Towards Resiliency Enhancement of Network of Grid-Forming and Grid-Following Inverters

Abstract

This paper proposes an autonomous control scheme to mitigate voltage-frequency excursions observed in a network of grid forming (GFM) and grid following (GFL) inverters in a power electronics dominated grid (PEDG). The proposed control scheme leverages GFL inverter's ability to dynamically adjust their power set-points as well as change their operation mode on-the-fly to enhance the PEDG resiliency. A supervisory controller (SC) comprising of a Droop-ΔP estimator coupled with an optimal power allocator (OPA) module dynamically adjusts the power injections from GFL inverters to maintain the power balance and restore frequency in response to disturbances. Moreover, the proposed self-ranking based coordinated mode selection (SR-CMS) algorithm dynamically reconfigures the inverter's operation mode (either GFM or GFL) to enhance the PEDG resiliency in response to events and ensure GFM inverter allocation in grid clusters. Several case studies are performed to validate the feasibility, performance, and robustness of proposed autonomous control. Finally, the proposed scheme is experimentally validated on a small-scale hardware testbed.

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

“…GFIs are generally used in Microgrids, wind, solar power plants, and hybrid distribution systems with different energy sources [36], [37], [38], [39]. As grid-forming inverters become more widespread, the need for advanced control strategies and algorithms to synchronize these inverters to the islanded microgrid or other GFIs becomes increasingly important [33], [34], [40], [41]. GFIs are an advanced type of inverter used in power systems to provide stable and reliable power to the grid [42], [43].…”

Maximum Power Point Tracking Algorithm of Photo-Voltaic Array through Determination of Boost Converter Conduction Mode

“…Systems can be attached in a microgrid to fulfill neighborhood capacity. For larger systems, the use of string inverters and a central inverter is preferred [13,14]. Standalone PV systems, on the other hand, work without needing to be connected to a grid, and are capable of supplying electricity in the absence of a grid using excess energy stored in a battery [15,16].…”