Generator Stator End Winding Resonance: Problems and Solutions

2013 ◽  
Author(s):  
Bill Moore ◽  
Clyde Maughan
Keyword(s):  
Visual Inspection ◽  
Fatigue Cracking ◽  
Vibration Monitoring ◽  
Stator Winding ◽  
Resonant Vibration ◽  
Primary Methods ◽  
Stator Windings ◽  
Problems And Solutions ◽  
On Line ◽  
Generator Stator

Stator windings that are in resonance will have high levels of vibration, if not properly damped or braced. Windings in resonance can suffer from early conductor strand fatigue cracking, arcing and failure during operation. Evidence of high vibration can sometimes be seen through visual inspection, with observance of dusting and greasing. There are two primary methods to anticipate and detect end winding resonant vibration — the bump test and on-line monitoring. Both are important and play a key role in identifying stator winding resonance problems, as well as implementing the appropriate solution. This paper will discuss the reasons that stator end winding resonance occurs. The technology, as well as the advantages and limitations of both the bump test and vibration monitoring, will be discussed. Solution approaches to end winding vibration are included, as well as one case history.

scholarly journals Dynamic Analysis of Series-Connected and Mechanically-Coupled Twin Synchronous Motor Drive

2020 ◽  
Vol 17 (1) ◽  
pp. 33-39
Author(s):  
I.K. Onwuka ◽  
G.C. Diyoke ◽  
E.S. Obe
Keyword(s):  
Reduction Gear ◽  
Motor Drive ◽  
Stator Winding ◽  
Speed Reduction ◽  
Synchronous Motors ◽  
Stator Windings ◽  
Three Phase ◽  
On Line ◽  
Winding Machine ◽  
The Mathematical Model

Series-connection of the stator windings of electric motors could serve a number of purposes, including load balancing between two synchronous motors. This paper modeled and analyzed a drive system of two separate three-phase synchronous motors whose stator windings are series- connected by a unique stator winding scheme, and whose shafts are mechanically coupled to a common load shaft through a speed reduction gear driven through the pinions of the respective motors. The mathematical model is developed in detail, and the system is simulated using MATLAB/SIMULINK. It is observed that for the case of a balanced load on the respective shafts of the two motors, the dynamic behavior of the two motors are identical. It is further observed that with the particular stator winding arrangement giving rise to six-windings per motor unit, each motor is essentially a three-phase motor and may be operated direct on line (DOL). Keywords: Common load shaft; DOL; series-connected stator windings; synchronous motors, six-winding machine

Frequency Characteristics of Generator Stator Windings

2013 ◽  
pp. 151-183
Author(s):  
Charles Su
Keyword(s):  
Pulse Propagation ◽  
Low Voltage ◽  
Travelling Wave ◽  
Wave Mode ◽  
Frequency Characteristics ◽  
Capacitive Coupling ◽  
Stator Winding ◽  
Stator Windings ◽  
Steel Core ◽  
Generator Stator

A generator stator winding consists of a number of stator bars and overhang connections. Due to the complicated winding structure and the steel core, the attenuation and distortion of a pulse transmitted through the winding are complicated, and frequency-dependent. In this chapter, pulse propagation through stator windings is explained through the analysis of different winding models, and using experimental data from several generators. A low voltage impulse method and digital analysis techniques to determine the frequency characteristics of the winding are described. The frequency characteristics of generator stator windings are discussed in some detail. The concepts of the travelling wave mode and capacitive coupling mode propagations along stator winding, useful in insulation design, transient voltage analysis, and partial discharge location are also discussed. The analysis presented in this chapter could be applied to other rotating machines such as high voltage motors.

scholarly journals Automatic PRPD Image Recognition of Multiple Simultaneous Partial Discharge Sources in On-Line Hydro-Generator Stator Bars

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 326
Author(s):  
Ramon C. F. Araújo ◽  
Rodrigo M. S. de Oliveira ◽  
Fabrício J. B. Barros
Keyword(s):  
Partial Discharge ◽  
Classification Problem ◽  
Input Pattern ◽  
Partial Discharges ◽  
Data Set ◽  
Stator Windings ◽  
Unknown Sample ◽  
On Line ◽  
A New Technique ◽  
Generator Stator

In this study, a methodology for automatic recognition of multiple simultaneous types of partial discharges (PDs) in hydro-generator stator windings was proposed. All the seven PD sources typical in rotating machines were considered, and up to three simultaneous sources could be identified. The functionality of identifying samples with no valid PDs was also incorporated using a new technique. The data set was composed of phase-resolved partial discharge (PRPD) patterns obtained from on-line measurements of hydro-generators. From an input PRPD, noise and interference were removed with an improved version of an image-based denoising algorithm previously proposed by the authors. Then, a novel image-based algorithm that separates partially superposed PD clouds was proposed, by decomposing the input pattern into two sub-PRPDs containing discharges of different natures. From the sub-PRPDs, one extracts features quantifying the PD distribution over amplitudes and the contour of PD clouds. Those features are fed as inputs to several artificial neural networks (ANNs), each of which solves a part of the classification problem and acts as a block of a larger system. Once trained, ANNs work collaboratively to identify an unknown sample. Good results were obtained, with overall accuracies ranging from 88% to 94.8% for all the considered PD sources.

Internal On-line Partial Discharge Analysis of 68.75 MVA Generator Stator Winding Insulation

2016 ◽  
Vol 6 (5) ◽  
pp. 2088 ◽  
Author(s):  
Waluyo Waluyo ◽  
Siti Saodah ◽  
Eltha Hidayatullah
Keyword(s):  
Electric Field ◽  
Partial Discharge ◽  
Surface Discharge ◽  
Damage Effect ◽  
Stator Winding ◽  
Measuring Point ◽  
Temperature Detector ◽  
On Line ◽  
Winding Insulation ◽  
Generator Stator

<p>Partial discharge is a phenomenon of electron ionization occurs due to concentrated electric field in a different edge plane. This phenomenon will be investigated by an electric field measurement in a measuring point. The internal partial discharge will give the insulation damage effect on a generator stator winding due to void existence. This manuscript presents the measurement results of the on-line internal partial discharge on the stator winding insulation of 68.75 MVA generator. It used the resistant temperature detector method and CM2000<sup>TM</sup>. The results were classified into three conditions based on the voids in the generator stator insulation, the internal delamination and the surface discharge.</p>

scholarly journals Internal On-line Partial Discharge Analysis of 68.75 MVA Generator Stator Winding Insulation

2016 ◽  
Vol 6 (5) ◽  
pp. 2088 ◽  
Author(s):  
Waluyo Waluyo ◽  
Siti Saodah ◽  
Eltha Hidayatullah
Keyword(s):  
Electric Field ◽  
Partial Discharge ◽  
Surface Discharge ◽  
Damage Effect ◽  
Stator Winding ◽  
Measuring Point ◽  
Temperature Detector ◽  
On Line ◽  
Winding Insulation ◽  
Generator Stator

<p>Partial discharge is a phenomenon of electron ionization occurs due to concentrated electric field in a different edge plane. This phenomenon will be investigated by an electric field measurement in a measuring point. The internal partial discharge will give the insulation damage effect on a generator stator winding due to void existence. This manuscript presents the measurement results of the on-line internal partial discharge on the stator winding insulation of 68.75 MVA generator. It used the resistant temperature detector method and CM2000<sup>TM</sup>. The results were classified into three conditions based on the voids in the generator stator insulation, the internal delamination and the surface discharge.</p>

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