 The modern power system is transitioning away from synchronous machines and toward inverter-dominated systems with large-scale renewable energy sources. To ensure system stability, many researchers have proposed using inverters with virtual inertia control algorithms to mimic synchronous generators. This paper reviews the current state of the art in virtual inertia implementations, discusses their advantages and disadvantages, and identifies areas where further research is needed. This article was authored by Ajwal Tamrakhar, Deepesh Shrestha, Manisha Maharjan, and others.