A study on partial discharge signals and noises at on-line generator stator windings

2009 ◽  
Author(s):  
Hee-Sang Shin ◽  
Jae-Chul Kim
Keyword(s):  
Partial Discharge ◽  
Stator Windings ◽  
On Line ◽  
Generator Stator

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.

scholarly journals On-line Partial Discharge Measurement of Hydrogenerator Stator Windings using Acoustic Emission Detection Techniques

2004 ◽  
Vol 124 (2) ◽  
pp. 274-280 ◽  
Author(s):  
Tadamitsu Kaneko ◽  
Akito Takemura ◽  
Osamu Takenouchi ◽  
Youl-Moon Sung ◽  
Masahisa Otsubo ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Partial Discharge ◽  
Discharge Measurement ◽  
Detection Techniques ◽  
Stator Windings ◽  
On Line ◽  
Emission Detection

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 Comparison of Low and High Frequency Partial Discharge Measurements on Stator Windings

2019 ◽  
pp. 134-138
Author(s):  
Greg C Stone ◽  
Howard Sedding
Keyword(s):  
High Frequency ◽  
Partial Discharge ◽  
Low Frequency ◽  
International Standards ◽  
Very High Frequency ◽  
Stator Windings ◽  
Advantages And Disadvantages ◽  
On Line ◽  
Winding Insulation

Partial discharge (PD) testing has been used for over 60 years primarily as a method to assess condition of the stator winding insulation in motors and generators rated 6 kV and above. More recently it has also been used by some machine manufacturers as a means of assuring the quality of the insulation on single winding elements (coils and bars). Although both on-line and off-line tests mainly use a high voltage capacitor to detect the PD, the PD measuring systems in use work either in the low frequency (LF) regime (less than about 1 MHz) or in the very high frequency (VHF) (30-300 MHz) range. By reference to several international standards, published work as well as some experiments described in this contribution, the advantages and disadvantages of the two approaches are compared. Based on this work, it is now clear that off-line PD tests should be done in the LF range. For on-line tests, either method may be used, but use of the VHF method has become more widespread with machine end users, since the owners themselves can perform and interpret the results with a relatively low risk of false indications.

Sign in / Sign up

Export Citation Format

Share Document