A nozzle sector for a turbine of a turbomachine, comprising: a radially outer platform for supporting vanes, a radially inner platform for supporting vanes, a first end vane, a second end vane and at least one first central vane (82, 83) between the end vanes (81, 84) along a circumferential direction of the platforms (Z-Z), the vanes (81, 82, 83, 84) radially extending between the platforms (24, 26) along a span direction (X-X) of these vanes, cooling means (37, 50, 44, 46, 54, 56) for cooling the vanes, configured to cool each of the vanes (81, 82, 83, 84) by circulating cooling air therein, wherein the cooling means (37, 50, 44, 46, 54, 56) are configured to differentially cool the or each central vane (82, 83) at least with respect to the first end vane (81, 84), the cooling means (37, 50, 44, 46, 54, 56) comprising cooling holes (44, 46, 54, 56), the cooling holes passing through an external wall of at least one of the vanes and/or a cooling jacket inside the vane, first cooling holes (44, 46, 54, 56) passing through the external wall of the first of the end vanes (81, 84), characterized in that second cooling holes (44, 46, 54, 56) are passing through the external wall of the first central vane (82, 83), the total area of the second cooling holes being higher than that of the first cooling holes. a radially outer platform for supporting vanes, a radially inner platform for supporting vanes, a first end vane, a second end vane and at least one first central vane (82, 83) between the end vanes (81, 84) along a circumferential direction of the platforms (Z-Z), the vanes (81, 82, 83, 84) radially extending between the platforms (24, 26) along a span direction (X-X) of these vanes, cooling means (37, 50, 44, 46, 54, 56) for cooling the vanes, configured to cool each of the vanes (81, 82, 83, 84) by circulating cooling air therein, wherein the cooling means (37, 50, 44, 46, 54, 56) are configured to differentially cool the or each central vane (82, 83) at least with respect to the first end vane (81, 84), the cooling means (37, 50, 44, 46, 54, 56) comprising cooling holes (44, 46, 54, 56), the cooling holes passing through an external wall of at least one of the vanes and/or a cooling jacket inside the vane, first cooling holes (44, 46, 54, 56) passing through the external wall of the first of the end vanes (81, 84), characterized in that second cooling holes (44, 46, 54, 56) are passing through the external wall of the first central vane (82, 83), the total area of the second cooling holes being higher than that of the first cooling holes. wherein the cooling means (37, 50, 44, 46, 54, 56) are configured to differentially cool the or each central vane (82, 83) at least with respect to the first end vane (81, 84), the cooling means (37, 50, 44, 46, 54, 56) comprising cooling holes (44, 46, 54, 56), the cooling holes passing through an external wall of at least one of the vanes and/or a cooling jacket inside the vane, first cooling holes (44, 46, 54, 56) passing through the external wall of the first of the end vanes (81, 84), characterized in that second cooling holes (44, 46, 54, 56) are passing through the external wall of the first central vane (82, 83), the total area of the second cooling holes being higher than that of the first cooling holes.