The PJM Interconnection board of managers authorized $1.2 billion in upgrades and improvements to the high-voltage electric transmission system that serves the Mid-Atlantic and all or parts of other states between the Mid-Atlantic and Chicago, Ill. The announced changes call for upgrades and improvements to transformers, substations and other transmission facilities throughout the region served by PJM. With these changes, the PJM regional transmission plan includes more than $24.2 billion of transmission additions and upgrades since the first plan was approved by the board in 2000.