• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.5
• /
• pp.1073-1077
• /
• 2011

The breaking capacity of circuit breakers could be no more increased in the electric power system. This is because the fault current increases due to continuous increases in electric power demand and facilities. To solve the problem, it is necessary to come up with an alternative. The superconducting fault current limiter (SFCL) has received an attention among various alternatives. The SFCL effectively reduce a fault current in cooperation with a power circuit breaker. A various types of the SFCL are suggested and a study on them have been progressed. As a result of it, the SFCL can be applyed to the electric power system in the near future. But, a study on recovery behaviors of the SFCL is not enough for applying to the electric power system. If the superconducting elements do not completely recover to the superconducting state after fault operation, it might be a breakdown of the superconducting elements due to heavy power burden and it gives an bad influence on the working of other electric devices. Additionally, the distribution power system has reclosing operation such as open-0.3sec-closed/open-3min-closed/open procedure. So we need to study more about improvement of the recovery behaviors of the SFCL. In this paper, we analyzed the recovery behaviors of a flux-coupling type SFCL according to reclosing operation when a single line-to-ground fault occurred and we compared recovery behaviors of the SFCL with and without a neutral line between secondary reactors and superconducting elements. Also, the flux-coupling type SFCL has advantageous for increases of capacity by controlling the variation in turn ratios between two reactors. Consequently, when the number of turns of the secondary reactors increased, the power burden of the superconducting elements was bigger due to the increase of impedances of the secondary reactors. To distribute the power burden, two superconducting elements connected in series and the balanced quenching of the superconducting elements was induced by connecting a neutral line.

• Korean Journal of Occupational Health Nursing
• /
• v.28 no.2
• /
• pp.114-123
• /
• 2019

Purpose: The aims of this study were to identify the effects of caring burden and the way of coping on burnout in caregivers of cancer patients. Methods: One-hundred and forty family caregivers of cancer patients who visited the cancer center at one tertiary hospital in metropolitan city B were included. The data collection was conducted from August 1st to October 1st, 2018, using a structured, self-reported questionnaire. The collected data were analyzed using descriptive statistics, t-test, one-way ANOVA, Pearson correlation coefficients, and multiple regression. Results: In the multiple regression analysis, the subject's gender (${\beta}=.12$, p=.028) and caring burden (${\beta}=.74$, p<.001) had a significant effect on burnout. The explanatory power of the subject's gender, education level, religion, caring time, number of family caregivers, monthly income, economic burden, expectation for treatment, caring burden, the way of aggressive coping, and the way of passive coping with burnout was 63.8% (F=23.28, p<.001). Conclusion: Reducing the caring burden in family caregivers of cancer patients will ultimately contribute to reducing burnout, thereby contributing to an improvement in the psychological well-being and quality of life of family members, as well as positively contributing to the recovery of patients.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.3
• /
• pp.414-417
• /
• 2014

At present, the demand for electric power increases, the electric power system is complicated. The size of the line-to-ground fault and the line-to-line fault occurred with complication of electric power system continue to increase, therefore several issues are raised. To address these issues effectively, the superconducting fault current limiter (SFCL) has been proposed, this study is ongoing. In this paper, we applied the SFCL in three-phase transformer and comparative analysis of the electric power burden to the SFCL. The superconductor is combined to the third winding of transformers in connection structure. In case of a third line-to-line fault, we did comparative analysis of the electric power burden to the SFCL based on the turn ratio of transformer third winding. In this case, we could confirm as the third turn ratio increased, electric power impressed to the superconducting element increased.

• Progress in Superconductivity and Cryogenics
• /
• v.19 no.2
• /
• pp.33-37
• /
• 2017

To protect the power systems from fault current, the rated protective equipment should be installed. However growth of power system scale and concentration of loads caused the large fault current in power transmission system and distribution system. The capacities of installed protective equipment have been exceeded the due to increase of fault current. This increase is not temporary phenomenon but will be steadily as long as the industry develops. The power system operator need a counter-measurement for safety, so superconducting fault current limiter (SFCL) has been received attention as effective solutions to reduce the fault current. For the above reasons various type SFCLs have been studied recently. In this paper, operation characteristics and power burden of trigger type SFCL is studied. The trigger type SFCL has been used for real system research in many countries. Another trigger type SFCL (double quench trigger type SFCL) is also studied. For this paper, short circuit test is performed.

• Journal of Korean Academic Society of Home Health Care Nursing
• /
• v.26 no.2
• /
• pp.199-209
• /
• 2019

Purpose: This study was conducted to determine factors affecting the positive feelings and care burden of elderly residents' primary caregivers in long-term care facilities. Methods: The survey was conducted between November and December 2018. A structured questionnaire was used to collect data, and 148 individuals voluntarily participated. The collected data were examined through descriptive statistical analysis using SPSS WIN ver.24.0, t-test, one-way Anova $Scheff{\acute{e}}$ test, Pearson's correlation coefficient, and multiple regression. Results: Factors that significantly affected caregivers' positive feelings included caregivers' education level(${\beta}=-.32$, p<.001), social support(${\beta}=.31$, p<.001), care burden(${\beta}=-.29$, p=.001), and total support fee(not more than 1.5million won)(${\beta}=-.18$, p=.012). The explanation power was as high as 40.0%(Adj $R^2=.40$). Factors that significantly affected caregivers' burden included social support(${\beta}=-.25$, p=.002), positive feelings(${\beta}=-.25$, p=.002), elderly individual's religion(${\beta}=-.17$, p=.007), and elderly individual's marriage status(${\beta}=.17$, p=.021). The explanation power was as high as 45.0%(Adj $R^2=.45$). Conclusion: Our results suggest that it is necessary to increase social support for elderly residents' primary caregivers in long-term care facilities. This can be helpful to decrease burden and enhance positive feelings in caregivers. We should also collect caregivers' information as well to provide appropriate assistance.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.2212-2213
• /
• 2008

In this paper, we studied the method for simultaneous quenching of a transformer type superconducting fault current limiter (SFCL) with two superconducting elements connected in series. Only an element between two elements of the transformer type SFCL was quenched like the case of the resistive type SFCL. By this quenching characteristics, the power burden of the superconducting element was increased. In order to solve this problem, we connected the neutral line between two superconducting elements and the center of secondary coils. The two elements were all quenched in the transformer type SFCL with a neutral line. As a result, the power burden of superconducting elements was decreased, so it was efficient for the increase of power capacity of the transformer type SFCL.

• Proceedings of the KIEE Conference
• /
• 2003.11a
• /
• pp.432-434
• /
• 2003

This paper developed the web based power flow program for education. Since a lot of users can connect and implement the web based program, the only one computer can get much evaluation burden not to compute. Using the XML technology, which supports the distributed computing technology, we have developed the web-based power flow software and system that are distributed the above calculation burden to three computers: web server, database server, application server. Also, this software was developed to get the difference of number of iteration and evaluation speed as veil as the results of state variables for each node according to the each calculation method for power flow using the chart. Therefore, users can get the physical concept of power flow in addition to the difference among the evaluation methods for power flow. We have performed the case studies with IEEE 14 bus system using the developed software.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.57 no.3
• /
• pp.323-327
• /
• 2008

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) depending on the methods of the serial and parallel connections between the superconducting elements. The flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil through an iron core, and the secondary coil is connected to the superconducting elements in series and parallel. In this paper, the analyses of voltage, current, and resistance of the superconducting elements connected in serial and parallel were performed to increase the power capacity of the flux-lock type SFCL. A part of the superconducting elements was not quenched in $2{\times}2$ serial connection between the elements and then the power burden of the quenched elements was increased. However the elements with $2{\times}2$ parallel connection was all quenched. This means that the power burden of each superconducting element can be reduced under the same conditions. We found that $2{\times}2$ parallel connection was more profitable for the current limiting effects and the increase of the power capacity.

• Nuclear Engineering and Technology
• /
• v.42 no.3
• /
• pp.231-236
• /
• 2010

The growth in global energy demand and the increased recognition of the impacts of carbon dioxide emissions from fossil fuel plants have aroused a renewed interest on nuclear energy. Many countries are looking afresh at building more nuclear power stations to deal with the twin problems of global warming and the need for more generating capacity. Many in the nuclear community are also anticipating a significant growth of new nuclear generation in the coming decades. If there is a nuclear renaissance, will the expansion of nuclear power be compatible with global non-proliferation and security? or will it add to the environmental burden from the large inventory of spent nuclear fuel already produced in existing nuclear power reactors? We learn from past peaceful nuclear activities that significant concerns associated with nuclear proliferation and spent-fuel management have resulted in a decrease in public acceptance for nuclear power in many countries. The terrorist attack in the United States (US) on September 11, 2001 also raised concern for security and worry that nuclear materials may fall into the wrong hands. As we increase the use of nuclear power, we must simultaneously reduce the proliferation, security and environmental risks in managing spent-fuel below where they are today.

• The Journal of the Korea Contents Association
• /
• v.14 no.5
• /
• pp.211-223
• /
• 2014

The aim of this study was to identify the levels of family members' burden and to describe factors influencing on famiCX*//8ly caregiver's burden when they are planned to transfer to general ward from the intensive care units (ICU). A descriptive survey was used with a convenience sampling of 101 family members of ICU patients at S university hospital in C city, Korea from August to November, 2010. The data were analyzed with SPSS 18.0 program. The level of object burden in family members had statistically significant differences with level of consciousness, number of patients' monitoring devices, and tracheostomy tube. The level of subject burden had statistically significant differences according to patients' gender, patients' education level, and relationship with patients. Transfer anxiety was showed statistically positive correlation with objective and subjective burden. We found transfer anxiety was statistically significant predictor of family caregiver's objective burden with explanatory power 12.7%. Family members' subjective burden were statistically influenced by patients' gender and transfer anxiety. These factors explained 23.8% out of total variance of family members' objective burden. The structured individualized method of transfer is recommended with further research of ICU families to further examine the dimension of transfer anxiety and how it affects family members' burden and patient outcomes.