• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.61-65
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• 2008

Because of the high increasing rate of load demand, these days the necessity of deciding what optimum reserve level is appropriate to most stably supply electricity is being emphasized. This research studies the downward tendency of reverve ratio by analyzing the trend of change of the network scale, reserve, and reserve ratio while optimum reserve has been increased as the network system scale grow up. This means, at this moment 6,000MW is optimum level for short term prospect of power supply and demand. And also, it has been analyzed that, as the annual peak load exceeded 50,000MW, confirming the amount of optimum reserve level is more stable than keeping 10 to 12% reserve ratio.

• 조명전기설비학회논문지
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• 제22권9호
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• pp.55-61
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• 2008

최근 전력수요의 높은 증가율로 인하여 전력계통에 가장 안정적으로 전력을 공급하기 위한 적정예비력을 얼마만큼을 가져야 할 것인가? 하는 필요성이 강조되고 있다. 본 연구에서는 연도별 계통규모와 예비력 및 예비율의 변화 풍향 분석을 통하여 계통규모가 증가할수록 적정 예비력은 증가하고 있는 반면에 예비율은 하락하는 추세를 보이고 있는 것을 분석하였다. 이 자료를 관계로 현재시점에서 단기 전력수급전망에 적용되는 공급예비력으로 산정한 600만[kW]는 적정수준이라 여겨진다. 또한 최대전력수요가 5,000만[kW]를 넘어서면서 적정수준인 $10{\sim}12[%]$ 예비율 보다는 적정수준의 예비력을 산정하여 적용하는 것이 전력계통을 경제적이고 안정적으로 운영할 수 있다고 분석되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.418-419
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• 2006

After electricity power industry restructuring, "Long term power development plan", setting up by government, is replaced by "Basic plan of electricity supply and demand". In this basic plan, one of the most important factors is assessment of appropriate capacity margin. The benefit of GENCO is decided by the market price, and the price is largely affected by the level of reserve margin. As a consequence, appropriate reserve margin is determined by market power. However, Cost Based Pool(CBP) is a limited competitive market, and government policy for supply and demand is very important factor or reserve margin determination. This paper points out issues about existing reserve margin assessment method which is used in basic plan and suggests improved assessment method. In the case study, capacity margin is calculated by proposed assessment method and result shows the advantages of suggested method.

• 전기학회논문지
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• 제62권11호
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• pp.1495-1504
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• 2013

Renewable energy integration and increased system complexities make system operator maintain supply and demand balance harder than before. To keep the grid frequency in a stable range, an appropriate spinning reserve margin should be procured with consideration of ever-changing system situation, such as demand, wind power output and generator failure. This paper propose a novel concept of dynamic reserve, which arrange different spinning reserve margin depending on time. To investigate the effectiveness of the proposed dynamic reserve, we developed a new short-term reliability criterion that estimates the probability of a spinning reserve shortage events, thus indicating grid frequency stability. Uncertainties of demand forecast error, wind generation forecast error and generator failure have been modeled in probabilistic terms, and the proposed spinning reserve has been applied to generation scheduling. This approach has been tested on the modified IEEE 118-bus system with a wind farm. The results show that the required spinning reserve margin changes depending on the system situation of demand, wind generation and generator failure. Moreover the proposed approach could be utilized even in case of system configuration change, such as wind generation extension.

• 전기학회논문지
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• 제59권1호
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• pp.26-32
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• 2010

This paper proposes a new effective installed reserve rate in order to evaluate reliability of power system considering renewable generators, which include uncertainty of resource supply. It is called EIRR(effective installed reserve rate) in this paper. It is developed with considering capacity credit based on ELCC by using LOLE reliability criterion. While the conventional installed reserve rate index yields over-evaluation reliability of renewable generators, the proposed EIRR describes actual effective installed reserve rate. However, it is not the probabilistic reliability index as like as LOLE or EENS but another deterministic effective reliability index. The proposed EIRR is able to evaluate the realistic contribution to the reliability level for power system considering wind turbine generators and solar cell generators with high uncertainty in resource supply. The case study in model system as like as Jeju power system size presents a possibility that the proposed EIRR can be used practically as a new deterministic reliability index for generation expansion planning or operational planning in future.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.511-517
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• 2015

Determination of the required reserve capacity has an important function in operation of power system and it is calculated based on the largest loss of supply. However, conventional method cannot be applied in future power system, because potential grid-connected distributed generator and abnormal temperature cause the large load imbalance. Therefore this paper address new framework for determining the optimal required reserve capacity taking into account the real time load imbalance. At first, we introduce the way of operating reserve resources which are the secondary, tertiary, Direct Load Control (DLC) and Load shedding reserves to make up the load imbalance. Then, the formulated problem can be solved by the Probabilistic Dynamic Programming (PDP) method. In case study, we divide two cases for comparing the cost function between the conventional method and the proposed method.

• 자원ㆍ환경경제연구
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• 제33권2호
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• pp.113-133
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• 2024

태양광과 풍력을 중심으로 한 변동성 재생발전(VRE)은 탄소중립 달성의 주요수단이지만 높은 변동성과 불확실성으로 인해 전력공급의 안정성을 훼손시킨다. 에너지저장장치(ESS)는 수요이전을 통해 재생발전의 출력제한을 경감시킬 뿐만아니라 보조서비스 제공을 통해 안정적인 전력시스템 운영에 기여할 수 있다. 본 연구는 VRE로 인한 문제점이 점점 본격화되는 상황에서 ESS자원을 수요이전 기능과 예비력 제공기능 간에 어떻게 분배하는 것이 전력공급 효율성 최대화에 기여할 수 있는지 분석한다. 분석모형으로 재생발전의 변동성과 불확실성을 현실적으로 모의할 수 있는 확률적 전력시스템 최적화 모형을 적용하였다. 분석시점은 2023년과 2036년으로 설정하여 재생발전 보급수준별 ESS 최적자원분배 전략과 편익을 분석하였다. 분석결과는 크게 다음의 3가지로 요약가능하다. 첫째, ESS는 수요이전과 예비력 제공 모두에 탁월한 기능을 제공하며, 예비력 가격이 높게 설정될수록 수요이전 기능은 제한하고 예비력 제공에 집중함을 확인할 수 있었다. 둘째, 재생발전 출력제한은 필요예비력에 대한 대체재 역할을 하며, 예비력 가격 수준이 높아질수록 출력제한은 증가하고 필요예비력은 감소하는 것이 비용 합리적이다. 셋째, 기회비용이 반영된 합리적인 예비력 가격이 적용될 경우 ESS는 가까운 미래에 경제성을 확보할 수 있으며, ESS의 경제성은 재생발전 비중이 높을수록 더 커짐을 확인할 수 있었다. 본 연구는 전력공급 자원이 효율적으로 분배될 수 있는 가격기능이 바로 설때 비용 효율적인 전력부문 저탄소 전환이 가능함을 시사한다.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.181-190
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• 2021

This paper empirically examines the asymmetric response of the Indonesian Islamic stock market to macroeconomic variables encompassing money supply, domestic output, exchange rate, and Federal Reserve rate. Our study employs the Jakarta Islamic Index (JII) after the financial crisis in the Southeast Asian country using monthly data from January 2000 to December 2019. Non-linear Autoregressive Distributed lag (NARDL) is applied. Our study considers two models consisting of the model without the Federal Reserve rate and the model with it. Our findings confirm the long-run link between Jakarta Islamic Index and macroeconomic factors being studied. Furthermore, the Jakarta Islamic Index asymmetrically responds to broad money supply and exchange rate, but not to domestic output and Federal Reserve rate. A reduction in the money supply has a worse effect on Islamic stock prices as compared to an increase in the money supply. The Jakarta Islamic Index responds differently to depreciation and appreciation. The transmission of the exchange rate to Islamic stock prices occurs only for appreciation. Our study finds an absence of transmission mechanism from the domestic output and the interest rate to Islamic stock prices. Our results imply that the easy money policy and stabilizing currency are key to supporting Indonesian Islamic stock prices.

• Clinical and Experimental Reproductive Medicine
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• 제46권1호
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• pp.30-35
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• 2019

Objective: Bilateral uterine artery ligation (UAL) is a fertility-preserving procedure used in women experiencing postpartum hemorrhage (PPH). However, the long-term effects of this procedure on ovarian function remain unclear. The aim of this study was to investigate whether bilateral UAL compromised ovarian reserve and ovarian blood supply. Methods: This prospective study included 49 women aged between 21 and 36 years who had undergone a cesarean section for obstetric indications. Of these, 25 underwent uterine bilateral UAL to control intractable atonic PPH. The control group consisted of 24 women who had not undergone bilateral UAL. Standard clinical parameters, the results of color Doppler screening, and ovarian reserve markers were assessed in all participants at 6 months after surgery. The clinical parameters included age, parity, cycle history, body mass index, and previous medication and/or surgery. Color Doppler screening findings included the pulsatility index (PI) and resistance index (RI) for both the uterine and ovarian arteries. The ovarian reserve markers included day 3 follicle-stimulating hormone (FSH) levels, antral follicle count, and $anti-M\ddot{u}llerian$ hormone (AMH) levels. Results: There were no significant differences in the ovarian reserve markers of day 3 FSH levels, antral follicle count, and AMH levels between the study and control groups (p> 0.05 for all). In addition, no significant differences were observed in the PI and RI indices of the uterine and ovarian arteries (p> 0.05 for all). Conclusion: In this study, we showed that bilateral UAL had no negative effects on ovarian reserve or ovarian blood supply, so this treatment should be used as a fertility preservation technique to avoid hysterectomy in patients experiencing PPH.

• 전기학회논문지
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• 제67권11호
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• pp.1415-1422
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• 2018

In Korea, prior to 2011, the electric reserve margin followed the probabilistic reliability view and the planning reserve margin had been operated at about 15% based on the assumption that power outage was permitted within 0.5 days a year. However, after experiencing the shortage of the electric generation capacity in Sept. 15, 2011, the planning reserve margin was selected as 22% to improve the reliability of the electric supply. In this paper, using panel data of 28 OECD countries over the period 2000-2014 we attempted to empirically examine the linkage between reserve margin, electricity tariffs, renewable energy share, GDP per capita, and summer / winter peak-to-peak ratios. As a result, all four independent variables have been significant for the electric reserve margin, and in particular, we found that countries with similar peaks in winter and summer have operated 4.3% higher reserve margin than countries experiencing only summer peak.