In the top oven you have 3 elements. You have the fan element, the grill element and the base element.
As you have replaced the fan element in there then we can rule that out.
So this just leaves either the grill element or the base element.
For this you need to pull the oven out from the unit and turn the power off.
Then remove the rear panel and there you will see the wiring to the elements.
Disconnect the wiring on the grill element and tape them up and then turn the oven back on and see if it stops tripping.
If it does then its the grill element at fault.
But if still tripping then do the same to the base element and see what you find.
Now most of the time for a tripping faut its one of the elements but the odd time if the elements are fine then the selector switch for the top oven can fail. If it is this you can usually see were its blown so check the switch on the top and see what you find from there.
But check the elements first as like i said most of the time for a tripping fault like this its one of the elements that causes this.