Fault diagnosis of synchronous generators by computer simulation of an external magnetic field

Currently, the development of non-invasive diagnostic methods for electric machines and especially generators, as the main producers of electric energy, using magnetic field fixation sensors is an urgent scientific and technical task. To solve this problem, research has been conducted to develop a method for troubleshooting a synchronous generator by analyzing an external magnetic field. The article discusses the main issues of computer modeling of an external magnetic field in the FEMM 4.2 system for troubleshooting. Mathematical expressions are given for creating a computer model of a synchronous generator in two-dimensional space, on the basis of which a numerical solution of the external magnetic field is formed using the finite element method. The modeling takes into account the design features of the synchronous generator. The main stages of work in the FEMM 4.2 system are defined. The geometric model of the synchronous generator is imported from the computer-aided design system. The physical properties of all elements of the model are determined by the structural materials of the synchronous generator and the external space. The control program, created on the basis of the algorithm presented in the article, allows you to simulate the rotation of the inductor of a synchronous generator, automate the calculations of the electromagnetic field and display the results. An example of using a computer model of a synchronous generator for troubleshooting by examining an external magnetic field is given. Based on the results of a numerical solution of the external magnetic field, a harmonic analysis of the magnetic induction of a working synchronous generator was carried out. The article shows that a diagnostic sign of static eccentricity of a synchronous generator inductor is the appearance of even harmonics in the magnetic induction spectrum of an external magnetic field Based on the results obtained, the dependence of the growth of even harmonics on the magnitude of the displacement of the inductor of the synchronous generator is determined.