Multiple-Time-Scales Hierarchical Frequency Stability Control Strategy of Medium-Voltage Isolated Microgrid

Abstract

Abstract-In this paper, an islanded medium-voltage (MV) microgrid placed in I. INTRODUCTIONThe increasing penetration of renewable-energy-based distributed generations (DGs) in distribution networks promotes the emergence of new changes in power generation, transmission and distribution. Integrated DGs, energy storage systems (ESS), and local loads within a certain area, microgrid is an effective way to achieve active distribution networks, which can reduce the impact . However, the proposed methods exist fundamental conflict that the secondary voltage control can worsen the already poor sharing of reactive power, while enforcing reactive power sharing can result in poorer voltage profiles than with only primary control conversely [35]. Moreover, most of the microgrid control structures reported in the current literature are proposed for particular microgrids only formed by ideal parallel inverters, which neglect the dynamic of the primary sources, thus being inappropriate to integrate the diversity of DGs in a certain area.

Multi-Time Scale Model Order Reduction and Stability Consistency Certification of Inverter-Interfaced DG System in AC Microgrid

“…IIDG in microgrid adopt the three-phase voltage source-type inverter interface that applies PQ control during the grid-connected operation and the droop control when switching to the islanding operation to regulate the grid voltage and frequency [25]. This process is equivalent to a voltage source.…”

“…According to the properties of the matrix Schur complement, the characteristic root of the system after order reduction satisfies Equation (25). When |sI 2 − A 22 /ε| = 0, ε = 0, the corresponding characteristic roots of |sI 1 − A n | = 0 and |sI − A| = 0 are the same:…”

Design of a Fractional Order Frequency PID Controller for an Islanded Microgrid: A Multi-Objective Extremal Optimization Method

“…However, how to control the voltage and frequency of a microgrid in an islanded model has been one of the major challenges for researchers recently [6], because it is often more difficult than-in grid-connected mode. More specifically, when the microgrids operate in the grid-connected mode, the control of voltage and frequency depends on the regulation of the main utility grid.…”

Optimal Load Shedding for Maximizing Satisfaction in an Islanded Microgrid

“…However, real-time optimal utility under various operating conditions is not possible. Although considerable research on load shedding systems such as islanding detection and autonomous operation/management have been extensively studied [5], research on load shedding algorithms remain an open issue for further research. A load shedding algorithm determines the amount of power demand that can be reduced.…”