• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.10
• /
• pp.102-108
• /
• 2011

The existing power flow has a single direction to the line end but the bidirectional power flow will possibly occur depending on the output capacity in the 22.9[kV] distribution power system connected with the dispersed generation(DG). So these characteristics would influence the power system management. The DG have many advantages such as assistance source, Load share etc. So the utility must apply the bidirectional protection system so as to maximize an advantage of DG. This paper describes the field test case of bidirectional protective device in order to investigate the device performance when applied to bidirectional power system. We have tested in the power system test site of KEPCO and these tests provide the basis for performance verification test of bidirectional protective device in the power system.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.359-360
• /
• 2006

This paper introduces a variable of methodology and models of solving Security-Constrained Price-Based Unit Commitment(SPUC) Problems in the Deregulated Power Market. The objective of SPUC is coordination between GENCOs and the ISO. GENCOs apply Price-Based Unit Commitment(PBUC) without security constraints and submit capacity bids to the ISO for maximizing their revenues. Using generation data and transmission data obtained from TRANSCOs, the ISO applies Security-Constrained Unit Commitment(SCUC), executes congestion management and contingency analysis for minimizing line flow violations and the risk supplying loads. Considering analysis data, the ISO should adjust GENCOS' bid. In this paper, we presents the result of survey and analyze on the approach of the SPUC problem.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.535-536
• /
• 2006

This paper reports investigation into the factors that influence the transient behavior of the wind power generation system following network fault conditions. It is shown that the critical clearing time(CCT) can be affected by various factors contributed by the host network. Such factors include capacity of wind power, power factor, the length of the interfacing line, etc. This investigation is conducted en a simulated grid-connected wind farm using Digsilent Power Factory.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.260-261
• /
• 2006

This paper describes a real time digital simulation method for the application of HTS tape to power devices. At present, in order to extend the power capacity of some area which has a serious problem of power quality, especially metropolitan complex city. there are so many problems such as ROW for cable line routes, space for downtown substations, and the environmental protection, etc. HTS technology is one of the best solutions. Simulation is required for safety before install of HTS power cable, a fabrication model used at the power system simulation. Here, in this paper, authors developed an algorithm connected with HTS by using Real-Time Digital Simulator(RTDS).

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.822-824
• /
• 2005

This paper presents a scheme to solve the congestion problem using phase-shifting transformer(PST) in power systems. Available transfer capability(ATC) is an important indicator of the usable amount of transmission capacity accessible by several parties for commercial trading in power transaction activities. This paper deals with an application of optimization technique for ATC calculation. Sequential quadratic programming(SQP) is used to maximize power flow of tie line subject to security constraints such as voltage magnitude and real power flow. The proposed method is applied to 10 machines 39 buses model systems to show its effectiveness.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.974-979
• /
• 2004

Recently, the development of paved track is required as a Low-maintenance of conventional line. The most important factor of paved track is stability and applicability. In this method, the ballast is grouted with mortar so that the ballast can turn into a structure like slab. This method can be subdivided into the followings. One is the method with switching the ballast, and the other is without switching the ballast. The ordinary and actual states of the ballast and roadbed were investigated to evaluate the applicability of the paved track structure in this study, and various In-situ tests were applied. Non-destructive tests such as GPR, SASW, FWD were used, and bearing capacity of roadbed, depth of the ballast, and deterioration, penetration, and contamination of the ballast were focused. The result of this investigation was utilized in the selection of optimal paved track structure and data for preliminary design.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2003.10b
• /
• pp.17-17
• /
• 2003

Enzymes involved in catecholamine synthesis are present in the highest concentration in the adrenal medulla, however they were found also in other, mainly nervous tissues. Increased transcription of genes for catecholamine biosynthetic enzymes is an important mechanism to increase the capacity for epineprine/norepinephrine biosynthesis with stress. Gastrodia elata(Chinese name: Tienma), are very important Chinese herbal medicines used for the medical treatment of headaches, migraine, dizziness, epilepsy, rheumatism, neuralgia, paralysis and other neuralgic and nervous disorders. Immobilize stressed rat markedly increased tyrosine hydroxylase (TH) mRNA and dopamine-${\beta}$-hydroxylase (DBH) mRNA transcriptior level more than control group. But treated Gastrodia elata extracts in immobilized stressed rat slightly increased TH mRNA and DBH mRNA transcription level more than normal group. In addition, we are obtained identical results in PC12 cell line. Decrease of transcription level of TH mRNA and DBH mRNA is indicating that Gastrodia elata have a anti-stress effects which decrease the transcription level of TH and DBH mRNA on catecholamine biosynthesis pathway.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.3
• /
• pp.77-82
• /
• 2001

반복하중을 받는 현장타설말뚝에 대한 두 가지의 주요 관심사항은: (a) 지지력의 변화 가능성 그리고 (b) 누적변형량에 의한 기초의 가능성 저하이다. 이러한 인자들에 대한 평가를 위하여, 모형점토지반에 설치된 24개의 모형현장타설말뚝에 대한 정적 및 동적경사재하시험(12개의 압축 및 12개의 인발)을 수행하였다. 경사반복압축재하시험에서는 반복하중에 의한 지지력의 변화가 무시할 정도였으며, 누적변형량은 송전철탑의 기능성에 영향을 줄수도 있을 것으로 사료된다. 그러나, 경사반복인발시험에서는 과도한 누적변형이 발생하게 되어 결과적으로 현장타설말뚝주변과 점토사이의 접촉면적이 감소하는 것으로 나타났다. 접촉면적의 감소 결과, 반복경사인발하중에 의해서 경사인발지지력의 현저한 감소가 일어난다는 사실을 알 수 있었다. 정적경사인발지지력의 50에서 70퍼센트에 해당되는 반복하중을 받는 대부분의 현장타설말뚝들은 인발되었다.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.9
• /
• pp.1073-1080
• /
• 1999

Optimal routing of distribution networks can be attained by keeping the line power capacity limit to handle load requirements, acceptable voltage at customer loads, and the reliability indices such as SAIFI, SAIDI, CAIDI, and ASAI limits. This method is composed of optimal loss reduction and optimal reliability cost reduction. The former is solved relating to the conductor resistance of all alternative routes, and the latter is solved relating to the failure rate and duration of each alternative route. The routing considering optimal loss only and both optimal loss and optimal reliability cost are compared in this paper. The case studies with 10 and 24 bus distribution networks showed that reliability cost should be considered as well as loss reduction to achieve the optimal routing in the distribution networks.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.1
• /
• pp.91-99
• /
• 2006

Fatigue properties of INVAR/AW wires have been investigated under the heat exposure in order to ensure stable operation and to estimate life span of their power line. In the case of heat exposure for 10000 hr, fatigue life and limit increased. For further heat exposure, fatigue limit decreased due to the decrease in yield strength. The variation fatigue of strand wire was strongly dependent on its amplitude. Also, cracks in wires of 7 strands were caused by stress concentration at the outer surface and fretting between each wire during vibration.