It's a bogus definition from a mathematical point of view, since under their definition the system could be a zillion MW short for 30 minutes, but that would not trigger an emergency as long as they believed they could scrounge up a zillion MW to cover during the next 30 minutes.
The protective relays on the system don't know that everything is going to be OK in thirty minutes; When they see an undervoltage or an underfrequency, they trip. It's that simple. Not all the PR BS in the world will prevent that from happening. Clearly, the rule was intended to be a line that, when crossed or projected to be crossed, the emergency would be declared. Period.
But Cal-ISO is saying "We can cross the line for a little while if we think we can come right back". IOW, it depends on what the definition of "is" is.
I'm cynical that anybody other than us FReepers will much care about this, though. [Unless there is a grid crash]. As we have seen lately, nobody cares about accounting rules until the company goes under.
But Cal-ISO is saying "We can cross the line for a little while if we think we can come right back". IOW, it depends on what the definition of "is" is.
I couldn't have said it better myself. If they lower frequency and don't trip off massive load because they are hoping that they will be OK the next hour, they are likely "leaning on neighboring" load control regions and risking uncontrolled outages in those other ISO regions to which they have major transmission interconnections. As a resident of one of those other ISO regions, I am shocked by the California ISO's approach to reliability and load control.
Now out the door and off to some vacation in the wilds of British Columbia. Ah?