Frequency Response Patterns of Transformer Windings with Mechanical Faults

2017 ◽  
Vol 1 (4) ◽  
pp. 119-122
Author(s):  
Szymon BANASZAK
Keyword(s):  
Frequency Response ◽  
Response Patterns ◽  
Mechanical Faults

EFFECT OF VARIATIONS IN MICROPHONE COVER SHAPE AND WEARING POSITION ON THE PERFORMANCE OF A HEARING-SUPPORT DEVICE MOUNTED ON EAR — SIMULATION STUDY

2016 ◽  
Vol 16 (04) ◽  
pp. 1650048
Author(s):  
HEEPYUNG KIM ◽  
KYOUNG WON NAM ◽  
JINRYOUL KIM ◽  
SUNHYUN YOOK ◽  
DONG PYO JANG ◽  
...  
Keyword(s):  
Frequency Response ◽  
Fine Tuning ◽  
Upper Body ◽  
Response Patterns ◽  
Actual Performance ◽  
Acoustic Environment ◽  
Hearing Ability ◽  
Environment Model ◽  
Actual Speech ◽  
Beamforming Algorithm

Morphological and positional factors that can affect the actual performance of the hearing-support (HS) devices are utilized to support the damaged hearing ability of the sensorineural hearing-impaired persons. However, there have been few studies that demonstrated the effects of variations in such design factors on the frequency response of the device experimentally. In this study, the effect of design variations in the shape of the microphone cover on the housing and the wearing position of the device mounted on the ear on the input frequency response of the device and on the performance of an embedded beamforming algorithm were investigated using a human upper body model, a hearing aid housing model, and an acoustic environment model using computer simulation. Experimental results showed that the implemented simulator could simulate the actual acoustic situations (differences less than 5 dB in audible frequency range) and that both of the response patterns of the device and beamforming algorithm were varied in accordance with the variations in the shape of the microphone cover and the mounting position of the device on the ear. These results demonstrate the necessity of additional design and algorithm fine-tuning of each (HS) device to improve its actual speech enhancement performance.

Detection of Transformer Faults Using Frequency Response Analysis with Case Studies

2013 ◽  
pp. 456-486
Author(s):  
Nilanga Abeywickrama
Keyword(s):  
Frequency Response ◽  
Case Studies ◽  
Low Voltage ◽  
Short Circuit ◽  
Diagnostic Methods ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Mechanical Deformations ◽  
Mechanical Faults ◽  
Non Destructive

Power transformers encounter mechanical deformations and displacements that can originate from mechanical forces generated by electrical short-circuit faults, lapse during transportation or installation and material aging accompanied by weakened clamping force. These types of mechanical faults are usually hard to detect by other diagnostic methods. Frequency response analysis, better known as FRA, came about in 1960s (Lech & Tyminski 1966) as a byproduct of low voltage (LV) impulse test, and since then has thrived as an advanced non-destructive test for detecting mechanical faults of transformer windings by comparing two frequency responses one of which serves as the reference from the same transformer or a similar design. This chapter provides a background to the FRA, a brief description about frequency response measuring methods, the art of diagnosing mechanical faults by FRA, and some case studies showing typical faults that can be detected.

scholarly journals The Influence of the Window Width on FRA Assessment with Numerical Indices

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 362
Author(s):  
Szymon Banaszak ◽  
Eugeniusz Kornatowski ◽  
Wojciech Szoka
Keyword(s):  
Frequency Response ◽  
Response Analysis ◽  
Response Curves ◽  
Data Window ◽  
Window Width ◽  
Window Method ◽  
Mechanical Faults ◽  
Recorded Data ◽  
Single Number

Frequency response analysis is a method used in transformer diagnostics for the detection of mechanical faults or short-circuits in windings. The interpretation of test results is often performed with the application of numerical indices. However, usually these indices are used for the whole frequency range of the recorded data, returning a single number. Such an approach is inaccurate and may lead to mistakes in the interpretation. An alternative quality assessment is based on the estimation of the local values of the quality index with the moving window method. In this paper, the authors analyse the influence of the width of the input data window for four numerical indices. The analysis is based on the data measured on the transformer with deformations introduced into the winding and also for a 10 MVA transformer measured under industrial conditions. For the first unit the analysis is performed for various window widths and for various extents of the deformation, while in the case of the second the real differences between the frequency response curves are being analysed. On the basis of the results it was found that the choice of the data window width significantly influences the quality of the analysis results and the rules for elements number selection differ for various numerical indices.

scholarly journals Intrinsic frequency response patterns in mechano-sensory neurons of the leech

Biology Open ◽  
2017 ◽  
Vol 6 (7) ◽  
pp. 993-999 ◽  
Author(s):  
Linda Fischer ◽  
Frank Scherbarth ◽  
Boris Chagnaud ◽  
Felix Felmy
Keyword(s):  
Frequency Response ◽  
Sensory Neurons ◽  
Response Patterns ◽  
Intrinsic Frequency

Stimulus Ratio Effects on Speech Discrimination by Children and Adults

1991 ◽  
Vol 34 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Joan E. Sussman
Keyword(s):  
Discrimination Task ◽  
Response Pattern ◽  
Response Patterns ◽  
Speech Discrimination ◽  
Adult Group ◽  
Discrimination Accuracy ◽  
Formant Frequency ◽  
Response Strategies ◽  
Place Of Articulation ◽  
Adults And Children

This investigation examined the response strategies and discrimination accuracy of adults and children aged 5–10 as the ratio of same to different trials was varied across three conditions of a “change/no-change” discrimination task. The conditions varied as follows: (a) a ratio of one-third same to two-thirds different trials (33% same), (b) an equal ratio of same to different trials (50% same), and (c) a ratio of two-thirds same to one-third different trials (67% same). Stimuli were synthetic consonant-vowel syllables that changed along a place of articulation dimension by formant frequency transition. Results showed that all subjects changed their response strategies depending on the ratio of same-to-different trials. The most lax response pattern was observed for the 50% same condition, and the most conservative pattern was observed for the 67% same condition. Adult response patterns were most conservative across condition. Differences in discrimination accuracy as measured by P(C) were found, with the largest difference in the 5- to 6-year-old group and the smallest change in the adult group. These findings suggest that children’s response strategies, like those of adults, can be manipulated by changing the ratio of same-to-different trials. Furthermore, interpretation of sensitivity measures must be referenced to task variables such as the ratio of same-to-different trials.

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