@article{wang_tang_2022, title={Modeling and Analysis of Baseline Manipulation in Demand Response Programs}, volume={13}, ISSN={["1949-3061"]}, DOI={10.1109/TSG.2021.3137098}, abstractNote={Baseline methods are used in demand response (DR) programs to estimate customers’ intrinsic load so as to reward them properly. While the accuracy of baseline methods has drawn considerable attention, the strategic behavior regarding baseline manipulation has not been well explored in the literature. In this paper, we formulate the customer’s payoff-maximizing problem as a Markov decision process (MDP). Several structural results have been established, including the characterization of underconsumption on event days and overconsumption on non-event days. We investigate the approximation of baseline methods to understand how the method parameters and the consumption statistics would affect the strategic behavior. Moreover, we develop a rollout algorithm, based on approximate dynamic programming, to solve the MDP efficiently. Finally, the proposed methodology is illustrated through case studies, which shed light on the analysis and design of baseline methods.}, number={2}, journal={IEEE TRANSACTIONS ON SMART GRID}, author={Wang, Xiaochu and Tang, Wenyuan}, year={2022}, month={Mar}, pages={1178–1186} }
 @article{wang_tang_2021, title={A Self-Reported Baseline Demand Response Program for Mitigation of Baseline Manipulation}, ISSN={["1944-9925"]}, DOI={10.1109/PESGM46819.2021.9638109}, abstractNote={The customer baseline is the counterfactual consumption without any demand response (DR) programs and thus is only known to end users. As a result, baseline manipulation arises in DR programs where the customer baseline is required to assign rebates. To address this issue, we propose a self-reported DR program under which customers only need to report their baseline. The customer's stochastic programming problem is simplified as a two-stage optimization, where the incentive-compatible (truth-telling) condition is derived. However, the incentive compatibility cannot be achieved due to the baseline information asymmetry between customers and program providers. As an alternative, we relax the threshold (allowed) baseline inflation from zero to a certain level and obtain the corresponding near-incentive compatibility. The self-report approach and the near-incentive compatibility provide new directions in designing effective DR programs.}, journal={2021 IEEE POWER & ENERGY SOCIETY GENERAL MEETING (PESGM)}, author={Wang, Xiaochu and Tang, Wenyuan}, year={2021} }
 @article{wang_dsouza_tang_baran_2021, title={Assessing the Impact of High Penetration PV on the Power Transformer Loss of Life on a Distribution System}, ISSN={["2165-4816"]}, DOI={10.1109/ISGTEUROPE52324.2021.9640091}, abstractNote={Increasing photovoltaic (PV) systems on a distribution system impact the operation and lifetime of its components. One of the key components to be impacted is the power transformer at the substation. In this paper, we aim to evaluate the impact of high penetration PV on the lifetime of the substation power transformer. At moderate levels of PV penetration, the loading on the substation transformer decreases, and therefore this will help to prolong the lifetime of the transformer. To estimate this expected benefit, a thermal model for the transformer is used to estimate its hot spot temperature as this temperature is the main factor affecting the degradation of the transformer under normal loading conditions. To illustrate the method, a case study is given. A 10-year period is considered for transformer loss of life evaluation, where practical load growth and PV penetration scenarios are considered. The simulation is carried out on a 15 MVA transformer in the IEEE 123 bus system. Simulation results show that PV penetrations below 100% indeed prolong the transformer lifetime. However, the saved transformer lifetime is not considerable compared to the total transformer lifespan.}, journal={2021 IEEE PES INNOVATIVE SMART GRID TECHNOLOGY EUROPE (ISGT EUROPE 2021)}, author={Wang, Xiaochu and DSouza, Keith and Tang, Wenyuan and Baran, Mesut}, year={2021}, pages={323–327} }
 @article{chen_xiao_baran_wang_2019, title={Online contingency analysis method for multi-terminal DC distribution networks with renewable resources}, volume={13}, ISSN={["1751-8695"]}, DOI={10.1049/iet-gtd.2018.5318}, abstractNote={In this study, an interval arithmetic-based method has been proposed for contingency analysis of line outage in DC distribution networks. This method incorporates the uncertainties in source/load which become considerable in the system with increasing renewable generations and time-varying loads. Two-stage contingency analysis approach is adopted in this method. For the first stage of contingency screening, a contingency filter has been developed based on interval matrix norm to quickly estimate the bounds of operating state in the post-outage period. For the second stage of detailed analysis to the selected contingencies, the interval analytical model is first transformed into a non-linear programming-based equivalent model. To solve this model accurately and efficiently, successive linear programming and reformulation-linearisation techniques are employed. The proposed method is benchmarked against Monte Carlo simulations and line outage distribution factor-based method.}, number={8}, journal={IET GENERATION TRANSMISSION & DISTRIBUTION}, author={Chen, Pengwei and Xiao, Xiangning and Baran, Mesut and Wang, Xiaochu}, year={2019}, month={Apr}, pages={1305–1314} }