{"title":"Technical Trends of VSC HVDC","authors":"Chan-Gi Kim","doi":"10.18770/KEPCO.2016.02.03.343","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.03.343","url":null,"abstract":"","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123716037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Complete, Reductive Depolymerization of Concentrated Sulfuric Acid Hydrolysis Lignin into a High Calorific Bio-oil using Supercritical Ethanol","authors":"A. Riaz, Jaehoon Kim","doi":"10.18770/KEPCO.2016.02.03.447","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.03.447","url":null,"abstract":"It is imperative to develop an effective pathway to depolymerize lignin into liquid fuel that can be used as a bioheavy oil. Lignin can be converted into liquid products either by a solvent-free thermal cracking in the absence air, or thermo-chemical degradation in the presence of suitable solvents and chemicals. Here we show that the solvent-assisted liquefaction has produced promising results in the presence of metal-based catalysts. The supercritical ethanol is an efficient liquefaction solvent, which not only provides better solubility to lignin, but also scavenges the intermediate species. The concentrated sulfuric acid hydrolysis lignin (CSAHL) was completely liquefied in the presence of solid catalysts (Ni, Pd and Ru) with no char formation. The effective deoxy-liquefaction nature associated with scEtOH with aid hydrodeoxygenation catalysts, resulted in significant reduction in oxygen-to-carbon (O/C) molar ratio up to 61%. The decrease in oxygen content and increase in carbon and hydrogen contents increased the calorific value bio-oil, with higher heating value (HHV) of 34.6 MJ·Kg-1. The overall process is energetically efficient with 129.8% energy recovery (ER) and 70.8% energy efficiency (EE). The GC-TOF/MS analysis of bio-oil shows that the bio-oil mainly consists of monomeric species such as phenols, esters, furans, alcohols, and traces of aliphatic hydrocarbons. The bio-oil produced has better flow properties, low molecular weight, and high aromaticity.","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115672623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flow Analysis of the Environmental Chemical Reaction Processes at Power Plant in accordance with the Baffle Structure","authors":"Y. Jeong, K. Hur, Joon-Woo Gil","doi":"10.18770/KEPCO.2016.02.03.433","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.03.433","url":null,"abstract":"In the area of environmental chemistry of power plant, flow analysis of the reactor with built-in impeller is a very important part from the perspective of the improvement of the efficiency of the entire process. As a wide range of methods are being proposed for the analysis of the flow pattern within the reactor, this study analyzed the flow within the reactor according to the baffle structure (height) installed on the internal wall of the reactor in order to improve the reaction efficiency through the inducing of the up and down stirring with the reactor. As the results of the execution of the flow analysis for each of a diverse range of cases by utilizing the Computational Fluid Dynamics (CFD) method, it was possible to confirm that the flow is markdely improved by inducing the up and down stirring among the reactants within the reactor if the baffle is elevated to the level below the water surface. In particular, as the results of the analysis of the general cases in which the baffle is elevated all 4 steps and the cases in which the baffle is elevated only 2 steps, elevating the baffle only 2 steps achieve the same effect as the elevating of the baffle by 4 steps. Therefore, it was possible to expect to improve the efficiency with out the need to increase the use of electric power substantially if the outcomes of this study is applied to the actual sites of power plants in the future.","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124297892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Donghwi Lee, Young-Dae Kim, Woo-Bin Park, Joon-Seok Kim, Seung-Ho Kang
{"title":"A Method to Find Feature Set for Detecting Various Denial Service Attacks in Power Grid","authors":"Donghwi Lee, Young-Dae Kim, Woo-Bin Park, Joon-Seok Kim, Seung-Ho Kang","doi":"10.18770/KEPCO.2016.02.02.311","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.311","url":null,"abstract":"Network intrusion detection system based on machine learning method such as artificial neural network is quite dependent on the selected features in terms of accuracy and efficiency. Nevertheless, choosing the optimal combination of features, which guarantees accuracy and efficienty, from generally used many features to detect network intrusion requires extensive computing resources. In this paper, we deal with a optimal feature selection problem to determine 6 denial service attacks and normal usage provided by NSL-KDD data. We propose a optimal feature selection algorithm. Proposed algorithm is based on the multi-start local search algorithm, one of representative meta-heuristic algorithm for solving optimization problem. In order to evaluate the performance of our proposed algorithm, comparison with a case of all 41 features used against NSL-KDD data is conducted. In addtion, comparisons between 3 well-known machine learning methods (multi-layer perceptron., Bayes classifier, and Support vector machine) are performed","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"282 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123094620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental Evaluation of Cohesion Properties for Various Coals","authors":"Min-Su Kim, Yongwoon Lee, C. Ryu, H. Park, H. Lee","doi":"10.18770/KEPCO.2016.02.02.279","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.279","url":null,"abstract":"Assessing the handling properties of coal becomes a major issue for the operation of a fuel supply system in power plants, due to the increased types of coal imported into Korea. In this study, the cohesion strengths of 13 bituminous and sub-bituminous coals from different countries were tested by measuring the amount of force that leads to a failure of consolidated particles. The particle size was in the range of 0.1-2.8 mm, which represents the coarse particles before pulverization. While the cohesion strength was proportional to the compression force in the tested range, the effects of the surface moisture content and the weight fraction of fines were crucial for cohesive coals. At fixed conditions of surface moisture and particle size, large variations were found in the cohesion propensity between coals. For coals of 0.1-0.5 mm with the moisture added close to the critical value, cohesive coals had the density over 900 kg/m 3 after consolidation. The cohesion propensity was not correlated with the basic properties of coals with sufficient statistical significance.","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114611366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"CIM and OPC-UA based Integrated Platform Development for ensuring Interoperability","authors":"Jun-Sung Kim, Hee-Jeong Park, Choi Seung-Hwan","doi":"10.18770/KEPCO.2016.02.02.233","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.233","url":null,"abstract":"Smart grid is called it as a system of systems. There are diverse types of systems in smart grid environment. Therefore, one of key factors to achieve smart grid successfully is interoperability among diverse systems. To secure interoperability, smart grid operating system should be developed complied with standards in terms of the data representation and communication. Common Information Model (CIM) and OLE Process for Control – Unified Architecture (OPC-UA) are the representative international standards in smart grid domain. Each standard defines data representation and communication by providing common information model and the unified architecture. In this paper, we explain a smart grid platform that we have developed to comply with CIM and OPC-UA standards for secure interoperability among numerous legacy systems.","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125139699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Software Functional Requirements and Architectures of Microgrid Energy Management System","authors":"Jin-Man Sohn, Sang-Yun Yun","doi":"10.18770/KEPCO.2016.02.02.269","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.269","url":null,"abstract":"Distribution management system or microgrid energy management system plays an important role in monitoring, operation and control of electrical distribution systems by utilizing IT infrastructure. Nowadays, the rapid increase of the distributed resources makes the conventional management system have some additional functionality for the reliable operation due to intermittent renewables and the efficient operation on the economical purpose. In this paper, the brief standard software functional requirements of microgrid energy management system are provided through survey of the recent commercial products of the major vendors, and furthermore the architectures of microgrid energy management system are provided in comparison with major suppliers’ microgrid energy management system. The summary of investigation will be able to make the developers and researchers focus on the specific functionality in the real world.","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131096597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of the Corrosion Deterioration Inspection Tool for Transmission Tower Members","authors":"S. Woo, I. Chu, B. Youn, Ki-Jung Kim","doi":"10.18770/KEPCO.2016.02.02.293","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.293","url":null,"abstract":"Recently, interests for maintenance of transmission tower are increasing to extend life of structures and reduce maintenance cost. However, existing classical diagnosis method of corrosion deteriorated degree on the transmission tower steel members, visual inspection, has a problem that error often due to difference of inspector’s individual knowledge and experience. In order to solve the problem, this study carried out to develop the corrosion deterioration inspection tool for transmission tower steel members. This tool is composed of camera equipment and computer-aided diagnosis system. We standardized the photographing method by camera equipment to obtain suitable pictures for image processing. Diagnosis system was designed to evaluate automatically degree of corrosion deterioration for member of transmission tower on the basis of the RGB color image processing techniques. It is anticipated that developed the corrosion deterioration inspection tool will be very helpful in decision of optimal maintenance time for transmission tower corrosion.","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130618035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Young-Il Kim, So-Jeong Park, Young-Jun Kim, Nam-Jun Jung, Moon-Suk Choi, B. Park
{"title":"Development of AMI NMS (Network Management System) using SNMP for Network Monitoring of Meter Reading Devices","authors":"Young-Il Kim, So-Jeong Park, Young-Jun Kim, Nam-Jun Jung, Moon-Suk Choi, B. Park","doi":"10.18770/KEPCO.2016.02.02.259","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.259","url":null,"abstract":"KEPCO installed AMI (Advanced Metering Infrastructure) metering system for low-voltage customers from 2008. AMI metering system of KEPCO has operated 2.55 million customers and will plan to operate 22 million customers until 2020. KEPCO developed AMI NMS (Network Management System) to operate the meter reading network efficiently. NMS monitors the network status of DCUs (Data Concentration Unit) and modems. NMS provides functionalities of data collection and analysis. It collects property data of network device, network topology information, communication performance information, fault information, and etc. It analyzes collected data and controls network devices by remote access. AMI NMS collects","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116983855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tae-Min Kim, S. Yim, S. Sohn, Ji-Hyun Lim, Sang-chul Han, K. Ryu, H. Yang
{"title":"Investigation on Effective Operational Temperature of HTS Cable System considering Critical Current and AC loss","authors":"Tae-Min Kim, S. Yim, S. Sohn, Ji-Hyun Lim, Sang-chul Han, K. Ryu, H. Yang","doi":"10.18770/KEPCO.2016.02.02.307","DOIUrl":"https://doi.org/10.18770/KEPCO.2016.02.02.307","url":null,"abstract":"The operational cost for maintaining the superconductivity of high-temperature superconducting (HTS) cables needs to be reduced for feasible operation. It depends on factors such as AC loss and heat transfer from the outside. Effective operation requires design optimization and suitable operational conditions. Generally, it is known that critical currents increase and AC losses decrease as the operational temperature of liquid nitrogen (LN 2 ) is lowered. However, the cryo-cooler consumes more power to lower the temperature. To determine the effective operational temperature of the HTS cable while considering the critical current and AC loss, critical currents of the HTS cable conductor were measured under various temperature conditions using sub-cooled LN 2 by Stirling cryo-cooler. Next, AC losses were measured under the same conditions and their variations were analyzed. We used the results to select suitable operating conditions while considering the cryo-cooler’s power consumption. We then recommended the effective operating temperature for the HTS cable system installed in an actual power grid in KEPCO’s 154/22.9 kV transformer","PeriodicalId":445819,"journal":{"name":"KEPCO Journal on electric power and energy","volume":"173 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124209826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}