Statistical and Physical Approaches on the Initial Failure Rate of High Voltage Power Transformers

2018 ◽  
Author(s):  
Lambert Pierrat ◽  
Elena Helerea ◽  
Livia Sangeorzan
Keyword(s):  
Failure Rate ◽  
High Voltage ◽  
Power Transformers ◽  
Initial Failure

scholarly journals High Voltage Insulating Materials—Current State and Prospects

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3799
Author(s):  
Pawel Rozga ◽  
Abderahhmane Beroual
Keyword(s):  
High Voltage ◽  
Power Transformers ◽  
Insulating Materials ◽  
Current State ◽  
Solid Liquid

Progression in the field of insulating materials for power transformers and other high voltage devices is visible regardless of the type of insulation: solid, liquid, or gas [...]

Angioplasty and Stenting for Intracranial Atherosclerotic Stenosis With Nitinol Stent: Factors Affecting Technical Success and Patient Safety

2011 ◽  
Vol 70 (suppl_1) ◽  
pp. ons104-ons113 ◽  
Author(s):  
Simon Chun Ho Yu ◽  
Thomas Wai Hong Leung ◽  
Esther Hiu Yee Hung ◽  
Kwok Tung Lee ◽  
Lawrence Ka Sing Wong
Keyword(s):  
Patient Safety ◽  
Failure Rate ◽  
Balloon Catheter ◽  
Technical Failure ◽  
Related Factors ◽  
End Points ◽  
Technical Problems ◽  
Vascular Morphology ◽  
Initial Failure ◽  
Angioplasty And Stenting

Abstract BACKGROUND: Angioplasty and stenting using nitinol stents is a recognized treatment option for intracranial atherosclerosis. OBJECTIVE: To identify procedure-related factors that may affect patient safety and technical outcome. METHODS: In this prospective study of 57 consecutive patients, the primary end points were intraprocedural technical problems, periprocedure morbidity, and complications. Major periprocedure complication was defined as all stroke or death at 30 days. Technical failure was defined as the inability to complete the procedure because of technical or safety problems. Procedure failure was defined as a procedure outcome of technical failure or major periprocedure complication. Secondary end points were procedure-related factors that may affect patient safety and technical outcome. RESULTS: Procedure failure rate was 12.3% (7/57) (major periprocedure complication rate, 5.3% [3/57]; technical failure rate, 7% [4/57]). Initial failure in tracking of balloon or stent occurred in 20 patients, other technical problems occurred in 11 patients, including kinking or trapping of balloon catheter (2 cases), difficulty in unsheathing of stent (3 cases), forward migration of stent during deployment (4 cases), trapping of nose cone after stent deployment (1 case), fracture of delivery system (2 cases), and guidewire fracture (1 case). Unfavorable vascular morphology signified by the presence of 2 or more reverse curves along the access path was found to associate with initial failure in the tracking of instruments (OR = ∞), and occurrence of other technical problems (OR = 25). CONCLUSION: Procedure-related factors could be identified and lead to improvements in patient safety and technical outcome. Tortuous vascular morphology is a key factor to be overcome.

Reducing failure rate at high voltage (HV) testing of insulator using Six Sigma methodology

2018 ◽  
Vol 67 (5) ◽  
pp. 791-808 ◽  
Author(s):  
Darshak A. Desai ◽  
Aurangzeb Javed Ahmed Shaikh
Keyword(s):  
Failure Rate ◽  
High Voltage ◽  
Six Sigma ◽  
Manufacturing Industry ◽  
Small Scale ◽  
Case Study Methodology ◽  
Content Type ◽  
Sigma Level ◽  
Ceramic Manufacturing

PurposeThis paper, a case study, aims to illustrate the application of Six Sigma in a small-scale ceramic manufacturing industry. The purpose of this paper is to demonstrate the empirical application of DMAIC methodology to reduce failure rate at high voltage (HV) testing of one of the most critical products, insulator.Design/methodology/approachThe case study is based on primary data collected from a real-life situation prevailing in the industry. The case study methodology adopted here is at one small-scale unit wherein the authors have applied DMAIC methodology and observed and recorded the improvement results, especially, reduction in failure rate at HV testing of insulator and, thus, increase in Sigma level.FindingsThe results found after implementation of the solutions are very significant. The rejection percentage has been reduced from 0.5 to 0.1 percent and consequently the Sigma level has been improved from 4.4 to 5.0.Research limitations/implicationsThis success story can be a guiding roadmap for other such industries to successfully implement Six Sigma to improve quality, productivity and profitability.Practical implicationsThis case study will serve as one of the resource bases for the industries which have till not implemented Six Sigma and benefited from the same.Social implicationsImproved quality and productivity leads to better economy. This case will help industries to serve the society with better economy with improved quality and productivity.Originality/valueThough ceramic industries in India are having enormous potential for growth, majority of them, especially, small and medium industries are either not aware of or not implementing Six Sigma to reap its multidimensional benefits of improving quality, productivity and profitability. This study highlights the benefits reaped by small-scale ceramic manufacturing industry opening up the avenues for its application at other such organizations.

LATERAL ARM FREE FLAPS IN THE DEFECTS OF THE UPPER EXTREMITY — A REVIEW OF 72 CASES

Hand Surgery ◽  
2005 ◽  
Vol 10 (02n03) ◽  
pp. 177-185 ◽  
Author(s):  
M. Akinci ◽  
Ş Ay ◽  
S. Kamiloglu ◽  
Ö. Erçetin
Keyword(s):  
Venous Thrombosis ◽  
Upper Extremity ◽  
Failure Rate ◽  
High Voltage ◽  
Free Flaps ◽  
Perforator Flaps ◽  
Operative Duration ◽  
Anastomosis Site ◽  
Extended Approach ◽  
Forearm Skin

Lateral arm flaps are versatile in the use of upper extremity moderate-sized defects with little morbidity and with acceptable cosmesis. The conditions are outlined in a series of 74 lateral arm flaps performed on 72 patients and the results are given. Five patients were operated on as emergencies, 12 were operated within the first 72 hours of injury and 57 patients were treated electively. Skin defects were between 6 × 4 cm and 20 × 9 cm . Five (7%) flaps were lost due to venous thrombosis, three that sustained a high-voltage electric burn. Two other patients that were treated for a high-voltage electric burn had a successful revision of the anastomosis site in the early post-operative duration. One flap was abandoned due to very thin pedicle and obesity of the patient. A higher failure rate is encountered most frequently with the cases of high-voltage electric burn. To deal with this problem, a modified approach such as an extended approach and/or including the forearm skin to the flap is recommended during the flap harvest. For a longer pedicle to be anatomized more proximally, perforator flaps with longer pedicles may be used as an alternative.

scholarly journals INSULATION FAULT DIAGNOSIS IN HIGH VOLTAGE POWER TRANSFORMERS BY MEANS OF LEAKAGE FLUX ANALYSIS

2011 ◽  
Vol 114 ◽  
pp. 211-234 ◽  
Author(s):  
Manes Fernandez Cabanas ◽  
Francisco Pedrayes Gonz�lez ◽  
Manuel Garc�a Melero ◽  
Carlos H. Rojas Garc�a ◽  
Gonzalo Alonso Orcajo ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
High Voltage ◽  
Power Transformers ◽  
Flux Analysis ◽  
Leakage Flux
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