Grid-Forming Inverters: Are They the Key for High Renewable Penetration?

Market design for system security in low carbon electricity grids

“…On a more fundamental level, there is also the development of new modes of control from IBRs that aim to resolve some of the interface issues between first-generation IBRs and the network. The approaches taken to meet the challenge vary from fitting new technology into existing modes of control, to creating entirely new operational paradigms more suited to an inverter dominated grid (Matevosyan et al, 2019). Research and development have been underway on classes of 'grid-forming inverters', 8 which adopt new control schemes that have less reliance on grid measurements.…”

“…A large presence of online synchronous generators inherently slows the dynamic changes in the system, thereby allowing grid-following inverters to accurately track the grid voltage (Matevosyan et al, 2019). A weak grid is susceptible to a number of issues including: (1) mal-operation of fault-protection systems;…”

“…There are some high-level metrics that provide high-level screening tools as to whether a system is strong (NERC, 2017;Wu et al, 2018). Often however, system operators need to undertake detailed and computationally intensive simulations to determine whether particular combinations of resources will give grid voltages that are sufficiently resistant to disturbances (Matevosyan et al, 2019).…”

“…In other cases, the tuning of inverter settings and constraints on IBRs has been utilized as alternative measures (Filatoff, 2020). Longer term, newer technology and control schemes (such as grid-forming inverters) are being considered (Matevosyan et al, 2019).…”

Sufficient Conditions for Robust Frequency Stability of AC Power Systems

“…For instance, conversion from primary sources and storage is performed using not only synchronous machines but also converter-interfaced generators (CIGs). The latter can supply up to 50% of the annual demand and 100% of the hourly demand in places such as Colorado, Denmark, Hawai'i, Ireland, Tasmania, Texas and South Australia [3], [4]. This introduces new dynamics into the electric power system that are "yet to be fully understood" [5] and blurry the boundaries to which well-established models can be applied [6].…”