My own experience with utilities predates wind and solar. Every time I look at one of those energy farms, I wanna puke. I can only imagine what they do to the grid! You are much younger than me. So I'm curious about your experience with the impact of these systems on the grid?
That is a great question. Hopefully all my blabbering won't be something you already know.......As often the answer is complicated. I imagine you already know that in Ontario we are just a small part of a very large interconnected grid of distributed generation and loads. All of the ac generators in this grid are synchronized with only small phase angle differences between say a generator in Niagara Falls and one in say New York. The flow of power across the grid is controlled by excitation of the individual generators. The protection schemes for the high voltage transmission lines that transfer power across the grid are quite sophisticated and have to be to maintain stability of such a large control system.
Maintaining grid stability when a transmission lines delivering 1000MW to the grid suddenly (1-2 cycles) has to be isolated because lightning strikes the line is tricky, now imagine two or more occurring in a portion of the grid at near the same time!
One of many bad situations is a power-swing condition where large amounts of power start flowing back and forth in an uncontrolled fashion driven by the massive flywheel effect of the grid along the remaining uninterrupted lines. The entire grid can start to oscillate. This occurred in 2003.
https://en.wikipedia.org/wiki/Northeast_blackout_of_2003
One thing that makes maintaining stability tricky is that the generation portion of the grid tends to be in big chunks that are physically separated creating the opportunity for the described power swings to occur. So having a bunch of distributed wind or solar farms can really help with stability.
When the concept of NUGS (Non Utility Generation) being connected to the grid was in its infancy the general opinion of the protection engineers that designed and maintained the grid was " keep your crap off of our grid" it's sensitive to being disturbed and your useless little 1MW generator has the potential to bring down the entire grid because you 1MW guys have no clue about anything and your protection systems are next to useless.
The politicians overruled the protection engineers, so they did their best to tweak the protections to accommodate whatever the little generators would throw at the grid.
I worked extensively on many of those protection schemes both the really sophisticated ones for 500kV all the way down to some of the bottom of the bucket simplistic ones for the windmills you mentioned. I imagine we will have another big "event" that is started by one of these small generators, hopefully the more distributed nature of the grid will help enough to minimize how far the next big outage stretches.
I expect we will see a lot more wind farms because the wind generator price has dropped so much with scale, that nowadays it is often the lowest cost solution, cheaper than all other forms unless you happen to have a large untapped river where you need the generation, and it seems we're all out of those.
Overall I think they are the best solution available at this time. However I think that many have inadequate protection schemes and there is no excuse to not better regulate the protections being used on many of these generators.
On a side note as I mentioned that power flow is controlled by manipulating the excitation at each generator. The excitation systems have become sophisticated with built in PSS Power System Stabilizers. The concept is that the power system operators have to react in human time when trying to balance load and generation as the various automatic protection systems isolate portions of the grid in an effort to keep it from collapsing during an event, PSSs see these events and do their best to manipulate the excitation QUICKLY to counter the building instability. We did some pretty cool testing with 300MW generators where we introduced small step changes into the excitation feedback loop while observing with a strobe the massive generator first accelerate, then slow down with the classical ringing sinewave type response. We did this starting with really small steps and no PSS, then with the PSS and then slowly tweaked the steps larger and larger while tweaking the feedback control parameters. Really cool stuff with so much at stake.
