• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.379-380
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• 2020

배터리의 효율적인 관리와 안정적인 운영을 위해서는 배터리의 노화에 따른 배터리의 모니터링이 중요하다. 그 중에서도 노화에 대한 문제는 실제 어플리케이션에서 매우 중요하기 때문에 더 정확하고 안정적인 운영을 위해서는 배터리 잔존 수명을 판단하는 지표인 State of Health (SOH)가 필수적이다. 따라서 실험을 통한 UDDS의 전압 차 (Voltage Difference) 이미지를 학습데이터로 구성하여, SOH의 파라미터인 용량을 추정하는 Convolutional Neural Network(CNN) 모델을 제안한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.139-146
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• 2008

Conductors in overhead transmission lines are exposed under various environmental conditions for a long period of time, so that they may be slowly degraded due to air pollutant or thermal history. Aged conductors may reduce power system reliability and public safety. Therefore, diagnosis of aged conductors in service becomes more important concerns with respect to keeping power delivery stable with a proper capability, replacing aged conductors, or constructing a new line. In this paper, we posed a new method to diagnose the refurbishment life and estimate the remaining life of aged conductors by measuring dips. As analyzing some relations of conductor temperature, conductor current, and tension load, it could be verified that dip exactly shows mechanical tension loss for aged conductor. Based on several simulation results, it was shown that the proposed method may be effectively used to diagnose the refurbishment life or remaining one of overhead conductors.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.1
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• pp.28-33
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• 2016

Batteries are used for main power engine in the fields such as mobiles, electric vehicles and unmanned submarines, for starter and lamp driver in general automotive, for emergency electric source in ship. These days, lead-acid and the lithium ion batteries are increasingly used in the fields of the secondary battery, and the lead-acid battery has a low price and safety comparatively, The lithium ion battery has a high energy density, excellent output characteristics and long life, whereas it has the risk of explosion by reacting with moisture in the air. But Recently, due to the development of waterproof, fireproof, dustproof technology, lithium batteries are widely used, particularly, because their usages are getting wider enough to be used as a power source for hybrid ship and electric propulsion ship, it is necessary to manage more strictly. Hybrid ship has power supply units connected to the packets to produce more than 500kWh large power source, and therefore, A number of the communication modules and wires need to implement the wire inspection and monitor system(WIIMS) that allows monitoring server to transmit detecting voltage, current and temperature data, which is required for the management of the batteries. This paper implements a low price type wireless inspection and monitoring system(WILIMS) of the lithium ion battery for hybrid vessels using BLE wireless communication modules and power line modem( PLM), which have the advantages of low price, no electric lines compared to serial communication inspection systems(SCIS). There are state of charge(SOC), state of health(SOH) in inspection parts of batteries, and proposed system will be able to prevent safety accidents because it allows us to predict life time and make a preventive maintenance by checking them at regular intervals.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.103-108
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• 2011

$Li_2MnSiO_4$/C was synthesized by solid state reaction and solution synthesis with sucrose for carbon source. The X-ray diffraction patterns of solid state reaction indicates small amount of impurities. By FE-SEM and HR-TEM, solution synthesis comprised several tens of nanometer comparing to 500~600 nm of $Li_2MnSiO_4$/C prepared by solid state reaction. The $Li_2MnSiO_4$/C prepared by solution synthesis show better electrochemical performance than solid state reaction. The first charge-discharge capacity are 236, 189 mAh/g respectively by solution synthesis. But its cycle performance was poor as yet and its capacity retention was 62% after 10 cycles.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.66-73
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• 2022

In order to induce users to purchase excellent products in the water industry that satisfy the technical standards of excellent products, in this study, it is to present the advantages of the cost aspect of the pumps as the objective basis. It will be to promote technology development of domestic water companies and to create a virtuous cycle structure in the water industry. In order to present an objective basis for the merits in terms of cost, an economic evaluation was conducted through life cycle cost analysis. For the LCC analysis, initial cost (pump cost and installation cost), operation cost (energy cost and maintenance cost) and demolition cost (disposal cost and residual value) are searched and calculated. As the results of comparison on two capacity of pumps, the energy cost of the excellent pump is 212 million KRW lower than the that of general pump in the large pump. The cost of excellent pump was 17 million KRW lower than that of general pump in small capacity pump. As the results of sensibility test, if the product is developed in the direction of improving pump efficiency and increasing the replacement cycle of consumables, it is predicted that the effect on LCC will be large.

• Journal of IKEEE
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• v.18 no.3
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• pp.298-304
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• 2014

Proper operation of the battery powered systems depends on the accuracy of the battery SOC(State of Charge) estimation, therefore it is critical for those systems that SOC is accurately determined. The SOC of the battery is related to the battery aging and the SOC estimation methods without considering the aging of the battery are not accurate. In this paper, a new method that accurately estimate the SOC of the battery is proposed considering the aging of the battery. A mathematical model for the Battery SOC-OCV(Open Circuit Voltage) relationship is presented using Boltzmann equation and aging indicator is defined, and then the SOC is estimated combining the mathematical model and aging indicator. The proposed method takes the aging of the battery into consideration, which leads to an accurate estimation of the SOC. The simulations and experiments show the effectiveness of the proposed method for improving the accuracy of the SOC estimation.

• Korean Journal of Construction Engineering and Management
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• v.7 no.3 s.31
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• pp.112-121
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• 2006

The purpose of this study is to execute economical analysis for two types of office building HVAC system using LCC technique : single vs, separated HVAC(equal partition installation, unequal partition installation) system. The research method of this study includes the case analysis and questionnaire surveys. The results of this study are as follows: (1) LCCs of 3 types of HVAC system are estimated and the most economical one is investigated as single HVAC system, (2) In this case study, the single HVAC system was investigated as 34% lower in LCC during 15 years per $100m^2$ compared to equal partition installation, as 41% compared to unequal partition installation.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.7-14
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• 2020

A Battery Monitoring System capable of State-of-Charge(SOC) estimation using the Extended Kalman Filter(EKF) is described in this paper. In order to accurately estimate the SOC of the battery, the battery cells were modeled as the Thevenin equivalent circuit model. The Thevenin model's parameters were measured in experiments. For the Battery Monitoring System, we designed a battery monitoring device that can calculate the SOC estimation using the EKF and a monitoring server that controls multiple battery monitoring devices. We also develop a web-based dashboard for controlling and monitoring batteries. Especially the computation of the monitoring server could be reduced by calculating the battery SOC estimation at each Battery Monitoring Device.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.1-7
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• 2004

In this paper, the new improved method for photovoltaic system was studied available for a lighting load by measuring the state of charge of lead-acid batteries. Photovoltaic systems has been evaluated as one of the most new and renewable energy and especially, the Stand-Alone Photovoltaic system has been used to a street light, a road sign light, an air caution light, an emergency call. Many Stand-Alone PV system are installed by a group. Although the pre-installation cost of PV system is high and it has not been operated due to the absence of optimal management standards. In this paper, it is proposed a new operating method by the measurement of lead-acid battery's SOC with a Ah balancing.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.67-74
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• 2014

The fluctuation of the output power of wind farms will be able to cause the impact on the Jeju power system such as power quality and stability. To settle the matter, many researchers have proposed the use of the BESS(Battery Energy Storage System) in the wind farm. In this paper, The BESS is applied to each wind farms for mitigating the fluctuation of wind power output. The BESS is controlled for smoothing the output of wind farms. Two kinds of simulation will be carried out. First, the simulation results by using PSCAD/EMTDC simulation program are compared to the measured data from the real power grid in Jeju Island. The other is to analyze the output of wind farms when the BESS is applied to the simulation works. The simulation results will demonstrate the effectiveness of using BESS to stabilize for power grid in Jeju Island.