• Title/Summary/Keyword: Load Curve

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Conversion Function and Relationship of Loss of Load Expectation Indices on Two Kinds of Load Duration Curve (두 종류의 부하곡선에 관한 공급지장시간기대치(LOLE)의 상호 변환관계성)

  • Lee, Yeonchan;Oh, Ungjin;Choi, Jaeseok;Cha, Junmin;Choi, Hongseok;Jeon, Donghun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.3
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    • pp.475-485
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    • 2017
  • This paper develops a conversion function and method transforming from daily peak load curve used $LOLE_D$ [days/year] to hourly load curve used $LOLE_H$[hours/year]and describes relationship between $LOLE_D$ [days/year] and $LOLE_H$ [hours/year]. The indices can not only be transformed just arithmetically but also have different characteristics physically because of using their different load curves. The conversion function is formulated as variables of capacity and forced outage rate of generator, hourly load daily load factor and daily peak load yearly load factor, etc. Therefore, the conversion function (${\gamma}={\varphi}$(.)) can not be simple. In this study, therefore, the function is formulated as linear times of separated two functions. One is an exponential formed conversion function of daily load factor. Another is formulated with an exponential typed conversion function of daily peak load yearly load factor. Futhermore, this paper presents algorithm and flow chart for transforming from $LOLE_D$[days/year] to $LOLE_H$[hours/year]. The proposed conversion function is applied to sample system and actual KPS(Korea Power System) in 2015. The exponent coefficients of the conversion functions are assessed using proposed method. Finally, assessment errors using conversion function for case studies of sample system and actual system are evaluated to certify the firstly proposed method.

Determination of the Tension-Softening Curve of Concrete at Different Strength Level using Fictitious Crack Model (가상균열모델에 의한 강도 수준이 다른 콘크리트의 인장연화곡선 결정)

  • 오성진;박현재;김희성;진치섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.125-130
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    • 2002
  • The most important material parameters are fracture energy and the stress-crack opening displacement($\sigma$-w) curve to determine the behavior of concrete. Especially, the relationship between the $\sigma$-w curve is strongly important to determine the load-displacement curve of concrete that has a major influence on the fracture behavior of a concrete. In this paper, notched plain concrete beams with different strength level were tested under three-point bending and fracture energy, the load-deflection curve, and the load-crack mouth opening displacement(CMOD) curve were obtained from the experimental data. Also, the fictitious crack model(FCM) was applied to determine the load-deflection curve of notched plain concrete beams using various types of $\sigma$-w curve model proposed by Petersson and we compared experimental results with numerical ones carried out by Finite Element Method(FEM).

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Applicability of Load Duration Curve to Nakdong River Wateished Management (낙동강 유역관리를 위한 부하량 유황곡선의 적용 가능성)

  • Han, Suhee;Shin, Hyun Suk;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.23 no.5
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    • pp.620-627
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    • 2007
  • In this study a general analysis method for watersheds with the entire runoff conditions and corresponding water quality is proposed and its applicability based on the currently available information is investigated. Using the 8-day-interval data set of runoff and water quality observed by Nakdong River Environment Research Center, the flow duration curve and discharge-load relation curve for each unit watershed are established, then the load duration curve is finally constructed. This paper discusses how the load duration curve can be used in the assessment of TMDL. The entire Nakdong river watershed is also divided into prior managing areas of point sources or non-point sources in a way of general management. It is thought that LDC can be a great tool for visualizing overall probabilities of current water quality and thus for the TMDL management.

Analysis of Load-Settlement Curves in Driven and Embedded Piles (항타 및 매입말뚝의 하중-침하량 곡선의 분석)

  • 천병식;조천환
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.61-70
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    • 1997
  • Although the load -settlement curve characteristics of embedded piles are different from those of driven piles, for the determination of their allowable loads the same analysis method has been adopted without any considerations. According to the related domestic chi teria, the analysis methods of load-settlement curve have some conflicts among themselves and have several vague points in obtaining the allowable capacity from ultimate or yield capacity. In order to solve those problems, the relevant literatures were reviewed. And also the result of 106 pile load tests was analysed. Analysis result indicates that analysis met hods of the load-settlement curve based on single mathematical curve are not suitable for the general analysis method of load-settlement curves due to their various characteristics. As a result, the appropriate analysis methods and safety factors for the determination of allowable capacity of pile are suggested in this paper.

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2-Step Modeling for Daily Load Curve of Up to and Including 100kVA Distribution Transformer (100kVA 이하급 배전용 변압기 일부하 패턴의 2-Step 모델링)

  • Lee, Young-Suk;Kim, Jae-Chul;Yun, Sang-Yun
    • Proceedings of the KIEE Conference
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    • 2001.11b
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    • pp.371-373
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    • 2001
  • In this paper, we present 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. Daily load patterns are classified by two methods dependent upon possession information. In case we possess daily load profiles make use of K-mean algorithm and in case we have not daily load profiles, make use of customer information of KEPCO. As the parameters of the load pattern classification, we use are daily load profiles and customer information of each distribution transformers. Data management system is used for NT oracle. We can present peak load magnitude, initial load magnitude and peak load duration for daily load patterns by 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. We think that this paper contributes to enhancing the distribution transformer overload criterion.

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Performance of Rock-socketed Drilled Shafts in Deep Soft Clay Deposits

  • Kim, Myung-Hak
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.10a
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    • pp.409-429
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    • 2006
  • In designing rock-socketed drilled shaft, bearing capacity evaluation is very important because the maximum values of base and side resistance are not generally mobilized at the same value of displacement, FHWA and AASHTO code suggest different ultimate bearing capacity formular according to rock type and shaft settlement. In domestic code suggest base resistance and side resistance can be added on condition that after confirming the result of field load test with axial load transfer test. This paper shows that static load test and hi-directional load test result analysis of deep rock-socketed drilled shaft in three different sites. Load-settlement curve, t-z, and q-w curve in rock-socketed part were calculated and compared. t-z curve in weathered and soft rock showed no deflection softening behavior in pretty large strain (about 2-3% of diameter). Ultimate resistance could be the summation of side resistance and base resistance in rock-socketed drilled shaft in domestic sites.

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Shear Behavior between Ground and Soil-Nailing (지반과 쏘일네일링 사이의 전단거동에 관한 연구)

  • Seo, Hyung-Joon;Lee, In-Mo
    • Journal of the Korean Geotechnical Society
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    • v.30 no.3
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    • pp.5-16
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    • 2014
  • Soil-nailing has two main resistance factors: skin friction between ground and grouting; and tension load of reinforced material. These two factors will affect the load-displacement curve when performing soil-nailing pullout tests. The purpose of this paper is to figure out the shear behavior between ground and soil-nailing focusing on the net load-displacement behavior during soil-nailing pullout tests. Firstly, the net load-displacement curve between ground and grouting is estimated theoretically. Then, in-situ pullout load tests are performed on various ground conditions to obtain the load-displacement curve occuring between ground and grouting. Since the measured shear displacement includes elongation of the reinforced material (steel nails), the net load-displacement curve can be obtained by subtracting the elongation magnitude of steels from the measured displacement. It was found that the measured net load-displacement curve matches reasonably well with the theoretically estimated curve.

Estimation of the Fracture Resistance Curve for the Nuclear Piping Using the Standard Compact Tension Specimen (표준 CT시험편을 이용한 실배관 파괴저항 곡선 예측)

  • Park, Hong-Sun;Heo, Yong;Koo, Jae-Mean;Seok, Chang-Sung;Park, Jae-Sil;Cho, Sung-Keun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.9
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    • pp.930-937
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    • 2009
  • The estimation method of the fracture resistance curve for the pipe specimen was proposed using the load ratio method for the standard specimen. For this, the calculation method of the load - CMOD curve for the pipe specimen with the common format equation(CFE) was proposed by using data of the CT specimen. The proposed method agreed well with experimental data. The J-integral value and the crack extension were calculated from the estimated load - CMOD data. The fracture resistance curve was estimated from the calculated J-integral and the crack extension. From these results, it have been seen that the proposed method is reliable to estimate the J-R curve of the pipe specimen.

Application of the Load Duration Curve (LDC) to Evaluate the Achievement Rate of Target Water Quality in the Han-River Watersheds (부하지속곡선(Load Duration Curve; LDC)을 이용한 한강수계 오염총량관리 목표수질 평가방법 적용 방안)

  • Kim, Eunkyoung;Ryu, Jichul;Kim, Hongtae;Kim, Yongseok;Shin, Dongseok
    • Journal of Korean Society on Water Environment
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    • v.31 no.6
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    • pp.732-738
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    • 2015
  • Water quality in four major river basin in Korea was managed with Total Maximum Daily Load (TMDL) System. The unit watershed in TMDL system has been evaluated with Target Water Quality (TWQ) assessment using average water quality, without considering its volume of water quantity. As results, although unit watershed are obtained its TWQ, its allocated loads were not satisfied and vice versa. To solve these problems, a number of TWQ assessments with using Load Duration Curve (LDC) have been studied at other watersheds. The purpose of this study was to evaluate achievement of TWQ with Flow Duration Curve (FDC) and Load Duration Curve(LDC) at 26 unit watersheds in Han river basin. The results showed that achievement rates in TWQ assessment with current method and with LDC were 50~56 % and 69~73%, respectively. Because of increasing about 20% of achievement rates with using LDC, the number of exceeded unit watershed at Han river Basin was decreased about 4~6 unit watersheds.

Development and Application of Coliform Load Duration Curve for the Geum River (금강에 대한 대장균 부하 지속곡선의 개발 및 적용)

  • Kim, Geonha;Yoon, Jaeyoung
    • Journal of Korean Society on Water Environment
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    • v.21 no.5
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    • pp.516-519
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    • 2005
  • An useful protocol coiled load duration curve methodology to estimate contaminant loading to a river on an exceedance probability scale was developed in this research. The technique was further applied to estimate total coliform loading to the Geum River, using the daily mean flow rate and total coliform concentration data during January, 1996 and July, 2004 for the Gongju where an automated monitoring station is located. Drought flow of the Gongju (=50.3 cms) was equivalent to 40% on an exceedance probability scale. Load duration curve for total coliform loading at the Gongju was constructed. Standard duration curve was constructed with the water quality criteria for the class 2 (total coliform concentration = 1000 MPN/100 mL). By plotting load duration curve with standard duration curve, it could be revealed that water quality do not meet the desired water quality for 47% on an exceedance probability scale. If linearity between flow rate and coliform concentration is assumed, it can be interpretated that water quality exceeds desired criteria when average mean flow rate is over 51 cms.