The Philadelphia School Partnership announced Wednesday nearly $3 million in grants to help three high-performing city charter schools expand.

The nonprofit's Great Schools Fund awarded First Philadelphia Preparatory Charter School $2.1 million to help support the addition of a second elementary school campus and a new high school in the Frankford area.

The grant will support adding 905 seats at First Philadelphia over the next three years. The expansion, which began last September, was approved by the Philadelphia School Reform Commission in 2013.

Mastery Charter Schools will receive $855,000 to expand two charters in the city. The funds will enable Mastery's Hardy Williams Academy in West Philadelphia to add 110 llth-grade seats in the fall and 40 12th-grade seats the following year.

Mastery also will use the funds to add 135 seats at its Gratz High School in North Philadelphia in the fall. The funds will help add a sixth grade and expand the seventh and eighth grades at the school on the Gratz campus.

In addition, Mastery will use the funds to add 90 12th-grade seats at Gratz in the 2015-16 academic year.

"We believe all students, regardless of background or neighborhood, deserve to attend a great school that will prepare them for success after graduation," said Mark Gleason, the partnership's executive director. "The school budget crisis is a challenge for all public schools, but there are teachers and principals throughout the city who are still finding ways to create transformational change.

"These grants will give more than a thousand Philadelphia young people access to high-performing schools and a better chance at college and a successful career," he said.

Founded in 2010, the partnership set a goal of raising $100 million to ensure more city students have access to high-quality schools. Its Great Schools Fund aims to add 35,000 seats in successful public, private, and charter schools by 2016-17.