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RISS 인기검색어
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- 저자 : 신은석(Eun-Suk Sin) (검색결과 4 건)
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역상분 전류 주입을 적용한 3상 인버터 기반 BESS의 단독 운전 검출 방법
신은석(Eun-Suk Sin),김현준(Hyun-Jun Kim),한병문(Byung-Moon Han) 대한전기학회 2015 전기학회논문지 Vol.64 No.9
This paper proposes an active islanding detection method for the BESS (Battery Energy Storage System) with 3-phase inverter which is connected to the AC grid. The proposed method adopts the DDSRF (Decoupled Double Synchronous Reference Frame) PLL (Phase Locked-Loop) so that the independent control of positive-sequence and negative-sequence current is successfully carried out using the detected phase angle information. The islanding state can be detected by sensing the variation of negative-sequence voltage at the PCC (Point of Common Connection) due to the injection of 2-3% negative-sequence current from the BESS. The proposed method provides a secure and rapid detection under the variation of negative-sequence voltage due to the sag and swell. The feasibility of proposed method was verified by computer simulations with PSCAD/EMTDC and experimental analyses with 5kW hardware prototype for the benchmark circuit of islanding detection suggested by IEEE 1547 and UL1741. The proposed method would be applicable for the secure detection of islanding state in the grid-tied Microgrid.
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BESS의 병렬운전 시 발생되는 순환 전류 저감을 위한 드룹 제어 기법
신은석(Eun-Suk Sin),김현준(Hyun-Jun Kim),양원모(Won-Mo Yang),한병문(Byung-Moon Han) 대한전기학회 2015 전기학회논문지 Vol.64 No.5
This paper proposes a new reduction scheme of circulating current when two units of BESS (Battery Energy Storage System) are operated in parallel with conventional droop control. In case of using conventional droop, the terminal voltage of each BESS are not equal due to the unequal line impedance, which causes the circulating current. The operation performance of BESS is critically dependant on the circulating current because it increases system losses which causes the increasement of required system rating. This paper introduces a new reduction scheme of circulating current in which the terminal voltage difference of each BESS is compensated by adding feed-forward path of line voltage drop to the droop control. The feasibility of proposed scheme was first verified by computer simulations with PSCAD/EMTDC software. After then a hardware prototype with 5kW rating was built in the lab and many experiments were carried out. The experimental results were compared with the simulation results to confirm the feasibility of proposed scheme. Two parallel operating BESS with proposed scheme shows more accurate performance to suppress the circulating current than those with the conventional droop control.
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2 - Bromopropane 에 노출된 여성에서 집단적으로 발생한 원발성 난소 기능 부전증
김철희,김기수,김효정,김영탁,고정민,신은석,조경식,윤길숙 대한내분비학회 1997 Endocrinology and metabolism Vol.12 No.2
Background: Primary ovarian failure is reportedly increasing in recent years. Environmental factors have been frequently implicated as responsible for this increase, However, only a few of the environmental factors have been proven to cause the ovarian failure in human. Methods: In June 1995, 24 female laborers, who worked in a factory which used Solvent #5200(with a main chemical component being 2-bromopropane), developed symptoms of amenorrhea or irregular menstruation. All subjects underwent laboratory tests including measure- ment of serum LH, FSH, and estradioL Magnetic resonance imaging and ultrasonography of the pelvis were performed in all subjects. Laparoscopic examination was performed in 6 out of 24 patients after obtaining informed consent and 4 of 6 underwent ovarian biopsy. Results: One subject was excluded because she had undergone hysterectomy previously. Among the remaining 23 subjects, 14 and 9 complained of amenorrhea and irregular menstrual periods, respectively. When we defined primary ovarian failure as FSH$gt;30mIU/mL, all of those 14 patients with amenorrhea could be classified as primary ovarian failure. On the other hand, those 9 patients with irregular menstruations had normal FSH levels. Pathologic examination of ovaries showed interstitial fibrosis, loss of primordial follicles, and development arrest of follicles in the group with amenorrhea, similar to what is found in those who received chemotherapy or were exposed to radiation. Conclusion: The female laborers who were exposed to the solvent with 2-bromopropane developed primary ovarian failure. This failure was associated with longer duration of exposure. To our knowledge, this is the first report in the world indicating 2-bromopropane as a possible agent for ovarian failure. (J Kor Soc Endocrinol 12:255-264, 1997)
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