• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.673-676
• /
• 2001

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel, which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three phase inverter is used for the connection between the photovoltaic array and the utility. This paper presents a three phase inverter for photovoltaic power system with current controller, voltage controller, PLL control system and the phase detector of interactive voltage by using dq transformation. The proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.137.2-137.2
• /
• 2010

With current real economic growth of more than 10% per year, the Chinese energy consumption is rapidly increasing. Coal supply consists of the vast majority of China's total energy consumption requirements in 2008. China, the largest energy consumer, is expected to be heavily dependent on coal for future power generation, too (IEA,2009). A growing concern on global warming, on the other hand, drives Chinese government to declare her commitment to the reduction of CO2 emission by 2020. In this paper, China's energy market is examined for the current and future primary energy mix. Coal is found to be the biggest part accounting for 68.7% of total primary energy consumption while coal-fired power accounts for over 80% of the total power generation. The importance of Clean Coal Technology is being discussed based on the findings of the importance of coal in China's economy and its sustainable development. Among the technologies involved, a brief investigation of IGCC(Integrated Gasification Combined Cycle) technology with a review on current IGCC projects in China are provided from the perspective of environmental benefits. Studies on regional Chinese power market is also conducted. It is found that the regulated power tariff in electricity system makes the power suppliers suffer from financial loss and changes in the electricity price system is under serious consideration by Chinese government. Even though Chinese power market system causes difficulties of commercialization for IGCC technology, the potential benefits will be high due to China's huge requirements of power generating capacity and its heavy reliance on coal if the electricity price system can be changed smoothly.

• 청정기술
• /
• 제18권1호
• /
• pp.22-30
• /
• 2012

지구온난화에 대한 해결방향으로 배가스 중 이산화탄소를 분리 및 저장하는 연구가 활발하게 진행되고 있다. 이산화탄소 흡수액은 주로 MEA와 같은 아민계 화합물이 사용되는데 이때 배가스에 함께 포함된 이산화황 ($SO_2$)은 $CO_2$ 흡수액의 성능을 저하시키는 원인이 되거나 공기중으로 배출될 경우 산성비의 원인이 된다. 지금까지의 $SO_2$ 흡수제로는 Ca계 고체 흡수제가 주로 사용되었는데 최근 액체 흡수액으로 이온성액체가 주목받고 있다. 이온성액체는 이온으로 이루어진 특징으로 인하여 넒은 액체 범위 및 극성가스에 대하여 높은 용해성을 갖고 있다. 본 총설에서는 최근 발표된 $SO_2$ 흡수제로 이온성액체에 대하여 그 구조 변화에 따른 $SO_2$ 흡수량 변화 그리고 흡수 메커니즘에 대하여 살펴보았다.

• Nuclear Engineering and Technology
• /
• 제55권4호
• /
• pp.1244-1249
• /
• 2023

Recently, the Kingdom of Saudi Arabia (KSA) announced the development of first-of-a-kind(FOAK) and most advanced futuristic vertical city and named as 'The LINE'. The project will have zero carbon dioxide emissions and will be powered by clean energy sources. Therefore, a study was designed to understand which clean energy sources might be a better choice. Because of its nearly carbon-free footprint, nuclear energy may be a good choice. Nowadays, the development of very small modular reactors (vSMRs) is gaining attention due to many salient features such as cost efficiency and zero carbon emissions. These reactors are one step down to actual small modular reactors (SMRs) in terms of power and size. SMRs typically have a power range of 20 MWe to 300 MWe, while vSMRs have a power range of 1-20 MWe. Therefore, a study was conducted to discuss different vSMRs in terms of design, technology types, safety features, capabilities, potential, and economics. After conducting the comparative test and analysis, the fuel cycle modeling of optimal and suitable reactor was calculated. Furthermore, the levelized unit cost of electricity for each reactor was compared to determine the most suitable vSMR, which is then compared other generation SMRs to evaluate the cost variations per MWe in terms of size and operation. The main objective of the research was to identify the most cost effective and simple vSMR that can be easily installed and deployed.

• Journal of Power Electronics
• /
• 제16권4호
• /
• pp.1551-1564
• /
• 2016

The high penetration level of inverter-based distributed generation (DG) power plants is challenging the low-voltage ride-through requirements, especially under unbalanced voltage sags. Recently, a flexible injection of both positive- (PS) and negative-sequence (NS) reactive currents has been suggested for the next generation of grid codes. This can enhance the ancillary services for voltage support at the point of common coupling (PCC). In light of this, considering distant grid faults that occur in a mainly inductive grid, this paper proposes a complete voltage support control scheme for the interface inverters of medium or high-rated DG power plants. The first contribution is the development of a reactive current reference generator combining PS and NS, with a feature to increase the PS voltage and simultaneously decrease the NS voltage, to mitigate voltage imbalance. The second contribution is the design of a voltage support control loop with two flexible PCC voltage set points, which can ensure continuous operation within the limits required in grid codes. In addition, a current saturation strategy is also considered for deep voltage sags to avoid overcurrent protection. Finally, simulation and experimental results are presented to validate the effectiveness of the proposed control scheme.

• 신재생에너지
• /
• 제17권3호
• /
• pp.16-23
• /
• 2021

Recently, the Korean government announced a plan to activate renewable energies, with focus on clean energy sources such as solar and wind power as the core and the goal of achieving carbon neutrality by 2050. Unlike other photovoltaic (PV) systems, offshore PV installations are advantageous for large-scale expansion because of the ease of securing sites; they also enable lowering the power generation costs based on construction of large-scale power facilities of megawatt class or higher owing to low noise and landscape damage. However, any power generation should proceed with consideration of the special environmental conditions of the ocean. Above all, when installing large-scale facilities, it is important to reduce fluctuations of the structure and secure stability to actively respond to waves. This study is concerned with the development of a floating body technology that actively responds to waves so as to enable commercialization of offshore solar power. A unit platform for research and development on offshore PV generation was installed in the Saemangeum sea, and the structural fluctuations and stability were analyzed to ensure conformity with the major performance indicators.

• 에너지공학
• /
• 제23권1호
• /
• pp.7-20
• /
• 2014

본 연구에서는 전국적으로 48만ha에 걸쳐 연료림으로 조성되어 있는 리기다소나무를 에너지연료로 활용하기 위해 최적의 생산시스템을 개발하고 이에 따른 공급가격과 전기 열 판매가격 및 이용률 등을 고려한 우드칩 연료한계가격을 산출하였으며 다양한 시나리오에 따른 경제성 민감도 분석을 수행하였다. 열 및 발전 전용시설에서의 경제성을 결정짓는 가장 중요한 변수는 연료공급가격이다. 열 전용시설에서는 본 연구에서 제안된 모든 생산시스템에서 생산되는 우드칩 연료의 활용이 가능하며 발전 전용시설에서는 생산비가 가장 높은 연료사용에는 일부 한계가 있으나 전기 판매가격이 현재의 SMP(pitch pine : 계통한계가격)보다 높아지거나 이용률이 80%이상으로 되는 경우 모두 활용 가능한 것으로 분석되었으며, 더욱이 RPS제도 시행에 따른 신재생에너지 인증서(REC:Renewable Energy Certificate)편익과 온실가스 절감효과로 CDM(Clean Development Mechanism)편익 등을 고려할 경우 충분히 활용 가능한 것으로 분석되었다. 따라서, 국내 발전부문에서의 RPS 공급의무율 이행을 위해서 산림 바이오매스의 활용이 적극 권장된다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 추계학술대회
• /
• pp.180-183
• /
• 2006

As a final step for developing a small-scale solar thermal power generation technology, a demonstration project for a dish-stirling power system has been carried out by KIER. During the two years project period, 10kW solar-only power system was built in Jinhae city and successful solar operations were demonstrated. In this paper an example of typical clean day operation and analysis results was introduced.

• Advances in Energy Research
• /
• 제4권1호
• /
• pp.29-45
• /
• 2016

There has been a growing interest in the recent time for the development of solar power tower plants, which are mainly used for utility scale power generation. Combined heat and power (CHP) is an efficient and clean approach to generate electric power and useful thermal energy from a single heat source. The waste heat from the topping Brayton cycle is utilized in the bottoming HRSG cycle for driving steam turbine and also to produce process steam so that efficiency of the cycle is increased. A thermal storage system is likely to add greater reliability to such plants, providing power even during non-peak sunshine hours. This paper presents a conceptual configuration of a solar power tower combined heat and power plant with a topping air Brayton cycle. A simple downstream Rankine cycle with a heat recovery steam generator (HRSG) and a process heater have been considered for integration with the solar Brayton cycle. The conventional GT combustion chamber is replaced with a solar receiver. The combined cycle has been analyzed using energy as well as exergy methods for a range of pressure ratio across the GT block. From the thermodynamic analysis, it is found that such an integrated system would give a maximum total power (2.37 MW) at a much lower pressure ratio (5) with an overall efficiency exceeding 27%. The solar receiver and heliostats are the main components responsible for exergy destruction. However, exergetic performance of the components is found to improve at higher pressure ratio of the GT block.

• 한국해양공학회지
• /
• 제23권1호
• /
• pp.109-113
• /
• 2009

Several tidal current power plants are being planned and constructed in Korea utilizing the strong tidal currents along the west and south coasts. A tidal current reaches 9.7 m on the west coast; there are few potential regions for tidal current power generation. The construction of a dam to store water can prevent the circulation of water, causing a great environmental impact on the coast and estuary. The tidal barrage could produce a large amount of power, but it should be carefully considered. The purpose of developing renewable energies is to minimize the environmental impact and to maximize the utilization of clean energy. To produce a great quantity of power, tidal current farms require the placement of numerous units in the ocean. The power generation is very dependent on the size of the rotor and the incoming flow velocity. Also, the interactions between devices contribute greatly to the production of power. The efficiency of a power farm is estimated to determine the production rate. This paper introduces 3 D interaction problems between rotating rotors, considering the axial, transverse, and diagonal distances between horizontal axis tidal current devices.