• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
• /
• pp.462-465
• /
• 1988

In this paper, it is described that digital back-up control system is developed and applied to the thermal power boiler control system which consists of many kinds of analog electronic cards. Also, by the installation of this system in ulsan power pllant, it was proven to have excellent capabilities of fault detection and digital back-up control.

• 대한전자공학회논문지
• /
• 제27권1호
• /
• pp.10-19
• /
• 1990

A fault tolerant control system, in which a digital back-up controller system is added on the existing analog control system, is developed for enhancing reliability of boiler control system in power plant. The digital back-up controller system(DBCS) has a multi-processor structure with capabilities of fault diagnosis, back-up control, self test, and graphic monitoring. Specifically, switching mechanism composed of expandable modules is designed so that back-up controller takes over any faulty control loops and the number of back-up control loops is determined as that of simultaneous faults. A process simulator that simulates the boiler analog control system is developed for safety test and performance evaluation prior to real plant application. DBCS is installed at the Ulsan thermal power plant, and fault tolerant control performance is assured under the faults that some controller modules are pulled out.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
• /
• pp.129.1-129.1
• /
• 2010

Since the commencement of the fuel cell business in 2007, POSCO POWER has been the major supplier of the MCFC (Molten Carbonate Fuel Cell), which is the most commercialized stationary fuel cell system in the world. With its quite, yet active movement, more than 20MW MCFC systems have been installed and are operating in Korea. While trying to localize the components and set up a firm supply chain in Korea to provide more reliable and cost-competitive products to its customers, POSCO POWER is also devoting itself to developing new MCFC application products. One such product is a back-up power system, in which a back-up algorithm is embedded to the present system so that the product can work as a back-up generator in case of grid failure. The technology to enhance load following capability of a stack module is also being developed with the back-up algorithm. Another example is a building application, the goal being to make the present Sub-MW product suitable for urban area. For this, downsizing and modularization are the main R&D scope. The project for developing ship service fuel cell for APU application will launch soon as well. In the project, a system which can operate in marine environment, and reforming technology for liquid logistic fuel will be developed.

• 한국정보기술학회 영문논문지
• /
• 제9권2호
• /
• pp.75-87
• /
• 2019

This paper presents a fully digital controlled power supply unit for the wireless controlled dimmable LED lighting system. The proposed power supply designed using a fly-back converter, which is directly controlled by a microprocessor. Although the proposed circuit does not sense the AC input current and has not AC input voltage feed-forward, it can achieve a high power factor. The proposed power supply directly regulates the output power for LED loads using the PWM and PFM control of the fly-back converter without additional regulator. For a wireless remote control function, the Zigbee modem is equipped in the proposed power supply. A prototype set-up has been built and tested. Through the experiment with a prototype set-up, the usefulness of the proposed power supply is verified.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 B
• /
• pp.1289-1291
• /
• 2000

The operation of Back-To-Back HVDC system for asynchronous connection is described. It can exchange electric power up to 300 MW between separately operated two rower systems, making the interaction on each system minimum. The analysis is done under three different AC transmission lines interconnected to BTB HVDC.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 1999년도 추계학술대회
• /
• pp.345-354
• /
• 1999

A new type of capacitor named "Super Capacitor" has been developed, in which the properties of electric double layer formed at the interface of activated carbon electrode- liquid organic electrolyte is applied. This capacitor is small In size, light in weight, wide In temperature range(-25~$70^{\circ}C$), large in charge-discharge capability and good in voltage preservation. And this super capacitor is applied as a power back-up for electricity failure in volatile memory devices etc., a power source for a short time and a power source for operating actuators. At present the development of high power back-up types of the capacitor system and improvement of their characteristics are being actively conducted in order to find wider applications.lications.

• 한국전자통신학회논문지
• /
• 제16권2호
• /
• pp.293-300
• /
• 2021

본 연구에서는 SCDF를 사용하여 전력공급의 가치를 산정하고, 부하점별 중요도를 다면적인 평가를 하는 방법을 제시한다. 이의 방법으로 지속정전, 순간정전, 전압 Sag/Swell에 대응할 수 있는 SCDF를 제공하고, 이 SCDF를 사용하여 정전과 관련하여 어느 부하점에 어느 정도의 비용이 발생하는지를 계산하였으며, 이들 비용을 다면평가를 통해 어느 부분이 어느정도 취약한지를 평가하고 어느 부분의 확장이 필요한 지를 수치적으로 설명할 수 있도록 하였다. 본 연구를 우리나라의 실배전계통에 적용하여 평가하고 유용성을 검증하였다.

• 전력전자학회논문지
• /
• 제16권1호
• /
• pp.20-29
• /
• 2011

본 논문에서는 동특성이 느린 용융탄산염 연료전지 (Molten Carbonate Fuel Cell, MCFC) 스택을 사용하여 계통사고 시 추가적인 UPS (Uninterruptible Power Supply) 없이 비상부하 (Critical Load)로 전력 공급이 가능하고, 사고 발생 후에도 정격전력으로 발전 가능한 비상부하 추종형 백업 시스템을 제안한다. 제안된 MCFC 발전 시스템용 비상부하 추종형 백업 시스템은 3상 인버터로 구성된 PCS (Power Conditioning System) 출력단에 3상 PWM 컨버터를 연결한 구조이고, 비상부하 추종이 가능한 추가적인 제어 알고리즘을 가지는 Load Leveler를 제어한다. 제안된 비상부하 추종형 백업 시스템의 회로와 제어 알고리즘의 타당성을 5kW 기반의 컴퓨터 시뮬레이션을 통하여 검증한다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2003년도 학술대회논문집
• /
• pp.305-309
• /
• 2003

In recent large power plants, the excitation system has the static type, which is characterized by the fast response to increase the transient stability. The high capacity excitation systems developed in KEPRI is either a hot back-up, hybrid hot back-up (analog + digital) or triple modular redundant digital type, both well proven by actual tests and applied in commercial operation. The large excitation systems have been developed taking into consideration the parameters of large scale power plants, resulting in high costs and subsequently are supplied at higher prices. When used at small sized power plants, the cost impact is relatively high. As a countermeasure to such a situation, KEPRI has recently developed a reliable, miniature digital excitation system, which is one-board type, convenient and adequate for low-price, small-sized (0.5MW∼200MW) power plants.

• 대한전자공학회논문지
• /
• 제24권1호
• /
• pp.28-34
• /
• 1987

As a means of improving the reliability of a process control system, a FTCS(Fault Tolerant Control System) is designed and applied to the boiler controller of a thermal power plant. The proposed FTCS has capabilities of fault detection and diagnosis as well as back-up control and bumpless switching. A prototype of FTCS is implemented on an IBM PC as an add-on system and it is experimentally verified by using a boiler process simulator together with simplified analog controllers and a switching unit that an one-fold fault is detected in real time and back-up controller takes over the role of the original controller, controlling the faulty loop.