@article{kim_ye_lee_lu_2024, title={A Contextually Supervised Optimization-Based HVAC Load Disaggregation Methodology}, volume={15}, ISSN={["1949-3061"]}, DOI={10.1109/TSG.2024.3367301}, abstractNote={This paper presents a novel contextually supervised optimization-based approach for disaggregating heating, ventilation, and air-conditioning (HVAC) loads using smart meter or Supervisory Control and Data Acquisition data. To disaggregate the load into HVAC loads, large and infrequently used loads (LIUL), and base loads, we formulate an optimization problem to minimize a set of five loss terms, consisting of the reconstruction errors of the overall load profile, the ramp rate losses, and three distinct loss functions linked with the HVAC load, base load, and LIUL, respectively. To enhance accuracy, we incorporate two forms of contextual information into the problem formulation. First, we utilize mutual information to estimate HVAC energy consumption. Second, we employ a base load dictionary to constrain HVAC load estimation errors. The obtained HVAC load profiles are fine-tuned by abnormal ramp detection followed by binary hypothesis testing. The proposed method is developed and tested using sub-metered residential and commercial building data. Simulation results show that the proposed method outperforms existing methods across various data resolutions and load aggregation levels, showing excellent transferability and generalizability.}, number={4}, journal={IEEE TRANSACTIONS ON SMART GRID}, author={Kim, Hyeonjin and Ye, Kai and Lee, Duehee and Lu, Ning}, year={2024}, month={Jul}, pages={3852–3863} } @article{hu_ye_kim_lu_2024, title={BERT-PIN: A BERT-Based Framework for Recovering Missing Data Segments in Time-Series Load Profiles}, volume={7}, ISSN={["1941-0050"]}, url={https://doi.org/10.1109/TII.2024.3417272}, DOI={10.1109/TII.2024.3417272}, journal={IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS}, author={Hu, Yi and Ye, Kai and Kim, Hyeonjin and Lu, Ning}, year={2024}, month={Jul} } @article{ye_kim_hu_lu_wu_rehm_2023, title={A Modified Sequence-to-point HVAC Load Disaggregation Algorithm}, ISSN={["1944-9925"]}, DOI={10.1109/PESGM52003.2023.10252553}, abstractNote={This paper presents a modified sequence-to-point (S2P) algorithm for disaggregating the heat, ventilation, and air conditioning (HVAC) load from the total building electricity consumption. The original S2P model is convolutional neural network (CNN) based, which uses load profiles as inputs. We propose three modifications. First, the input convolution layer is changed from 1D to 2D so that normalized temperature profiles are also used as inputs to the S2P model. Second, a drop-out layer is added to improve adaptability and generalizability so that the model trained in one area can be transferred to other geographical areas without labelled HVAC data. Third, a fine-tuning process is proposed for areas with a small amount of labelled HVAC data so that the pre-trained S2P model can be fine-tuned to achieve higher disaggregation accuracy (i.e., better transferability) in other areas. The model is first trained and tested using smart meter and sub-metered HVAC data collected in Austin, Texas. Then, the trained model is tested on two other areas: Boulder, Colorado and San Diego, California. Simulation results show that the proposed modified S2P algorithm outperforms the original S2P model and the support-vector machine based approach in accuracy, adaptability, and transferability.}, journal={2023 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, PESGM}, author={Ye, Kai and Kim, Hyeonjin and Hu, Yi and Lu, Ning and Wu, Di and Rehm, P. J.}, year={2023} } @article{kim_ye_lee_hu_lu_wu_rehm_2023, title={An ICA-Based HVAC Load Disaggregation Method Using Smart Meter Data}, ISSN={["2167-9665"]}, DOI={10.1109/ISGT51731.2023.10066402}, abstractNote={This paper presents an independent component analysis (ICA) based unsupervised-learning method for heat, ventilation, and air-conditioning (HVAC) load disaggregation using low-resolution (e.g., 15 minutes) smart meter data. We first demonstrate that electricity consumption profiles on mild-temperature days can be used to estimate the non-HVAC base load on hot days. A residual load profile can then be calculated by subtracting the mild-day load profile from the hot-day load profile. The residual load profiles are processed using ICA for HVAC load extraction. An optimization-based algorithm is proposed for post-adjustment of the ICA results, considering two bounding factors for enhancing the robustness of the ICA algorithm. First, we use the hourly HVAC energy bounds computed based on the relationship between HVAC load and temperature to remove unrealistic HVAC load spikes. Second, we exploit the dependency between the daily nocturnal and diurnal loads extracted from historical meter data to smooth the base load profile. Pecan Street data with sub-metered HVAC data were used to test and validate the proposed methods. Simulation results demonstrated that the proposed method is computationally efficient and robust across multiple customers.}, journal={2023 IEEE POWER & ENERGY SOCIETY INNOVATIVE SMART GRID TECHNOLOGIES CONFERENCE, ISGT}, author={Kim, Hyeonjin and Ye, Kai and Lee, Han Pyo and Hu, Rongxing and Lu, Ning and Wu, Di and Rehm, P. J.}, year={2023} } @article{hu_ye_kim_lee_lu_wu_rehm_2023, title={Design Considerations of a Coordinative Demand Charge Mitigation Strategy}, ISSN={["1944-9925"]}, DOI={10.1109/PESGM52003.2023.10252618}, abstractNote={This paper presents a coordinative demand charge mitigation (DCM) strategy for reducing electricity consumption during system peak periods. Available DCM resources include batteries, diesel generators, controllable appliance loads, and conservation voltage reduction. All resources are directly controlled by load serving entities. A mixed integer linear programming-based energy management algorithm is developed to optimally coordinate DCM resources considering the load payback effect. To better capture system peak periods, two different kinds of load forecast are used: the day-ahead load forecast and the peak-hour probability forecast. Five DCM strategies are compared for reconciling the discrepancy between the two forecasting results. The DCM strategies are tested using actual utility data. Simulation results show that the proposed algorithm can effectively mitigate the demand charge while preventing the system peak from being shifted to the payback hours. We also identify the diminishing return effect, which can help load serving entities optimize the size of their DCM resources.}, journal={2023 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, PESGM}, author={Hu, Rongxing and Ye, Kai and Kim, Hyeonjin and Lee, Hanpyo and Lu, Ning and Wu, Di and Rehm, P. J.}, year={2023} }