• Korean Chemical Engineering Research
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• 제58권3호
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• pp.424-429
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• 2020

에너지 시스템의 다양한 수요와 공급 대응 문제를 해결하기 위해 에너지 저장시스템이 새로운 해결책으로 주목 받고 있다. 특히 재생에너지의 공급 비중이 커져가면서 에너지 공급과 수요의 불확실성을 고려하는 것이 에너지 시스템의 운영에 가장 어려운 문제가 되었다. 본 논문에서는 에너지 저장 시스템이 필요한 용량을 산정하는데, 수요와 공급의 불확실성을 몬테 카를로 시뮬레이션 기법으로 반영하고 이에 연관된 이슈들을 다루었다. 본 연구에서 제기된 이슈들은 에너지 시스템이 가지고 있는 불확실성속에서도 향후 에너지 저장 시스템의 안정적 운영에 활용되어 후속 연구들의 기반이 될 수 있을 것이다.

• 전기학회논문지P
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• 제67권2호
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• pp.94-99
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• 2018

Depending on how the energy storage system(ESS) is used in a system that can construct a microgrid by using an independent power source such as campus, surplus power can be generated that can not be charged to the ESS. For example, assuming that heat is supplied by a fuel cell in the case of a system in which thermal self-sustaining is prioritized, the fuel cell capacity required differs depending on the heat load. The amount of surplus power that can not be stored in the ESS will appear differently depending on the load operation of the fuel cell for each cycle. This power is hydrogenated through a water electrolytic device to present the amount of hydrogen energy that can be operated for each cycle. Therefore, this paper propose the possibility of utilizing University campus as a hydrogen station.

• 전기학회논문지
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• 제65권3호
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• pp.404-410
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• 2016

This paper proposed a program of an energy storage system(ESS) for peak shaving of high-speed railway substations The peak shaving saves cost of equipment and demand cost of the substation. To reduce the peak load, it is very important to know when the peak load appears. The past data based load profile forecasting method is easy and applicable to customers which have relatively fixed load profiles. And an optimal scheduling method of the ESS is helpful in reducing the electricity tariff and shaving the peak load efficiently. Based on these techniques, MS. NET based peak shaving program is developed. In case study, a specific daily load profile of the local substation was applied and simulated to verify performance of the proposed program.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1864-1873
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• 2018

Energy shifting is an innovative method used to obtain the highest profit from the operation of energy storage systems (ESS) by controlling the charge and discharge schedules according to the electricity prices in a given period. Therefore, in this study, we propose an optimal charge and discharge scheduling method that performs energy shift operations derived from an ESS efficiency model. The efficiency model reflects the construction of power conversion systems (PCSs) and lithium battery systems (LBSs) according to the rated discharge time of a MWh-scale ESS. The PCS model was based on measurement data from a real system, whereas for the LBS, we used a circuit model that is appropriate for the MWh scale. In addition, this paper presents the application of a genetic algorithm to obtain the optimal charge and discharge schedules. This development represents a novel evolutionary computation method and aims to find an optimal solution that does not modify the total energy volume for the scheduling process. This optimal charge and discharge scheduling method was verified by various case studies, while the model was used to realize a higher profit than that realized using other scheduling methods.

• 전기학회논문지
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• 제66권11호
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• pp.1554-1560
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• 2017

Prepare a lose of 765kV transmission route in power system operation condition, there are some Special Protection Scheme(SPS)s in Korean power system. These SPS can make some preselected generators are tripped to avoid generator overspeed. Because of many of the new large power plants are installed to existing power generation sites due to the siting problem, the number of generator tripped by SPS should be increased. But that can be a cause of system frequency change under the Under Frequency Relay(UFR) 1st pickup level 59.0Hz. Therefore generation constraint should be considered until new transmission lines are installed. In this paper, we propose the ESS application for generation constraint mitigation by frequency damping control of ESS. To analysis an effect of ESS application, we use PSS/E dynamic simulation tool, CBEST model and controller model. The proposed ESS application is applied to the empirical Korean power system.

• 한국태양에너지학회 논문집
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• 제39권5호
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• pp.53-63
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• 2019

This paper in order to efficiently operate zero energy buildings developed a methodology for optimal operation of PV + ESS active systems. This program consists of three steps. First step is PV optimal operation and second step is PV + ESS optimal operation. Third step is the analysis of the results by PV + ESS optimal operation. The optimal operation of PV + ESS was calculated by using Dynamic Programming (DP). Therefore, the optimal capacity and operating plan of PV + ESS in this study are calculated for electric load at building. This paper conducted case study to verify the validity of the developed algorithm. Also, the sensitivity analysis analyzed the effect of each variable on the optimal operation.

• 한국전기전자재료학회논문지
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• 제35권6호
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• pp.568-575
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• 2022

This paper is a study on frequency analysis and electronic noise reduction of energy storage system (ESS). We acquired 4 necessary data for about 2 minutes and 4 seconds using a sampling frequency of 10,000 Hz in ESS. Fast Fourier transform (FFT) was used for electronic noise analysis from the acquired data. As a result, it was confirmed that DC component, fundamental wave, second and higher harmonic component exist. For the attenuation of harmonics, low-pass filter (LPF) was applied. We confirmed that an attenuation of approximately 59.3% appears from the second harmonic. The presence of many harmonic components in the data of the ESS was expected to occur due to the insufficiency of optimization among the modules inside the ESS. Therefore, we propose that a national certification system for ESS should be introduced to settle down the issue properly.

• 전기화학회지
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• 제16권3호
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• pp.111-122
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• 2013

나트륨 유황전지(NAS)는 대용량 에너지 저장시스템(energy storage system, ESS) 중 하나로서, 최근 풍력에너지, 태양에너지, 해양에너지 등 그린재생에너지의 사용증가로 ESS에 대한 수요가 급증함에 따라 NAS 전지에 대한 관심이 고조되고 있다. NAS 전지는 에너지 밀도가 높고(납 축전지밀도의 3배), 사이클 수명이 길고, 자가방전이 없어 대용량 전력저장 시스템에 적합하다. NAS 전지는 양극으로 황(Sulfur), 음극으로 나트륨(Na), 고체전해질 및 분리막으로 ${\beta}$"-알루미나($Al_2O_3$)로 구성되어 있고, 양극 활물질인 황은 부도체이기 때문에 도전재인 탄소섬유(carbon felt)에 함침시켜 양극으로 사용해야 함으로, 양극재 구성 및 특성은 전지성능에 상당한 영향을 미치게 된다. 따라서 본 논문에서는 NAS 전지의 구성, 다황화나트륨($Na_2S_x$, 방전생성물) 및 양극재의 특성, 전지 성능에 미치는 영향인자들에 대해서 알아보고자 한다.

• 한국산학기술학회논문지
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• 제21권9호
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• pp.380-386
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• 2020

소방용 비상발전기는 화재와 같은 비상상황에서 인명과 재산을 보호하는 소방시설에 비상전원을 공급하는 중요한 시설이다. 이러한 중요성에 따라 비상발전기는 주기적인 부하시험으로 성능과 상태를 확인하여야 한다. 비상발전기의 일반적인 부하시험 방법은 R, L, C 부하로 구성된 Load Bank를 이용하여 시험하고 있다. 최근, 비상발전기의 효율적인 부하시험을 위하여, 시험 중에 발생한 전력을 저장하였다가 전기사업자에게 판매하는 ESS 부하시험장치의 도입이 검토되고 있다. 그러나 리튬이온배터리의 높은 가격으로 인하여, ESS 부하시험장치는 기존의 Load Bank 방식보다 초기투자비가 많이 소요될 수 있어, 상용화가 어려운 실정이다. 하지만, 비상발전기의 부하시험 동안 발전된 전력의 판매를 고려하면, ESS 부하시험장치는 경제적인 사업모델이 될 가능성이 있다. 따라서, 본 논문에서는 ESS 부하시험장치의 정확한 경제성을 평가하기 위하여, ESS 부하시험장치에 충전된 전력의 판매를 고려한 비용요소와 편익요소로 구성된 경제성평가 모델링을 제시한다. 또한, 제시한 모델링을 바탕으로 ESS 부하시험장치와 Load Bank에 대한 투자회수율과 회수년도를 비교 및 분석한 결과, 전력판매를 고려할 경우 ESS 부하시험장치의 상용화가 가능함을 확인하였다.

• Journal of Power Electronics
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• 제9권1호
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• pp.51-60
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• 2009

Hybrid Electric Vehicles (HEVs) utilize electric power as well as a mechanical engine for propulsion; therefore the performance of HEV s can be directly influenced by the characteristics of the Energy Storage System (ESS). The ESS for HEVs generally requires high power performance, long cycle life and reliability, as well as cost effectiveness. So the Hybrid Energy Storage System (HESS), which combines different kinds of storage devices, has been considered to fulfill both performance and cost requirements. To improve operating efficiency, cycle life, and cold cranking of the HESS, an advanced dynamic control regime with which pertinent storage devices in the HESS can be selectively operated based on their status was presented. Verification tests were performed to confirm the degree of improvement in energy efficiency. In this paper, an advanced HESS with improved an Battery Management System (BMS), which has optimal switching control function based on the estimated State of Charge (SOC), has been developed and verified.