A Novel Universal Model Considering SAGE for MFD-based Faulty Property Analysis under RISC in Synchronous Generators

This paper proposes a new rotor interturn short circuit (RISC) fault analysis model for the electromechanical property study in synchronous generators. The specific novelty of this model lies in two aspects: 1) It considers that most generators exist static air-gap eccentricity (SAGE), so it analyzes the RISC fault under normal and SAGE, making the model more versatile, and 2) it takes into account not only the short circuit degree but also the short circuit position, consequently it is more universal. By feeding the number of short circuit turns (denotes the short circuit degree), the angle between the two slots where the short circuit takes place (denotes the short circuit position) and the detailed parameters of the generator into the model, the developing tendency of the key magnetic flux density MFD-based parameters can be conveniently predicted. The advantages of the proposed model primarily lie in the universality and the calculation speed. It can quickly evaluate the generator operating conditions. The phase current and the electromagnetic torque (EMT) are selected in this paper as the representatives of the electrical parameter and the mechanical parameter, respectively. 2D finite element analysis (FEA) and experimental studies validate the proposed model.