查看更多>>摘要：Networked microgrids (MGs) have emerged as a favored and promising scheme to facilitate the integration of distributed energy resources and enhance the resiliency of power support. To advance the flexible operation of distribution systems, this paper proposes an optimal scheduling model for networked MGs, embedding three innovative medium-voltage direct current (MVDC) technologies with voltage source converters, namely two-terminal back-to-back MVDC systems (BMSs), three-terminal BMSs, and multi-terminal BMSs. Compared to traditional MVDC systems, these newly introduced back-to-back MVDC technologies exhibit strengthened operational flexibility. We first formulate their explicit models based on real-world applications, incorporating constraints related to normal operation and power supply modes. Then, we present a day-ahead scheduling model for networked MGs equipped with these BMSs. Subsequently, we develop tractable reformulations for nonlinear constraints considered in the scheduling model, leading to a mixed-integer linear programming problem. Finally, numerical simulations on the IEEE 123-bus test system are conducted to demonstrate the effectiveness and superiority of the proposed scheduling model.
查看更多>>摘要：Building energy planning is significantly challenged by climate change, particularly the increasing frequency of heat waves impacting heating and cooling demands. Current planning methodologies neglect the impacts of heat waves on energy consumption and do not accurately model the temperature-dependent performance of heat pumps (HPs). This paper addresses the critical issue of designing energy-efficient and climate-resilient buildings through optimal resource configuration under uncertain weather conditions. A two-stage stochastic optimization model for building energy system planning is proposed. In the first stage, the capacities of energy resources are optimized; in the second stage, operational strategies under various weather scenarios are determined. A novel long-term load forecasting method using morphing techniques is developed to generate scenario trees accounting for both normal conditions and heat waves, capturing the impact of climate change on energy demand. Additionally, a temperature-dependent HP model with finite partial output levels is introduced, improving upon existing fixed coefficient of performance models to reflect practical operational characteristics. Simulation results on a real educational building in Stockholm demonstrate the effectiveness of the approach, showing an 8.33% reduction in heating capacity requirements and a 62.14% decrease in solution time, enhancing both resilience and computational efficiency.
查看更多>>摘要：Multiple DC Microgrids (MGs) can be interconnected by interlinking converters (ICs) to support each other through coordinated control strategies. However, the nonnegligible transmission line resistance results in inaccuracies in decentralized coordination at steady state. To address this issue, an adaptive and decentralized control strategy is proposed to eliminate the impact of transmission line resistance and facilitate accurate power sharing among the DC MGs. The proposed strategy injects a perturbance to estimate the transmission line resistance based on the IC signals sampled before and after the perturbance, obviating the need for additional measuring devices on the transmission line. With the estimated results, the proposed strategy compensates for the transmission line resistance through virtual resistance, achieving accurate power sharing among the DC MGs under coordinated control. The compensation and coordination operations rely on the local signals from the IC, ensuring this power coordination in a decentralized manner. Furthermore, the estimation and compensation algorithm is decoupled at each IC port, allowing the easy extension of the proposed strategy. This paper discusses the application of the proposed strategy in three scenarios: two interconnected DC MGs, and several DC MGs interconnected via a multiport IC or multiple ICs. Using the example of two DC MGs with line impedance considered, the system stability is analyzed based on a small-signal model. Lastly, the feasibility of the proposed strategy in these scenarios is validated by the simulation and hardware-in-loop tests.
查看更多>>摘要：This paper proposes a two-layer distributed network predictive control strategy for AC microgrids (MGs) clusters with communication delays. The strategy involves establishing a two-layer communication network to regulate the voltage/frequency of all distributed generators (DGs) within the MG cluster to predefined reference values while ensuring consistency in incremental costs across individual MGs. Furthermore, a multi-step predictive controller is designed, where delay information in the controller is replaced by the latest predictions, enabling proactive compensation for delays. Stability analysis of the closed-loop AC MG clusters is conducted and the response matching condition is derived between the second and tertiary levels. Finally, real-time simulations on an OPAL-RT platform are performed for AC MG clusters, validating the robustness of the proposed control method against communication delays.
查看更多>>摘要：DC microgrids, due to their deep integration of control, computing, communication technologies, and physical equipment, are susceptible to cyber-attacks. Consequently, this paper is dedicated to the development of a novel attack-defense framework for generalized DC microgrids. Firstly, an unknown-inputs-based false data injection (FDI) attack strategy is studied from the adversary’s perspective, unlike traditional stealthy attacks requiring non-minimum phase zeros or unstable poles, which conceals the attack signal as false unknown inputs (FUI) to maliciously disrupt current sharing and voltage balancing. Secondly, a comprehensive analysis of the stealthiness and destructiveness of FUI attack is provided, and a dual-observer-based detector is well constructed to detect the FUI attack and isolate the compromised distributed generation units. Then, structured Lyapunov matrix and semidefinite programming are ingeniously employed to solve the distributed observer gains simultaneously. Moreover, plug and play (PnP) performance is also analyzed to ensure the scalability of proposed FUI attack detector. Finally, the destructiveness and stealthiness of proposed FUI attack, as well as the effectiveness of designed detection scheme are demonstrated through simulations using MATLAB/SimPowerSystems Toolbox.
查看更多>>摘要：In DC microgrids (DCMGs), DC-bus signaling based control strategy is extensively used for power management, where mode switching plays a crucial role in achieving multi-source coordination. However, few studies have noticed the impact of mode switching and switching strategies on system voltage stability. To fill this gap, this paper aims to provide a general analysis framework for mode switching-induced instability in multi-source DCMGs. First, manifold theory is employed to analyze the stability of the DCMG switched system. Subsequently, the instability mechanism and its physical interpretation are explored. The positive feedback activated by the decreasing DC bus voltage during the switching process leads to instability. Switching strategy may inadvertently contribute to this instability. To improve stability, a novel control method based on mode scheduling is proposed, by adjusting switching strategy and thereby correcting the system trajectory. Finally, both real-time simulations and experimental tests on a DCMG system verify the correctness and effectiveness of theoretical analysis results.
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IEEE