Didn't look like an offsite power loss but a regular turbine trip because you lost condenser vacuum. If offsite power went out, you hear a loud buzz alarm coming from the electrical control panel and the indicators on the transformers will go red. If you only trip the turbine and you're quick enough you can keep the reactor going with the shutdown cooling system together with main cooling loop 1 pumps on low speed. RCIC will isolate the steam circuit and trip the reactor automatically.
If your referring to the transformer physically exploding due to the overload: There are safety systems that disconnect the plant from the transformer before that happens. If your referring to the transformer tripping every 0.5 seconds: Too many things where on so it kept dying lol else: I am not sure what you are referring to.