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Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems

Ante Elez ; KONČAR – Generators and Motors
Josip Študir ; KONČAR – Generators and Motors
Stjepan Tvorić ; KONČAR – Electrical Engineering Institute CROATIA

Puni tekst: engleski, pdf (4 MB) str. 0-0 preuzimanja: 152* citiraj
APA 6th Edition
Elez, A., Študir, J. i Tvorić, S. (2018). Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems. Journal of Energy, 67 (3), 0-0. Preuzeto s https://hrcak.srce.hr/213504
MLA 8th Edition
Elez, Ante, et al. "Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems." Journal of Energy, vol. 67, br. 3, 2018, str. 0-0. https://hrcak.srce.hr/213504. Citirano 24.09.2021.
Chicago 17th Edition
Elez, Ante, Josip Študir i Stjepan Tvorić. "Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems." Journal of Energy 67, br. 3 (2018): 0-0. https://hrcak.srce.hr/213504
Harvard
Elez, A., Študir, J., i Tvorić, S. (2018). 'Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems', Journal of Energy, 67(3), str. 0-0. Preuzeto s: https://hrcak.srce.hr/213504 (Datum pristupa: 24.09.2021.)
Vancouver
Elez A, Študir J, Tvorić S. Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems. Journal of Energy [Internet]. 2018 [pristupljeno 24.09.2021.];67(3):0-0. Dostupno na: https://hrcak.srce.hr/213504
IEEE
A. Elez, J. Študir i S. Tvorić, "Application of Differential Magnetic Field Measurement (DMFM method) in inding fault detection of AC rotating machines as part of expert monitoring systems", Journal of Energy, vol.67, br. 3, str. 0-0, 2018. [Online]. Dostupno na: https://hrcak.srce.hr/213504. [Citirano: 24.09.2021.]

Sažetak
Stator and rotor winding damages in rotating machines are result of electrical, mechanical, and thermal stress. Online magnetic field monitoring via
permanently installed measuring coils inside air gap is a well-established methodology which enables winding fault detection. The paper deals with a
new method for detection of stator and rotor winding inter-turn short circuits of synchronous machines and slip rings induction machines, as well as
rupture of rotor bars and cage ring of induction machines. The method novelty is based on differential measurement of magnetic field by using two
serial connected measuring coils. They are installed on the places (stator or rotor teeth) in the machine which have, by absolute value, equal magnetic
vector potential. The distance between the measuring coils is n·p, where p is a pole pitch, and n = 1, 2, 3, 4,... is a multiple of the pole pitch. Measuring
the coil-induced voltage enables us to detect stator and rotor winding faults, which means that measured voltage is approximately zero without fault
and increases in the presence of fault. Analysis of the measuring signal allows us to detect and locate fault. With this new method it is possible with
high sensitivity to determine winding fault, which enables more reliable fault detection. For example, in comparison with the motor current signature
analysis method (the most widely used method for motor faults detection), this new method gives 200 times higher sensitivity to fault occurrence.
Also, by using the DMFM method, faults can be detected in the time domain and there is no need for spectral or other complex signal analysis. This
is very important because the measuring equipment used for machine fault detection can be simple and more economically acceptable. The DMFM
method enables fault detection for even small machines with small expense in a very effective way. The only downside of the DMFM method is the
fact that machine should be disassembled in order to install measuring coils. This problem is solved during the machine overhaul or during the manufacturing
of the machine, when sensors can be easily implemented in the machine. For machines with large air gap, measuring coils can be installed
without a machine disassembly. For the purpose of the method testing, numerous finite-element (FE) simulations on the 2- and 3-D machine models
have been carried out to verify the method. Powerful numerical tools generate realistic results with properly selected starting and boundary conditions.
By FEM models, actual machines with embedded measuring coils where created and simulated. The voltage induced inside the measuring coils is
calculated for different machine states, load point and with and without a fault (broken rotor bar or inter-turn short circuit). Also, this method was experimentally
validated via series of laboratory tests performed on the real electric machines specially designed for fault study (broken rotor bars, broken
ring and inter-turn short circuits in a stator and rotor winding). Additionally, this method is applied on more than 20 real machines in industry. Due to
the large amount of measured data, in this paper, it will be presented only one measurement performed on an induction motor on which we have
Journal
of Energy journal homepage: http://journalofenergy.com/
VOLUME 67 Number 3 | 2018 Special Issue
A. Elez, J. Študir, S. Tvorić, Application of Differential Magnetic Field Measurement (DMFM method) in winding fault detection of AC rotating machines as
part of expert monitoring systems, Journal of Energy, vol. 67 Number 3 (2018), Special Issue, p. 7–12
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detected one broken rotor bar. The thickness of the measuring coil designed in the printed circuit board technique is 0.3 mm. The number of turns
is from 3 to 10. This new method and performed FEM calculations together with the experimental measurements improve fault detection portfolio
knowledge that can be used in monitoring and diagnostics of rotating machines. Furthermore, this patent-pending method is already implemented in
three innovative products placed on market (expert monitoring systems), so this method is fully confirmed in practice.

Ključne riječi
finite element; induction machine; inter-turn shorted circuits; rotor bars; rotor cage faults; synchronous generator; magnetic field; measuring coil; induced voltage; air gap

Hrčak ID: 213504

URI
https://hrcak.srce.hr/213504

Posjeta: 267 *