Abstract: A kite power system includes a ground control unit with a generator (30), and a kite connected to the generator (30) via at least two main traction cables (10, 11). A rotor part (31) of the generator (30) includes a winch pulley (32, 33) for each of the at least two main traction cables (10, 11), and each of the winch pulleys (32, 33) is indirectly mechanically connected to the generator (30). A further aspect relates to a kite for use in a kite power generation system, having an airfoil shaped body (20) with one or more air filling apertures (23) in a leading edge part of the airfoil shaped body (20). At least two main traction cables (10, 11) are connected to the airfoil shaped body (20), which further includes an additional filling aperture (21) in a side part of the airfoil shaped body (20).