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In an article in the Institute of Electrical and Electronic Engineers (IEEE)
Spectrum Magazine, contributing editor Peter Fairley reports on how
Canadian power utility operators are using a technology called "synthetic
inertia" that can turn wind turbines from being "potential liabilities to
power grid stability into substantial contributors to it."

Originally Posted by Peter Fairley, IEEE

As renewable power displaces more and more coal, gas, and nuclear generation, electricity grids are losing the conventional power plants whose rotating masses have traditionally helped smooth over glitches in grid voltage and frequency. One solution is to keep old generators spinning in sync with the grid, even as the steam and gas turbines that once drove them are mothballed. Another emerging option will get a hearing next week at the 15th International Workshop on Large-Scale Integration of Wind Power in Vienna: synthetic inertia.

Synthetic inertia is achieved by reprogramming power inverters attached to wind turbines so that they emulate the behaviour of synchronized spinning masses.

Montréal-based Hydro-Québec TransÉnergie, which was the first grid operator to mandate this capability from wind farms, will be sharing some of its first data on how Québec's grid is responding to disruptive events such as powerline and power plant outages. “We have had a couple of events quite recently and have been able to see how much the inertia from the wind power plants was working,” says Noël Aubut, professional engineer for transmission system planning at Hydro-Québec.

Originally Posted by Peter Fairley, IEEE

Recent ride-through trouble in Australia appears to be an anomaly. Nine Australian wind farms did shut down during a series of storm-induced faults, that blacked-out the state of South Australia in September, and Australia's prime minister attacked renewable energy as a threat to energy security. However, an investigation by the Australian Energy Market Operator blamed errant wind farm control settings, and it says some operators have corrected them.

In fact, most wind and solar farms can do much more than just stick around during trouble. For example, most utility-scale installations—and even some residential rooftop solar systems—are designed to combat voltage sags on power grids. Their electronic inverters can detect brownouts and generate reactive power (AC whose current wave leads its voltage wave) to raise the grid voltage.

Synthetic inertia is about responded to crashing AC frequency, usually after the loss of a big power plant. When a big generator goes offline, it leaves the grid under-supplied. That will cause the AC frequency to fall.