59.774Hz? That's a huge frequency error. I saw 59.6 go by. 29.5 seconds behind. Those are load-shedding levels. Unusually cold weather and heat pumps. Ouch.
Back up to 60.080. They'll run a little fast if they can to make the remaining synchronous clocks catch up.
Power system inertia is defined as the ability of a power system to oppose changes in system frequency due to resistance provided by rotating masses. The level of inertia present in a system at any time is dependent on the amount of kinetic energy stored in rotating masses of synchronously-interconnected machines, including various types of generators as well as synchronously operating motor loads.
Back up to 60.080. They'll run a little fast if they can to make the remaining synchronous clocks catch up.