Synthetic Inertia

Inertia is the capability of a system to store kinetic energy in rotating mass. There is no commonly agreed on definition of synthetic inertia yet. However synthetic inertia could be defined as the controlled contribution of electrical torque from a unit that is proportional to the Rate of Change of Frequency (RoCoF) measured at the terminals of the unit. [1] This provides an electrical torque which is proportional to the RoCoF, which resists changes in frequency and thus mimics the release of energy of rotating synchronous generator.

Technology Types

• Virtual Synchronous Machine (VSM)

• Swing Equation Based Inertial Response (SEBIR)

Components & enablers

• Converters

• Control unit

• Others depending on technology chosen

• Active power source (e.g. battery, rotating mass of wind turbine, HVDC link)

Advantages & field of application


Technology Readiness Level

TRL 7 – Integrated pilot system demonstrated

Supply Chain

Commercial availability: Partly \nProduction capacity: Medium \nExemplary vendors:\nMarket development: The technology is currently still in discussion. In the future synthetic inertia and/or FFR could potentially become subject to an ancillary services market or could be defined in the grid connection requirements. The development of a market for a product is likely related to the definition of a product or technical requirements in the future.

Research & Development

Current fields of research: Power system integration with regard to unintended interactions, transient behaviour, use of different sources, distributed synthetic inertia, synchronisation in low inertia grids

Other: Enhanced dynamic modelling is needed to fully understand effects on the system depending on the level power system inertia and the quantity as well as speed of FFR and synthetic inertia.

Number of IEEE publications since 2013: 92

Best practice performance


Best practice application


Within the Hydro-Quebec region a mandatory requirement to provide synthetic inertia was introduced to all newly connected wind farms. [1]





2 Eriksson, Robert, et al.: Synthetic Inertia versus Fast Frequency Response: a Definition. 15th Wind Integration Workshop, Vienna 2016.