TVSS vs. Surge Arrester

What is the application? Is it for utility power or are you designing electronic circuits?

TVS - Big honkin' zener diode designed for abuse

TVS - Two big honkin' zener diodes back-to-back for AC applications

MOV - Metal oxide varistor, fast breakdown device usually looks like an overgrown ceramic capacitor, these do 'wear out' over time and use.

GDT - Gas discharge tube, somewhat slow, but very effective in clearing a fuse or circuit breaker when hit with an overvoltage, conducts a lot of current, very reliable and long lived as long as they are not physically damaged.

These are the most common for protecting electronics from surges. Littelfuse has a nice document explaining these plus some other lesser known ones.

http://www.littelfuse.com/~/media/Electronics/Application_Guides/Littelfuse_Circuit_Protection_Technology_Application_Matrix_Application_Guide.pdf.pdf

TDK, Panasonic, EPCOS, Eaton, AVX, Bourns, Kemet, Murata, Schurter, Vishay and others all offer these kinds of products.

As for determining the correct size, it will depend on the application, voltage, current, etc. Plus you will have to use a crystal ball to guess what levels of surges to protect against unless your customer has spelled out the requirements. For utility work, there are probably guidelines for that but since I am in the electronics field and not utility, my knowledge is limited there.

^{"What is the difference between transient voltage surge suppressor and surge arrester? and how can i determine the correct size."}

Are you in North America or referring to a specification for North America? If so, one thing that is still confusing to people is the fact that officially, we no longer use the term "TVSS", it is now called an "SPD" for Surge Protective Device. That has caused a lot of confusion because the changes took place within "the community" of manufacturers, testing agencies and suppliers but the word didn't get out to everyone using, buying or specifying them. The article referenced above for example is dated 2003, BEFORE this change took place in 2009 with the adoption of the 3rd edition of ANSI/UL standard 1449. So that article is using TVSS where it should have been using SPD and implying there is a difference when there no longer is.

http://www.nemasurge.org/what-is-spd/

Now, what is the difference between and SPD and an SA (Surge Arrester)? Well, that depends on where in the electrical system it is located. If the device is located in the SECONDARY of a distribution system, i.e. the low voltage (<1000V) side, then there is no difference, the concept of a "secondary" SA was absorbed into the definitions of an SPD as well. So the only remaining difference is in that SAs are now relegated to being defined as PRIMARY (medium and high voltage) distribution system protections, along with Lightning Arresters.

If you are not referring to systems in North America, I have no idea...