Elucidation of Short-Circuit Phenomena of Element Conductors in Ac Power Cord and Establishment of Its Detection Method

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420231
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Power engineering/Power conversion/Electric machinery
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: MIZUNO YUKIO 名古屋工業大学, 工学(系)研究科(研究院), 教授 (50190658)
• Research Collaborator: YOSHIDA ATSUSHI 河村電器産業株式会社, 研究開発部, 主任技師
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 電源コード / 素線 / 短絡 / 電圧波形 / 検出器 / 壁付コンセント

Outline of Final Research Achievements

Short-circuit of element conductors in AC power cords of household appliances/extension cords is one of the main causes of fire accidents originating from electric equipment. This kind of short-circuit is observed when a cord is crushed by heavy material, bent and stretched repeatedly, or even the exerted force from earthquake. It is difficult to detect short-circuit with a conventional circuit breaker, because of its smaller current magnitude than the threshold and short duration of short-circuit.
The present research revealed that short-circuit was characterized by distortion of voltage waveform from the sinusoidal shape. A novel detection method was proposed based on the distortion, which enables to distinguish short-circuit from transient phenomena at the time of turning on/off of household appliances. Furthermore, a prototype wall outlet combining short-circuit detector and circuit breaker was made. It was confirmed in laboratory that the detector performed as designed.

Free Research Field

電気絶縁、故障診断、信頼性評価