• Title/Summary/Keyword: 보호기

Search Result 2,112, Processing Time 0.033 seconds

A Study on Operation Method of Protection Device for LVDC Distribution Feeder in Light Rail System (경전철용 LVDC 배전계통의 보호기기 운용 방안에 관한 연구)

  • Kang, Min-Kwan;Choi, Sung Sik;Lee, Hu-Dong;Kim, Gi-Yung;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.4
    • /
    • pp.25-34
    • /
    • 2019
  • Recently, when a fault occurs at a long-distance point in a LVDC (low voltage direct current) distribution feeder in a light rail system, the magnitude of the current can decrease to less than that of the load current of a light rail system. Therefore, proper protection coordination method to distinguish a fault current from a load current is required. To overcome these problems, this paper proposes an optimal algorithm of protection devices for a LVDC distribution feeder in a light rail system. In other words, based on the characteristics of the fault current for ground resistance and fault location, this paper proposes an optimal operation algorithm of a selective relay to properly identify the fault current compared to the load current in a light rail system. In addition, this paper modelled the distribution system including AC/DC converter using a PSCAD/EMTDC S/W and from the simulation results for a real light rail system, the proposed algorithm was found to be a useful and practical tool to correctly identify the fault current and load current.

Safety Computer System, CPCS Design in Nuclear Power Plant (안전등급 컴퓨터, 노심보호계산기계통 설계)

  • Sohn, Se-Do;Young Suh;Kang, Byung-Heon;Shin, Ji-Tae;Chun, Chong-Son
    • Nuclear Engineering and Technology
    • /
    • v.26 no.4
    • /
    • pp.502-506
    • /
    • 1994
  • The design of safety computer system is described along with the case of software design and testing in the Core Protection Calculator System (CPCS). The application of computer system in safety system requires not only hardware qualification but thorough testing on software to verify its correctness and completeness. The testing on software for CPCS is performed by comparing the outputs of two versions of code. One is implemented in assembly language and the other is in Fortran. The testing is performed in sequencial and overlapping manner. Phase I test verifies that each software module is implemented correctly by executing every branch. Phase II test verifies that the integrated software is complete, meeting its requirements specification and also the integrated system meet its requirement and timing constraints. Through these testing, the Yonggwang Nuclear Power Plant Units (YGN) 3 and 4 CPCS software is verified to be correct and complete, and the integrated system is designed as in its requirements specification.

  • PDF

Low-cost AES Implementation for RFID tags (RFID 태그를 위한 초소형 AES 연산기의 구현)

  • Koo, Bon-Seok;Ryu, Gwon-Ho;Yang, Sang-Woon;Chang, Tae-Joo;Lee, Sang-Jin
    • Journal of the Korea Institute of Information Security & Cryptology
    • /
    • v.16 no.5
    • /
    • pp.67-77
    • /
    • 2006
  • Radio Frequency IDentification (RFID) will soon become an important technology in various industries. Therefore, security mechanisms for Rm systems are emerging crucial problems in RFID systems. In order to guarantee privacy and security, it is desirable to encrypt the transferred data with a strong crypto algorithm. In this paper, we present the ultra-light weight Advanced Encryption Standard (AES) processor which is suitable for RFID tags. The AES processor requires only 3,992 logic gates and is capable of both 128-bit encryption and decryption. The processor takes 446 clock cycles for encryption of a 128-bit data and 607 clock cycles for decryption. Therefore, it shows 55% improved result in encryption and 40% in decryption from previous cases.

SAMHYUN (업체탐방 - 삼현CNS(주))

  • Son, Yeong-Seon
    • Electric Engineers Magazine
    • /
    • s.333
    • /
    • pp.48-49
    • /
    • 2010
  • 삼현CNS(주)는 1997년 5월 설립되어 FAN TRAY, 정류기 개발 기술을 기본으로 다양한 기술 집약형 특수용도의 전원공급부에 필요한 안정화 장치와 서지보호기를 공급해 한국전력, 수자원공사, 발전회사, KT 등으로부터 높은 기술력과 제품력을 인정받고 있다.

  • PDF