• Title/Summary/Keyword: reliability and safety

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The Liability of Participants in Commercial Space Ventures and Space Insurance (상업우주사업(商業宇宙事業) 참가기업(參加企業)의 책임(責任)과 우주보험(宇宙保險))

  • Lee, Kang-Bin
    • The Korean Journal of Air & Space Law and Policy
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    • v.5
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    • pp.101-118
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    • 1993
  • Generally there is no law and liability system which applies particulary to commercial space ventures. There are several international treaties and national statutes which deal with space ventures, but their impact on the liability of commercial space ventures has not been significant. Every state law in the United States will impose both tort and contract liability on those responsible for injuries or losses caused by defective products or by services performed negligently. As with the providers of other products and services, those who participate in commercial space ventures have exposure to liability in both tort and contract which is limited to the extent of the resulting damage The manufacturer of a small and cheap component which caused a satellite to fail to reach orbit or to operate nominally has the same exposure to liability as the provider of launch vehicle or the manufacturer of satellite into which the component was incorporaded. Considering the enormity of losses which may result from launch failure or satellite failure, those participated in commercial space ventures will do their best to limit their exposure to liability by contract to the extent permitted by law. In most states of the United States, contracts which limit or disclaim the liability are enforceable with respect to claims for losses or damage to property if they are drafted in compliance with the requirements of the applicable law. In California an attempt to disclaim the liability for one's own negligence will be enforceable only if the contract states explicitly that the parties intend to have the disclaimer apply to negligence claims. Most state laws of the United States will refuse to enforce contracts which attempt to disclaim the liability for gross negligence on public policy grounds. However, the public policy which favoured disclaiming the liability as to gross negligence for providers of launch services was pronounced by the United States Congress in the 1988 Amendments to the 1984 Commercial Space Launch Act. To extend the disclaimer of liability to remote purchasers, the contract of resale should state expressly that the disclaimer applies for the benefit of all contractors and subcontractors who participated in producing the product. This situation may occur when the purchaser of a satellite which has failed to reach orbit has not contracted directly with the provider of launch services. Contracts for launch services usually contain cross-waiver of liability clauses by which each participant in the launch agrees to be responsible for it's own loss and to waive any claims which it may have against other participants. The crosswaiver of liability clause may apply to the participants in the launch who are parties to the launch services agreement, but not apply to their subcontractors. The role of insurance in responding to many risks has been critical in assisting commercial space ventures grow. Today traditional property and liability insurance, such as pre-launch, launch and in-orbit insurance and third party liability insurance, have become mandatory parts of most space projects. The manufacture and pre-launch insurance covers direct physical loss or damage to the satellite, its apogee kick moter and including its related launch equipment from commencement of loading operations at the manufacture's plant until lift off. The launch and early orbit insurance covers the satellite for physical loss or damage from attachment of risk through to commissioning and for some period of initial operation between 180 days and 12 months after launch. The in-orbit insurance covers physical loss of or damage to the satellite occuring during or caused by an event during the policy period. The third party liability insurance covers the satellite owner' s liability exposure at the launch site and liability arising out of the launch and operation in orbit. In conclusion, the liability in commercial space ventures extends to any organization which participates in providing products and services used in the venture. Accordingly, it is essential for any organization participating in commercial space ventures to contractually disclaim its liability to the extent permitted by law. To achieve the effective disclaimers, it is necessary to determine the applicable law and to understand the requirements of the law which will govern the terms of the contract. A great deal of funds have been used in R&D for commercial space ventures to increase reliability, safety and success. However, the historical reliability of launches and success for commercial space ventures have proved to be slightly lower than we would have wished for. Space insurance has played an important role in reducing the high risks present in commercial space ventures.

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Simulation analysis and evaluation of decontamination effect of different abrasive jet process parameters on radioactively contaminated metal

  • Lin Zhong;Jian Deng;Zhe-wen Zuo;Can-yu Huang;Bo Chen;Lin Lei;Ze-yong Lei;Jie-heng Lei;Mu Zhao;Yun-fei Hua
    • Nuclear Engineering and Technology
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    • v.55 no.11
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    • pp.3940-3955
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    • 2023
  • A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: 60Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable.

Implementation of Responsive Web-based Vessel Auxiliary Equipment and Pipe Condition Diagnosis Monitoring System (반응형 웹 기반 선박 보조기기 및 배관 상태 진단 모니터링 시스템 구현)

  • Sun-Ho, Park;Woo-Geun, Choi;Kyung-Yeol, Choi;Sang-Hyuk, Kwon
    • Journal of Navigation and Port Research
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    • v.46 no.6
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    • pp.562-569
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    • 2022
  • The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

Effect of Eco-Friendly Food Store Attributes on Perceived Value and Loyalty: Moderating Effect of Delivery Service (친환경 식품 전문점의 점포속성이 지각된 가치와 충성도에 미치는 영향: 배송 서비스의 조절효과)

  • KIM, Jin-Kyu;PARK, Jong-Hyun;YANG, Jae-Jang
    • The Korean Journal of Franchise Management
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    • v.13 no.2
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    • pp.33-51
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    • 2022
  • Purpose: The online market is growing the most in history due to the expansion of non-face-to-face commerce. In addition, as consumers' interest in health, food safety, and environment increases, interest in and consumption of eco-friendly agricultural products is also increasing. Therefore, in the case of a specialty store that sells eco-friendly organic agricultural products, a marketing strategy that can increase customer loyalty by reflecting these consumer needs is necessary. In this study, the store attributes of eco-friendly food stores are classified into location, assortment, price, quality, and employee service, and the effect of each store attribute on utilitarian and hedonic value is investigated. Research design, data, and methodology: The subjects of this study were customers who visited an eco-friendly food store. Of the 511 survey responses, 311 were used for statistical verification, excluding 200 who had not visited within the last 3 months. For statistical analysis, Smart PLS 3.0 was used, and after checking the validity and reliability of the items, hypothesis testing was performed. Result: As a result of the study, it was found that assortment, quality, and employee service among store attributes had a positive (+) effect on utilitarian and hedonic value. Second, location had no significant effect on utilitarian and hedonic value. Third, price did not appear to have a positive (+) effect on the utilitarian value, and it was found to have a positive (+) effect on the hedonic value. Fourth, It was investigated whether the presence or absence of delivery service had an effect on store attributes between utilitarian and hedonic value, and it was found that there was a significant effect between employee service and hedonic value. Conclusions: Among eco-friendly food store environment management will be required in order to provide food that meets the tastes and needs of consumers by diversifying the taste, standard, and quality grade of food, and to maintain or improve the quality. In order to unlike other stores, eco-friendly food stores have high price resistance from the point of view of consumers, so it is necessary to diversify promotional media such as YouTube and SNS to raise awareness of eco-friendly organic food.

A Study on Occupational Environment Assessment Strategies for Respirable Particulate Matter at Coal-Fired Power Plants (석탄화력발전소 호흡성분진 작업환경 평가 전략 사례에 관한 연구)

  • Eun-Seung Lee;Yun-Keun Lee;Dong-Il Shin
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.33 no.3
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    • pp.375-383
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    • 2023
  • Objectives: Coal-fired power plants feature diverse working conditions, including multi-layered employment structures and irregular work cycles due to outsourcing and non-standardized tasks. The current uniform occupational environment measurement systems have limitations in accurately assessing and evaluating these varied conditions. This study aims to propose alternative measurement and assessment strategies to supplement existing methods. Methods: Major domestic coal-fired power plants were selected as the study targets. To prepare for the study and establish strategies, work processes were identified and existing occupational environment measurement results were compared and analyzed. The study proceeded by employing three strategies: specific exposure groups (SEGs) measurement, continuous monitoring, and supplementary measurements, which were then compared and discussed. Results: Previous exposure index evaluations (5,268 cases) indicated that crystalline silica, a type of respirable particulate matter, had detection limits below the threshold (non-detectable) in 82.6% (4,349 cases) of instances. Exposures below 10% of the exposure limit were observed at a very low concentration of 96.1%. Similar exposure group measurements yielded results where detection limits were below the threshold in 38.2% of cases, and exposures below 10% of the limit were observed in 70.6%. Continuous monitoring indicated detection limits below the threshold in 12.6% of cases, and exposures below 10% of the limit were observed in 75.6%. Instances requiring active workplace management accounted for more than 30% of cases, with SEGs at 11.8% (four cases), showing a higher proportion compared to 3.0% (four cases) in continuous monitoring. For coal dust, exposures below 10% of the limit were highest in legal measurements at 90.2% (113 cases), followed by 74.0% (91 cases) in continuous monitoring, and 47.0% (16 cases) in SEGs. Instances exceeding 30% were most prevalent in SEGs at 14.7% (five cases), followed by legal measurements at 5.0% (eight cases), and continuous monitoring at 2.4% (three cases). When examining exposure levels through arithmetic means, crystalline silica was found to be 104.7% higher in SEGs at 0.0088 mg/m3 compared to 0.0043 mg/m3 in continuous monitoring. Coal dust measurements were highest in SEGs at 0.1247 mg/m3, followed by 0.1224 mg/m3 in legal measurements, and 0.0935 mg/m3 in continuous monitoring. Conclusions: Strategies involving SEGs measurement and continuous monitoring can enhance measurement reliability in environments with irregular work processes and frequent fluctuations in working conditions, as observed in coal-fired power plants. These strategies reduce the likelihood of omitting or underestimating processes and enhance measurement accuracy. In particular, a significant reduction in detection limits below the threshold for crystalline silica was observed. Supplementary measurements can identify worker exposure characteristics, uncover potential risks in blind spots of management, and provide a complementary method for legal measurements.

A Study on Real-Time Monitoring for Moisture Measurement of Organic Samples inside a Drying Oven using Arduino Based on Open-Source (오픈 소스 기반의 아두이노를 이용한 건조기 내 유기 시료의 실시간 수분측정 모니터링에 관한 연구)

  • Kim, Jeong-hun
    • Journal of Venture Innovation
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    • v.5 no.2
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    • pp.85-99
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    • 2022
  • Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.

The Safety of Microsurgical Head and Neck Reconstruction in the Elderly Patients (고령 환자군에 있어서 유리피판술을 이용한 두경부재건의 안전성)

  • Choi, Bong Kyoon;Kim, Young Seok;Lee, Won Jai;Lew, Dae Hyun;Tark, Kwan Chul
    • Archives of Plastic Surgery
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    • v.33 no.3
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    • pp.289-293
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    • 2006
  • By means of microsurgical free-tissue transfer providing a large amount of required tissue, the surgeon can resect tumoral tissue more safely, which allows tumor-free margins and enhances the reliability of the ablative surgery that otherwise could not be performed radically. The morbidity of elective free-tissue transfer seems to be quite low, carrying acceptable risks for most patients. But the elderly patients are at risk for cardiac and respiratory problems, deep vein thrombosis, pulmonary emboli and infection merely as a function of age. This study was undertaken to define further risks of the elderly population with regards to free-tissue transfer. We retrospectively reviewed our experience with 110 microsurgical free-tissue transfers for head and neck reconstruction in patients greater than 60 years of age. Microsurgical procedures in all cases were preformed by the plastic and reconstructive department at Yonsei medical center. The investigated parameters were patient demographics, past medical history, American Society of Anesthesiologists(ASA) status, site and cause of defect, the free tissue transferred and postoperative complication including free-flap success or failure. There were 46 patients in the age group from 60 to 64 years, 34 patients from 65 to 70 years, and 30 patients 70 years or older. There happened 3 flap losses, resulting in a flap viability rate of 97%. Patients with a higher ASA designation experienced more medical complication(p=0.05, 0.01, 0.03 in each age group I, II, III) but not surgical complication p=0.17, 0.11, 0.54 in each age group I, II, III). And the relationship between postoperative complication and age groups was not significant. These observations suggest that major determinant for postoperative medical complication be the patient's American Society of Anesthesiologists score, and chronologic age alone should not be an exclusion criterion when selecting patients for free-tissue transfer

Demand for the Radiological Technologist Independent Act for the Performance of the Duties of a Radiological Technologist (방사선사 직무수행을 위한 방사선사 단독법 제정에 대한 요구도)

  • Kim, Eun-Hye;Lim, Cheong-Hwan;Lim, Woo-Taek;Joo, Young-Cheol;Hong, Dong-Hee;Jung, Hong-Ryang;Moon, Young-Ju;Kim, Hoon;Jung, Young-Jin;Choi, Ji-Won;Yoon, Yong-Su;Cho, Pyong-Kon;Park, Myeong-Hwan;Yang, Oh-Nam;Jeong, Bong-Jae
    • Journal of radiological science and technology
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    • v.44 no.5
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    • pp.525-534
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    • 2021
  • In order to provide high-quality medical services to the public and contribute to the improvement of public health, it is necessary to enact an independent law according to the work of radiological technologists. Therefore, this study intends to review the regulations related to radiographers in the Medical Service Technologists, etc. Act. and to present opinions and directions for enactment of individual laws for radiological technologists. An online survey was conducted to 15,000 radiological technologists working in medical institutions and education sites in Korea; 1,027 people (6.85%) responded. The questionnaire consisted of 3 questions on demographic characteristics, 5 questions on the scope of work, and 12 questions on the revision of the Medical Service Technologists, etc. Act. and the establishment of the Radiological Technologist Independent Act. Reliability and factor analysis were performed on 9 questions measured on a Likert 5-point scale in "Revision of the Medical Service Technologists, etc. Act. and the establishment of the Radiological echnologist Independent Act" among the questionnaire items. Reliability for the total 9 questions was Chronbach α=0.728. There was a high perception that the regulations related to radiological technologists were insufficient in the current Medical Service Technologists, etc. Act., and the perception that examinations performed by radiological technologists at medical institutions were included in medical practice was high. If the Radiological Technologist Independent Act is enforced, a high percentage of respondents said that they could receive legal protection through the institutionalization of the scope of work, that the status of radiological technologists would be improved, and the scope of work would be expanded. The response that the scope of work of radiological technologists should be included was the highest at 96.6%. In the analysis according to demographic characteristics, it was found that 96.7% of the respondents were agreed regardless of the factors. Radiological technologists will have to work hard to secure the public health by coping with new radiology devices, procedures and treatment methods. Therefore, as the results of this study, it is expected that the enactment and implementation of the Radiological Technologist Independent Act will contribute to the improvement of the quality of treatment for patients and to the public health.

A Study on Obesity Index and Attributes of Selecting Places to Eat Out by Food-Related Lifestyle Types - Focusing on Pusan University Students - (식생활 라이프스타일에 따른 비만도와 외식선택속성에 관한 연구 - 부산지역 대학생을 중심으로 -)

  • Lee, Jong-Ho
    • Culinary science and hospitality research
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    • v.18 no.4
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    • pp.47-58
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    • 2012
  • This study, targeting the students of "K" university in Busan City area, was performed to draw the groups by food-related lifestyle types and to identify the correlation between each group's attributes of selecting places to eat out and obesity index. The purpose of the study was achieved by means of the PASW Statistic 18.0(Predictive Analytics Software) which conducted frequency analysis, factor analysis, reliability analysis, t-test, ${\chi}^2$-test, non-hierarchical cluster analysis and ANOVA. It turned out that the male university students were 175.59 cm tall and weigh 69.53 kg on average. And the female university students showed their average height of 162.81 cm and weight of 53.42 kg. When examined by the body mass index(BMI), male students were composed of 1.7% of underweight, 64.6% of normal weight, 19.7% of overweight and 14.0% of obese. As for the female students, 22.9% were classified as underweight, 62.7% as normal weight, 8.5% as overweight and 5.9% as obese. The food-related lifestyle categories were divided into five factors; health seeking type, safety seeking type, mood seeking type, taste seeking type, and western food seeking type. The four attributes of selecting places to eat out included quality of food and service, price reasonableness, accessibility and atmosphere, and experience to have eaten. With regard to food-related lifestyle, the groups were named by cluster 1 [careless diet group], Cluster 2 [health oriented group], and cluster3 [careless healthcare group]. In terms of the correlation between the clusters by food-related lifestyle and their attributes of selecting places to eat out, Cluster 1 had a high mean value in experience to have eaten, Cluster 2 quality of food and service, Cluster 3 accessibility and atmosphere.

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Partial Discharge Characteristics and Localization of Void Defects in XLPE Cable (XLPE 케이블에서 보이드 결함의 부분방전 특성과 위치추정)

  • Park, Seo-Jun;Hwang, Seong-Cheol;Wang, Guoming;Kil, Gyung-Suk
    • Journal of the Korean Society for Railway
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    • v.20 no.2
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    • pp.203-209
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    • 2017
  • Research on condition monitoring and diagnosis of power facilities has been conducted to improve the safety and reliability of electric power supply. Although insulation diagnostic techniques for unit equipment such as gas-insulated switchgears and transformers have been developed rapidly, studies on monitoring of cables have only included aspects such as whether defects exist and partial discharge (PD) detection; other characteristics and features have not been discussed. Therefore, this paper dealt with PD characteristics against void sizes and positions, and with defect localization in XLPE cable. Four types of defects with different sizes and positions were simulated and PD pulses were detected using a high frequency current transformer (HFCT) with a frequency range of 150kHz~30MHz. The results showed that the apparent charge increased when the defect was adjacent to the conductor; the pulse count in the negative half of the applied voltage was about 20% higher than that in the positive half. In addition, the defect location was calculated by time-domain reflectometry (TDR) method, it was revealed that the defect could be localized with an error of less than1m in a 50m cable.