Optimization of retrofit period for control system in thermal power plants

Man-Su Shin,Du-Yong Park,Geon-Pyo Lim,Tae-Won Jeong 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

There are thermal power plants constructed in South Korea in 1990s. Usually it is estimated 25-30 years as economic life. On contrary, because the control systems for thermal power plants consist of high-technology electronic components, the economic life is estimated 10-30 years. The large variation is based on operation environment. According bath-tub curve, the faults increases during the beginning of operation after construction completion. and the end of system life. It is effective to retrofit existing system before increase of faults. By the way, it is effective to shorten the period of retrofit of existed system. But, the curtailment of the retrofit construction period causes unit trip. As for this point, it is necessary of optimization of construction period and procedures without unit trips or fault.

진동주기가 다른 듀얼프레임을 이용한 내진보강시스템의 성능검증을 위한 실험적 연구

오상훈,최광용,유홍식,김영주 한국구조물진단유지관리공학회 2018 한국구조물진단유지관리공학회 논문집 Vol.22 No.5

본 연구에서 제안하는 내진보강기법은 듀얼시스템으로 비내진상세로 설계된 저층구조물을 대상으로 적용하기 위한 기법이다. 듀얼시스템은 기존의 구조체, 외부보강체, 강재이력댐퍼로 구성되고 구조체와 외부보강체 사이에 강재이력댐퍼를 설치한다. 구조체와 외부보 강체는 강성과 적재하중에 의해 서로 다른 주기에 의해 상대변위가 발생되고 강재이력댐퍼를 통해 지진에너지를 흡수한다. 본 연구에서 제안 된 듀얼시스템의 내진성능을 검증하기 위해 동적실험을 수행한다. 동적 실험결과, 듀얼시스템 보강 시 에너지가 1.84배 더 많이 입력됨에도 불구하고 56%의 변형 저감과, 93%의 손상 저감이 됨에 따라 듀얼시스템 적용 시 내진성능을 향상시킬 것으로 판단된다. 그리고 연구결과는 듀얼시스템의 설계범위를 설정하기 위한 추후 연구의 기초자료로 제시하고자 한다. The new seismic retrofit system in study propose is the Dual system, which aims to be applied to the seismically vulnerable low-story buildings. The Dual system is composed of existing structure, external retrofit frame and hysteretic steel dampers installed between former two components. The Dual system dissipates the energy by plastic deformation of steel damper caused by relative displacement due to the differences in stiffness, weight, and eigenperiod of each components. The dynamic test with shaking table was performed to verify the seismic performance of the proposed Dual system. As a result of the dynamic test, it is expected that the Dual system will improve the seismic performance due to the reduction of strain of 56% and the damage reduction of 93%, even though the energy is 1.84 times higher than that of the dual system. And the results of the study are presented as basic data of the study for setting the design range of the dual system.

지진에 대비한 기존 건축물의 내진보강 활성화를 위한 지원제도 방안

하기주,이동렬 대한건축학회지회연합회 2022 Vol.24 No.6

In order to protect the lives and property of the people in the event of an earthquake and minimize social and economic damage, we have continuously established legal grounds for seismic design of buildings on a national level. In particular, under the Earthquake and Volcanic Disaster Countermeasures Law, existing buildings will be completed before the seismic design standards are established or strengthened. Therefore, it is judged that it is difficult to achieve the seismic performance level required by the current seismic design standards. Budget support for domestic public buildings is continuously expanding in order to further increase the seismic retrofitting rate by 17% by 2025 (the overall seismic retrofitting rate is equivalent to 62.6%), but compared to private buildings. Is an inadequate reality. Therefore, in order to establish a policy and institutional foundation for activating seismic retrofitting of existing buildings, we raised awareness of the need for seismic retrofitting of buildings to which seismic retrofitting has not been applied, and built buildings by implementing seismic retrofitting. Ensuring safety is required. Therefore, in this study, in order to activate seismic retrofitting of existing buildings in Japan in preparation for an earthquake, we will look at the current state of the seismic retrofitting support system for domestic buildings, and plan a support system for activating seismic retrofitting of existing buildings. 지진에 대비하여 국민의 생명과 재산을 보호하고 사회· 경제적 피해를 최소화하기 위하여 국가적 차원에서 건축물의 내진설계를 위한 법적인 근거를 지속적으로 마련하고 있다. 특히 지진·화산재해대책법에서는 기존 건축물의 내진설계기준이 제정되거나 강화되기 이전에 준공되어 현행 내진설계기준에서 요구하는 내진성능수준을 달성하기 어려울 것으로 판단된다. 국내의 공공건축물은 2025년까지 추가로 내진보강율을 17% 더 높이기 위하여(전체 내진성능 확보율은 62.6%에 해당) 예산지원이 지속적으로 확대되고 있으나, 민간 건축물에 대한 대비는 미흡한 실정이다. 그러므로 기존 건축물의 내진보강 활성화를 위한 정책 및 제도적 기반을 마련하기 위하여 내진설계가 미적용된 건축물의 내진보강 필요성에 대한 인식을 제고하1여야 한다. 또한 기존 민간건축물의 내진보강 실시를 통한 건축물의 안전성 확보가 요구된다. 따라서 본 연구에서는 지진에 대비한 국내 기존 건축물의 내진보강 활성화를 위하여 국내 건축물 내진보강 지원제도 현황을 살펴보고, 기존 건축물의 내진보강 활성화를 위한 지원제도 방안을 제시하였다.

실대형 모형실험에 의한 2층 토글형 변위증폭 감쇠시스템의 내진보강 성능검증

유영찬(You, Young-Chan),정인용(Jung, In-Yong) 대한건축학회 2018 대한건축학회 학술발표대회 논문집 Vol.38 No.2

The purpose of this study was to verify the performance of 2-story toggle damper system which is used for seismic retrofit. Real-size experiments were conducted to evaluate structural performances of the damping system. The 2-story toggle damper system, which is made of 7x6m steel frame, showed significant nonlinear behavior within 2% drift. The damper system was attached on 2-story, 2-bay concrete frame and tested in the same way. The test results show that the concrete frame has no severe damages and the damping system operated as well as the system-sole-test.

RC 슬래브 휨 보강을 위한 복합보강 시스템의 정모멘트 구간에 대한 실험적 검증

김정중(Kim Jung Joong) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.2

본 연구에서는 철근콘크리트 슬래브의 휨 보강을 위하여 전단 연결재를 포함한 복합 보강 시스템이 제안되었다. 제안된 시스템은 강재 전단 연결재, 섬유보강폴리머, 오버레이 콘크리트로 구성되어 있다. 제안된 보강 시스템은 설치의 편의를 고려하여 부(-)모멘트와 정(+)모멘트가 작용하는 슬래브 구간 모두 슬래브의 상면에 설치하도록 설계되었다. 부(-)모멘트와 정(+)모멘트 구간에서의 보강 매카니즘이 분석되었다. 또한, 오버레이 콘크리트와 슬래브의 탈착을 방지하기 위하여 전단 연결재를 사용하였다. 두 개의 일방향 단순 지지 슬래브가 실험되었고 오버레이 콘크리트의 탈착과 전단파괴 없이 제안된 시스템의 휨 보강에 대한 유효성이 확인되었다. In this study a hybrid retrofit system including shear connector is proposed for the flexural strengthening of reinforced concrete (RC) members. The proposed system consists of steel shear connector, fiber reinforced polymer (FRP) and overlay concrete. Considering the installation convenience of the proposed system, it is designed to be placed at the top surface of RC slabs for flexural strengthening of the sections in both positive and negative moment zones. The enhancing mechanisms of the proposed system for both positive and negative moment regions are analyzed. Steel shear connector is also installed between overlay concrete and RC slabs to prevent delamination of the overlay concrete until the flexural failure of the retrofitted slab with the proposed system. Two simply supported one-way slabs were tested and the efficiency of the proposed system for the flexural strengthening without shear failure and delamination of overlay concrete was observed.

철근콘크리트 구조물 내 부착된 수계 관망시스템의 내진거동 및 손상예측

정우영,주부석 한국지진공학회 2011 한국지진공학회논문집 Vol.15 No.3

구조물 내 설치된 파이프시스템은 주로 내부구성원들의 인간생활에 근간이 되는 기반시설로서 현대 도시생활의 생명선과 같은 역할을 한다. 이들 구조물 내 파이프시스템이 만약 지진발생에 의하여 손상될 경우 1차적으로 구조물 내 기능성이 저하되고 구조물 내 많은 정신적, 물질적 피해가 발생할 수 있다. 실제 내진공학에서 지진발생에 따른 비구조재요소의 거동은 크게 중요하게 고려되지 않으나 인적 및 물적 피해와 매우 밀접하게 연관되는 가스 혹은 수계파이프시스템에 대한 비구조적 요소의 거동예측 및 성능평가 연구는 보다 효과적인 구조물 유지관리를 위하여 그 필요성이 크다고 판단된다. 본 연구는 현재 일반적으로 널리 시공되어져 있는 노후 철근콘크리트 빌딩구조물 내 설치된 가스 혹은 수계파이프시스템에 대하여 실제 지진발생이 예측되는 거동을 살펴보고 이들 거동에 따른 성능평가 및 현 설계기준에 대한 검토도 병행하여 수행하고자 한다. 이를 위하여 본 연구에서는 해석적으로 발생 가능한 총 10회의 지진파에 대하여 현재 실제 건물 내 기설치된 수계파이프시스템 모델링 및 해석을 통하여 그 결과를 검증, 평가하였으며 부가적으로 실제 발생 가능한 파괴유형 분석을 통하여 현 설치된 수계파이프시스템의 설계에 대한 적절한 내진보강방법에 대하여도 제안하고자 한다. Reliability of piping systems is essential to the safety of any important industrial facilities. During an earthquake, damage to the piping system can occur. It can also cause considerable economic losses and the loss of life following earthquakes. Traditionally, the study of the secondary system was less important than primary structure system, however it has recently been emerging as a key issue for the effective maintenance of the structural system and to help reduce nonstructural earthquake damage. The primary objectives of this study are to evaluate seismic design requirements and the seismic performance of gas and fire protection piping systems installed in reinforced concrete (RC) buildings. In order to characterize the seismic behavior of the existing piping system in an official building, 10 simulated earthquakes and 9 recorded real earthquakes were applied to ground level and the building system by the newmark average acceleration time history method. The results developed by this research can be used for the improvement of new seismic code/regulatory guidelines of secondary systems as well as the improvement of seismic retrofitting or the strengthening of the current piping system.

Open source-based modeling of power plants retrofit and its application to the Korean electricity sector

Chung, Yongjoo,Paik, Chunhyun,Kim, Young Jin Elsevier 2019 International journal of greenhouse gas control Vol.81 No.-

<P><B>Abstract</B></P> <P>It is widely acknowledged that the power generation sector is a major source of greenhouse gas emissions. Especially, carbon dioxide emissions from the coal-fired power plant fleet are estimated to be 8.5 Giga tons in 2010 accounting for one-quarter of the global anthropogenic carbon emissions. It has often been claimed that the power plants retrofit may be considered one of the most promising emissions reduction alternatives. This study presents a noble approach to modeling the power plant retrofit based on the bottom-up formulation of OSeMOSYS, which provides a wide range of flexibility in energy systems modeling. The proposed approach has been demonstrated for the Korean electricity sector. The optimal solutions for the schedule of power plants retrofit have been obtained, and the effect of retrofit options on greenhouse gas emissions and associated costs has been further examined. It is shown that the power plants retrofit can be highly cost-effective for emissions reduction from the power generation sector. The proposed approach to retrofit modeling may contribute to attaining a deeper understanding on the analysis of power plants retrofit.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Modeling approach to power plants retrofit is proposed and the corresponding OSeMOSYS code is also developed. </LI> <LI> The applicability of the proposed approach is demonstrated with coal-fired power plants retrofit of the Korean electricity sector. </LI> <LI> It is shown that power plants retrofit may be considered one of the most promising mitigation measures for the power generation sector. </LI> </UL> </P>

지진에 대비한 기존 건축물의 내진보강 활성화를 위한 지원제도 방안

하기주,이동렬 대한건축학회지회연합회 2022 대한건축학회연합논문집 Vol.24 No.6

In order to protect the lives and property of the people in the event of an earthquake and minimize social and economic damage, we have continuously established legal grounds for seismic design of buildings on a national level. In particular, under the Earthquake and Volcanic Disaster Countermeasures Law, existing buildings will be completed before the seismic design standards are established or strengthened. Therefore, it is judged that it is difficult to achieve the seismic performance level required by the current seismic design standards. Budget support for domestic public buildings is continuously expanding in order to further increase the seismic retrofitting rate by 17% by 2025 (the overall seismic retrofitting rate is equivalent to 62.6%), but compared to private buildings. Is an inadequate reality. Therefore, in order to establish a policy and institutional foundation for activating seismic retrofitting of existing buildings, we raised awareness of the need for seismic retrofitting of buildings to which seismic retrofitting has not been applied, and built buildings by implementing seismic retrofitting. Ensuring safety is required. Therefore, in this study, in order to activate seismic retrofitting of existing buildings in Japan in preparation for an earthquake, we will look at the current state of the seismic retrofitting support system for domestic buildings, and plan a support system for activating seismic retrofitting of existing buildings.

외단열시스템에 적용한 드렌처설비의 화재성능에 관한 실험연구

최지훈,최수환,조경숙,채승언 한국방재학회 2020 한국방재학회논문집 Vol.20 No.3

The exterior insulation finish system, in which insulation is installed on the outer wall of the building, is widely used due to its ease of construction and the effect of a shorter working period. However, the combustible insulation installed in the external insulation system is vulnerable to fire due to the sudden flame propagation in the event of a fire. For this reason, the Ministry of Land, Infrastructure, and Transport is carrying out support projects to strengthen the fire stability for buildings vulnerable to fire. In this study, the performance of the drencher system was evaluated through a large-scale exterior material experiment in a building equipped with a drench system. When a flammable insulation material was used as EPS, the fire spread to the inside and outer side of EPS after 530 s and 540 s of ignition, respectively, and the results of this experiment did not meet the performance evaluation criteria. When the drencher system was installed under the same conditions as stated above, the fire spread to the outside after 266 s of ignition, and this experiment satisfied the performance evaluation criteria. 건물 외벽에 단열재가 시공되는 외단열시스템은 시공의 용이성 및 공사기간 단축 효과로 인해 널리 사용되는 공법이다. 그러나 외단열시스템에 설치되는 가연성 단열재는 화재 시 급격한 화염전파의 특성 상 화재에 취약하다. 이러한 이유로 국토교통부에서는 화재취약요인을 갖춘 기존건축물의 화재안전성능강화를 위하여 지원 사업을 실시하고 있다. 본 연구에서는 제시된 보강공법 중에서 드렌처설비의 성능을 확인하고자 실대형 외장재 실험을 통해 검증하였다. 일반 EPS의 경우 점화시간을 기준으로 503초에 화염이 EPS 내부로 확산되었고, 540초에 마감재 외부로 화재 확산이 이루어지며 성능평가기준에 미달되었다. 동일한 조건에 드렌처설비를 설치한 경우 266초에 시작시간에 도달하였으며, 성능평가기준에 만족하였다.

Seismic retrofit design method using friction damping systems for old low- and mid-rise regular reinforced concrete buildings

Moon, Ki Hoon,Han, Sang Whan,Lee, Chang Seok Elsevier 2017 ENGINEERING STRUCTURES Vol.146 No.-

<P><B>Abstract</B></P> <P>In seismically active regions, many old low- to mid-rise reinforced concrete (RC) buildings are in use that have poor reinforcement details and suffer from material deterioration. Because these buildings are vulnerable to earthquakes, they represent a threat to human lives and economy. To impart such a building with satisfactory seismic performance, a friction damping system can be used, which consists of dampers and a braced frame. In this study, a method for the design of friction damping systems is proposed for the seismic retrofit of old low- to mid-rise regular reinforced concrete (RC) buildings. The proposed method is verified using a six-story RC building designed considering only gravity loads.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A seismic retrofit design method using friction-damping systems is developed. </LI> <LI> The maximum displacement of a system is estimated using a simple SDF system. </LI> <LI> The proposed seismic retrofit design method is verified by one example building. </LI> </UL> </P>