Fault diagnosis of inter-turn short circuit in turbogenerator rotor windings based on vibration-current signal fusion

The inter-turn short circuit of rotor winding is a common fault of turbogenerator, and fault diagnosis in the early stage is of great significance to ensure the safe and reliable operation of turbogenerator. In this paper, an inter-turn short circuit fault diagnosis model based on vibration-current fusion is proposed by using the real-time state data collected by the distributed control system (DCS) of turbogenerators. Firstly, Pearson correlation coefficient (PCC) analysis method is used to analyze the correlation characteristics between the square of generator excitation current and the shaft radial vibration when the inter-turn short circuit occurs in the rotor winding of the turbogenerator. Then, the method of cooperative gain transformation is adopted to fuse current-vibration correlation coefficient which can amplify the weak correlation between the square of the excitation current and the vibration signal during the early defect, and the residual between the measured and predicted excitation current is combined to further calculate the cooperative gain residual, and an early warning signal can be issued when cooperative gain residual exceeds threshold. Finally, the model is verified by the historical DCS data of a 600 MW large turbogenerator. The results show that the proposed model can sensitively and accurately diagnose the early defects of inter-turn short circuit in turbogenerator rotor windings and ensure the safe operation of the generator. (c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).