Confining strings in the Abelian-projected

String representation of the Wilson loop is constructed in the 3D Abelian-projected SU(3)-gluodynamics, where the monopole condensation is modelled by the grand-canonical ensemble with the Coulomb interaction. It is demonstrated that the summation over world sheets, bounded by the contour of the Wilson loop, is realized by the summation over branches of a certain effective multivalued potential of the monopole densities. Finally, by virtue of the so-constructed representation of the Wilson loop in terms of the monopole densities, this quantity is evaluated in the approximation of a dilute monopole gas, which makes confinement in the model under study manifest