Inertial responses provide a rapid and automatic injection of energy to suppress rapid FrequencyThe number of cycles occurring in each second in an Alternat... Click for more deviations, slowing the rate of change of frequency (RoCoF) This response has predominantly been provided in the NEM by the inherent electromechanical inertial response of large Synchronous GeneratorsA Generation Plant which is directly connected to the Power ... Click for more, as a by-product of energy production. It arises because the rotating parts of Synchronous GeneratorsAn entity that owns, operates and maintains large-scale Gene... Click for more (such as the turbine and rotor) connected to an AC power system spin in lock-step with the system frequency. The response is provided by the physical properties of the machines and does not require control system interaction.
This inertial response was historically abundant in many parts of the network. This is, however, no longer the case in certain parts of the network that have high levels of inverter-based resources (IBR)A diverse range of Energy Resources that, unlike many conven... Click for more. A lack of inertial response can present risks to system security in the event that these regions become separated from the rest of the NEM.