A turbine vane is provided. The turbine vane may include an inner shroud having an upper surface and a lower surface, a seal unit disposed in the lower surface of the inner shroud and defining a first region and a second region in the lower surface of the inner shroud, a first impingement unit arranged in the first region and comprising a first impingement plate facing the inner shroud defining a first impingement chamber therebetween, wherein the first impingement plate is configured to receive cooling air and form impingement jet directed to the first impingement chamber, a second impingement unit arranged in the second region and comprising a second impingement plate facing the inner shroud defining a second impingement chamber therebetween, and at least one connector flow channel configured to direct cooling air from the first impingement chamber to the second region, wherein the second impingement plate is configured to receive cooling air from the at least one connector flow channel and form impingement jet directed to the second impingement chamber.