• Title/Summary/Keyword: PQ system

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Reassessment of SMES Application Studies and Systematic approach Method under Deregulation (전력계통 제어용 초전도에너지 저장장치(SMES)의 검토사례 분석과 전력시장에서의 적용방안)

  • Lee, Geun-Joon;Yoon, Y.B.;Hwang, S.D.
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.54-56
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    • 2003
  • With the advancement of superconductor materials, especially in HTC YBCO(Gen II), the feasibility of SMES in power systems become much higher than previous days application[1]. Also, with the de-regulation of electricity market, it is indispensable to have a proper estimation of power quality index and power quality cost calcluation mechanism to stabilize highly industrialized society and to vitalize the investment for electric power system. This paper suggests a comprehensive algorithm[2] to determine the policy of SMES investment with the PQ Indices[3] based on aggregated load CBEMA curve reflecting the voltage characteristics such as volatge sags and interruptions which make electric load in unstable operation.

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A Power Quality monitoring system using Neural Network (신경망을 이용한 전력품질 진단시스템)

  • Kim Hong Kyun;Lee Jin Mok;Choi Jea Ho;Lee Sang Hoon;Kim Jea Sig
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.202-204
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    • 2004
  • This paper presents a neural network technology for the detection and classification of the various types of power quality disturbances. Power quality phenomena are short-time problems and of many varieties. Particularly, the transients happen during very short durations to the nano- and microsecond. Thus, a method for detecting ·md classifying transient signals at the same time and in an automatic combines the properties of the wavelet transform and the advantages of neural networks. We test two neural network and compare the results of Backpropagation Neural (BPN) network with Radial basis function network (RBFN). RBFN is more useful to detect and classify than BPN. The configuration of the hardware of PQ-DAS and some case studies are described.

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Problems and Improvement Directions of Fire Protection Designing and Supervising Jobs (소방 설계·감리업의 문제점 및 개선방향에 관한 연구)

  • Cha, Jong-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8745-8752
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    • 2015
  • Since many accidents have occurred in Korea in these days, many people have lost their health and have been damaged. The damages caused by fires which occur to many buildings where many people always reside takes a substantial share of the total damages. And since the proportions of the domestic fire protection designing/supervising industries are relatively much disregarded compared to other kinds of work, it is in the situation that there are many cases of serious damages because the fire protection equipment didn't exert the proper functions on fire after a building is constructed since the supervision against the poor construction along with the inadequate design. In order to improve such situations, in case of the design industry, the criteria on registration and workforce placement, the scope of operation, the design documents required when requesting the agreement to the construction permits, the responsibilities and authorities about the jobs of the fire protection facility designers must be improved and, in case of supervising industry, the registration criteria, the operation scope and the kinds, methods, targets and criteria of supervision, the criteria on the additional placement of assistant supervisors, the contents and scope of work must be improved, the PQ system and Public Supervision System must be reviewed and the systems for preventing any poor supervision must be improved in order to pursue the security of the people and their properties at the same level as the other kinds of work by preparing for the firm position and foundation of the fire protection design and supervision.

Antioxidative and Antimutagenic Activity of Ethanolic Extracts from Giant Embroynic Rices (거대배아미 에탄올 추출물의 항산화활성 및 항변이원성)

  • Kang, Mi-Young;Lee, Yun-Ri;Koh, Hee-Jong;Nam, Seok-Hyun
    • Applied Biological Chemistry
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    • v.47 no.1
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    • pp.61-66
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    • 2004
  • 70% ethanolic extracts were prepared from the three mutant rice cultivars with giant embryo termed Shinsunchal-giant embryonic rice, Whachung-giant embryonic rice and Nampung-giant embryonic rice, and its antioxidative and antimutagenic properties were evaluated and compared. For analysing antioxidativity, various antioxidative indices, such as electron donating ability to DPPH radical, scavenging capacity to hydroxyl radicals generated by Fenton reaction, scavenging capacity to superoxide radicals generated by HPX/XOD system, inhibitory effect on autoxidation of linoleic acid and inhibitory effect on membrane lipid peroxidation derived from rabbit erythrocyte ghost, were determined. For analysing antimutagenicity, suppressive effects on mutagenesis induced by the chemical mutagen, mitomycin C, were measured using E. coli PQ 37 as a indicator cell. The results showed that for both antioxidativity and antimutagenicity the giant embryonic rices were more effective compared to the general cooking rice, Among the giant embryonic rice cultivars, Nampung-giant embryonic rice tended to be most effective, showing its scavenging activity to DPPH radical, superoxide radical and hydroxyl radical, and inhibitory activity to lipid peroxidation was 2,3-, 3,3-, 1.7-, and 2.5-fold greater than those of normal rice, respectively.

Control Strategy for Selective Compensation of Power Quality Problems through Three-Phase Four-Wire UPQC

  • Pal, Yash;Swarup, A.;Singh, Bhim
    • Journal of Power Electronics
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    • v.11 no.4
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    • pp.576-582
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    • 2011
  • This paper presents a novel control strategy for selective compensation of power quality (PQ) problems, depending upon the limited rating of voltage source inverters (VSIs), through a unified power quality conditioner (UPQC) in a three-phase four-wire distribution system. The UPQC is realized by the integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a three-phase, four-leg voltage source inverter (VSI), while a three-leg VSI is employed for the series APF of the three-phase four-wire UPQC. The proposed control scheme for the shunt APF, decomposes the load current into harmonic components generated by consumer and distorted utility. In addition to this, the positive and negative sequence fundamental frequency active components, the reactive components and harmonic components of load currents are decomposed in synchronous reference frame (SRF). The control scheme of the shunt APF performs with priority based schemes, which respects the limited rating of the VSI. For voltage harmonic mitigation, a control scheme based on SRF theory is employed for the series APF of the UPQC. The performance of the proposed control scheme of the UPQC is validated through simulations using MATLAB software with its Simulink and Power System Block set toolboxes.

Comparison of Toxic Effects of Mercury, Copper and Zinc on Photosystem II of Barley Cholroplasts (보리 엽록체의 광계 II에서 수은, 구리 및 아연의 저해효과 비교)

  • 전현식
    • Journal of Plant Biology
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    • v.36 no.3
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    • pp.195-201
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    • 1993
  • The room temperature fluorescence induction of chloroplasts was utilized as a probe to locate the site of inhibition by mercury, copper and zinc on PS II by mercury. Inhibitory effect of Hg2+ on electron transport activity was notable as compared with Cu2+ and Zn2+. At concentrations of HgCl2 over 50 $\mu$M, activities of PS II and whole-chain electron transport decreased more than 70%, while that of PS I decreased about 10~30%. This suggests that PS II is more susceptible to Hg2+ than PS I is. In the presence of diphenylcarbazide (DPC), 50 $\mu$M HgCl2 inhibited the reduction of dichlorophenolindophenol (DCPIP) about 50%. Addition of heavy metals induced marked decrease in maximal variable fluorescence/initial fluorescence [(Fv)m/Fo], but no changes in Fo. With various concentrations of heavy metals, changes of chlorophyll a fluorescence emitted by PS II showed gradual decrease in photochemical quenching (qQ), which indicates an increase in reduced state of electron acceptor, QA. Especially, the addition of HgCl2 caused a notable decrease of qQ. In the presence of 50 $\mu$M CuCl2, energy-depended quenching (qE) was completely reduced, whereas in the presence of 50 $\mu$M CuCl2 and ZnCl2 it was still remained. The above results are discussed on the effects of mercury in relation to water-splitting system and plastoquinone (PQ) shuttle system.

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Power Interruption Cost Calculation based on Value-based Methodology (가치평가법을 사용한 정전관련비용의 산정)

  • Lee, Buhm;Kim, Kyoung-Min;Choi, Nam-Sup
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.2
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    • pp.293-300
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    • 2021
  • This study presents a Power Quality(:PQ) costs calculation methodology based on Value-Based Methodology. A SCDF including Voltage Sag Costs is presented to calculate Sustained Interruption Costs, Momentary Interruption Costs, and Voltage Sags Costs. Authors compared between interruption costs without Back-Up Power Supply and interruption costs with Back-Up Power Supply, and showed reduction of interruption costs by investing Back-UP Power Supply by multi-lateral analyzation. By applying this method to the real system, evaluated and analyzed power quality of the system.

A Basis Study on the Integrated System for the Evaluation and Public Announcing System of the Contractor's Construction Capacity (시공능력평가 통합시스템 기반구축에 관한 기초연구)

  • Noh, Jae-Yoon;Jun, Young-Joon;Park, Eun-Soo;Lee, Tai-Sik
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2008.11a
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    • pp.568-571
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    • 2008
  • To help a owner selecting proper contractors about the specified contract, the Evaluation and Public Announcing System of the Contractor's Construction Capacity has been introduced since 1997. But, the system has been done violence to its original meaning and purpose as time went on. When annually announcing the Contractor's Construction Capacity, especially, there was frequently a large range of opinion on the issues. On that account, MLTM(Ministry of Land, Transport and Maritime Affairs) has had to make a alteration to improve those and is making efforts for a constructive policy now. The purpose of this paper is to conduct a basis study on the Integrated System after reflecting points to be considered about improvements and the current of the times.

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Genotoxicological Safety of Gamma-Irradiated Kwamegi(semi-dried Colobabis seira) (감마선 조사된 과메기의 유전독성학적 안전성 평가)

  • 육홍선;정영진;송현파;이주운;변명우
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.1
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    • pp.182-192
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    • 2004
  • Gamma irradiation at 5 and 10 kGy was applied to Kwamegi (semi-dried Colobabis seira) for their possible hygiene quality and carried out genotoxicological safety. In vitro genotoxicological safety of each 5 and 10 kGy-irradiated Kwamegi was evaluated by Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and E. coli WP2 uvrA reversion assay, SOS chromotest (Escherichia coli PQ37) and chromosome aberration test (Chinese hamster lung fibroblast cells) in the absence and presence of an exogenous metabolizing system (S9 mix). Gamma-irradiated samples were not different from nonirradiated-control to respective in vitro tests. And in vivo micronucleus test using ICR mice (male) micronucleus was not observed. Kwamegi exposed to 10 kGy-gamma ray revealed negative results in these three in vitro mutagenetic tests and in vivo micronucleus test up to 10,000 $\mu\textrm{g}$/plate, respectively. The results indicated that 5 and 10 kGy gamma-irradiated Kwamegi (semi-dried Colobabis seira) did not have mutagenicity.

Design of a VCM actuator for dual servo system

  • Choi, Hyeun-Seok;Han, Chang-Soo;Kim, Seung-Soo;Kim, Eung-Zu;Choi, Tae-Hoon;Na, Kyoung-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.301-306
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    • 2004
  • In this study, Dual servo mechanism with VCM(Voice Coil Motor) and PZT is designed for a high precision force and position control. We designed the VCM actuator and dual servo mechanism with leaf spring. VCM actuators, with their high linearity, simple structure, low weight, and high efficiency, are increasingly being used in micro-positioning applications. There are many kinds of VCM with a structure. VCM actuators are divided into two types by moving parts. One is moving magnet type and the other moving coil type. We described the properties of these two types of VCM. Design parameters of VCM are defined through the FEM simulation analysis of magnetic field and dynamic model of dual servo mechanism. These researches help to for decreasing loss in the air gap of VCM. We present dual servo mechanism is effective mechanism for a force control in hi h precision, properties of designed VCM.

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