What is the term used to describe the recovery method from a total system blackout using a generating unit that can start and synchronize without external power?

The term used to describe the recovery method from a total system blackout, utilizing a generating unit that can initiate and synchronize without needing external power, is known as a "Black Start." This process is crucial for restoring power after a complete grid failure since it relies on generation units equipped to operate independently until other generating stations come online.

Black Start units are specially designed to start without relying on the electrical grid for power, which is essential in situations where no external power sources are available to aid in the restart process. By using these units, operators can gradually restore system frequency and voltage levels, enabling other units to synchronously connect back to the grid as stability is reestablished.

In contrast, the other terms refer to different types of starting scenarios in power generation. A Cold Start typically refers to starting a unit that has been completely offline for a long period; a Hot Start involves restarting a unit that was merely shut down recently, and a Warm Start lies somewhere in between these two scenarios, generally indicating a unit that has been offline but still retains some residual heat or operational readiness. None of these terms encompass the specific function of starting a generating unit without external power following a blackout.