frequency fluctuations

[Jraef]

I'd say either you are not in the US and you have a terrible utility, or you have a measurement issue. I have never heard of a grid-connected utility in the US who has an issue with line frequency. If they did, it would wreak havoc with every other utility that shared lines.

 

[72.5kv]

Typically its 60 +/- .2 for normal operations. Anything beyond those values for an extended amount of time, generators begin to drop out to protect themselves.