Energization of Transformers in Medium Voltage Island Microgrids by Leveraging Grid Forming Inverter Control

Westman, Jan; Hadidi, Ramtin; Fox, Curtiss; Leonard, Jesse

doi:10.1109/icps51807.2021.9416595

Cited by 4 publications

(2 citation statements)

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“…When the switch is closed, the sudden deactivation of the synchronization values (ω sync and v sync ) causes power oscillations and circulation or inrush current. In addition, problems such as voltage collapse, power oscillations, and circulation inrush currents can cause black-out in the microgrids and GFIs [100], [102]. Therefore, problems that may occur in loading conditions after synchronization may adversely affect the frequency and voltage stability of the island-mode microgrid [99], [101].…”

Section: Commissioning or Loading Of Grid-forming Inverters After Syn...mentioning

confidence: 99%

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Frequency, Phase, and Magnitude Difference Locked-Loop Based Linear Synchronization Scheme for Islanded Inverters and Microgrids

Atmaca

Karabacak

2023

IEEE Access

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In recent years, integrating renewable energy sources (RESs) has achieved significant attention due to the growing demand for sustainable energy solutions. Inverter-interfaced Islanded Microgrids (IGs) have appeared as an advantageous approach to integrating RESs into the power grid. Grid-forming inverters (GFIs) are a critical component of IGs, and their synchronization is essential for stable and reliable operation. The literature has widely proposed soft transition, pre-synchronization, and re-synchronization to synchronize IGs to the main grid. However, methods for synchronizing GFIs in the islanded microgrid are restricted. Parallel operation of GFIs is required to guarantee the high-power demand of IG and improve voltage-frequency stability. For parallel operation, GFIs must be synchronized with each other. In the conventional synchronization control systems that are highly nonlinear, the linear proportional-integral (PI) controllers are commonly used in synchronization loops without considering the nonlinearity resulting from the initial condition dependency and cross-coupling. Thus, conventional synchronization methods can be exposed to concerns of stable operation, narrow operation area, and performance degradation. This study proposes a new linearized synchronization control system for GFIs in IGs. In this way, it is possible to analytically design robust linear controllers and ensure a stable operation, high performance, and wide (full) operation area. In addition, a new soft-commissioning method is proposed to deactivate synchronization loops and soft-start the synced GFI. The proposed system has been tested in real-time and CHIL hardware setups for two 550 kW GFIs operating in parallel, and the results in the perfect agreement are presented in this study.INDEX TERMS Commissioning, control hardware-in-the-loop (CHIL), grid-forming inverter, islanded microgrid, load sharing, microgrid, synchronization.

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Section: Commissioning or Loading Of Grid-forming Inverters After Syn...mentioning

confidence: 99%

“…[38], [48]. It can be difficult for the GFIs to take on a load without causing issues such as voltage collapse or circulating currents in the islanded microgrid and each other GFIs [58], [73], [72], [78], [101], [102]. It can also adversely affect the frequency and voltage stability of the islanded microgrid [34], [49], [99], [100], [101].…”

Section: Introductionmentioning

confidence: 99%