• Smart Structures and Systems
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• v.33 no.4
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• pp.313-323
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• 2024

Deterioration of buildings is one of the biggest problems in modern society, and the importance of a safety diagnosis for old buildings is increasing. Therefore, most countries have legal maintenance and safety diagnosis regulations. However, the reliability of the existing safety diagnostic processes is reduced because they involve subjective judgments in the data collection. In addition, unstructured tasks increase rework rates, which are time-consuming and not cost-effective. Therefore, This paper proposed the method that can calculate the safety grade of deterioration automatically. For this, a DNN structure is generated by using existing precision inspection data and precision safety diagnostic data, and an objective building safety grade is calculated by applying status evaluation data obtained with a UAV, a laser scanner, and reverse engineering 3D models. This automated process is applied to 20 old buildings, taking about 40% less time than needed for a safety diagnosis from the existing manual operation based on the same building area. Subsequently, this study compares the resulting value for the safety grade with the already existing value to verify the accuracy of the grade calculation process, constructing the DNN with high accuracy at about 90%. This is expected to improve the reliability of aging buildings in the future, saving money and time compared to existing technologies, improving economic efficiency.

• Transactions on Electrical and Electronic Materials
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• v.7 no.5
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• pp.262-266
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• 2006

The insulation diagnostic test and the AC breakdown test were performed under off-line using the 3.3 kV class induction motor which have been served for 10 years. These tests were conducted in means of nondestructive and destructive test. In this paper, we compared the correlation between the nondestructive and destructive test. Furthermore we setup an experimental condition with moisture and compared the insulation characteristics between moist and dry sample. From the results of the nondestructive and destructive test, it was found that the second AC current, which is the previous step of insulation breakdown, suddenly increased at a point of around 8.5 kV. The insulation breakdown of moist sample occurred at 12-14 kV, which is 4-5 kV lower than dry sample.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1191-1192
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• 2015

To assess the deterioration condition of stator insulation, diagnostic and overpotential tests were performed on two high voltage(HV) motors for circulating water pump (CWP). Following the long term rewinding program, the diagnostic test was performed on two motors during the planning maintenance period. After completing the diagnostic test, overpotential test was done on the stator windings of HV motors. During the overpotential test, the No. 1 and No. 2 of HV motors failed at 8.8 kV and 7.9 kV, respectively. Stator windings of two HV motors had deteriorated significantly.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.57-63
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• 2003

Aluminum Stranded Conductors Steel Reinforced (ACSR) in overhead transmission lines have slowly degraded due to pollutants in the air for a long period of time, so in the 2000, a number of them has been exceeded over their forecasted useful life. Since most of them are faced with assessment their present conditions in regard to economical maintenance, in this paper, we have suggested a method in order to evaluate the current condition of aged conductors by using dominant parameters such as elapsed years, environment index, and conductor configuration. A diagnostic system for predicting the deterioration grades corresponding to the lifetime of aged conductors is described, which is designed as an Adaptive Neuro-fuzzy Inference System (ANFIS) based on knowledge and experiences of experts. Applying this diagnostic system to practical transmission lines in domestic, it is shown that the system can be effectively used as a guide to perform nondestructive diagnosis and economical operation for old ACSR conductors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.5
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• pp.135-140
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• 2024

DC capacitors used in PV inverters have a relatively short lifespan compared to other power semiconductor devices and have a failure rate of 60%, making them the most vulnerable among the elements that make up a power conversion system (PCS). In addition, the lifespan of the capacitor varies depending on environmental factors, greatly affecting the lifespan and operating conditions of PV inverters and PV power generation systems. Therefore, research is needed on the development of inverter deterioration diagnostic sensor technology optimized for building-integrated and general PV power generation systems and the development of bypass compensation capacitor modules that can maintain the efficiency of the inverter in the event of a failure. Based on this research, the DC capacitor deterioration diagnosis module inside the PV inverter measures the capacity of the actual internal components and can check the trend information of the deterioration state in the long term, enabling rapid response to fires. In addition, it seeks to improve the efficiency of power generation facilities and reduce carbon emissions, and prevents electrical fires, allowing the PV power generation system to be maintained in optimal condition.

• Journal of Veterinary Clinics
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• v.34 no.4
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• pp.268-271
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• 2017

A 1.3 year-old Castrated male Bedlington terrier (10.0 kg of body weight) was presented with heart murmur and occasional coughing. Diagnostic imaging studies revealed supravalvular pulmonic stenosis (maximal velocity 2.91 m/s) from abnormal membranous structure (aperture) distal to the pulmonary valve in the main pulmonary artery. Further study also revealed pulmonic regurgitant (1.82 m/s of peak velocity, 13.2 mmHg of pressure gradient) jets started from the abnormal membranous structure. Since the dog had no obvious clinical signs related to heart failure, no interventional therapy including balloon dilation was considered in this case. Instead, medical treatment for preventing further deterioration of clinical signs related to PS was done with enalapril. This case report described a rare case of type III supravalvular PS in a dog, which has never been reported. Further deterioration of clinical signs has yet been recognized after medical treatment.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2072-2074
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• 2005

This test was performed to assess the insulation condition of the stator winding of 3.45kV hydro generator in insulation deterioration condition which was due to long service period(30years) since installed We extracted 12 stator wingdings from the hydro generator core, cut the stator windings into three parts(Middle winding part, slot winding part, end wingding part), and evaluated the insulation condition to know the deterioration condition of each parts. This insulation diagnostic tests include AC current, dissipation factor, and partial discharg test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.449-452
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• 2004

The life of power transformer is basically dependent on the aging deterioration of insulating paper. Analysis of insulating paper for its DP value or tensile strength requires removal of a few strips of paper but direct measurement of this properties is not practical for in-service transformers. For this reason furfural analysis by HPLC has gained increasing favor as a means of estimating degradation of insulating papers in power transformers and this paper reports on the analysis of data on the concentration of furfural in oil samples from about 50 power transformers and the case study. The data showed that furfural content can estimate more accurately aging characteristics compared to concentration of CO, $CO_2$. We expect that these results can be useful to predict the aging characteristics and life diagnosis of power transformers and further the study must be continued.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1353-1355
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• 1995

While the modern society has been highly diversified and civilized, the demand for the safty of a power transmission has been greatly increased. For the underground cable, the performance of the electrical equipments is being improved by developing a new technology, and the reliability of the power supply is being up graded by impressing the diagnostic and monitoring technology of the system. In this paper the aging procedure of O.F and XLPE cables are described, including the diagnostic and monitoring equipments and the future subject.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.71-73
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• 2006

Our company(KOWACO) has periodically performed off-line diagnostic test for 14 hydro generators (rated 11 kV over) for 15 years. In this paper, we summarized results of dissipation factor tip-up test and partial discharge test about these generators. Among these, we chose two generators and performed insulation reinforcement (cleaning and varnish Painting). We compared change of insulation condition for the stator winding based upon off-line diagnostic test result before and after repair. Test result shows that insulation condition was improved after insulation reinforcement. This insulation reinforcement has a function to reduce cause of deterioration, so we can know that it extends lifetime of generator and it is a very important factor for stable operation of facilities.