It is against building codes to install a power cable or extension cord through the wall. The electricity to your TV must be ran using ROMEX cable. This is an approved electrical cable for in-wall use. This means you need to install a new outlet behind the TV. To make sure your TV power cable doesn’t hit the back of the TV, make sure you install a recessed outlet.
That being said, every piece of equipment in your home theater system should be on a surge protector. You can get a surge protected circuit up to your TV by placing a surge protector behind your TV which is difficult and expensive.
To kill two birds with one stone, we use an AC outlet extension like the Vanco Rapid Link Power. By clicking the link, you can see a cool video on how it works. This is specific to home theater installers so you won’t find it at your home supply warehouse. It allows you to send a surge protected circuit up to your TV while obeying all building codes.