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기상 확률 모델 및 기상 민감도를 이용한 연중 주별 전력수요 예측에 관한 연구
위영민(Young-Min Wi),민용기(Yongki Min) 한국조명·전기설비학회 2016 조명·전기설비학회논문지 Vol.30 No.5
Load forecasting is an essential component for operating and planning power systems. There are various prediction time horizons in accordance with applications. This paper proposes a forecasting model for mid-term load forecasting which is used for planning electricity supply and demand, electrical equipment maintenance schedule, and demand response programs. This paper presents weekly peak load forecasting method using time series and temperature sensitivity model with temperature stochastic modeling. Using Monte-Carlo simulation, the proposed method can also make probability distribution of weekly peak loads. The results of case studies show the effectiveness of the proposed load forecasting method.
The Dielectric Relaxation Characteristics fod (BaCa)tiO_3 Ceramic Dielectrics by ZnO Addition
Min, Yongki,Hong, Kyungjin 광주대학교 산업기술연구소 1996 産業技術硏究 Vol.6 No.-
본 연구에서는 첨가제인 ZnO를 (Ba_0.85 Ca_0.15)TiO_3에 혼합하여 세라믹 유전체의 전기적 특성을 연구하였다. 구조적 특성으로 상대밀도는 모든 시료에서 높은 값을 나타났으며, BCTZ4가 95[%]로 가장 우수하였다. 입자의 평균 크기는 1.0[㎛]∼1.22[㎛]이었으며, 첨가제인 ZnO의 증가와 더불어 증가하였다. 또한 충전 및 방전전류도 첨가제인 ZnO량의 증가에 의해서 증가하였다. 주변 온도 110[℃]이상에서는 공간전하 분극에 의하여 유전율이 증가하였으며, 110[℃]이하에서는 상유전층의 공간전하 분극의 영향으로 유전율의 변화는 일정하였다. 시정수는 입자의 크기가 증가하고 충전전류가 방전전류보다 클 때 가장 큰 값을 나타내었다. In this paper, the (Ba_0.85, Ca_0.15)TiO_3 was mixed by ZnO additive material and the electric characteristics was studied. The structural characteristics has shown high relative density in all specimen. The relative density of BCTZ4, (Ba_0.85 Ca_0.15)TiO_3 was mixed 0.4 mol by ZnO additive material, has a 95[%]. The average grain size was 1.0[㎛]∼1.22[㎛] and it was increased with adding ZnO. The charge and discharge current was increased with ZnO addition. The dielectric factor was increased with the space charge polarization at above 110[℃] and the dielectric factor variation was fixed by the space charge polarization of para-dielectric layer at below 110[℃]. The time constant value was maximum when the grain size was large and the charging current was higher than discharge current.
지중배전용 전력케이블의 열화진단을 위한 특성분석과 파괴수명예측
김창원,민용기,김충배 광주대학교 1998 産業技術硏究 Vol.11 No.-
1973년부터 국내에서 포설되기 시작한 지중전력케이블은 인구증가, 도시화 등에 편승하여 계속적으로 증가하고 있다. 대부분의 지중배전용 전력케이블은 가교폴리애틸렌(XLPE)으로 된 절연층과 전계완화를 목적으로 한 반도전층을 사용하고 있다. 최근의 조사에 의하면, 국내 지중전력 케이블은 포설 후 5, 6년 후에 일어나는 사고가 가장 많고, 포설 후 5, 6년 사이에 파괴가 일어나지 않은 자연열화에 의한 파괴도 예상수명에 훨씬 못미치는 10여년 정도로 보고되고 있다. 지중케이블의 특성을 평가하는 방법에는 기존의 전기적 방법 이외에도 외국의 경우처럼 화학적, 물리적, 미세구조적 분석 방법을 응용한 새로운 진단기술들을 이용하는 것이 바람직하다. 본 연구에서는 케이블의 절연층과 반도전층에 대하여 여러가지 특성분석과 이와 연계하여 전기적 특성시험을 실시하였고, 이로부터 결과를 바탕으로 국내에서 사용되었던 지중배전케이블의 특성을 평가하였다. Crosslinked polyethylene(XLPE) cable has been installed widely because it's predominant properties and heat-resisting qualities superior to polyethylene. A recent investigation has revealed that a large number of XLPE insulated Underground Residential Distribution(URD) power cables fail in 5 to 6 years after installation though the lifetime of URD power cable is expected about 30 years. In this study, proper degradation values were first endowed to the degradation and lifetime factors of serviced URD power cables based upon results from cable characterization. Then, degradaton diagnosis of XLPE insulated URD cables was accomplished through out new method, which was to be analyzed and synthesized by physical, chemical and micro-structural properties. To supplement this method, it was also carried out using several electrical analyses ; dielectric characteristics such as tan δ , dielectric loss, dielectric constant and capacitance, DC leakage current, partial discharge. In addition, breakdown voltages were measured and breakdown lifetimes were predicted appling for Weibull distribution function. As a result, most of failure cables showed bad traits in both non-electrical analysis and electrical analysis. It was expected that adequate degradation point fitted for domestic XLPE insulated URD power cable was about 60 [point]. It was very available to estimate cable degradation using above method, but it needs further study on XLPE insulated URD cables in order to improve reliability.