I am aware of steam/water cleaning technique for PV panels but I am not sure if there is vacuum cleaning technique available. If available can anyone suggest some vendors for this? Else is it possible to do vacuum cleaning technique

If only suspended dust is to be removed then vacuum can be used. But vacuum can not remove the dirt which sticks on the surface of glass due to moisture/oil. Vacuum on wet panels can be used same as wet vacuum cleaner but water anyway evaporates easily under sun that's why water cleaning still a best method. Other difficulties in vacuum cleaning may be length of the pipe (longer the pipe more drop in vacuum), more electrical energy requirement in vacuum and not easy to use.

As my early experiences in Dispaly industry. The excimer UV ( ~193 nm) could treat the glass very clean. But before that, water cleaning is necessary.

@ Ivan. Display industry cleaning was part of manufacturing process. Here we are talking outside environment. In have also worked in displays and there we used UV as well as vacuum with air gun for dust cleaning. The dust in that was suspended one and not like we see on panels in outside environment.

Mr Jiju, to my knowledge a small group of entrepreneurs in poona are working on developing such a system since nov 2012.please send inmail to deepesh.gujarathi@gmail.com giving my reference and he could give you a solution.

Dear Sir,
If you can send me your e mail id i can send you the attachment and the price .
Regards
Tanuja
suryasolarpower@hotmail.com