The utility model discloses a power capacitor, including capacitor case, core and porcelain bushing, the capacitor case top is equipped with boss and antenna grounding assembly, is equipped with the inside oiling copper pipe that communicates with capacitor case on the boss, antenna grounding assembly includes center post, top board, holding down plate, compression spring and lock nut, the center post lower part is the polished rod, and upper portion is equipped with the screw thread, and the center post bottom links firmly at the capacitor case top, and by lower supreme holding down plate, top board and the compression spring of cup jointing in proper order on the center post, lock nut threaded connection is on center post upper portion, be equipped with between core top or / and bottom and the capacitor case and fall the board of making an uproar, should fall the inboard of making an uproar and be equipped with inclosed cavity of making an uproar that falls. The utility model discloses a from the mode of top oiling, the inside flooding of power capacitor is effectual, can not the breaking vacuum state when finally sealed, and reliability, security and noise resistance can be outstanding, can be connected to a plurality of power capacitor's shell ground connection together.