No. The wali can not just be arbitrarily assigned to some stranger. It has to be a legal guardian of the girl who is a Muslim adult of sound mind. If your father fits this description, then he is the wali.. therefore, he has to give consent and be present. Otherwise it is not valid.
(..If your father has passed away or is not Muslim, etc. then the wali is your paternal grandfather, if not him then your brother, etc. and the list goes down the relatives until it reaches that there is no suitable wali from the relatives, and thus guardianship is then placed upon the Muslim ruler/judge/leader).
Anyway - my dear sister, you could marry anyone suitable but you only have one set of parents who raised you and want what is best for you. If you do things secretly behind their backs, then subconsciously you know that they wouldn't approve of this guy you are 'with' because he is not very good/righteous. Do you want to end up with someone like that and possibly lose the love/support of your parents (not to mention be involved in sin since the marriage contract may not be valid)? No. So do things in a proper/halal and honorable manner, with the knowledge and approval of your parents. [It is a different story if the parents are being irrational. But if they are not, then obey them].