Abstract
Inter-turn short circuit of field windings (ISCFW) is a common generator fault which can result in serious safety accidents for power systems, if the fault is not eliminated in time. Taking advantage of the electrical and mechanical characteristics of the generator after a fault as a fault criterion is a new idea for fault monitoring, so finding out the frequency and amplitude frequency characteristics of rotor unbalanced magnetic pull (UMP)—the vibration excitation source of the fault—is the basis and key of the research. Taking a six-pole generator as an example, the effects of harmonic magnetic motive force (MMF) interaction on rotor UMP, as well as the frequency characteristics of rotor UMP after generator faults in different stator windings, are obtained based on the analysis of the air-gap MMF of the generator after a fault, and the results of theoretical analysis are verified by simulation. Based on the above results, the simulation calculation on rotor UMP of generators with three stator winding forms under different operating conditions has been achieved, to get the relation between rotor UMP amplitude and active power and field current, and to find out the mechanism of rotor UMP amplitude change along with operating conditions and effect of stator winding forms on UMP amplitude by theoretical analysis. The conclusions are of important significance for studying fault mechanical characteristics of generators and lay a foundation for online monitoring on ISCFW by integrating mechanical and electrical information.
Highlights
In recent years, the power industry has been developing rapidly, while building size and installed capacity for all kinds of power stations are increasingly being enhanced, the safety and reliable running of generators is more and more important
In order to cover the three shortcomings in existing research and the problems faced, this paper presents a more detailed and in-depth study on the amplitude and frequency characteristics of generator rotor unbalanced magnetic pull (UMP) with Inter-turn short circuit of generator field windings (ISCFW)
(a) After the ISCFW occurs in a generator, the force waves in rotor UMP with the same mechanical rotation frequency as in thea rotor are dominant
Summary
The power industry has been developing rapidly, while building size and installed capacity for all kinds of power stations are increasingly being enhanced, the safety and reliable running of generators is more and more important. Reference [7] described that the comparative measurement of the magnetic flux density produced by each winding can provide a coil detection method by placing a measuring coil tangentially and near to the rotor; Reference [8] analyzed the magnetic field in detail for several operating conditions under healthy and faulty states which are difficult or even impossible to carry out by available measurement methods in industrial environments and realizes on-line condition monitoring by the permanent installation of a flux probe on the stator to measure the rotor magnetic flux. The conclusions of this research provide a basis for the investigations on rotor vibration features with ISCFW and lay a foundation for on-line monitoring of rotor inter-turn short circuits, based on the integration of mechanical and electrical information
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
