@article{gong_cheng_sou_lam_chow_2023, title={Collaborative Distributed Optimal Control of Pure and Hybrid Active Power Filters in Active Distribution Network}, volume={38}, ISSN={["1937-4208"]}, DOI={10.1109/TPWRD.2023.3240462}, abstractNote={The high penetration of power electronics in the active distribution network (ADN) induces system-level voltage quality issues. Conventionally, pure and hybrid active power filters (APF/HAPF) have been adopted in ADN for voltage quality improvement. However, each APF/HAPF can only compensate for local voltage quality issues due to a lack of coordination. This paper proposes a collaborative distributed optimal control (CoDOC) of APFs/HAPFs for ADN system-level voltage quality improvement. First, the operational characteristic of APF/HAPF is discussed, which formulates the APF/HAPF constraints. Then, the objective functions, harmonic power flow equations, and APF/HAPF operational constraints are proposed to formulate the proposed CoDOC as a convex problem. Moreover, a primal-dual subgradient (PDS) based optimization algorithm is proposed to solve the CoDOC problem in a distributed manner. The practical application aspects of the proposed CoDOC are also studied and discussed. Finally, the proposed CoDOC is verified by case studies compared to other representative ADN-level control methods.}, number={4}, journal={IEEE TRANSACTIONS ON POWER DELIVERY}, author={Gong, Cheng and Cheng, Zheyuan and Sou, Wai-Kit and Lam, Chi-Seng and Chow, Mo-Yuen}, year={2023}, month={Aug}, pages={2326–2337} }
 @article{cheng_narayanan_holbach_stevens_cummings_rohde_guo_encarnacion_2022, title={Investigating Inverter-Based Resources Impacts on the Transmission Line Protection via Hardware-in-the-loop Simulation}, url={https://www.techrxiv.org/articles/preprint/Investigating_Inverter-Based_Resources_Impacts_on_the_Transmission_Line_Protection_via_Hardware-in-the-loop_Simulation/19561597}, DOI={10.36227/techrxiv.19561597}, abstractNote={Fault responses of inverter-based resources (IBR) are primarily dictated by the control algorithms and are fundamentally different from conventional synchronous generators. Hardware-in-the-loop simulation, commonly viewed as a robust tool for protection setting prototyping and testing, is used in this paper to investigate the impact of a wind farm, with type-4 full converter wind turbines, on the protection of a 345 kV transmission line in Texas, United States. This paper discusses two critical topics in detail: (1) wind farm IBR model development and validation against vendor PSCAD model, and (2) IBR impacts on distance and current differential protection.}, author={Cheng, Zheyuan and Narayanan, Srinidhi and Holbach, Juergen and Stevens, Jeremiah and Cummings, Michael and Rohde, Randall and Guo, Chenyan and Encarnacion, Noe}, year={2022}, month={Apr} }
 @article{cheng_chow_2022, title={Resilient Collaborative Distributed AC Optimal Power Flow Against False Data Injection Attacks: A Theoretical Framework}, volume={13}, ISSN={["1949-3061"]}, url={http://dx.doi.org/10.1109/tsg.2021.3113287}, DOI={10.1109/TSG.2021.3113287}, abstractNote={The cybersecurity of the distributed AC optimal power flow (ACOPF) against false data injection attacks (FDIA) is investigated in this paper. A collaborative distributed ACOPF solver, rooted in the dual decomposition concept, is first formulated, based on which a theoretical framework is then developed to model the distributed ACOPF and its cybersecurity in the presence of FDIA. Under this proposed cybersecurity framework, a reputation-based peer-to-peer trust management system (TMS) is proposed to secure the resilience of the system against FDIA. Finally, the proposed TMS is validated on the IEEE 69-bus benchmark system. The primary contribution of this paper is the proposed holistic resilience framework, in which the FDIA is analytically assessed and effectively defended. In the analytical results, we have established two key propositions: the FDIA generally has one degree of freedom; and the FDIA can be effectively detected and mitigated using the proposed TMS with one-hop redundancy.}, number={1}, journal={IEEE TRANSACTIONS ON SMART GRID}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Cheng, Zheyuan and Chow, Mo-Yuen}, year={2022}, month={Jan}, pages={795–806} }
 @article{cheng_ye_cao_chow_2021, title={A Homomorphic Encryption-Based Private Collaborative Distributed Energy Management System}, volume={12}, ISSN={["1949-3061"]}, DOI={10.1109/TSG.2021.3091624}, abstractNote={This article investigates the privacy issues in the distributed energy management system (EMS) of smart distribution systems and microgirds. A novel private collaborative distributed energy management system (P-CoDEMS) is proposed to solve the AC optimal power flow (ACOPF) problem in a distributed and private fashion. The proposed P-CoDEMS algorithm is based on an original primal dual subgradient distributed optimization technique and a state-of-the-art fully homomorphic encryption algorithm. The convergence and optimality of the proposed P-CoDEMS algorithm are evaluated on four representative systems. Simulation results indicate that the proposed P-CoDEMS algorithm can accurately solve the ACOPF problem in a fully distributed way while preserving individual agent privacy.}, number={6}, journal={IEEE TRANSACTIONS ON SMART GRID}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Cheng, Zheyuan and Ye, Feng and Cao, Xianghui and Chow, Mo-Yuen}, year={2021}, month={Nov}, pages={5233–5243} }
 @article{liu_cheng_zhang_sun_deng_cheng_chow_2021, title={A Multi-Agent System Based Hierarchical Control Framework for Microgrids}, ISSN={["1944-9925"]}, DOI={10.1109/pesgm46819.2021.9638070}, abstractNote={The Microgrid is one of the most cost-effective solutions for integrating Distributed Energy Resources (DERs) into distribution systems. The hierarchical control framework, which typically includes primary, secondary and tertiary control layers, is adopted in the Microgrid to meet the control requirements of different spatial and time scales. Given the growing concern on the centralized control framework's scalability and robustness, the distributed control framework has become an indispensable development trend. In this paper, we propose a Multi-Agent System (MAS) based hierarchical control framework for Microgrids, where each agent consists of a series of DERs (i.e., distributed generations, storage units and loads). In the proposed framework, each agent has its specific task for regulating the local output voltage, and will collaborate with neighbors to achieve the overall objective of Microgrids in a totally distributed manner. Through extensive simulations and experiments, it is demonstrated that the proposed framework possesses high robustness to link failures and good scalability.}, journal={2021 IEEE POWER & ENERGY SOCIETY GENERAL MEETING (PESGM)}, publisher={IEEE}, author={Liu, Mengxiang and Cheng, Zheyuan and Zhang, Zhenyong and Sun, Mingyang and Deng, Ruilong and Cheng, Peng and Chow, Mo-Yuen}, year={2021} }
 @article{ye_cheng_cao_chow_2021, title={A Random-Weight Privacy-Preserving Algorithm With Error Compensation for Microgrid Distributed Energy Management}, volume={16}, ISSN={["1556-6021"]}, url={http://dx.doi.org/10.1109/tifs.2021.3106161}, DOI={10.1109/TIFS.2021.3106161}, abstractNote={Recently, collaborative distributed energy management systems (CoDEMS) have emerged as an effective solution to manage distributed energy resources in microgrid. In CoDEMS, devices collaborate in a distributive manner over communication networks to meet electrical loads and supply balance at minimum cost. However, mutual information exchanges among the devices in CoDEMS may leak important information about the devices states. In this paper, we investigate the challenging problem of how to achieve optimality while preserving the privacy of CoDEMS at relatively low cost. Unlike many previous works that preserve the privacy by using additive noises, we propose a novel random-weight privacy-preserving algorithm with error compensation, termed as REP-CoDEMS, for CoDEMS. In the proposal, each distributed device generates two random weights each time and it communicates with its neighbor conveying values based on the weights, incremental cost estimation and power imbalance estimation information along with a novel error compensation term to eliminate the error induced by the random weights. We theoretically prove that the proposed REP-CoDEMS algorithm converges and preserves the privacy of all devices. We also derive analytical expressions of the maximum privacy disclosure probability for initial and final states of the CoDEMS. In addition, we conduct extensive simulations and the results demonstrate the effectiveness of the proposed algorithm.}, journal={IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Ye, Feng and Cheng, Zheyuan and Cao, Xianghui and Chow, Mo-Yuen}, year={2021}, pages={4352–4362} }
 @article{huang_cheng_chow_2021, title={A Robust and Efficient State-of-Charge Estimation Methodology for Serial-Connected Battery Packs: Most Significant Cell Methodology}, volume={9}, ISSN={["2169-3536"]}, DOI={10.1109/ACCESS.2021.3081619}, abstractNote={Safely and efficiently managing a battery pack consisting of hundreds to thousands of battery cells is a critical but challenging task due to commonly observed uncertainties, e.g. temperature, battery degradation and SOC estimation inaccuracy. This paper proposes a robust and efficient most significant cell methodology that estimates the battery pack SOC depending on the determined most significant cells. The estimation adopting this methodology is robust to variations of temperature, battery degradation and battery cell SOC estimation inaccuracy. A battery pack simulator and a real battery pack designed for electric vehicles were used as prototypes to illustrate the high performance, robustness and effectiveness of the proposed methodology. Moreover, the proposed algorithm requires light computational effort, making it suitable for real-time operation.}, journal={IEEE ACCESS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Huang, Cong-Sheng and Cheng, Zheyuan and Chow, Mo-Yuen}, year={2021}, pages={74360–74369} }
 @article{cheng_cheng_2021, title={Collaborative Distributed AC Optimal Power Flow: A Dual Decomposition Based Algorithm}, volume={9}, ISSN={["2196-5420"]}, DOI={10.35833/MPCE.2020.000395}, abstractNote={This paper proposes a novel dual decomposition based algorithm that solves the AC optimal power flow (ACOPF) problem in the radial distribution systems and microgrids in acollaborative and distributed manner. The proposed algorithm adopts the second-order cone program relaxed branch flow ACOPF model. In the proposed algorithm, bus-level agents collaboratively solve the global ACOPF problem by iteratively sharing partial variables with its 1-hop neighbors as well as carrying out local scalar computations that are derived using augmented Lagrangian and primal-dual subgradient methods. In addition to the algorithm innovation, this paper proposes two distributed computing platforms, i.e. high performance computing based and hardware-in-the-loop platforms, to validate and evaluate the proposed distributed algorithm. The computationand communication performances of the proposed algorithm are quantified and analyzed over typical IEEE test distribution systems. Experimental results indicate that 1) the proposed collaborative distributed ACOPF solver can be executed on a fully distributed computing structure and yield accurate ACOPF solution; and 2) the proposed distributed algorithm has a low communication overhead.}, number={6}, journal={JOURNAL OF MODERN POWER SYSTEMS AND CLEAN ENERGY}, author={Cheng, Zheyuan and Cheng, Mo Yuen}, year={2021}, month={Nov}, pages={1414–1423} }
 @article{lucia_she_chen_cheng_chow_dunai_hilairet_huang_monmasson_umetani_et al._2021, title={Emerging Trends in Industrial Electronics: A Cross-Disciplinary View}, volume={15}, ISSN={["1941-0115"]}, DOI={10.1109/MIE.2020.3032942}, number={1}, journal={IEEE INDUSTRIAL ELECTRONICS MAGAZINE}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Lucia, Oscar and She, Jinhua and Chen, Allen C. and Cheng, Zheyuan and Chow, Mo Yuen and Dunai, Larisa and Hilairet, Mickael and Huang, Victor and Monmasson, Eric and Umetani, Kazuhiro and et al.}, year={2021}, month={Mar}, pages={127–139} }
 @article{hang_ye_cheng_cao_chow_2021, title={Simulating and Evaluating Privacy Issues in Distributed Microgrids: A Cyber-Physical Co-Simulation Platform}, ISSN={["1553-572X"]}, DOI={10.1109/iecon48115.2021.9589187}, abstractNote={Privacy is of great importance for microgrids and has gained much attention recently. By eavesdropping on the communications among the devices, attackers may infer sensitive system operation information and user behavior due the intimate interplay between communication and control in mircogrids. In this paper, in order to facilitate simulational evaluations of privacy preservation techniques for microgrids, we develop a versatile cyber-physical co-simulator which integrates both networked communication and power system control subsystems as a whole. The co-simulator is built upon MATLAB/Simulink and OMNeT++ along with a module that coordinates the two tools in real-time simulations. Based on the co-simulator, we evaluates three privacy-preserving algorithms proposed in the literature, and find that SFPA performs better than PEMA and REP-CoDEMS in aspect of protecting the privacy of controllable inputs, but REP-CoDEMS and PEMA has a better performance considering both controllable inputs and uncontrollable inputs.}, journal={IECON 2021 - 47TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY}, publisher={IEEE}, author={Hang, Nianzhi and Ye, Feng and Cheng, Zheyuan and Cao, Xianghui and Chow, Mo-Yuen}, year={2021} }
 @article{huang_cheng_balagopal_chow_2020, title={A Novel Most Significant Cell Methodology in a Battery Pack with Serial Cell Connection}, DOI={10.1109/ieses45645.2020.9210686}, abstractNote={Rechargeable lithium-ion batteries are now widely adopted in our life. To fulfil various energy and power requirements in real-world applications, battery cells are connected to form battery packs. The cell-to-cell difference exists in the battery pack after manufactured, and this difference will further deteriorates when the battery cells are exposed and used in various operating conditions. This unavoidable cell-to-cell difference results in early cut-off on the battery pack, which influences the performance of the battery pack and makes accurately estimating the battery pack SOC challenging. This paper proposes a novel real-time algorithm to effectively identify the most significant cells in a serial-connected battery pack in order to accurately estimate the SOC of the battery pack. A battery pack composed of ten serial-connected battery cells is carried out in this paper to evaluate the performance of the proposed algorithm. The results show that the most significant cells are successfully identified, and the SOC of the battery pack is estimated accurately based on the identified most significant cell.}, journal={2020 2nd IEEE International Conference on Industrial Electronics for Sustainable Energy Systems (IESES)}, publisher={IEEE}, author={Huang, Cong-Sheng and Cheng, Zheyuan and Balagopal, Bharat and Chow, Mo-Yuen}, year={2020}, month={Sep} }
 @article{ye_cheng_cao_chow_2020, title={A Random-Weighted Privacy-Preserving Distributed Algorithm for Energy Management in Microgrid with Energy Storage Devices}, DOI={10.1109/ieses45645.2020.9210675}, abstractNote={In collaborative distributed energy management system (CoDEMS) with distributed energy storage devices (DESDs), privacy is getting more and more attention, because customer and grid may suffer losses due to unintentional privacy disclosure. In this paper, we firstly introduce the networked model, distributed energy management problem and consensus-based CoDEMS algorithm. Then, we analyze the disclosure of true power supply and demand with adding-noise privacy-preserving consensus-based distributed (APCD) algorithm. To preserve the privacy, we proposed the random-weighted privacy-preserving consensus-based collaborative distributed energy management system (RP-CoDEMS) algorithm to preserve the confidentiality of the neighborhood communication. The effectiveness of RP-CoDEMS algorithm is demonstrated by simulation.}, journal={2020 2nd IEEE International Conference on Industrial Electronics for Sustainable Energy Systems (IESES)}, publisher={IEEE}, author={Ye, Feng and Cheng, Zheyuan and Cao, Xianghui and Chow, Mo-Yuen}, year={2020}, month={Sep} }
 @article{cheng_chow_2020, title={An Augmented Bayesian Reputation Metric for Trustworthiness Evaluation in Consensus-based Distributed Microgrid Energy Management Systems with Energy Storage}, DOI={10.1109/ieses45645.2020.9210638}, abstractNote={Consensus-based distributed microgrid energy management system is one of the most used distributed control strategies in the microgrid area. To improve its cybersecurity, the system needs to evaluate the trustworthiness of the participating agents in addition to the conventional cryptography efforts. This paper proposes a novel augmented reputation metric to evaluate the agents' trustworthiness in a distributed fashion. The proposed metric adopts a novel augmentation method to substantially improve the trust evaluation and attack detection performance under three typical difficult-to-detect attack patterns. The proposed metric is implemented and validated on a real-time HIL microgrid testbed.}, journal={2020 2nd IEEE International Conference on Industrial Electronics for Sustainable Energy Systems (IESES)}, publisher={IEEE}, author={Cheng, Zheyuan and Chow, Mo-Yuen}, year={2020}, month={Sep} }
 @article{vu_nguyen_cheng_chow_zhang_2020, title={Cyber-Physical Microgrids: Toward Future Resilient Communities}, volume={14}, ISSN={["1941-0115"]}, DOI={10.1109/MIE.2019.2958039}, abstractNote={Microgrids can be isolated from large-scale power transmission/distribution systems (macrogrids) to deliver energy to their local communities using local energy resources and distribution systems when power outages occur in the macrogrids. In such situations, microgrids could be considered the last available resource to provide energy to critical infrastructure.}, number={3}, journal={IEEE INDUSTRIAL ELECTRONICS MAGAZINE}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Vu, Tuyen V. and Nguyen, Bang L. H. and Cheng, Zheyuan and Chow, Mo-Yuen and Zhang, Bin}, year={2020}, month={Sep}, pages={4–17} }
 @article{cheng_chow_2020, title={Reputation-based Collaborative Distributed Energy Management System Framework for Cyber-physical Microgrids: Resilience against Profit-driven Attacks}, DOI={10.1109/isgt45199.2020.9087737}, abstractNote={This article investigates the resilience of the consensus-based distributed microgrid energy management system (MG-EMS) against profit-driven attacks. A holistic framework, called reputation-based collaborative distributed EMS (R-CoDEMS), is proposed to model the system dynamics, profit-driven adversaries, and the cybersecurity of the distributed MG-EMS under profit-driven attacks. Simulation results on a real microgrid system indicate that the R-CoDEMS can effectively detect, mitigate, and recover from the attacks in a fully distributed fashion. The main technical contributions of this research work are: (1) systematically formulating and quantifying the system adversary, assets, threats, vulnerabilities, and risks of the consensus-based distributed MG-EMS; (2) proposing a reputation-based attack detection and mitigation strategy to overcome single and coordinated profit-driven attacks.}, journal={2020 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT)}, publisher={IEEE}, author={Cheng, Zheyuan and Chow, Mo-Yuen}, year={2020}, month={Feb} }
 @article{cheng_chow_2020, title={Resilient Collaborative Distributed Energy Management System Framework for Cyber-Physical DC Microgrids}, volume={11}, ISSN={["1949-3061"]}, DOI={10.1109/TSG.2020.3001059}, abstractNote={This article investigates the resilience of the consensus-based distributed economic dispatch (ED) in cyberphysical DC microgrid energy management system (EMS). A holistic framework, called resilient collaborative distributed EMS (R-CoDEMS), is proposed to model the system dynamics, adversaries, and the cybersecurity of the consensus-based distributed ED. Under the R-CoDEMS framework, a reputation-based distributed attack detection and mitigation algorithm is also proposed to improve the system's resilience against typical non-colluding and colluding false data injection attacks. The effectiveness and scalability of the proposed R-CoDEMS countermeasure is evaluated on a typical microgrid system and large-scale networks via numerical simulations.}, number={6}, journal={IEEE TRANSACTIONS ON SMART GRID}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Cheng, Zheyuan and Chow, Mo-Yuen}, year={2020}, month={Nov}, pages={4637–4649} }
 @inproceedings{cheng_feng_2018, title={A Study of DER Volt and Var Droop Aggregation for Reactive Power Support to Transmission System}, DOI={10.1109/pesgm.2018.8585986}, abstractNote={Rapid growth of distributed energy resources (DERs) is shifting the center of gravity of power supply towards the distribution system. DERs can provide real and reactive power support to the transmission system through aggregation as virtual power plant (VPP). The challenge is how to control the individual DERs to realize the desired volt and var droop response at the grid supply point (GSP). This paper analyzes the aggregation behavior of droop-controlled DERs on a study system designed to capture the essential attributes of the problem being studied. The simulation result shows that the aggregate droop curve deviates significantly from the ideal droop reference by more than 25% on average and by 230% in the worst case. The deviation tends to deteriorate in heavy loading conditions, and the load model effect on the deviation is found to be less than 1% on average. Notably, the study demonstrates that a given target piece-wise linear droop curve can best be approximated by tuning the individual piece-wise linear droop curves. These conclusions are meaningful in defining GSP performance indices and control targets in the context of DER-dominated VPP.}, booktitle={2018 IEEE Power & Energy Society General Meeting (PESGM)}, publisher={IEEE}, author={Cheng, Zheyuan and Feng, Xiaoming}, year={2018}, month={Aug} }
 @inproceedings{cheng_chow_2018, title={The Development and Application of a DC Microgrid Testbed for Distributed Microgrid Energy Management System}, DOI={10.1109/iecon.2018.8591816}, abstractNote={The microgrid is envisioned to be the building block of the future smart grid, for its abilities to host distributed energy resources, to improve grid reliability, and to enhance system resiliency. One of the most studied research topics of the microgrid is the distributed microgrid energy management system. However, the algorithm prototyping and hardware validation still remain great challenges at the current stage. This paper proposes a highly scalable, customizable, and low-cost DC microgrid testbed framework that enables fast distributed MG-EMS prototyping and provides proof-of-concept validation. Moreover, an application example is presented to demonstrate the functionality and validity of the proposed microgrid testbed.}, booktitle={IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society}, publisher={IEEE}, author={Cheng, Zheyuan and Chow, Mo-Yuen}, year={2018}, month={Oct} }
 @article{cheng_duan_chow_2018, title={To Centralize or to Distribute: That Is the Question A Comparison of Advanced Microgrid Management Systems}, volume={12}, ISSN={["1941-0115"]}, DOI={10.1109/mie.2018.2789926}, abstractNote={The advanced microgrid is envisioned to be a critical part of the future smart grid because of its local intelligence, automation, interoperability, and distributed energy resources (DER) hosting capability. The enabling technology of advanced microgrids is the microgrid management system (MGMS). In this article, we discuss and review the concept of the MGMS and state-of-the-art solutions regarding centralized and distributed MGMSs in the primary, secondary, and tertiary levels, from which we observe a general tendency toward decentralization.}, number={1}, journal={IEEE INDUSTRIAL ELECTRONICS MAGAZINE}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Cheng, Zheyuan and Duan, Jie and Chow, Mo-Yuen}, year={2018}, month={Mar}, pages={6–24} }
 @inproceedings{cheng_chow_jung_jeon_2017, title={A big data based deep learning approach for vehicle speed prediction}, DOI={10.1109/isie.2017.8001278}, abstractNote={Vehicle speed prediction plays an important role in Data-Driven Intelligent Transportation System (D <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ITS) and electric vehicle energy management. Accurately predicting vehicle speed for an individual trip is a challenging topic because vehicle speed is subjected to various factors such as route types, route curvature, driver behavior, weather and traffic condition. A big data based deep learning vehicle speed prediction algorithm featuring big data analytics and Adaptive Neuro-Fuzzy Inference System (ANFIS) is presented in this paper. Big data analytics examines copious amounts of speed related data to identify the pattern and correlation between input factors and vehicle speed. ANFIS model is constructed and configured, based on the analytics. The proposed speed prediction algorithm is trained and evaluated using the actual driving data collected by one test driver. Experiment results indicate that the proposed algorithm is capable of accurately predicting vehicle speed for both freeway and urban traffic networks.}, booktitle={2017 IEEE 26th International Symposium on Industrial Electronics (ISIE)}, author={Cheng, Zheyuan and Chow, Mo-Yuen and Jung, Daebong and Jeon, Jinyong}, year={2017}, month={Jun}, pages={389–394} }
 @inproceedings{cheng_duan_chow_2017, title={Reliability assessment and comparison between centralized and distributed energy management system in islanding microgrid}, DOI={10.1109/naps.2017.8107366}, abstractNote={As the number of DER in the microgrid increases, the electrical interfaces and communication interactions are more sophisticated and frequent than ever, which poses a great challenge for microgrid Energy Management System (EMS). Efforts has been made to address this challenge. The solutions generally fall into two categories: centralized and distributed solution. Comparing with centralized EMS, distributed EMS is commonly considered as a more promising and reliable approach. Nonetheless, the current microgrid reliability research are focused on the physical layer of microgrid, such as overhead lines, transformers, circuit breakers and the DER device itself. The reliability analysis that considers controller failure and EMS framework are not reported in current publications. In this paper, a general reliability assessment methodology based on Monte Carlo simulation is presented to assess the reliability of both centralized EMS and distributed EMS in islanding microgrid. Different performance metrics such as system-average-interruption-frequency-index (SAIFI) and expected-energy-not-supplied (EENS) are used to quantify and evaluate the reliability. Simulation results indicates that using the same controller, the microgrid with distributed EMS is able to achieve better reliability indices, and the distributed EMS can achieve same level of reliability using less reliable controllers.}, booktitle={2017 North American Power Symposium (NAPS)}, author={Cheng, Zheyuan and Duan, Jie and Chow, Mo-Yuen}, year={2017}, month={Sep} }