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H. Song
Department of Electrical and Information Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul 01811, Korea

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Journal article
Published: 29 June 2021 in Energies
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Maintaining transient stability is crucial in power system operation. Transient stability is mainly affected by the generation amount of the study region, as well as the transmission topology. Several countermeasures can be taken for transient stability, but the usually used control means are generating unit tripping and generation curtailment. In terms of economic operation, one can say that the solution of generating unit tripping is more beneficial. To maintain the transient stability of the east coast region in the Korean power system, applying generation curtailment in the normal state is further needed, because the required tripping amount is too large for the case of only taking generator tripping, and this might cause a critical decrease in system frequency, possibly resulting in operation of the first stage of under frequency relay (UFR). This paper presents the application of battery energy storage systems (BESSs) to relieve the generation curtailment, using the characteristic of fast response of BESS. Assuming that BESSs are installed in the candidate location in the study region, the adequate BESS action of absorbing the kinetic energy from those critical generators after disturbances can improve transient stability, and it can decrease the amount of generation curtailment. This paper includes the results of simulation studies to show the effectiveness of the BESS control for the relief of generation curtailment.

ACS Style

Hyeongpil Bang; Dwi Aryani; Hwachang Song. Application of Battery Energy Storage Systems for Relief of Generation Curtailment in Terms of Transient Stability. Energies 2021, 14, 3898 .

AMA Style

Hyeongpil Bang, Dwi Aryani, Hwachang Song. Application of Battery Energy Storage Systems for Relief of Generation Curtailment in Terms of Transient Stability. Energies. 2021; 14 (13):3898.

Chicago/Turabian Style

Hyeongpil Bang; Dwi Aryani; Hwachang Song. 2021. "Application of Battery Energy Storage Systems for Relief of Generation Curtailment in Terms of Transient Stability." Energies 14, no. 13: 3898.

Journal article
Published: 28 October 2020 in Energies
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This paper proposes an optimal Energy Storage System (ESS) scheduling algorithm Building Energy Management System (BEMS). In particular, the focus is placed on how to reduce the peak load using ESS and load forecast. To this end, first, an existing deep learning-based load forecast method is applied to a real building energy prediction and it is shown that the deep learning-based method leads to an accuracy-enhanced load forecast. Second, an optimization problem is formulated in order to devise an ESS scheduling. In the optimization problem, the objective function and constraints are defined such that the peak load is reduced; the cost for electricity is minimized; and the ESS’s lifetime is elongated considering the accuracy-enhanced load forecast, real-time electricity price, and the state-of-charge of the ESS. For the purpose of demonstrating the effectiveness of the proposed ESS scheduling method, it is implemented using a real building load power and temperature data. The simulation results show that the proposed method can reduce the peak load and results in smooth charging and discharging, which is important for the ESS lifetime.

ACS Style

Jin Hwang; Ismi Rosyiana Fitri; Jung-Su Kim; Hwachang Song. Optimal ESS Scheduling for Peak Shaving of Building Energy Using Accuracy-Enhanced Load Forecast. Energies 2020, 13, 5633 .

AMA Style

Jin Hwang, Ismi Rosyiana Fitri, Jung-Su Kim, Hwachang Song. Optimal ESS Scheduling for Peak Shaving of Building Energy Using Accuracy-Enhanced Load Forecast. Energies. 2020; 13 (21):5633.

Chicago/Turabian Style

Jin Hwang; Ismi Rosyiana Fitri; Jung-Su Kim; Hwachang Song. 2020. "Optimal ESS Scheduling for Peak Shaving of Building Energy Using Accuracy-Enhanced Load Forecast." Energies 13, no. 21: 5633.

Journal article
Published: 26 April 2020 in Applied Sciences
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The development of state estimators for local electrical energy supply systems is inevitable as the role of the system’s become more important, especially with the recent increased interest in direct current (DC) microgrids. Proper control and monitoring requires a state estimator that can adapt to the new technologies for DC microgrids. This paper mainly deals with the DC microgrid state estimation (SE) using a modified long short-term memory (LSTM) network, which until recently has been applied only in forecasting studies. The modified LSTM network for the proposed state estimator adopted a specifically weighted least square (WLS)-based loss function for training. To demonstrate the performance of the proposed state estimator, a comparison study was done with other SE methods included in this paper. The results showed that the proposed state estimator had high accuracy in estimating the states of DC microgrids. Other than the enhanced accuracy, the deep-learning-based state estimator also provided faster computation speeds than the conventional state estimator.

ACS Style

Faya Safirra Adi; Yee Jin Lee; Hwachang Song. State Estimation for DC Microgrids using Modified Long Short-Term Memory Networks. Applied Sciences 2020, 10, 3028 .

AMA Style

Faya Safirra Adi, Yee Jin Lee, Hwachang Song. State Estimation for DC Microgrids using Modified Long Short-Term Memory Networks. Applied Sciences. 2020; 10 (9):3028.

Chicago/Turabian Style

Faya Safirra Adi; Yee Jin Lee; Hwachang Song. 2020. "State Estimation for DC Microgrids using Modified Long Short-Term Memory Networks." Applied Sciences 10, no. 9: 3028.

Journal article
Published: 27 December 2019 in Energies
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Load power forecast is one of most important tasks in power systems operation and maintenance. Enhancing its accuracy can be helpful to power systems scheduling. This paper presents how to use partial real-time temperature information in forecasting load power, which is usually done using past load power and temperature data. The partial real-time temperature information means temperature information for only part of the entire prediction time interval. To this end, a long short-term memory (LSTM) network is trained using past temperature and load power data in order to forecast load power, where forecasted load power depends on the temperature prediction implicitly. Then, in order to deal with the case where nontrivial temperature prediction errors happen, a multi-layer perceptron (MLP) network is trained using the past data describing the relation between temperature variation and load power variation. Then, the temperature is measured at the beginning of the prediction time-interval and compensated load forecast is computed by adding the output of the LSTM and that of the MLP whose input is the temperature prediction error. It is shown that the proposed compensation using the real-time temperature information indeed improves performance of load power forecast. This improved load forecast is used to predict system marginal price (SMP). The proposed method is validated using the real temperature and load power data of South Korea.

ACS Style

Khikmafaris Yudantaka; Jung-Su Kim; Hwachang Song. Dual Deep Learning Networks Based Load Forecasting with Partial Real-Time Information and Its Application to System Marginal Price Prediction. Energies 2019, 13, 148 .

AMA Style

Khikmafaris Yudantaka, Jung-Su Kim, Hwachang Song. Dual Deep Learning Networks Based Load Forecasting with Partial Real-Time Information and Its Application to System Marginal Price Prediction. Energies. 2019; 13 (1):148.

Chicago/Turabian Style

Khikmafaris Yudantaka; Jung-Su Kim; Hwachang Song. 2019. "Dual Deep Learning Networks Based Load Forecasting with Partial Real-Time Information and Its Application to System Marginal Price Prediction." Energies 13, no. 1: 148.

Journal article
Published: 11 December 2019 in Sustainability
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The popularity and role of renewable energy in the power grid are increasing nowadays as countries are shifting to cleaner forms of energy. This brings new challenges in maintaining a secure and stable power system, as renewable energy is known to be intermittent in nature and may introduce stability issues to the grid. In this paper, a screening framework of renewable energy generation scenarios is proposed to determine which power system conditions and scenarios will make the system unstable. The scenario screening framework is based on a sensitivity analysis of the system eigenvalues with respect to the renewable energy penetration to the system. The average scheduled renewable energy output, forecasting error standard deviation, average forecasting error, and bus location of the renewable energy source were used to define a renewable energy generation scenario. Depending on the amount and variability of renewable energy, there is a possibility for a critical eigenvalue to cross the imaginary axis. The estimated eigenvalue location resulting from the penetration of variable renewable energy is computed by adding the computed eigenvalue sensitivity to the initial operating point. If any of the estimated system eigenvalues cross the imaginary axis, the power system might be unstable in this scenario, so it requires more detailed simulations and countermeasures. Renewable energy forecasting was done using the long short-term memory model, and the proposed method was simulated using the IEEE 39-bus New England test system. The results of the proposed method were verified by comparing the simulation results to the eigenanalysis solution. The obtained results have shown that the proposed method can determine whether the renewable energy generation scenario is critical in power system operation.

ACS Style

Mark Brian Dastas; Hwachang Song. Renewable Energy Generation Assessment in Terms of Small-Signal Stability. Sustainability 2019, 11, 7079 .

AMA Style

Mark Brian Dastas, Hwachang Song. Renewable Energy Generation Assessment in Terms of Small-Signal Stability. Sustainability. 2019; 11 (24):7079.

Chicago/Turabian Style

Mark Brian Dastas; Hwachang Song. 2019. "Renewable Energy Generation Assessment in Terms of Small-Signal Stability." Sustainability 11, no. 24: 7079.

Journal article
Published: 10 September 2019 in IFAC-PapersOnLine
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DC microgrids provide high efficiency for the integration of dc sources and loads. The increasing integration of photovoltaic (PV) source and battery energy storage system (BESS) in distribution systems, as well as the rapid growth of DC loads, make DC microgrids becoming more favorable. This paper presents voltage regulation using droop control method for a DC microgrid consisted of a PV source, a BESS, and DC loads in the stand-alone mode operation. The coordination control between the PV source and the BESS is required to achieve a power balance in the system. The scheme will be tested using PSCAD/EMTDC software.

ACS Style

Dwi Riana Aryani; Hwachang Song. Voltage Regulation in a Stand-Alone DC Microgrid. IFAC-PapersOnLine 2019, 52, 36 -39.

AMA Style

Dwi Riana Aryani, Hwachang Song. Voltage Regulation in a Stand-Alone DC Microgrid. IFAC-PapersOnLine. 2019; 52 (4):36-39.

Chicago/Turabian Style

Dwi Riana Aryani; Hwachang Song. 2019. "Voltage Regulation in a Stand-Alone DC Microgrid." IFAC-PapersOnLine 52, no. 4: 36-39.

Journal article
Published: 10 September 2019 in IFAC-PapersOnLine
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This paper proposes a method to regulate the voltage output in DC sub-grid of a hybrid AC/DC microgrid by designing a model-based controller for bi-directional interlink converter (IC). A linear time-invariant (LTI) model representing the DC sub-grid is constructed by applying a step response in the IC. Then, the model-based controller of IC is made by forming a closed-loop system based on the obtained LTI model and a PID controller. To get proper values of PID gain in the closed loop system, an optimization problem needs to be solved. The result shows that using the model-based controller and PID gains from optimization, the modified system has better performance than the original one.

ACS Style

Faya Safirra Adi; Hwachang Song; Jung-Su Kim. Interlink Converter Controller Design based on System Identification of DC Sub-Grid Model in Hybrid AC/DC Microgrid. IFAC-PapersOnLine 2019, 52, 45 -50.

AMA Style

Faya Safirra Adi, Hwachang Song, Jung-Su Kim. Interlink Converter Controller Design based on System Identification of DC Sub-Grid Model in Hybrid AC/DC Microgrid. IFAC-PapersOnLine. 2019; 52 (4):45-50.

Chicago/Turabian Style

Faya Safirra Adi; Hwachang Song; Jung-Su Kim. 2019. "Interlink Converter Controller Design based on System Identification of DC Sub-Grid Model in Hybrid AC/DC Microgrid." IFAC-PapersOnLine 52, no. 4: 45-50.

Journal article
Published: 14 January 2019 in Applied Sciences
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This study applies a decomposed method to determine adequate countermeasures against excessive fault current levels in power systems. A set of candidate locations for the countermeasures such as bus splitting and current limiting reactors are pre-defined and modeled using variable reactances. A decomposition method is applied for the decision-making on the selection of the location and type of countermeasures. The main problem is to identify the optimal settings of the variable reactances by considering the sensitivities of the bus fault currents and generation costs with respect to the incremental increase in the reactance values of each countermeasure. For the subproblem, the optimization tool of fuzzy fault level constrained optimal power flow (FFLC-OPF) is applied to obtain the optimal operating point for the system with the given reactance settings. The FFLC-OPF incorporates both traditional constraints and fault level constraints in solving for the power flow. In addition, illustrative examples using the modified 28-bus system are included to show the effectiveness of the decomposition method.

ACS Style

BenJeMar-Hope Flores; Hwachang Song. Determining Countermeasures against Fault Currents Using a Decomposition Method Based on Fuzzy Fault Level Constrained Optimal Power Flow. Applied Sciences 2019, 9, 274 .

AMA Style

BenJeMar-Hope Flores, Hwachang Song. Determining Countermeasures against Fault Currents Using a Decomposition Method Based on Fuzzy Fault Level Constrained Optimal Power Flow. Applied Sciences. 2019; 9 (2):274.

Chicago/Turabian Style

BenJeMar-Hope Flores; Hwachang Song. 2019. "Determining Countermeasures against Fault Currents Using a Decomposition Method Based on Fuzzy Fault Level Constrained Optimal Power Flow." Applied Sciences 9, no. 2: 274.

Journal article
Published: 10 January 2019 in Sustainability
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This paper describes a methodology and specifics for technical studies on fault-induced delayed voltage recovery (FIDVR) mitigation to ensure power system reliability. Optimal locations of the dynamic volts-ampere-reactive (VAR) sources are determined for addressing the FIDVR issues in the voltage stability analysis and assessment methodology. We propose a voltage stability analysis method for planning dynamic VAR sources for bettering electric power transmission systems under contingency conditions. A time-domain dynamic simulation is performed to assess short-term voltage stability. While conducting dynamic simulations, sensitivity analysis is performed to assess the need for dynamic VAR sources. This study focuses on a reactive power compensation strategy to determine system voltage recovery performance by optimal flexible alternating current transmission system (FACTS) placement in a metropolitan region. The objective of this study is to determine the optimal installation of dynamic VAR sources while satisfying the requirements of voltage stability margin and transient voltage dip under a set of criteria. New insights are presented on the effect of FACTS controls on the reactive power compensation, which supports voltage recovery. The main features of the proposed method are (i) the development based on a load model for FIDVR, (ii) the use of sensitivity analysis of the network to the variations of the IM load, (iii) the establishment of the control function and compensation strategy to maintain the voltage of system within criteria limits, and (iv) the use of the sensitivity analysis based on branch parameterization for unsolvable cases. Case studies on the Korean power system validated the performance of the proposed strategy, showing that it effectively installed FACTS under contingency scenarios.

ACS Style

Yunhwan Lee; Hwachang Song. A Reactive Power Compensation Strategy for Voltage Stability Challenges in the Korean Power System with Dynamic Loads. Sustainability 2019, 11, 326 .

AMA Style

Yunhwan Lee, Hwachang Song. A Reactive Power Compensation Strategy for Voltage Stability Challenges in the Korean Power System with Dynamic Loads. Sustainability. 2019; 11 (2):326.

Chicago/Turabian Style

Yunhwan Lee; Hwachang Song. 2019. "A Reactive Power Compensation Strategy for Voltage Stability Challenges in the Korean Power System with Dynamic Loads." Sustainability 11, no. 2: 326.

Journal article
Published: 12 November 2018 in Sustainability
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An energy paradigm shift has rapidly occurred around the globe. One change has been an increase in the penetration of sustainable energy. However, this can affect the reliability of power systems by increasing variability and uncertainty from the use of renewable resources. To improve the reliability of an energy supply, a power system must have a sufficient amount of flexible resources to prevent a flexibility deficit. This paper proposes a countermeasure for protecting nonnegative flexibility under high-level penetration of renewable energy with robust optimization. The proposed method is divided into three steps: (i) constructing an uncertainty set with the capacity factor of renewable energy, (ii) searching for the initial point of a flexibility deficit, and (iii) calculating the capacity of the energy storage system to avoid such a deficit. In this study, robust optimization is applied to consider the uncertainty of renewable energy, and the results are compared between deterministic and robust approaches. The proposed method is demonstrated on a power system in the Republic of Korea.

ACS Style

Jinwoo Jeong; Heewon Shin; Hwachang Song; Byongjun Lee. A Countermeasure for Preventing Flexibility Deficit under High-Level Penetration of Renewable Energies: A Robust Optimization Approach. Sustainability 2018, 10, 4159 .

AMA Style

Jinwoo Jeong, Heewon Shin, Hwachang Song, Byongjun Lee. A Countermeasure for Preventing Flexibility Deficit under High-Level Penetration of Renewable Energies: A Robust Optimization Approach. Sustainability. 2018; 10 (11):4159.

Chicago/Turabian Style

Jinwoo Jeong; Heewon Shin; Hwachang Song; Byongjun Lee. 2018. "A Countermeasure for Preventing Flexibility Deficit under High-Level Penetration of Renewable Energies: A Robust Optimization Approach." Sustainability 10, no. 11: 4159.

Journal article
Published: 26 October 2018 in Electronics
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This study develops an analytical method for assessing the voltage stability margins of a decentralized load shedding scheme; it then examines the challenges related to the existing load shedding scheme. It also presents a practical application for implementing the proposed method, based on the synchrophasor measurement technology in modern power grid operations. By applying the concept of a continuously-computed voltage stability margin index to the configuration of the Thévenin equivalent system, the maximum transfer power could be used as an index to monitor the voltage instability phenomenon and thus determine the required load shedding amount. Thus, the calculated voltage stability margin might be a useful index for system operators in the critical decision-making process of load shedding. Dynamic simulations are performed on real Korean power systems as case studies. Simulation results, when comparing the existing and proposed methods, showed that there was a considerable reduction in the amount of load shedding in the voltage instability scenario. This indicates that the synchrophasor measurement technology has a considerable effect on the proposed load shedding method. The simulation results have validated the performance of the proposed method.

ACS Style

Yunhwan Lee; Hwachang Song. Decentralized Load Shedding Method Based on Voltage Stability Margin Index Using Synchrophasor Measurement Technology. Electronics 2018, 7, 277 .

AMA Style

Yunhwan Lee, Hwachang Song. Decentralized Load Shedding Method Based on Voltage Stability Margin Index Using Synchrophasor Measurement Technology. Electronics. 2018; 7 (11):277.

Chicago/Turabian Style

Yunhwan Lee; Hwachang Song. 2018. "Decentralized Load Shedding Method Based on Voltage Stability Margin Index Using Synchrophasor Measurement Technology." Electronics 7, no. 11: 277.

Conference paper
Published: 26 October 2018 in MATEC Web of Conferences
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In 2017, the aggregate electrification ratio in Indonesia has been achieving 92.8%. However, some rural areas such as in Maluku and Papua Islands still have low electrification ratio (~70%). One of the main problems in supplying electricity to rural areas in Indonesia is the geographical concern which consisted of islands leading to the difficulty of electricity grid development. In some areas, diesel power plant has been being built to supply the electricity. However, it causes another problem to transport the primary energy source to the targeted area which would increase the cost of electricity supply. Besides, it also needs investment cost to build transmission and distribution systems, as well as the maintenance expenses. To resolve this issue, a new scheme of battery-based Tabung Listrik or TaLis (DC-based power bank) and DC house system is proposed to be the solution to provide electricity to rural areas. The potential of local renewable energy sources such as biomass, hydro, wind, and solar could be utilized to be charging sources of batteries (TaLis). This study presents the TaLis prototype, DC house installation, supply chain process and charging scheme of TaLis, and cost comparison between the proposed system with other existing power systems such as communal PV farm and diesel power plant. We found that TaLis and DC house system provided the least cost of electricity production compared to other power systems, i.e. $0.88/kWh for TaLis and DC house system, $1.65/kWh for diesel power plant, and $1.47/kWh for communal PV farm. Implementation of this approach is expected to improve the welfare and quality of life of rural communities immediately.

ACS Style

Aryani Dwi Riana; Faiz Hunsnayain; Edward Andres Pramana; Hwachang Song; Pambudi Yoyok Dwi Setyo; Anne Zulfia; Chairul Hudaya. Implementation of talis and dc house system for rural areas in indonesia. MATEC Web of Conferences 2018, 218, 01006 .

AMA Style

Aryani Dwi Riana, Faiz Hunsnayain, Edward Andres Pramana, Hwachang Song, Pambudi Yoyok Dwi Setyo, Anne Zulfia, Chairul Hudaya. Implementation of talis and dc house system for rural areas in indonesia. MATEC Web of Conferences. 2018; 218 ():01006.

Chicago/Turabian Style

Aryani Dwi Riana; Faiz Hunsnayain; Edward Andres Pramana; Hwachang Song; Pambudi Yoyok Dwi Setyo; Anne Zulfia; Chairul Hudaya. 2018. "Implementation of talis and dc house system for rural areas in indonesia." MATEC Web of Conferences 218, no. : 01006.

Journal article
Published: 10 July 2018 in Applied Sciences
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This paper aims to develop a multi-phase under voltage load shedding (MUVLS) strategy that effectively sheds the load to mitigate delayed voltage recovery (DVR). The major cause of the DVR phenomenon is related to the dynamic characteristics of induction motor (IM) loads. The deaccelerating and stalling of the IM load during disturbances is the main driving force of short-term voltage instability, resulting in an amount of reactive power consumption and excessive current draw. With the economic efficiency of energy use, the proportion of IM loads is gradually increasing, and this trend might deteriorate system stability. This paper focuses on the impact of IM loads in the Korean power system and analyzes the parameter sensitivity of IM loads and the proportion of appropriate IM loads. The proposed procedure for under voltage load shedding (UVLS) applies voltage stability criteria to decide the most efficient load shedding scheme. The determined MUVLS scheme can offer new and more effective remedial actions to maintain voltage stability, considering the characteristics of IM loads. Case studies on the Korean power system have validated the performance of the proposed MUVLS scheme under severe contingency scenarios, showing that the proposed strategy effectively mitigates DVR.

ACS Style

Yunhwan Lee; Hwachang Song. Multi-Phase under Voltage Load Shedding Scheme for Preventing Delayed Voltage Recovery by Induction Motor Power Consumption Characteristics. Applied Sciences 2018, 8, 1115 .

AMA Style

Yunhwan Lee, Hwachang Song. Multi-Phase under Voltage Load Shedding Scheme for Preventing Delayed Voltage Recovery by Induction Motor Power Consumption Characteristics. Applied Sciences. 2018; 8 (7):1115.

Chicago/Turabian Style

Yunhwan Lee; Hwachang Song. 2018. "Multi-Phase under Voltage Load Shedding Scheme for Preventing Delayed Voltage Recovery by Induction Motor Power Consumption Characteristics." Applied Sciences 8, no. 7: 1115.

Journal article
Published: 29 May 2018 in Energies
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A hybrid AC/DC microgrid is established with the aim of exploiting numerous types of renewable energy to meet the needs of different loads. The microgrid is decomposed by AC DC sub-grids which are connected by an interlink converter (IC). To maintain the security and reliability of the microgrid, an automatic controller for the interlink converter is needed. In this paper, we propose a Linear Matrix Inequalities (LMI)-based current control method for the interlink converter. As the main features here, the interlink converter permits bidirectional power exchange between both sub-grids when a power–demand imbalance occurs in one sub-grid regardless of the converter system parameters. Simulations with various filter parameters are performed using the Matlab/Simulink software to validate the effectiveness of the proposed controller. In comparison with the existing Linear Quadratic Regulator (LQR)-based current control, the proposed method is more robust against unknown system parameters and high load perturbation.

ACS Style

Ismi Rosyiana Fitri; Jung-Su Kim; Hwachang Song. A Robust Suboptimal Current Control of an Interlink Converter for a Hybrid AC/DC Microgrid. Energies 2018, 11, 1382 .

AMA Style

Ismi Rosyiana Fitri, Jung-Su Kim, Hwachang Song. A Robust Suboptimal Current Control of an Interlink Converter for a Hybrid AC/DC Microgrid. Energies. 2018; 11 (6):1382.

Chicago/Turabian Style

Ismi Rosyiana Fitri; Jung-Su Kim; Hwachang Song. 2018. "A Robust Suboptimal Current Control of an Interlink Converter for a Hybrid AC/DC Microgrid." Energies 11, no. 6: 1382.

Conference paper
Published: 01 January 2018 in 2018 International Conference on Platform Technology and Service (PlatCon)
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To monitor public infrastructure systems such as power grid during and after a disaster or emergency, radio communication requiring neither an external power source nor a pre-deployed connection point is needed. Ambient backscatter communication meets such requirements thanks to its ultra-low power consumption and ad hoc connectivity, thus being suitable as a backup method for infrastructure monitoring in such situations. In this paper, we describe the detailed methods to realize ambient backscatter communication particularly using Wi-Fi signals as carrier signals and demonstrate an experimental testbed system to discuss its feasibility in practice.

ACS Style

Hwanwoong Hwang; Ji-Hoon Yun; Hwachang Song. Ultra-Low Power Communication for Infrastructure Monitoring During a Disaster. 2018 International Conference on Platform Technology and Service (PlatCon) 2018, 1 -6.

AMA Style

Hwanwoong Hwang, Ji-Hoon Yun, Hwachang Song. Ultra-Low Power Communication for Infrastructure Monitoring During a Disaster. 2018 International Conference on Platform Technology and Service (PlatCon). 2018; ():1-6.

Chicago/Turabian Style

Hwanwoong Hwang; Ji-Hoon Yun; Hwachang Song. 2018. "Ultra-Low Power Communication for Infrastructure Monitoring During a Disaster." 2018 International Conference on Platform Technology and Service (PlatCon) , no. : 1-6.

Conference paper
Published: 01 January 2018 in 2018 International Conference on Platform Technology and Service (PlatCon)
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LCL filters are being more and more preferred over the L filter in a grid-connected inverter due to the smaller physical size and better harmonic attenuation characteristics. However, additional control loops are often required to control inverter-side current as well as capacitor voltage. These additional control loops complicate the controller design process. To overcome such a limitation, a discrete-time control design for a three-phase grid-connected inverter using a full state observer is presented in this paper. The controller design is accomplished based on the state-space model of the inverter system. Furthermore, to reduce the steady-state error in output currents, a discrete-time integral state feedback controller is employed. Generally, all state variables should be available to implement a state feedback controller. For the purpose of reducing the number of sensors in a practical system, an observer which uses the measured grid-side currents, grid voltages, and control inputs is constructed in discrete-time domain to predict the inverter-side currents and capacitor voltages. As a result of using both the feedback controller and the observer, the proposed control scheme provides a better control performance in a systematic design approach. Simulation results are given to demonstrate the feasibility and performance of the proposed control scheme.

ACS Style

Seung-Jin Yoon; Ngoc-Bao Lai; Kyeong-Hwa Kim; Hwachang Song. Discrete-Time Control Design for Three-Phase Grid-Connected Inverter Using Full State Observer. 2018 International Conference on Platform Technology and Service (PlatCon) 2018, 1 -6.

AMA Style

Seung-Jin Yoon, Ngoc-Bao Lai, Kyeong-Hwa Kim, Hwachang Song. Discrete-Time Control Design for Three-Phase Grid-Connected Inverter Using Full State Observer. 2018 International Conference on Platform Technology and Service (PlatCon). 2018; ():1-6.

Chicago/Turabian Style

Seung-Jin Yoon; Ngoc-Bao Lai; Kyeong-Hwa Kim; Hwachang Song. 2018. "Discrete-Time Control Design for Three-Phase Grid-Connected Inverter Using Full State Observer." 2018 International Conference on Platform Technology and Service (PlatCon) , no. : 1-6.

Conference paper
Published: 01 January 2018 in 2018 International Conference on Platform Technology and Service (PlatCon)
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Microgrids can operate either connected to the utility grid or disconnected, respectively called grid-connected and islanding mode. If an emergency occurs, a rapid transition to islanding mode is executed to evaluate the cause of problem and to prevent further damage. However, seamless transition control is not realizable because of speed constraints introduced by the communication protocols being used today. This paper reviews the current technologies applied in a microgrid communication system and presents a new study to solve this problem using EtherCAT, a real-time Ethernet protocol. The advantages of this solution with respect to the state-of-the-art are summarized. We also conducted a performance analysis using minimum cycle time as the performance index to verify the feasibility of EtherCAT in a microgrid application. Potential future work is suggested related to integration of EtherCAT in an actual microgrid system for practical field experiments.

ACS Style

Raimarius Delgado; Byoung Wook Choi; Hwachang Song. Application of EtherCAT in Microgrid Communication Network: A Case Study. 2018 International Conference on Platform Technology and Service (PlatCon) 2018, 1 -6.

AMA Style

Raimarius Delgado, Byoung Wook Choi, Hwachang Song. Application of EtherCAT in Microgrid Communication Network: A Case Study. 2018 International Conference on Platform Technology and Service (PlatCon). 2018; ():1-6.

Chicago/Turabian Style

Raimarius Delgado; Byoung Wook Choi; Hwachang Song. 2018. "Application of EtherCAT in Microgrid Communication Network: A Case Study." 2018 International Conference on Platform Technology and Service (PlatCon) , no. : 1-6.

Conference paper
Published: 01 January 2018 in 2018 International Conference on Platform Technology and Service (PlatCon)
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This paper tackles the problem of short-term wind fluctuation with the imposition of strict ramp rate limits. A control strategy is proposed to reduce the output ramp-rate of a wind farm to a required level using model predictive control (MPC). The system consists of a wind farm coupled with a battery energy storage system (BESS) with the sole function of ramp-rate control (RRC) that optimizes the wind power output as well as the BESS output energy while observing the physical constraints. A variation of up to 10% of the maximum plant capacity per minute is observed in the implementation of RRC as required the grid code for the acceptable penetration of wind farms into the power system.

ACS Style

Marlon A. Capuno; Jung-Su Kim; Hwachang Song. MPC Based Ramp-Rate Control Strategy with Battery Energy Storage Systems for Wind Farms. 2018 International Conference on Platform Technology and Service (PlatCon) 2018, 1 -6.

AMA Style

Marlon A. Capuno, Jung-Su Kim, Hwachang Song. MPC Based Ramp-Rate Control Strategy with Battery Energy Storage Systems for Wind Farms. 2018 International Conference on Platform Technology and Service (PlatCon). 2018; ():1-6.

Chicago/Turabian Style

Marlon A. Capuno; Jung-Su Kim; Hwachang Song. 2018. "MPC Based Ramp-Rate Control Strategy with Battery Energy Storage Systems for Wind Farms." 2018 International Conference on Platform Technology and Service (PlatCon) , no. : 1-6.

Conference paper
Published: 01 December 2017 in 2017 11th Asian Control Conference (ASCC)
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The paper proposes a fully distributed approach for economic dispatch problem (EDP) in power systems. The goal is to determine the output power to meet the load demand economically. In this paper, a simple algorithm is proposed to solve EDP under capacity constraint. The proposed method only needs its local cost parameters and the local predicted load. Simulation studies show the effectiveness of the approach.

ACS Style

Ismi Rosyiana Fitri; Jung-Su Kim; Hwachang Song. Distributed economic dispatch for power systems. 2017 11th Asian Control Conference (ASCC) 2017, 2808 -2812.

AMA Style

Ismi Rosyiana Fitri, Jung-Su Kim, Hwachang Song. Distributed economic dispatch for power systems. 2017 11th Asian Control Conference (ASCC). 2017; ():2808-2812.

Chicago/Turabian Style

Ismi Rosyiana Fitri; Jung-Su Kim; Hwachang Song. 2017. "Distributed economic dispatch for power systems." 2017 11th Asian Control Conference (ASCC) , no. : 2808-2812.

Journal article
Published: 08 November 2017 in Energies
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A hybrid alternate current/direct current (AC/DC) microgrid consists of an AC subgrid and a DC subgrid, and the subgrids are connected through the interlink bidirectional AC/DC converter. In the stand-alone operation mode, it is desirable that the interlink bidirectional AC/DC converter manages proportional power sharing between the subgrids by transferring power from the under-loaded subgrid to the over-loaded one. In terms of system security, the interlink bidirectional AC/DC converter takes an important role, so proper control strategies need to be established. In addition, it is assumed that a battery energy storage system is installed in one subgrid, and the coordinated control of interlink bidirectional AC/DC converter and battery energy storage system converter is required so that the power sharing scheme between subgrids becomes more efficient. For the purpose of designing a tracking controller for the power sharing by interlink bidirectional AC/DC converter in a hybrid AC/DC microgrid, a droop control method generates a power reference for interlink bidirectional AC/DC converter based on the deviation of the system frequency and voltages first and then interlink bidirectional AC/DC converter needs to transfer the power reference to the over-loaded subgrid. For efficiency of this power transferring, a linear quadratic regulator with exponential weighting for the current regulation of interlink bidirectional AC/DC converter is designed in such a way that the resulting microgrid can operate robustly against various uncertainties and the power sharing is carried out quickly. Simulation results show that the proposed interlink bidirectional AC/DC converter control strategy provides robust and efficient power sharing scheme between the subgrids without deteriorating the secure system operation.

ACS Style

Dwi Riana Aryani; Jung-Su Kim; Hwachang Song. Interlink Converter with Linear Quadratic Regulator Based Current Control for Hybrid AC/DC Microgrid. Energies 2017, 10, 1799 .

AMA Style

Dwi Riana Aryani, Jung-Su Kim, Hwachang Song. Interlink Converter with Linear Quadratic Regulator Based Current Control for Hybrid AC/DC Microgrid. Energies. 2017; 10 (11):1799.

Chicago/Turabian Style

Dwi Riana Aryani; Jung-Su Kim; Hwachang Song. 2017. "Interlink Converter with Linear Quadratic Regulator Based Current Control for Hybrid AC/DC Microgrid." Energies 10, no. 11: 1799.