• Title/Summary/Keyword: 무효 전력 보상

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Cooperation Algorithms of LTC and SC for Distribution Volt/Var Regulation (배전계통 전압/무효전력 보상을 위한 LTC변압기와 SC의 협조운전 알고리즘)

  • Choi, Joon-Ho;Kim, Jae-Chul;Nam, Hae-Kon;Moon, Seung-Il
    • Proceedings of the KIEE Conference
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    • 2003.07a
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    • pp.399-402
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    • 2003
  • In this paper, the on line volt/var control algorithms of the food Load Tap Changer (LTC) transformer and Shunt Capacitor(SC) are proposed for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

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The Comparison of Operating Characteristics of SVC and STATCOM for Compensating the Reactive Power in the Jeju Power System (제주계통의 무효전력보상을 위한 SVC와 STATCOM의 운전특성 비교)

  • LEE, SEUNGMIN;Kim, Eel-Hwan;Kim, Ho Min;Oh, Sung-Bo;LEE, DOHEON
    • Journal of the Korean Solar Energy Society
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    • v.35 no.3
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    • pp.49-56
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    • 2015
  • This paper presents a comparative operating characteristics of static var compensator(SVC) and static synchronous compensator(STATCOM) for compensating the reactive power in the Jeju power system. There are two kinds of reactive power compensating systems, which are active and passive system in the applications of the line commutated converter type high voltage direct current (LCC-HVDC). In the Jeju power system, two STATCOMs as active compensating system have been operating. Even though STATCOM has good performance compared with SVC, economical efficiency of former system is not good to the latter system. So, it is necessary to examine the performance and economical efficiency depend on the intention before appling the system. To compare the operating characteristics of two systems in the Jeju power system, simulations have been carried out for case studies that both of the HVDC system have transient state by using PSCAD/EMTDC program.

Assessment of System Stability via Loss Reduction in 154[㎸]System Supplying High Speed Railway (손실감소를 통한 고속철도부하를 포함한 154[㎸]벼 배전계통의 시스템 안정도 평가)

  • 정현수;오재경;김진오
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.5
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    • pp.83-89
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    • 2002
  • The purpose of this paper is to assess experimentally system stability of the 154[㎸]transmission system due to the current of the forthcoming AC High-Speed Railway (HSR) era. It introduces a simple method to evaluate the system stability. The proposed method also shows the relationship between stability and power losses, and the stability indices made by the numerical process proposed in this paper will be used to assess whether a system can be stabilized or not. This paper also presents the improvement of the stability via loss reduction using a shunt compensator. Reactive power compensation is often the most effective way to improve both power transfer capability and system stability. The suitable modeling of the traction power system should be applicable to the PSS/E. The proposed method is tested on a practical system which will be expected to accommodate the heavy HSR load.

GA based Selection Method of Weighting Matrices in LQ Controller for SVC (GA를 이용한 SVC용 LQ 제어기의 가중행렬 선정 기법)

  • 허동렬;이정필;주석민;정형환
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.6
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    • pp.40-50
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    • 2002
  • In this paper, we present a GA(Genetic Algorithm) approach to select weighting matrices of an optimal LQ(Linear Quadratic) controller for SVC(Static VAR Compensator). A SVC, one of the FACTS(Flexible AC Transmission System), constructed by a FC(Fixed Capacitor) and a TCR(Thyristor Controlled Reactor), was designed and implemented to improve the damping of a synchronous generator, as well as to control the system voltage Also, a design of LQ controller depends on choosing weighting matrices. The selection of weighting matrices which is not a trivial solution is usually carried out by trial and error. We proposed an efficient method using GA of finding weighting matrices for optimal control law. Thus, we proved the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system by eigenvalues analysis and simulation.

A Study on Effect of B/L's Exemption Clauses Relating to the Governing Law of English Law (영국법의 준거법과 관련한 선하증권 면책약관의 효력에 관한 연구)

  • Han, Nak-Hyun;Jung, Jun-Sik
    • Journal of Korea Port Economic Association
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    • v.22 no.4
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    • pp.1-17
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    • 2006
  • In the Bill of Lading of The Irbenskiy Proliv is not subject to the Hague-Visby Rules in accordance with paragraphs (A) and/or (E) of cl.1 or to the Hague Rules in accordance with paragraphs (B) and/or (D) of cl.1. The Irbenskiy Proliv is very rare case that is effective to exempt the carrier as literal words of Bill of Lading. The action concerns cargoes of perishable goods shipped from Brazil to Japan, under Bills of Lading each of which contained an extensive carrier's exemption clause. A preliminary issue was ordered to be determined on the question whether c1.4 is effective to exempt the ralliers from any potential liability for the claims in this case. The court held that there is no reason to reject c1.4 as part of each of the contracts contained in or evidenced by the bills of lading; and it protects the carrier where damage to the goods shipped results from such causes. It is therefore effective to exempt the carriers from any potential liability for those claims.

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