Optimal Algorithms for Voltage Management in Distribution Systems Interconnected with New Dispersed Sources

노대석,국경수,왕용필 대한전기학회 2011 Journal of Electrical Engineering & Technology Vol.6 No.2

The optimal evaluation algorithms for voltage regulation in the case where new dispersed sources are operated in distribution systems are studied. Handling the interconnection issues for proper voltage managements are often difficult and complicated because professional skills and enormous amounts of data during evaluations are needed. Typical evaluation algorithms mainly depend on human ability and quality of data acquired, which inevitably cause the different results for the same issue. Thus, unfair and subjective evaluations are unavoidable. In order to overcome these problems, we propose reasonable and general algorithms based on the standard model system and proper criterion,which offers fair and objective evaluation in any case. The proposed algorithms are divided into two main themes. One is an optimal algorithm for the voltage control of multiple voltage regulators in order to deliver suitable voltage to as many customers as possible, and the other is a proper evaluation algorithm for the voltage management at normal and emergency conditions. Results from a case study show that proposed methods can be a practical tool for the voltage management in distribution systems including dispersed sources.

배전계통기술의 신조류

노대석(盧大錫),김응상(金應相),김재언(金在彦) 대한전기학회 2000 전기의 세계 Vol.49 No.4

ESS용 리튬이온전지의 열폭주 방지용 오프가스 검출 알고리즘에 관한 연구

노대석,황소연,최성문,신 건,최형석 대한전기학회 2022 전기학회논문지 Vol.71 No.12

Recently, large-scaled ESS is rapidly installed in Korea according to the green growth and carbon neutralization policy, however, the related industries have been severely damaged since the first ESS fire accident occurred in August, 2017. Even though diverse measures such as limiting the operation range of SOC and installing additional protection devices in ESS are being performed, fire accidents in ESS are being occurred continuously. And also, as the scale of fire accidents in ESS may be increased due to the thermal runaway and the fire can not be suppressed by using existing fire extinguishing facilities, researches on preventing the thermal runaway in Li-ion battery in advance are being required. Therefore, this paper evaluates the mechanism of off-gas and thermal runaway in Li-ion battery and proposes an off-gas detection algorithm to prevent thermal runaway in advance, and then implements an off-gas detection device, accordingly. From the test results of thermal runaway, installation location of off-gas sensors and malfunction of off-gas detection based on the proposed test device for evaluating the operation characteristics of off-gas detection device, it is confirmed that the off-gas detection device and algorithm can effectively prevent fire accidents in advance by accurately detecting the off-gas and avoiding the malfunction of off-gas detection due to irrelevant gas from surroundings.

전기저장장치용 SPD의 최적운용 평가 알고리즘에 관한 연구

노대석,황승욱,김지명,한병길,최성문 대한전기학회 2022 전기학회논문지 Vol.71 No.6

Recently, ESS(energy storage system) for output stabilization of renewable energy source, peak demand management, frequency control, etc. is actively installed and operated. However, as the fire accidents are continuously occurred in ESS, the korean government has presented the causes of fire accidents and countermeasures for safety enhancement through the public-private joint accident investigation committee, which recommends the installation of electrical protection devices such as SPD(surge protect device) and IMD(insulation monitoring device). However, it is reported that the capacity of SPD (   ) installed and operated in each ESS site is different and improper due to the absence of installation regulations. When the inappropriate capacity of SPD is adapted at DC side in ESS, there are possibilities that the battery may be negatively affected as SPD cannot properly protect the battery from the lightning and switching surges. Therefore, this paper proposes an algorithm to calculate the appropriate capacity of SPD for the stable operation of ESS and performs the modeling of surge test device, which is composed of surge generator, SPD, battery, etc., using PSCAD/EMTDC, in order to evaluate operation characteristics of SPD for the lightning and switching surges. And also this paper implements surge test device which generates 3rd class combination wave for lightning surge and switching surges. From the simulation and test results based on the presented modeling and test device, it is confirmed that the SPD can safely protect the battery from the lightning and switching surges when the proper SPD calculated by the proposed algorithm is installed.

전력저장전지시스템의 평가방법에 관한 연구

노대석 한국기술교육대학교 1999 論文集 Vol.6 No.1

This paper deals with the evaluation methods on role of new energy storage systems in Korea, especially base on the secondary Battery Energy Storage (BES) systems. It is important to perform the evaluation on the role of new energy storage systems in a synthetical and quantitative fashion, because they are very costly. The direct and indirect benefits according to the BES systems's role are classified and analyzed for the case where it is interconnected with the power distribution systems.

전기설비해석 프로그램 개발에 관한 연구

노대석 한국기술교육대학교 산학협동연구센터 2004 교수현장연구학기제 연구결과보고서 Vol.2004 No.1

특집(스마트 그리드의 발전방향) - 신 에너지전원이 연계된 배전계통의 양방향 보호협조 방안에 관한 연구

노대석,No, Dae-Seok 대한전기협회 2009 전기저널 Vol.393 No.-

최근, 국가적인 차원에서 추진되고 있는 풍력발전, 태양광발전 등과 같은 신 에너지전원(분산전원)은 기존의 전원에 비하여 소규모 전원인 관계로 주로 수용가에 가까운 배전계통에 도입되어지고 있으며, 그 특성상 배전계통과 연계하여 운전함으로써 보다 안정된 전력의 확보 및 전력설비의 효율적인 활용, 자원의 효율적인 이용 등의 이점을 얻을 수 있다. 한편, 태양광과 풍력 등의 자연에너지를 이용한 분산전원은 일정한 출력을 내는 기존의 전원보다 기후나 온도, 지형적인 영향을 많이 받는 간헐적인 전원이의로, 이들이 도입된 배전계통은 기존의 단 방향 공급형태의 배전계통과는 달리 부하와 전원이 혼재되어 운용되는 형태로 된다. 분산전원이 연계된 배전계통의 경우에는 분산전원의 출력 용량 여부에 따라 양방향의 전력조류가 발생할 가능성이 있어, 계통운용상 여러 가지 문제점이 야기될 수 있다. 따라서 본 연구에서는 분산전원 연계에 따른 보호협조 기본 방안과 부하절체 운전과 변압기결선에 따른 보호협조 방안 등에 대한 알고리즘을 제시하였다. 또한, 이론적인 계산법(대칭좌표법)에 의하여 실 계통에서의 양방향 보호협조에 관련된 문제점을 분석하고, 해결방안을 제시하였다.

변동부하 공급을 위한 하이브리드 ESS의 연축전지와 리튬이온전지의 최적구성방안에 관한 연구

노대석,최성식,이후동,장병훈,김수열,Rho, Dea-seok,Choi, Seong-sik,Lee, Hu-dong,Chang, Byunh-hoon,Kim, Su-yeol 한국전력공사 2016 KEPCO Journal on electric power and energy Vol.2 No.1

현재 대부분의 도서지역에서는 태양광발전을 효율적으로 운용하기 위하여 대용량 연축전지가 많이 사용되고 있지만, 풍력발전의 도입, 축전지 교체로 인하여 리튬이온전지의 도입이 증가하고 있다. 따라서 본 논문에서는 기존에 많이 보급되어 사용되고 있는 연축전지와 리튬이온전지의 장점을 최대한 활용하기 위하여, 연축전지와 리튬이온전지용 하이브리드 ESS의 최적 운용평가를 할 수 있는 알고리즘을 제시하였다. 상기의 알고리즘을 이용하여 시뮬레이션을 수행한 결과, 각 전지의 도입비용과 운용비용이 최소화 되는 운용조건에서 최적구성비를 산출하였다. 이에 따라 본 논문에서 제안한 하이브리드 ESS의 최적구성 알고리즘에 대한 유용성을 확인하였다. The large scaled lead-acid battery is widely used for efficient operation of the photovoltaic system in many islands. However, lithium-ion battery is now being introduced to mitigate the fluctuation of wind power and to replace lead-acid battery. Therefore, hybrid ESS (Energy Storage system) that combines lithium-ion battery with lead-acid battery is being required because lithium-ion battery is costly in present stage. Under this circumstance, this paper presents the optimal algorithm to create composition rate of hybrid ESS by considering fixed and variable costs in order to maximize advantage of each battery. With minimization of total cost including fixed and variable costs, the optimal composition rate can be calculated based on the various scenarios such as load variation, life cycle and cost trend. From simulation results, it is confirmed that the proposed algorithms are an effective tool to produce a optimal composition rate.

배전계통에 있어서 태양광전원의 수용성 향상을 위한 SVR 및 ESS의 운용방안

노대석,이세연,김지명,한병길,김기영 대한전기학회 2022 전기학회논문지 Vol.71 No.11

According to the 3020 RE policy of korean government, renewable sources including PV and WP systems have been actively installed and operated in distribution systems. However, if large-scale PV systems are interconnected in distribution system, hosting capacity in PV systems may be reduced because they may violate the allowable voltage limits(220±13V) due to reverse power flow of PV systems. Under these circumstances, this paper proposes the operation algorithms of SVR(step voltage regulator) and ESS(energy storage system) to improve the hosting capacity of PV systems. Specifically, optimal LDC setting values are obtained by calculation algorithm of LDC setting values for SVR using the Least-squares method that minimizes the error for the entire time interval based on the distribution characteristics of upper and lower limits for the sending voltage of SVR considering the reverse power flow by PV systems. In addition, the minimum introduction capacity of ESS is obtained by evaluation algorithm of the required capacity of ESS to maintain the customer voltage within the allowable voltage limits for each time interval. From the simulation results, it is confirmed that the proposed algorithms are useful and practical tool to improve the hosting capacity of PV system.

신에너지전원이 연계된 배전계통의 보호협조기기의 운용특성 검토

노대석,서인용 대한전기학회 2011 전기의 세계 Vol.60 No.11