such effect could be introduced in the ray-tracing simulation as a gaussian shaped optical deviation error. I do not know your software, but if it allows the definition of specular deviation deviations in mirror surfaces, normally defined after a standard deviation value (values in the order of 2 to 4 mrad, e.g.) you could add wind load effects as a "tracking deviation", after a composed standard deviation.

you have also to take in account the fact that, with a wind speed greater than 40 (or 60) km/h, your collector (PT, heliostat) is in stow position, and looses some solar energy.

The answer of Pedro Horta is correct, but it remains the problem, that no one can predict the actual specular deviation of Your tracking device in dependency of wind speed an wind direction. You could eventually make experiments at an outdoor facility. Or You can try to define different deviation between wind perpendicular and parallel to the trough. But it remains a guess.

I am working on the ASAP (Advance system analysis program). This is an advance optical simulation software based on monte-carlo ray tracing concept. i have made a parabolic trouch with receiver on solidworks and import this file in ASAP. but after that i don't know how to create a light source for parellel rays and wind loading. Is there any tool. Can i do optical analysis in Ansys. Or any one from you have worked on any optical simulation software.

There is so references in Chapter 3 of this Thesis:

https://www.researchgate.net/publication/260844761_Automatic_positioner_and_control_system_for_a_motorized_parabolic_solar_reflector

Also check Chapter 8 in the book power from the sun, there you will find

references to studies where loading factors are modelled.

Thesis Automatic positioner and control system for a motorized para...

Also search for this type of simulations:

http://www.cfdsupport.com/construction-at-wind.html