There are several manufacturers that make TLP generators. It's a bit of an investment, but I believe that they can also be rented. Another toolset that is gaining some popularity are ESD scanners. These scanners use TLP like (square wave) pulses injected into ESD sensitive points. One scanner manufacturer also offers a current scanning module that can generate a susceptibility map of a pcb, giving a visual representation of the current spreading on the board.
Thank u for a very useful information. Is there a tool that helps in performing TLP analysis much before going to the compliance testing, during design phase? Are there tools those could help in simulating TLP analysis for the ports prone to ESD?