@article{xie_mcentee_zhang_lu_ke_vattern_samaan_2021, title={Networked HIL Simulation System for Modeling Large-scale Power Systems}, ISSN={["2163-4939"]}, DOI={10.1109/NAPS50074.2021.9449646}, abstractNote={This paper presents a networked hardware-in-the-loop (HIL) simulation system for modeling large-scale power systems. Researchers have developed many HIL test systems for power systems in recent years. Those test systems can model both microsecond-level dynamic responses of power electronic systems and millisecond-level transients of transmission and distribution grids. By integrating individual HIL test systems into a network of HIL test systems, we can create large-scale power grid digital twins with flexible structures at required modeling resolution that fits for a wide range of system operating conditions. This will not only significantly reduce the need for field tests when developing new technologies but also greatly shorten the model development cycle. In this paper, we present a networked OPAL-RT based HIL test system for developing transmission-distribution coordinative Volt-VAr regulation technologies as an example to illustrate system setups, communication requirements among different HIL simulation systems, and system connection mechanisms. Impacts of communication delays, information exchange cycles, and computing delays are illustrated. Simulation results show that the performance of a networked HIL test system is satisfactory.}, journal={2020 52ND NORTH AMERICAN POWER SYMPOSIUM (NAPS)}, author={Xie, Fuhong and McEntee, Catie and Zhang, Mingzhi and Lu, Ning and Ke, Xinda and Vattern, Mallikarjuna R. and Samaan, Nader}, year={2021} }
 @article{ke_wu_lu_2019, title={A Real-Time Greedy-Index Dispatching Policy for Using PEVs to Provide Frequency Regulation Service}, volume={10}, ISSN={["1949-3061"]}, DOI={10.1109/TSG.2017.2754241}, abstractNote={This paper presents a real-time greedy-index dispatching policy (GIDP) for using plug-in electric vehicles (PEVs) to provide frequency regulation services. A new service cost allocation mechanism is proposed to award PEVs based on the amount of service they provided, while considering compensations for delayed-charging and reduction of battery lifetime due to participation of the service. The GIDP transforms the optimal dispatch problem from a high-dimensional space into an 1-D space while preserving the solution optimality. When solving the transformed problem in real-time, the global optimality of the GIDP solution can be guaranteed by mathematically proved “indexability.” Because the GIDP index can be calculated upon the PEV’s arrival and used for the entire decision making process till its departure, the computational burden is minimized and the complexity of the aggregator dispatch process is significantly reduced. Simulation results are used to evaluate the proposed GIDP, and to demonstrate the potential profitability from providing frequency regulation service by using PEVs.}, number={1}, journal={IEEE TRANSACTIONS ON SMART GRID}, author={Ke, Xinda and Wu, Di and Lu, Ning}, year={2019}, month={Jan}, pages={864–877} }
 @inproceedings{ke_jiang_lu_2016, title={Load profile analysis and short-term building load forecast for a university campus}, DOI={10.1109/pesgm.2016.7742034}, abstractNote={Nowadays, advanced metering infrastructure allows us to record building energy consumption at much higher resolutions. This paper presents the methods for building load profile analysis and forecast using the 15-minute data collected at a substation feeder at the Centennial Campus of North Carolina State University from May 2012 to April 2014. Building load signatures for benchmarking building load consumptions are first analyzed and extracted from load related environmental factors such as time of the day, temperature and humidity, etc. Then, methods to forecast hours-ahead building energy consumptions are developed. Comparisons are made to derive the benefit of having high resolution environmental data sets.}, booktitle={2016 ieee power and energy society general meeting (pesgm)}, author={Ke, X. D. and Jiang, A. J. and Lu, N.}, year={2016} }
 @inproceedings{ke_lu_wu_kintner-meyer_2015, title={A modified priority list-based MILP method for solving large-scale unit commitment problems}, DOI={10.1109/pesgm.2015.7286561}, abstractNote={This paper presents a two-step modified priority list (MPL) based mixed integer linear programming (MILP) method for improving the computational speed of unit commitment (UC) programs while preserving optimality. In the first step, the heuristics of UC results for a given generation fleet are investigated to develop the MPL. A subset of the generators are determined to be online (committed) or offline (uncommitted) within a planning period (e.g., a week), based on the demand curve and generator priority list. Then, for generators whose on/off status is predetermined, the corresponding binary variables are removed from the MILP solving process. After this simplification, the remaining problem can be solved much faster using an off-the-shelf MILP solver, based on the branch-and-bound algorithm. Scale factors are used to adjust the tradeoff between solution speed and level of optimality. Simulation results show that the proposed method can significantly speed up the large-scale UC problem with negligible compromise in optimality by selecting appropriate scale factors.}, booktitle={2015 ieee power & energy society general meeting}, author={Ke, X. D. and Lu, N. and Wu, D. and Kintner-Meyer, M.}, year={2015} }
 @article{ke_lu_jin_2015, title={Control and Size Energy Storage Systems for Managing Energy Imbalance of Variable Generation Resources}, volume={6}, ISSN={["1949-3029"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000346733200008&KeyUID=WOS:000346733200008}, DOI={10.1109/tste.2014.2355829}, abstractNote={This paper presents control algorithms and sizing strategies for using energy storage to manage energy imbalance for variable generation resources. The control objective is to minimize the hourly generation imbalance between the actual and the scheduled generation of wind farms. Three control algorithms are compared: 1)tracking minute-by-minute power imbalance; 2)postcompensation; and 3)precompensation. Measured data from a wind farm are used in the study. The results show that tracking minute-by-minute power imbalance achieves the best performance by keeping hourly energy imbalance zero. However, the energy storage system (ESS) will be significantly oversized. Postcompensation reduces the power rating of the ESS but the hourly energy imbalance may not be reduced to zero when a large and long-lasting power imbalance occurs. A linear regression forecasting algorithm is developed for a two-stage precompensation algorithm to precharge or predischarge the ESS based on the predicted energy imbalance. An equivalent charge cycle estimation method is proposed to evaluate the effect of providing the energy balancing service on battery life. The performance comparison shows that the precompensation method reduces the size of the ESS by 30% with satisfactory performance.}, number={1}, journal={IEEE TRANSACTIONS ON SUSTAINABLE ENERGY}, author={Ke, Xinda and Lu, Ning and Jin, Chunlian}, year={2015}, month={Jan}, pages={70–78} }
 @inproceedings{ke_lu_jin_2015, title={Control and size energy storage systems for managing energy imbalance of variable generation resources}, DOI={10.1109/pesgm.2015.7286609}, abstractNote={Summary form only given: This paper presents control algorithms and sizing strategies for using energy storage to manage energy imbalance for variable generation resources. The control objective is to minimize the hourly generation imbalance between the actual and the scheduled generation of wind farms. Three control algorithms are compared: (1) tracking minute-by-minute power imbalance; (2) postcompensation; and (3) precompensation. Measured data from a wind farm are used in the study. The results show that tracking minute-by-minute power imbalance achieves the best performance by keeping hourly energy imbalance zero. However, the energy storage system (ESS) will be significantly oversized. Postcompensation reduces the power rating of the ESS but the hourly energy imbalance may not be reduced to zero when a large and long-lasting power imbalance occurs. A linear regression forecasting algorithm is developed for a two-stage precompensation algorithm to precharge or predischarge the ESS based on the predicted energy imbalance. An equivalent charge cycle estimation method is proposed to evaluate the effect of providing the energy balancing service on battery life. The performance comparison shows that the precompensation method reduces the size of the ESS by 30% with satisfactory performance.}, booktitle={2015 ieee power & energy society general meeting}, author={Ke, X. D. and Lu, N. and Jin, C. L.}, year={2015} }
 @article{du_li_ke_lu_ciniglio_colburn_anderson_2015, title={Probabilistic-Based Available Transfer Capability Assessment Considering Existing and Future Wind Generation Resources}, volume={6}, ISSN={["1949-3029"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000361680800010&KeyUID=WOS:000361680800010}, DOI={10.1109/tste.2015.2425354}, abstractNote={This paper presents a probabilistic-based approach for available transfer capability (ATC) assessment. A composite algorithm is developed to generate ensembles of future wind generation scenarios for the existing and planned wind sites using both measured and model-produced wind data. Then, the ensembles of wind and load are used to calculate their respective probability density functions (pdfs), which are subsequently used to calculate the probabilistic-based ATC for a selected transmission corridor. The method has been tested and validated using historical and operational data provided by the Idaho Power Co. The results show that the method can effectively quantify the uncertainties in the ATC assessment introduced by variable generation resources and load variations. As a result, the grid planners will inform the likelihood for the transmission corridor to exceed its transfer capacity in any targeted future years as well as the duration of such events.}, number={4}, journal={IEEE TRANSACTIONS ON SUSTAINABLE ENERGY}, author={Du, Pengwei and Li, Weifeng and Ke, Xinda and Lu, Ning and Ciniglio, Orlando A. and Colburn, Mitchel and Anderson, Phillip M.}, year={2015}, month={Oct}, pages={1263–1271} }
 @inproceedings{ke_lu_jin_2014, title={Control and size energy storage for managing energy balance of variable generation resources}, DOI={10.1109/pesgm.2014.6939484}, abstractNote={This paper presents control algorithms and sizing strategies for using energy storage to manage energy balance for variable generation resources. The control objective is to minimize the hourly generation imbalance between the actual and the scheduled generation of the wind farm. Three control algorithms are compared: tracking power imbalance, post-compensation, and pre-compensation. Measurement data from a wind farm located in South-central Washington State are used in the study. The results show that tracking power imbalance yields the best performance by keeping the hourly energy imbalances zero. However, the energy storage system (ESS) will be significantly oversized. Post-compensation reduces power rating of the ESS but the hourly imbalance may not be kept as zero when large and long-lasting energy imbalances occur. A linear regression forecasting algorithm is developed for the pre-compensation algorithm to pre-charge or pre-discharge the ESS based on predicted energy imbalances. The performance comparison shows that the pre-compensation method significantly reduces the size of the ESS while maintaining satisfactory performance.}, booktitle={2014 ieee pes general meeting - conference & exposition}, author={Ke, X. D. and Lu, N. and Jin, C. L.}, year={2014} }