Analysis of Insulation Diagnosis for Generator‑Motor Stator Winding in Pumped Storage Power Plant

Soo‑Hoh Lee,Tae‑Sik Kong,Hee‑Dong Kim 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

In this study, insulation diagnostic tests were conducted on pumped storage power plant (PSPP) generator-motor stator bars with artifcially simulated defects in order to improve solutions to perform preventive maintenance and track insulation diagnostic data for generator-motors by proving the efectiveness of insulation indices. Moreover, ozone (O3) concentration was estimated in order to relate it to partial discharge (PD) in laboratory to ensure the efectiveness of ozone as another index for insulation deterioration. By performing an ofine PD test and ultraviolet (UV) observation on one of the generator-motors during overhaul, and an ozone concentration measurement for the identical machine after the overhaul, it was concluded that ozone estimation could be a powerful index for insulation diagnosis under actual operational conditions. It was further developed that ozone measurement is useful to detect not only discharges in slots as mentioned in some studies but also discharges at the end-winding as proven in this study. The fndings of this study are expected to contribute to more reliable maintenance of generator-motors in PSPPs by achieving elaborate insulation diagnosis via multiple diagnostic indices.

네모나프라이드의 유효성 및 추체외로 부작용 : Haloperidol 및 Risperidone과의 자연관찰적 개방형 비교연구 A Naturalistic Open Comparative Study with Haloperidol and Risperidone

서영수,김용관,신동환,공보금,이정구,박정환,윤성환,정치영,이상경,김영훈 대한생물치료정신의학회 2001 생물치료정신의학 Vol.7 No.2

Objectives : This open prospective study was performed in order to evaluate the efficacy and extrapyramidal adverse effects of nemonapride in the schizophrenic patients, and was compared wit one of typical antipshchotics. haloperidol and one of atypical antipsychotics, risperidone. Methods : Thirty male and female schizophrenic patients(DSM-Ⅳ) were treated for 12 weeks with haloperidol(n=10), risperidone(n=10) and nemonapride(n=10). The overall efficacy was assessed at baseline, 1st week, 2nd week, 4th week, 8th week, and 12th week by the Positive and Negative Syndrome Scale for Schizophrenia(PANSS). Also the overall safety was assessed in the same time period by the Extrapyramidal Symptom Rating Scale(ESRS). Results : There were no significant differences in PANSS scores(total, positive, negative, and general psycho­pathology subscale) among haloperidol, risperidone, and nemonapride groups, Treatment responders, defined as at least 20% reduction of baseline total PANSS score, were achieved by 8 patients(80%) in haloperidol group, 10 patients(100%) in risperidone group, and 8 patients(80%) in nemonapride group. And there were no significant differences in ESRS total scores among haloperidol, risperidone, and nemonapride group. Inter-group comparison among haloperidol, risperidone and nemonapride group, as assessed by the ESRS, revealed no significant differences in the shifts to the maximum score, 9.4(±9.4), 6.2(±8.4), and 11.3(±8.1) respectively, and also revealed no significant differences in the mean time reaching the maximum score, 4.5(±4.5) week, 7.8(±4.8) week, and 4.6(±4.4) week, respectivily. Conclusion : There wee no significant differences in the efficacy and extrapyramidal adverse effects among haloperidal, rispecridone and nemonapride groups. These results suggest that nemonapride was as efficacious and safe in he treatment of schizophrenia, as well known and widely used antipsychotics, haloperidol and risperidone.

관개수원에 따른 논에서의 영양물질 배출 특성

황하선,공동수,신동석,전지홍 한국물환경학회 2004 한국물환경학회지 Vol.20 No.6

Field experimental study was performed to examine characteristics of nutrient export from paddy rice fields with irrigation practices. Experimental fields with surface-water and ground-water irrigation were monitored and analyzed during rice culture period. The water balance showed that outflow generally balanced the inflow showing that about half (58∼68%) of total outflow was lost by surface drainage. Water and nutrient export are more in surface-water irrigation paddy than in ground-water irrigation paddy. The reasons might be more irrigation water available and easy to use in surface-water irrigation. If irrigation water reduced, it could result in reduction of nutrient export in paddy rice fields, which can save water and protect water quality. However, deviation from conventional standard practices might affect the rice yield and further investigations are necessary.

골다공증을 동반한 척추제 압박골절을 가진 노령환자에서 경피적 척추제 성형술 후 생활이 질 향상

박재우,공민호,이상구,송관영,강동수 The Korean Neurosurgical Society 2003 Journal of Korean neurosurgical society Vol.34 No.6

얕은 부영양 저수지의 동·식물플랑크톤 군집변화 특성

김호섭,공동수,황순진 한국육수학회 2005 생태와 환경 Vol.38 No.1

본 연구는 수심이 얕은 부영양 저수지에서 동·식물플랑크톤 천이양상을 이해하기 위해 2002년 11월부터 2004년 2월까지 수행하였다. 봄철 규조류와 녹조류가 우점한 시기를 제외하고는 연중 남조류가 우점하였다. 남조류 군집 내 종 조성의 변화는 6월과 12월에 나타났으며, 식물플랑크톤 밀도 증가는 유입부하량이 많았던 7월과 11월에 관찰되었다. 남조류는 5월에 Oscillatoria spp.와 Aphanizomenon sp.의 우점 이후 Oscillatoria spp.가 우점하였으며, 12월 이후에는 Oscillatoria spp.와 Aphanizomenon sp.의 밀도가 증가하였다. 남조류 군집 중 Microcystis spp.가 우점한 6월부터 12월가지 수체 내 TN/TP비는 13~46의 범위 (평균 27±5)였다. 동물플랑크톤 군집 중 Keratella cochlearis, Keratella valga, Polyarthra spp., Conochilus unicornis, Pompholyx complanata와 같을 윤충류의 점유율이 평균 67.8%로 높았다. 동물플랑크톤의 최대 밀도는 Pompholyx cornplanata (12,388 ind L^(-1))가 우점한 6월에 관찰되었다. 최대 생물량은 Conochilus unicornis (1,0484±28 ㎍C L^(-1))가 우점한 5월에 관찰되었고 투명도가 현저히 증가하였다(Z_(eu)/Z_m =1.1). 본 연구 결과는 수심이 얕은 부영양 저수지에서 식물플랑크톤 군집 변화가 수온, 광도 그리고 영양염 농도치 복합적인 영향으로 이해될 필요가 있고, 윤충류가 식물플랑크톤의 생물차질 조절자로서 중요한 역할을 수행할 수 있음을 제시한다. This study was conducted to understand seasonal dynamics of phyto- and zoo-plankton co㎜unities in a shallow eutrophic reservoir (Shingu reservoir) from November 2002 to February 2004. Cyanophyceae dominated throughout the year, except for spring (March~May) when Bacillariophyceae (Melosira varians) and Chlorophyceae (Dictyosphaerium puchellum) were dominant. The change of dominant species in Cyanophytes occurred in June and December 2003, and the increase of phytoplankton cell density in July and November was observed when the P loading through two inflows was high. In May, Oscillatoria spp. and Aphanizomenon sp. were dominant, but replaced by Microcystis spp. in the end of May. Dominant Microcystis spp. sustained until December and shifted to Oscillatoria spp. and Aphanizomenon sp. TN/TP ratio ranged from 13 to 46 (Avg. 27 ± 6) from June to December when cyanobacteria (Microcystis spp.) dominated. Rotifers such as Keratella cochlearis, Keratella valga, Polyarthra spp., Conochilus unicornis, Pompholyx complanata dominated in average 67.8% of the zooplankton community. Abundance of zooplankton was the highest in June 2003, when Pompholyx cornplanata (12,388 ind L^(-1)) was dominant. In May, the significant increase of Conochilus unicornis biomass (1,048± 28 ㎍ C L^(-1)) was observed with distinct improvement of transparency (Z_(e)/Z_m = 1.1). These results suggest that the seasonal variation of phytoplankton co㎜unities in this reservoir are to be understood as results of multi-interactive factors such as temperature, light condition and nutrients, and small- sized rotifers as important predator.

수질환경척도

박재홍,최의소,공동수 한국물환경학회 2005 한국물환경학회지 Vol.21 No.2

Understanding the condition of our nation's water resources, identifying what caused problems, and determining how to solve these problems are essential but difficult undertakings. The natural water cycle is itself intricate, and the addition of human activities increased this complexity. Consequently, answering the basic question "How clean and safe is our water?" is not easy. One way to present the condition of our water resources and the impacts of related human activities is to develop understandable measures, or indicators, that singly or in combination provide information on water quality. Managers and scientists can then use this information to develop effective solutions and make sound decisions to protect our water resources. It is important to note that environmental indicators can be used to measure a variety of phenomena. Indicators can present information on status or trends in the state of the environment, can measure pressures or stressors that degrade environmental quality, and can evaluate society's responses aimed at improving environmental conditions.

인축적 미생물의 인방출과 세포내 저장물질 합성관계

신응배,김미경,홍준혁,공동수 한국물환경학회 2004 한국물환경학회지 Vol.20 No.6

Biological phosphorus removal is characterized by complex interactions between different intracellular components of energy as PHA. Therefore, fundamental understanding of the behavior of the intracellular components and their influence on the removal of phosphorus is essential before control strategies to stabilize the proper process. The purpose of this study is to investigate relationship between release of phosphorus and synthesis of intracellular storage polymer. Mass of stored intracellular storage polymer was 21.2 ㎎ PHA/L, 28.8 ㎎ PHA / g MLSS. And phosphorus release/ intracellular storage polymer synthesis rate was 1.8545 ㎎ stored polymer/㎎ Phosphate. In the aerobic phase, mass of PAOs synthesis is 49.37 ㎎ PAOs/L. And PAOs fraction was 6.7-6.9%. Thus intracellular storage polymer synthesis by PAOs is calculated as 493㎎ PHA / g PAOs.

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

Limnological and Ecological Characteristics of a River - Reservoir ( Paldang ) , Korea

Dong Soo Kong 한국하천호수학회 1997 생태와 환경 Vol.30 No.5

N/A The Paldang Reservoir has the mean depth of 6.55 m, the surface area of 38.2 km^2, and the average hydraulic residence time of 6.5 days ·yr^-1. After the dam was constructed in 1973, biotic communities and abiotic conditions have been rapidly changed. Particularly, diatoms and cyanobacteria blooms have decreased the transparency of water and have caused several problems in drinking water purification plants. External phosphorus load is 28.69 gP·m^-2·yr^-1, the efflux from the reservoir is 24.69 gP ·m^-2·yr^-l, and the net settling flux is 4.01gP ·m^-2. yr^-1. Algal growth in the reservoir appears to depend on the hydraulic residence time (HRT) rather than nutrient concentration, because the water body is disturbed physically during the rainy season, while the trophic state is eutrophic during the whole year. A broad littoral zone has been developed after the construction of the Paldang dam, which caused an increase of benthic fauna, the bivalves in particular. Ecological solar energy intake efficiency (ESEIE) of phytoplankton including aquatic macrophytes is 0.40% and ESEIE of benthic macroinvertebrates is 0.10%. However, zooplankters are not so abundant, but composed mostly of small-bodied species (Bosmina, Keratella). It may be related to the rapid increase of an introduced alien planktivorous flesh (bluegill).

와이블 분포함수를 이용한 저서성 대형무척추동물의 종수-조사면적 관계 해석

공동수 ( Dong Soo Kong ),김아름 ( Ah Reum Kim ) 한국물환경학회 2015 한국물환경학회지 Vol.31 No.2

The relationship between the number of benthic macroinvertebrate species and the accumulated survey area were investigated in a clean stream and an impaired stream of Korea. Five models to characterize species-area functions were compared, and the Weibull model fitted species-area data well. The other models (Arrhenius, Romell-Gleason, Kylin, Lognormal model) had small or notable bias. The maximum number of species and half-saturation area derived from the Weibull model may be used as the indicators of the carrying capacity and the habitat complexity respectively.