• Title/Summary/Keyword: KRI

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A Study on Development of 345kV Class High-Voltage Suspension Insulators(210KN) (345kV 초고압 현수애자 210KN 개발 연구)

  • Suh, H.K.;Chon, K.W.;Shin, Y.G.;Park, Y.C.;Mung, K.S.;Lee, G.T.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1575-1577
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    • 2000
  • 345kV급 210KN 초고압 현수애자의 개발 시험 결과, 과전파괴하중시험에서 품질관리지수가 3.0 이상인 11.2였으며, 유중파괴전압시험에서는 기준치보다 40% 정도 높은 값을 보였다. 그리고 72kA$\cdot$ Cycle $\pm$10% 조건의 power arc시험에 파괴없이 만족하였으며, 경년변화시험 후의 확인시험에서도 품질관리지수가 11.47로 높게 나타났다. 애자련의 피로시험 및 진동피로시험 후의 하중확인시험에서도 기준치보다 10% 이상의 값을 보였다. 전체적인 시험조건에서 경년변화시험의 조건이 가장 가혹한 것으로 나타났다.

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Parameter Estimation of VfloTM Distributed Rainfall-Runoff Model by Areal Rainfall Calculation Methods - For Dongchon Watershed of Geumho River - (유역 공간 강우 산정방법에 따른 VfloTM 분포형 강우-유출 모형의 매개변수 평가 - 금호강 동촌 유역을 대상으로 -)

  • Kim, Si Soo;Jung, Chung Gil;Park, Jong Yoon;Jung, Sung Won;Kim, Seong Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.1
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    • pp.9-15
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    • 2013
  • This study is to evaluate the parameter behavior of VfloTM distributed rainfall-runoff model by applying 3 kinds of rainfall interpolation methods viz. Inverse Distance Weighting (IDW), Kriging (KRI), and Thiessen network (THI). For the 1,544 $km^2$ Dongcheon watershed of Nakdong river, the model was calibrated using 4 storm events in 2007 and 2009, and validated using 2 storm events in 2010. The model was calibrated with Nash-Sutcliffe model efficiency of 0.97 for IDW, 0.94 for KRI, and 0.95 for THI respectively. For the sensitive parameters, the saturated hydraulic conductivity ($K_{sat}$) for IDW, KRI, and THI were 0.33, 0.31, and 0.43 cm/hr, and the soil suction head at the wetting front (${\Psi}_f$) were 4.10, 3.96, and 5.19 cm $H_2O$ respectively. These parameters affected the infiltration process by the spatial distribution of antecedent moisture condition before a storm.

Analysis of Dynamic characteristics for live-line insulator (단일 활선 애자의 동특성 분석)

  • Oh, Ki-Yong;Park, Joon-Young;Lee, Jae-Kyung
    • Proceedings of the KIEE Conference
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    • 2008.10b
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    • pp.375-376
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    • 2008
  • 송전선로에 절연물로 사용되는 애자는 설치 이후 장시간 사용에 따라 고전압 스트레스, 기계적 스트레스, 열 및 환경 스트레스 등으로 열화가 진행되기 때문에 안정적인 전력설비 운영을 위하여 활건 애자 비파괴 열화 상태 점검이 필요하다. 본 연구에서는 비파괴 상태 진단 감시 기술인 주파수 응답 함수 측정을 통한 고유 진동수 분석을 통하여 현재 활선 애자로 사용되고 있는 NGK210, KRI210, NGK300 및 KRI300 4가지 종류 애자의 동특성 실험을 수행하였으며, 이를 통하여 애자의 결함이 발생하였을 때 고유진동수 변화를 분석하였다.

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Diagnosis and Management of Post-Partum Hemorrhage Caused by Acquired Hemophilia A: A Case Report

  • Rashid, Nawshirwan G.;Amin, Shaema Salih;Abdulqader, Aveen M. Raouf
    • Korean Journal of Clinical Laboratory Science
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    • v.54 no.2
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    • pp.163-166
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    • 2022
  • Acquired hemophilia A (AHA) is an uncommon autoimmune bleeding disorder in which autoantibodies that affect the functions of factor VIII (FVIII) are present in the blood. The initial diagnosis of AHA is difficult as the presentations of AHA differ from those of congenital hemophilia A. Moreover, the treatment of AHA is more complex due to the presence of autoantibodies against FVIII. Here, we present a case report of postpartum AHA, to increase the perception and knowledge regarding the recognition and management of such cases. We present a young female with the chief complaint of vaginal bleeding and upper arm ecchymosis. Laboratory results exhibited isolated prolonged activated partial thromboplastin time (APTT) and FVIII inhibitors. The patient was treated with corticosteroids, FVIII concentrates, and a bypassing agent. In conclusion, unexplained postpartum bleeding, unmanageable with basic hemostatic measures, should lead to clinical suspicion of an acquired bleeding disease.

Simulation-Based Operational Risk Assessment (시뮬레이션 기법을 이용한 운영리스크 평가)

  • Hwang, Myung-Soo;Lee, Young-Jai
    • Journal of Information Technology Services
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    • v.4 no.1
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    • pp.129-139
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    • 2005
  • This paper proposes a framework of Operational Risk-based Business Continuity System(ORBCS), and develops protection system for operational risk through operational risk assessment and loss distribution approach based on risk management guideline announced in the basel II. In order to find out financial operational risk, business processes of domestic bank are assorted by seven event factors and eight business activities so that we can construct the system. After we find out KRI(Key Risk Indicator) index, tasks and risks, we calculated risk possibility and expected cost by analyzing quantitative data, questionnaire and qualitative approach for AHP model from the past events. Furthermore, we can assume unexpected cost loss by using loss distribution approach presented in the basel II. Each bank can also assume expected loss distributions of operational risk by seven event factors and eight business activities. In this research, we choose loss distribution approach so that we can calculate operational risk. In order to explain number of case happened, we choose poisson distribution, log-normal distribution for loss cost, and estimate model for Monte-Carlo simulation. Through this process which is measured by operational risk. of ABC bank, we find out that loss distribution approach explains closer unexpected cost directly compared than internal measurement approach, and makes less unexpected cost loss.

A Study on Characteristics of Suspension Insulator for 400kN Transmission Lines (400kN 송전용 현수애자의 특성연구)

  • Choi, I.H.;Shin, T.W.;Choi, Y.G.;Min, B.W.;Lee, D.I.
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1434-1436
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    • 2002
  • The 400KN suspended insulator was fabricated with feldspar, quartz, clay and $Al_2O_3$ wt% for extra high voltage. These materials were grinded with ball milling for 25 hours after mixing them. The grinded materials were sintered at $1300^{\circ}C$ for 50 minutes in the tunnel kiln after mading with jiggering method. The sintered density of specimen was reached at 97% in comparison with that of theory. The specimen had the characteristic of temperature rise with the increase of electrical losses. Also, the flexural strength and the fracture toughness of sintered parts respectively were 1658 kg/$cm^2$ and 2.3 $MPa{\cdot}m^{1/2}$.

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A Study on Electric Field Analysis for 300 kN Suspension Insulator Design (300 kN 현수애자의 설계를 위한 전계해석에 관한 연구)

  • Kim, I.S.;Choi, J.G.;Moon, I.W.;Jang, W.Y.;Joo, B.S.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2047-2050
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    • 1999
  • This paper presents some of the results of current research on 300 kN Suspension Insulator Design. In this paper, authors first used 2-dimensional field calculation to solve the electric field distribution of an insulator unit and insulator strings, and then 3-dimensional field calculation in order to overcome the shortcomings of 2-dimensional field calculation in which an axis-symmetrical coordinate has been used. And, it was found that the environmental configuration of 300 kN Suspension Insulator String gives great roles to the field distribution of the insulators.

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Evaluation and Performance Test of Ball and Socet type Suspension Insulator for 300 kN Ultra High Voltage (300kN 초고압용 초고압용 볼소켓형 현수애자의 성능평가)

  • Kim, S.S.;Kim, K.U.;Her, J.C.;Cho, H.G.;Park, T.G.;Seo, H.K.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.2026-2028
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    • 2000
  • As the results of evaluation of its performance for 300 kN Ball and Socket type suspension insulators. There was electrically internal puncture of the solid insulating body of the insulating due to the steep front impulse voltage, which usually occurs puncture before external flash-over of insulators, moreover we have obtained satisfactory results in power arc test of 7.2kA cycle fatigue test with high qualify control index of 4.6, especially we have obtained more satisfactory results than that before improvement of its materials.

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