Fault detection algorithm used in a magnetic monitoring system of the hydrogenerator

Abstract

In this study, the authors propose a fault detection algorithm used in an on-line magnetic monitoring system in the hydropower plant. The proposed algorithm is based on two magnetic measuring methods: measurement of (inner) flux within generator in air gap and measurement of stator leakage (outer) flux outside of the generator. The system has to ensure, in situ and real time, magnetic monitoring and fault detection of hydrogenerator. The monitoring system is also useful for modern maintenance approach such as a condition based maintenance without generators' work interruption and better planned and preventive maintenance in the power plant. The proposed system successfully detects the presence of magnetic unbalance of hydrogenerator, occurring as a consequence of shorted turns in the windings of the rotor poles or air gap asymmetry. The presented measurement results are achieved in real exploitation conditions.

An overview of various faults detection methods in synchronous generators

“…The above‐mentioned methods can be combined to present a comprehensive approach which has the advantages of the both for fault diagnosis. One of these methods uses air‐gap flux, stray flux, and vibration to detect the rotor‐winding fault in hydro‐generator precisely [116].…”

Bi‐Signature optical spectroscopy for online fault detection in electrical machines

“…In another pairing, MCSA and vibration were utilised by [9–12] to detect bowed rotor fault, inter‐turn short‐circuit fault, dynamic eccentricity, and bearing faults. Also, the use of flux and vibration was explored for the detection of short‐circuit and phase unbalance faults [13–15]. The identified limitations of such research works are the use of extra sensors due to the extraction of two signatures, and the sensors are all susceptible to EMI as they are conventional sensors.…”

Electromagnetic Analysis and Electrical Signature-Based Detection of Rotor Inter-Turn Faults in Salient-Pole Synchronous Machine

“…From vibration perspective, the most important spatial in radial force density distribution are the ones with lowest orders. The reason is that the amplitude of stator deformations are inversely proportional to 𝑚 4 , where 𝑚 is the mode number (i.e. order of the spatial harmonic).…”

“…voltage drop test and recurrent surge oscillography method [1]) can be employed for rotor windings inspection and finding the short-circuited turns. A well-known on-line method is to install flux sensors inside the machine to be able to monitor the airgap field [1,2,4]. If stator windings consist of parallel circuits, measurement of the circulating current caused by the asymmetry in the airgap field may also be used for on-line fault detection [1,5].…”