MW hydro-generator station was simulated,and calculated the generator synchronous reactances. Finally, this paper takes the different conditions within the motor magnetic field like saturated and unsaturated into account, and calculate 1000MW generator's synchronous reactance values changes with different conditions based on which analyzed and summarized the rule of change of the values.