• Journal of Advanced Marine Engineering and Technology
• /
• 제32권7호
• /
• pp.1044-1050
• /
• 2008

Most of developed countries, the consumption of fossil fuels has been serious problems that cause serious environment pollution like acid rain, global warming. Also, we have faced that limitation fossil fuels will be exhausted. Currently, small hydropower attracts attention because of its small, clean, renewable, and abundant energy resources to develop. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Tubular-turbine among small hydraulic power generation can be used at low-head. The purpose of this study is to research turbine's efficiency due to runner vane angle using CFD analysis.

• 전기학회논문지
• /
• 제62권5호
• /
• pp.632-638
• /
• 2013

In this study, we described voltage fluctuation characteristics of distribution line during starting and normal operation condition of the small hydro generators. Based on these theories, we scrutinized the starting and operating characteristics of induction generators installed in two small hydro power plants that is connected to the distribution line and researched necessary factors when selecting the generator type. The type of turbines and capacity of generators are different. One is below 1,000kW and the other is above 1,000kW. Two generators are tested during starting, and it acts as motor not generator at the instant that the machine is connected to the grid. After connecting to the grid, the machine rotates above synchronous speed before converting to the generator mode. Therefore the characteristic of the generator during starting is same as it of motor.

• 연구논문집
• /
• 통권27호
• /
• pp.75-86
• /
• 1997

Combined cycle power plant is a system where a gas turbine or steam turbine is used to produce shaft power to drive a generator for producing electrical power and the steam from the HRSG is expanded in a steam turbine for additional shaft power. Combined cycle plant is a one from of cogeneration. The temperature of the exhaust gases from a gas turbine ranges from $400^\circC$ to $600^\circC$, and can be used effectively in a heat recovery steam generator to produce steam. Combined cycle can be classed as a "topping(gas turbine)" and a "bottoming(steam turbine)" cycle. The first cycle, to which most of the heat is supplied, is called the topping cycle. The wasted heat it produces is then utilized in a second process which operates at a lower temperature level and is therefore referred to as a "bottoming cycle". The combination of gas/steam turbine power plant managed to be accepted widely because, first, each individual system has already proven themselves in power plants with a single cycle, therefore, the development costs are low. Secondly, the air as a working medium is relatively non-problematic and inexpensive and can be used in gas turbines at an elevated temperature level over $1000^\circC$. The steam process uses water, which is likewise inexpensive and widely available, but better suited for the medium and low temperature ranges. It, therefore, is quite reasonable to use the steam process for the bottoming cycle. Only recently gas turbines attained inlet temperature that make it possible to design a highly efficient combined cycle. In the present study, performance analysis of a dual pressure combined-cycle power plant is carried out to investigate the influence of topping cycle to combined cycle performance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.184-186
• /
• 2007

절연물의 열화가 진행되면 최초로 1선 지락사고가 발생할 가능성이 많고 1선 지락사고는 2선 지락 및 단락사고로 파급되어 설비에 심각한 손상으로 이어지게 된다. 따라서, 1선지 락 사고에 대한 완전한 보호방식의 적용은 설비 신뢰성 증대라는 측면에서 매우 중요한 사항이라고 판단된다. 이에 시화호조력 발전소에 설치될 수차발전기는 고정자권선의 지락사고에 대한 100%보호방식을 적용하였으며 이 설계사례를 토대로 실제적으로 적용가능한 발전기 고정자권선의 지락보호증대방식을 공유코자 한다.

• 한국기계가공학회지
• /
• 제11권5호
• /
• pp.104-108
• /
• 2012

Recently, small scale hydropower needs to be developed due to its clean, renewable and abundant energy resources. However, suitable draft of hydro-turbine body in combination with differences in wheel blade shapes is not determined yet in the range of small hydropower and it is necessary to study for the effective draft in combination with type. Therefore, watermill shaped of 250mm diameter. hydro-turbine aiming 20 watt class generator is adopted in this study because of its simple structure and high possibility of applying to small hydropower. The result shows that effective draft for the turbine body is variable concerning the size of turbine and flow rate of water. Thus, the difference of water depth between fore and aft turbine body contributes to the increase of torque, angular momentum and power output.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.69-72
• /
• 2001

A novel water-turbine, Katamax, for micro hydropower generator is proposed, which has reasonable efficiency even in two meters of water head. The basic concept of Katamax is similar to that of waterwheel except that Katamax has two axis on which the blades rotate, where general waterwheel has only one. Brief structure and principles of Katamax are explained and analysis for efficiency of each module are provided. The result of the prototype product of Katamax is briefly explained.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.69-72
• /
• 2001

A novel water-turbine, Katamax, for micro hydropower generator is proposed, which has reasonable efficiency even in two meters of water head. The basic concept of Katamax is similar to that of waterwheel except that Katamax has two axis on which the blades rotate, where general waterwheel has only one. Brief structure and principles of Katamax are explained and analysis for efficiency of each module are provided. The result of the prototype product of Katamax is briefly explained.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2018년도 추계학술대회
• /
• pp.59-60
• /
• 2018

진동수주형 파력발전장치는 수주, 터빈, 발전기 그리고 전력변환 장치 등이 연계된 복잡한 물리적인 특성을 나타낸다. 본 연구는 1/4 스케일의 모형시험을 통해 진동수주와 터빈의 물리적인 관계의 도출에 중점을 두고 있다. 진동수주실과 연성된 터빈의 공력특성은 오리피스를 활용하여 모사하였다. 진동수주실 성능평가에 핵심요소인 터빈효과는 오리피스를 통과하는 유속과 압력강하로 대표할 수 있다. 진동수주형 파력발전장치의 터빈효과는 모형시험에서 계측된 유속과 압력강하로부터 비선형적인 관계를 갖는 것을 확인하였다.

• 신재생에너지
• /
• 제20권1호
• /
• pp.116-125
• /
• 2024

Ultra-low-head is an unexplored classification among the sites in which hydroelectric power can be produced. This is typically owing to the low power output and the economic value of the turbines available in this segment. A turbine capable of operating in an ultra-low-head condition without the need of a dam to produce electricity is developed in this study. A gate structure installed at a shallow water channel acting as a weir generates artificial head for the turbine mounted on the gate to produce power. The turbine and generator are designed to be compact and submersible for an efficient and silent operation. The gate angle is adjustable to operate the turbine at varying flow rates. The turbine is designed and tested using computational fluid dynamics tools prior to manufacturing and experimental studies. A parametric study of the runner blade parameters is conducted to obtain the most efficient blade design with minimal hydraulic losses. These parameters include the runner stagger and runner leading edge flow angles. The selected runner design showed improved hydraulic characteristics of the turbine to operate in an ultra-low-head site with minimal losses.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
• /
• pp.379-380
• /
• 2002

Steam generators (S/G) of pressurized water reactors are large heat exchangers that use the heat from the primary reactor coolant to make steam in the secondary side for driving turbine generators. Reciprocating sliding wear experiments have been performed to examine the wear properties of Incoloy 800 and Inconel 690 steam generator tubes in high temperature water. In present study, the test rig was designed to examine the reciprocating and rolling wear properties in high temperature (room temperature - $300^{\circ}C$) water. The test was performed at constant applied load and sliding distance to investigate the effect of test temperature on wear properties of steam generator tube materials. To investigate the wear mechanism of material, the worn surfaces were observed using scanning electron microscopy. At $290^{\circ}C$, wear rate of Inconel 690 was higher than that of Incoloy 800. It was assumed to be resulted from the oxide layer property difference due to the a\loy composition difference. Between 25 and $150^{\circ}C$ the wear loss increased with increasing temperature. Beyond $150^{\circ}C$, the wear loss decreased with increasing temperature. The wear loss change with temperature were due to the formation of wear protective oxide layer. From the worn surface observation, texture patterns and wear particle layers were found. As test temperature increased, the proportion of particle layer increased.