In "Deathly Hallows", when Harry was being moved, his wand made golden flames, how and why did it make golden flames on its own?

tu have to understand that Voldemort's soul in Harry and Harry's blood in voldemort and their wands share cores.Also when they fight in graveyard voldy's wand's some magic and Voldy's own magical skills(only a bit)transferred into Harry's wand. Thus his wand started to recognise voldy's magic as one who is both friend(in terms of bonds b/w their bodies) and a foe(in terms of bonds b/w their wands).
Thus when voldy performed magic in sky fight, Harry's wand recognised this magic as the person's who is both enemy and friend and in response it cast some of its kind of magic against Lucius's wand.
Its a bit lenghty but this is the best i can explain.

I hope you've finished the seventh befor tu read this! I think it has to do with the... kind of like the, as Dumbledore explanes, the blood of harry's in voldemort that binds harry to life and the "the wand chooses the wizard" thing - I think - but even ollivander doesn't know.

well it's a difficult subject even though dumbledore explained it in the end... i think that when harry was fighting voldemort in the graveyard and their wands connected thx to the twin cores harry's wand took sth from voldemort and "understood" that he was danger for him. so when the wand saw him again it recognised him even though voldemort didn't have his wand...that's why itself casted a really powerful spell to him... hope u get it now!

I dont get it either!!!!

harry's wand senced lord voldemort was near and shot the golden flames and how is still unknown 2 me

basically from what I have read and understood, Harry's wand spinning in his hand and shooting the golden flames is a reflex/defense mechanism, Harry's wand 'sensed' that Voldy was close por and reacted to protect its owner/master.

THIS IS LENGHTLY, BARE WITH ME- Wands take on and imbibe the characteristics of their masters. Since Harry has a piece of Voldemort's soul inside him, Harry and Voldemort's wand mimicked the relationship b/w the two. Bc of the connection between the two wizards, that night in the graveyard, Harry's wand absorbed some of the powers and qualities of Voldies wand(mimicking the relationship bc since Harry has part of Voldies soul, his wand-taking on the characteristics of it's master-absorbed the powers of Voldies wand like how, theoretically, Harry "absorbed" part of Voldies soul. The same thing happened to Harry's wand as it did to Harry himself. The wands were able to do this bc they share the same core. So, when Voldie pursued Harry that night of the 7 Potters, Harry's wand recognized Voldemort( an enemy) and since it absorbed Voldies powers earlier, it acted on it's own to protect Harry por shooting the golden flames. The flames being Voldies powers that harry's wand now posses. Also, Harry's courage helped create the powerful flames.