Analysis on unbalanced magnetic pull generated by turn-to-turn short circuit of rotor windings within turbine generator
WU Yu-ca · Dianji yu kongzhi xuebao · 2015
Unbalanced magnetic pull by rotor windings turn-to-turn short circuit fault was analyzed,both analytic and numerical methods were adopted to calculate the unbalanced magnetic pull,and the relationships between unbalanced magnetic pull and generator running status were analyzed. Comparison shows that: whether generator runs on load or not,the unbalanced magnetic pull by analytic method has a large deviation,as saturation,field skew,high-order harmonics and structural factors were considered in numerical method,and the results are more accurate and reliable. When the active power remains unchanged,the unbalanced magnetic pull does not always increase with the excitation current,so the rotor vibration discriminant method for rotor windings turn-to-turn short circuit based on excitation current adjustment is valid within a certain range. Relatively speaking,the no-load test is more suitable for the rapid diagnosis of the rotor windings turn-to-turn short circuit fault.