Your schematic looks like a typical AC dimmer. Definitely not a crowbar. AC or DC might be referring to Universal motors which can operate on AC or DC.
So it will blow a breaker or fuse when that happens?
Do you want to trip on the the peak of the waveform or its average value for the overvoltage detect point?
Tripping on the peak would make it susceptible to noise spikes.
Here's my attempt at a demo
The simulation shows a sudden rise in line voltage between 50-70ms. The fuse blows as shown by the sudden drop of current thru the load.
First circuit looks fine to me - esenntially the same as eTech's in #7. You can adjust the value of the 0.1u cap to trade off noise immunity vs. response time.
It is essentially the same as a dimmer, just that there is no load in series with the triac (except for the fuse).
Try adding a few ohm resistor in place of the fuse in the model because spice models don't like infinite current circuits. The crowbar is supposed to represent throwing a crowbar across the bus bars - infinite current and blown fuse.
I also had a very bad time trying to simulate the circuit on LTSpice of even Proteus for that matter. Finally decided to give the hardware directly a try since it had only minimum components. I also used a much more simple circuit that only employs a thyristor and zener. You can find detials of it here https://circuitdigest.com/electronic-circuits/crowbar-circuit-diagram
Needless to say you have to use a TRIAC in place of Thyristor if your supply is AC. Also do people still use these circuits? I mean there are better options available not considering the cost though