Search

With the proliferation of distributed generation in distribution networks, quickly and smoothly converting to a state of regional autonomy in the case of distribution network failure is one of the main challenges for the stable operation of a multimicrogrid (MMG). To address the aforementioned problem, this paper proposes coordinated control of the passive transition from grid-connected to islanded operation for a three/single-phase hybrid MMG. Under the premise of fully considering the constraints on the tie-line transfer power undertaken by the master power supply (MPS), the following two scenarios regarding safety and emergency are formulated: 1) when the output power of the MPS is in the safe range, the proposed strategy coordinates the energy storage (ES) in each submicrogrid (SMG) to achieve power balance; 2) when the output power is in the emergency range, this paper proposes a three-phase balance method based on a bubble sort to realize the combination optimization of the single-phase source-load-storage (SLS) and a fast power regulation method based on implicit enumeration for the SLS to reduce the tie-line transfer power, which could prevent failure of the mode transition from power overload. The test results verify the effectiveness and feasibility of the proposed coordination strategy. [ABSTRACT FROM AUTHOR]

With the microgrids large-scale interconnect to the power grid, a number of neighboring microgrids in a certain region will form a multi-microgrids (MMGs) system. In the development from microgrid to smart grid, the MMGs will be a new research hotspot after microgrid. The paper analyses the basic structure of the MMGs from many aspects such as voltage grade classification, AC/DC constitutional forms, and phase-sequence constitutional forms. Next the remote-area type, residential-area type, office-building type, industrial-park type and research-study type MMGs are analyzed according to the typical application scenarios. Lastly, based on the research of the four aspects of the planning and design, mode switching, optimal operation and control devices, the key technology of the MMGs is discussed and explored. [ABSTRACT FROM AUTHOR]

In this paper, a novel type of voltage control strategy based on internal model robust and compound control is proposed for three/single-phase hybrid multimicrogrid, which is composed of two parts, feedforward control and internal model robust feedback control. Feedforward control is mainly used to improve the dynamic response and reduce the steady-state error of the system. The objective of the internal model robust feedback control system is to achieve the optimization of control performance, robustness, and the ability to suppress disturbances of the whole system. In order to achieve the goal, the design of the internal model robust feedback controller is transformed into solving a convex optimization problem with linear matrix inequality constraints and linear objective functions. The proposed voltage control strategy is verified by a variety of experimental tests. The experimental results show that the controller can get better voltage output characteristics and robustness in dealing with micro-source output power fluctuations, loads abrupt change or nonlinear loads and unbalanced loads. [ABSTRACT FROM PUBLISHER]