A New Effective Method of Induction Machine Condition Assessment Based on Zero-Sequence Voltage (ZSV) Symptoms

Abstract

<jats:p>Non-invasive diagnostic methods for electric machines’ diagnostics, which can be used during their operation in a drive system, are needed in many branches of the production industry. For the reliable condition assessment of electric machines, especially those operating in drive systems, various tools and methods have been suggested. One diagnostic method that has not been fully recognized and documented is a diagnostic method based on zero-sequence voltage component (ZSV) applications for the condition assessment of induction machines. In this paper, the application of ZSV in induction machine diagnostics is proposed. A factor that speaks in favor of applying this signal in such diagnostics is the high sensitivity of the signal to damage occurrence, and the distinct change of extracted symptoms in the case of asymmetry. It is possible to obtain a high signal amplitude, which simplifies its processing and the elaboration of reliable diagnostic factors. This ZSV-based method is also able to be applied to big machines used in industry. Due to the saturation effects visible in the ZSV signal, new diagnostic symptoms can appear, which allows for an easier condition assessment of certain machines. The usefulness of the described diagnostic method in machine condition assessment was shown through an equivalent circuit modeling process, finite element analysis, and laboratory tests of the machine.</jats:p>

Induction Motor Fault Diagnosis Based on Zero-Sequence Current Analysis

“…This paper is a continuation of the research presented in [1] regarding the application of magnetic core saturation effects in induction motor diagnosis. In that paper, research on the application of the zero-sequence voltage component (ZSV) in the detection of rotor cage faults and eccentricity was undertaken.…”

“…Such modeling method was the background for determining spectrum of ZSV and ZSC characteristic for damages of the cage and three types of eccentric rotor position: static, dynamic, and mixed. This was applied in [10], but without influence of the machine core slotting, and was used in the mentioned paper [1]. In the presented paper the 2 of 25 methodology of analysis is similar as applied in [1] but concerns ZSC spectrum used for diagnosis of damages.…”

“…This was applied in [10], but without influence of the machine core slotting, and was used in the mentioned paper [1]. In the presented paper the 2 of 25 methodology of analysis is similar as applied in [1] but concerns ZSC spectrum used for diagnosis of damages. The zero-sequence current component is a signal that carries a lot of information about a machine's symmetry.…”

“…When analyzing the zero-sequence current, it is worth mentioning the zero-sequence voltage component [1,10,[12][13][14][15], the spectrum of which has the same qualities as the zero-sequence current component [10]. In ZSV and ZSC signals, the dominant harmonic is the harmonic of the frequency equal to triple the supply frequency originating from magnetic core saturation.…”

Eccentricity in Induction Machines—A Useful Tool for Assessing Its Level

“…This method consists of finding harmonics in the current spectrum with frequencies characteristic for a given type of eccentricity and then analyzing their amplitudes. For the diagnosis of eccentricity, the zero-sequence current [16][17][18] can also be used in the case of a delta connection of the windings or the zero-sequence voltage [19] in the case of star-connected windings. The formulas on characteristic frequencies of these two methods take into account the saturation effect of the magnetic core of the motor, which strongly affects the zero-sequence component of current and voltage.…”