• 조명전기설비학회논문지
• /
• 제29권2호
• /
• pp.47-53
• /
• 2015

The study concerning about the grid connection of the large-capacity energy storage system(ESS) is increasing. However, the transient study such as lightning or switching surge necessarily occurred at power system with ESS has been hardly performed. Therefore, this paper performs the analysis of lightning surge in distribution system with ESS using electromagnetic transient program(EMTP). The battery model in Matlab/Simulink is modeled by EMTP, which is the specialized software for power system transient study. Also, the bi-directional power electronics for interconnection of the battery and distribution system are modeled by EMTP. When the lightning is occurred at interconnection point of ESS, this paper simulates the existence of ESS and operation conditions of ESS and analyzes the surge in distribution system and ESS according to the various conditions.

• 디지털산업정보학회논문지
• /
• 제15권2호
• /
• pp.11-17
• /
• 2019

As interest in the efficiency use of energy has been recently rising, studies have been performed in utilizing various types of eco-friendly green energy and natural energy. Especially there has been rapidly increase in the fields using ESS (Energy Storage System), which is the technology for storing the energy from nature. The application fields of ESS is continuously growing and expanding to various types of technologies. However, in recent years there have been continuing problems with the safety of ESS. And related researches are going on. In this paper, we has proposed a system structure to utilize more secure ESS and has monitored the system status of ESS in real time by using smart phone app. This paper has also proposed a new method to configure secure ESS by implementing GUI (Graphical User Interface) to control the system. And then explain experimental results to investigate the efficiency of the proposed ESS.

• Journal of Advanced Marine Engineering and Technology
• /
• 제31권5호
• /
• pp.592-598
• /
• 2007

The fuel charge is getting higher in navigation cost. Therefore, shipowners try to find the method for reducing oil consumption. ESS(Energy Saving System) is one of he method. ESS is the system consisted with two inverters, ESS control unit and monitoring system. Two inverters control two main sea water cooling pumps. In the ESS control Unit, the control algorithm finds optimized point to decrease a power consumption of main sea water cooling pumps. Monitoring system observes ESS not to work improperly. ESS is experimented in the laboratory with real condition and analyzed in every view. After experiment, the result of the experiment shows that the control algorithm works correctly and safely. ESS has a plan to be operated in the ship soon. In that case, additional devices are needed to connect ESS with cooling system of the vessel. So the development of addition device is needed and being studied.

• KEPCO Journal on Electric Power and Energy
• /
• 제2권2호
• /
• pp.227-232
• /
• 2016

To test the effectiveness of using an energy storage system for frequency regulation, the Energy New Business Laboratory at KEPCO Research Institute installed a 4 MW energy storage system (ESS) demonstration facility at the Jocheon Substation on Jeju Island. And after the successful completion of demonstration operations, a total of 52 MW ESS for frequency regulation was installed in Seo-Anseong (28 MW, governor-free control) and in Shin-Yongin (24 MW, automatic generation control). The control system used in these two sites was based on the control system developed for the 4 MW ESS demonstration facility. KEPCO recently finished the construction of 184 MW ESS for frequency regulation in 8 locations, (e.g. Shin-Gimjae substation, Shin-Gaeryong substation, etc.) and they are currently being tested for automatic operation. KEPCO plans to construct additional ESS facilities (up to a total of about 500 MW for frequency regulation by 2017), thus, various operational tests would first have to be conducted. The high-speed characteristic of ESS can negatively impact the power system in case the 500 MW ESS is not properly operated. At this stage we need to verify how effectively the 500 MW ESS can regulate frequency. In this paper, the effect of using ESS for frequency regulation on the power system of Korea was studied. Simulations were conducted to determine the effect of using a 524 MW ESS for frequency regulation. Models of the power grid and the ESS were developed to verify the performance of the operation system and its control system. When a high capacity power plant is tripped, a 24 MW ESS supplies power automatically and 4 units of 125MW ESS supply power manually. This study only focuses on transient state analysis. It was verified that 500 MW ESS can regulate system frequency faster and more effectively than conventional power plants. Also, it was verified that time-delayed high speed operations of multiple ESS facilities do not negatively impact power system operations. It is recommended that further testing be conducted for a fleet of multiple ESSs with different capacities distributed over multiple substations (e.g. 16, 24, 28, and 48 MW ESS distributed across 20 substations) because each ESS measures frequency individually. The operation of one ESS facility will differ from the other ESSs within the fleet, and may negatively impact the performance of the others. The following are also recommended: (a) studies wherein all ESSs should be operated in automatic mode; (b) studies on the improvement of individual ESS control; and (c) studies on the reapportionment of all ESS energies within the fleet.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제18권3호
• /
• pp.229-239
• /
• 2018

Purpose: There is a difficulty in Environmental Stress Screening (ESS) test design for weapon system's electrical/electronic components/products in small and medium-sized enterprises. To overcome this difficulty, I propose an easy ESS test design approach algorithm that is optimized with only one environment tolerance design information parameter (${\Delta}T$). Methods: To propose the mass production weapon system ESS test design for cost-effective optimization, I define an optimum cost-effective mathematical model ESS test algorithm model based on modified MIL-HDBK-344, MIL-HDBK-2164 and DTIC Technical Report 2477. Results: I clearly confirmed and obtained the quantitative data of ESS effectiveness and cost optimization along our ESS test design algorithm through the practical case. I will expect that proposed ESS test method is used for ESS process improvement activity and cost cutting of mass production weapon system manufacturing cost in small and medium-sized enterprises. Conclusion: In order to compare the effectiveness of the proposed algorithm, I compared the effectiveness of the existing ESS test and the proposed algorithm ESS test based on the existing weapon system circuit card assembly for signal processing. As a result of the comparison, it was confirmed that the test time was reduced from 573.0 minutes to 517.2minutes (9.74% less than existing test time).

• 전력전자학회논문지
• /
• 제23권2호
• /
• pp.101-105
• /
• 2018

Shortage of electric power occurs frequently along with increased electric power demand. ESS is a precaution to solve this issue. Household ESS has a capacity of approximately 3 kW/7 kWh. Household ESS batteries are typically designed with nominal voltages between 40 and 50 V. To connect household ESS with a 220 V AC system, low battery voltages in power conditioning system (PCS) should be boosted. To boost low battery voltage and match it with AC grid voltage, the use of a transformer for a commercial frequency can be considered. To attenuate switching harmonics of the household single-phase ESS-PCS, LC filter can be installed in two positions: on the primary side or on the secondary side of a transformer. A method has been used generally in single-phase inverters for the ESS-PCS. In another method, however, the output efficiency of the ESS-PCS may be decreased. Parasitic components of the transformer can affect voltage losses, when the square wave with the switching frequency in the ESS-PCS is passed through the transformer windings. In this work, the characteristics of the transformer according to the position of an LC filter are investigated for household single-phase ESS-PCS.

• 전기학회논문지P
• /
• 제67권1호
• /
• pp.37-41
• /
• 2018

In this paper, the ESS(Energy Storage System) is interconnected in order to reduce the maximum load in the distribution system and the target location of the ESS is set to be close to the rated voltage. We also applied the weights to nodes with large capacity and number of customers in the system. In the future, the interconnected location of the ESS was determined until 2029 in consideration of the load increase rated of the system. We propose a cooperative decision algorithm of interconnected location of ESS for Power Distribution System.

• 한국전자통신학회논문지
• /
• 제13권1호
• /
• pp.29-34
• /
• 2018

ESS가 연계된 시스템은 24시간 충 방전 스케줄링을 수행되어야 하므로 시스템이 중단되지 않고 운영, 관리되어야 하며, 전력 IT설비의 고장 발생이나 통신장애가 발생된 경우라도 ESS시스템의 스케줄링이 정상적으로 이루어져야 한다. 따라서, 다양한 장애가 발생하더라도 이를 능동적으로 대처하여 고정밀의 전력데이터를 수집, 관리하고 ESS 시스템을 제어하는 시스템이 요구되고 있다. 본 논문에서는 태양광 발전설비와 연계된 ESS 시스템을 대상으로 통신 장애 발생을 대처하는 통신 이중화된 전원관리유닛과 마이크로그리드 사이트 관리, 유지보수 및 모니터링을 수행할 수 있는 통합 관리 시스템을 제안한다.

• 전기전자학회논문지
• /
• 제23권3호
• /
• pp.1027-1032
• /
• 2019

본 논문에서는 PV-ESS 연계형 시스템의 운용방법에 대한 알고리즘의 개발로 수용가의 경제성 측면에서 PV-ESS 시스템 운용 시 발생할 수 있는 모든 경제적 변수의 변화에 대처할 수 있는 강인한 알고리즘을 구현하였다. 이를 토대로 수용가의 전기요금을 최소화 할 수 있는 PV-ESS의 최적 운용 스케줄을 결정하였다. 즉, PV-ESS 시스템의 운용에 영향을 주는 외생 변수가 바뀌어도 항상 안정적으로 최적의 PV-ESS 운용 스케줄을 결정할 수 있으며 이를 위하여 케이스 생성 기반 3차원 동적 계획법을 개발하였다.

• 에너지공학
• /
• 제23권4호
• /
• pp.106-111
• /
• 2014

매년 증가하는 전력수요에 대한 해결방안으로 미국, 일본 및 유럽에서는 스마트그리드 도입 등의 방법으로 전력계통의 전반적인 변화를 도모하고 있다. 이 중 전력저장장치 ESS는 전력의 효율적 사용을 도모하고, 신재생에너지시스템의 계통연계를 위한 대안으로 이에 대한 연구가 활발히 진행 중에 있다. 우리나라 정부도 ESS 보급 활성화 방안으로 ESS를 신재생에너지 부대설비로 포함토록 법개정을 완료하였다. 본 연구에서는 정부의 ESS 보급을 활성화 시키고자 하는 정책에 발맞춰 신재생 발전사업자가 ESS 도입 시 투자경제성을 보장할 수 있는 수준의 REC 가중치를 결정하는 방법론을 제시하였다.