Setting different electricity prices for different types of loads can effectively reduce the peak power consumption in microgrids (MGs). This paper proposes a category-specific pricing strategy for demand response program in dynamic MGs that can efficiently utilize renewable energy to achieve peak shaving and valley filling via establishing a Stackelberg game model. A state characteristic clustering (SCC) based non-intrusive load monitoring (NILM) scheme is first proposed, by which both the MG market operator (MMO) and users can access the detailed power consumptions of shiftable and non-shiftable loads. MMO then specifies detailed electricity prices dynamically based on user-side demand and satisfaction feedback, while users adjust their shiftable loads in a timely manner accordingly. Through solving the game optimization problem, the uniqueness and existence of the Stackelberg equilibrium is derived. Moreover, a distributed solution algorithm is presented to seek the unique equilibrium. Finally, a real residential power dataset is used to verify the effectiveness of the proposed category-specific pricing strategy. Numerical results show that the strategy reduces the peak-valley difference significantly, mitigates the power imbalance, and improves the utility of MG participators.

With the development of distributed generation (DG) technologies, distributed energy resources (DERs) with low capacity and low inertia are highly penetrated in the islanded AC microgrid. This has highlighted the need for secondary control strategies to remedy frequency deviation and strongly limitation of the frequency synchronization rate, which are associated with the primary control. To solve this problem, an optimal condition, in terms of explicit synchronization rate formula, is derived. Then, a distributed event-triggered control strategy is proposed to synchronize the microgrid frequency to the nominal value and maximize the synchronization rate for the primary control process. To reduce the communication and computation burdens, an event-triggered mechanism that enables each agent to update its input based on discrete information from only one of its neighbors are provided. The stability of the event condition and event interval are also analyzed using Lyapunov method. Finally, the theoretical results are applied to a parallel-feeder test system consisting of fourteen DGs, which verifies the effectiveness of the proposed strategy.

Research on the optimal power allocation of large-scale distributed generator (DG) units based on user power generation to access microgrids (MGs) in a multi-agent system framework has recently become the focus of modern grid and energy concerns. In this paper, according to the Cournot oligopoly game, the Nash equilibrium point between the power generation company and power generation user of the MG operating in island mode is obtained. According to the obtained Nash equilibrium point, the optimal ratio of power generated by the power generation company and by the power generation user in the model is calculated. At the same time, to achieve the maximum benefit and stable operation of the MG, a distributed cooperative control algorithm based on consensus theory is proposed. This control algorithm can cause each DG to generate power according to the total consumption load. The optimal power generation ratio distribution based on the Nash equilibrium point eliminates the steady-state frequency deviation of each DG in the MG, thereby ensuring the user’s power quality. The simulation results show that the control algorithm can achieve the above research goals.
© 2020, Springer-Verlag London Ltd., part of Springer Nature.

When distributed generation (DG) technologies are implemented in an islanded low-voltage microgrid (LVMG), the topological architecture directly affects the frequency synchronisability. Especially in cases of high DG penetration, the synchronisability of existing traditional topological architectures for LVMGs is very limited. However, a cobweb network topology, which combines the characteristics of several traditional topological architectures, has become a novel alternative for LVMGs. In this context, a compact criterion related to the Moore-Penrose inverse of the incidence matrix for the synchronisability of an LVMG is derived. Then, based on a linear transformation and Moore-Penrose inverse theory, a comparative analysis of the synchronisability of LVMG systems with different topological architectures is presented, the results of which indicate that the synchronisability can be significantly enhanced in a cobweb network topology and that the Braess paradox can also be effectively avoided during the corresponding topological transformation. The effectiveness of the proposed synchronisation criterion is validated based on the Iceland power network, modelled as a cobweb-based LVMG with large-scale DG integration, which exhibits excellent sychronisability.

This paper deduces some novel asymptotic stability criteria for different forms of multivariable fractional order systems (MFOS) whose fractional-order parameters are between 0 and 1 with time delays based on M-matrix. First, we extend the general asymptotic stability condition of ordinary systems to MFOS. Then, we investigate into the linear and nonlinear MFOS, then the asymptotic stability criterion of which derived based on M-matrix. Then, for the asymptotically stability study of the relatively complex MFOS with time delay, we also present the asymptotic stability criterion via the new method. In addition, we conduct an in-depth discussion on the stability of MFOS and integer order multivariable systems, and intuitively show the advantages of fractional-order systems through time responses. Compared with the fractional-order comparison principle, the new asymptotic stability criteria have the advantages of fewer restrictions, less conservativeness, and a wider applicability. Finally, four examples which contain MFOS covering different categories are shown.(c) 2022 Elsevier Ltd. All rights reserved.

This paper develops an improved distributed finite-time control algorithm for multiagent-based ac microgrids with battery energy storage systems (BESSs) utilizing a low-width communication network. The proposed control algorithm can simultaneously coordinate BESSs to eliminate any deviation from the nominal frequency as well as solving state of charge (SoC) balancing problem. The stability of the proposed control algorithm is established using Lyapunov method and homogeneous approximation theory, which guarantees an accelerated convergence within a settling time that does not dependent on initial conditions. Based on this, to significantly reduce the communication burdens, an event-triggered communication mechanism is designed which can also avoid Zeno behavior. Then sufficient conditions on the event-triggered boundary are derived to guarantee the stability and reliability of the whole systems. Practical local constraints are imposed to implement the control protocol, and the theoretical results are applied to a test system consisting of five DGs and five BESSs, which verifies the effectiveness of the proposed strategy.

In actual microgrids (MGs) networks, the information exchange between distributed energy resources (DERs) agents may be subject to various types of measurement noises and effected by communication time delays. This article proposes a resilient distributed multiagent control scheme for ac MG networks subject to additive noise and time-delay disturbances. The proposed multiagent control scheme is composed of three distributed consensus protocols, which is able to synchronize the output voltages and frequencies of inverter-based DERs to their reference values and achieve the optimal active power-sharing property by a low bandwidth communication network with noise and time-delay disturbances in almost sure convergence. By means of the stochastic analysis tools and algebraic graph theory, distributed consensus control protocols are designed to be employed for the secondary control level of MGs. On this basis, we deduce the stability criteria of the closed-loop MG system under noise and time-delay disturbances. As a result, the proposed consensus protocols can well restore the voltage and frequency's derivation produced at the primary control level, meanwhile, can well achieve the optimal power sharing even though there exist communication disturbances. Several simulation scenarios on an islanded MG network are provided to verify the proposed control protocols' performance.

Heterogeneous microgrids provide a promising solution for accommodating different distributed energy resources (DERs) and enhancing the system performance in terms of reliability, resilience, flexibility, and energy efficiency. With the penetration of microgrids, the cyber-enabled distributed control techniques are playing an increasingly important role in microgrids for coordinating a multitude of heterogeneous and spatially distributed DERs. To identify the influence of communication constraints on the reliability and stability operation of heterogeneous microgrids, this survey presents a comprehensive review and comparison of cyber-enabled distributed control techniques for microgrid's secondary control layer. Local controls of an unavailable state signal are calculated in a distributed and cooperative matter according to merely invoked cyber messages. Then, the recent developments in the communication constraints of distributed controlled microgrids are discussed. Specifically, the communication constraints (e.g., time-varying network topology, communication delay, noise disturbance, limited communication bandwidth, uncertainties of communication links, and cyber attacks) on the operation of the distributed controllers and the possible challenges are presented and compared. Finally, a short discussion section is contained to summarize the existing research and suggest some interesting research directions along with several open issues that are critical to further exploring the promising research area.