I could not find much better than the Wikipedia article:https://en.wikipedia.org/wiki/Surge_protector
Also may I point out that surge protectors are not really electromechanical devices (unless you are talking about high voltage reclosers used on electricity networks?)
A surge protector to my knowledge will protect anything plugged into from spikes of electricity, of 'surges', that come into the house from the power wires outside. These spikes can be from a distant lightning strike or some other disturbance in the generation or distribution of the public power. There are all levels of 'surges', so there is not just one level of protection.
Hope this helps
Hlo @Erric!! A surge protector is an appliance or device designed to protect electrical devices from voltage spikes when a sudden increase in voltage occurs, such as from a lightning strike or damage to a power line. A surge protector detects the excess current and safely diverts it through the house’s grounding path. More detail about this here ...https://www.cnet.com/how-to/10-things-you-should-know-about-surge-protectors/
See dude, surge protection is an electrical device that is used to protect equipment against power surges and voltage spikes while blocking voltage over a safe threshold (approximately 120 V). When a threshold is over 120V, a surge protector shorts to ground voltage or blocks the voltage. It works for Safety equipment.
We have to protect structures and buildings from lightning strikes and possible fire, or from the consequences caused by load independent active lightning current. In order to achieve above goals, we must use LPS. By using this we have to design suitable protection for internal or external part of the protection required component. This is known as Surge protection.
