The Baltimore Ravens football franchise is footing the bill for $1.5 million in renovations at Renaissance Academy High School after owner Steve Bisciotti was moved by stories of students at the troubled school overcoming tough obstacles and the devotion they showed to the school when officials threatened to shut it down. Baltimore schools officials had announced earlier this year that a private donor, whom they declined to name, had come forward with $1 million for Renaissance. The Ravens revealed this week that they were the donors and said they agreed to give an additional $500,000 after getting a better idea of the costs to renovate the school. Ravens executives said they believe revealing the team’s involvement would bring some positive attention to the school, located on McCulloh Street in West Baltimore “We saw it as an opportunity to get involved and where the Ravens could make a difference,” said Richard W. Cass, the team’s president. Biscotti, who read about Renaissance in The Baltimore Sun, declined to be interviewed for this article.