The transposition bar is an important component in large generators, the insulation fault in transposition bars is extremely dangerous for the daily operation of generators. The circulating current losses of the stator windings are usually considered in traditional transposition designs. The risk and hazard of the transposition bar inter-strands short-circuit fault are neglected. Therefore, it is necessary to evaluate the risk of the transposition bars. This paper proposes a new risk assessment method for transposition bars. This method enables the comprehensive risk assessment of the design, circulating current losses, and fault risk of transposition bars. Firstly, the strand current of all short-circuit fault schemes of the transposition bar is calculated by the leakage reactance electromotive potential method and the fault dataset is established. Further, based on the fault dataset, risk indexes: severity and probability are proposed. The probability of short-circuit fault for each category is calculated by Markov chain. Finally, the risk indexes of three transposition types are calculated and compared with the traditional index. The risk of 360° and 360°+25 mm transposition is 7.5 times larger than that of 308° transposition. A risk assessment method for the transposition bar is proposed, which considers both operation efficiency and reliability. This method provides a new basis for the transposition designs.
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