A gas turbine electrical power plant comprising: - a combustor provided with at least one burner unit; wherein the burner unit extends around a longitudinal axis and comprises: • an internal burner supplied with air and fuel, which extends around the longitudinal axis and is provided with at least one internal swirler; • an external burner supplied with air and fuel, which extends around the internal burner and is provided with at least one external swirler; • an intermediate burner supplied with air and fuel, which is arranged between the external burner and the internal burner around the internal burner and is provided with an intermediate swirler; • the outlet of the intermediate swirler being arranged upstream of the outlet of the internal swirler or aligned with the outlet of the internal swirler in the supply direction of the air and the fuel directed towards the inside of the combustor; the outlet of the external swirler is arranged upstream of the outlet of the intermediate swirler; - a fuel supply unit provided with at least one first manifold configured to supply fuel to the internal burner of the at least one burner unit of the combustor, a second manifold configured to supply fuel to the external burner of the at least one burner unit of the combustor, and a third manifold configured to supply fuel to the intermediate burner of the at least one burner unit of the combustor; wherein the first manifold, the second manifold and the third manifold are connected to the same tank by respective supply lines provided with respective regulating valves (21a, 21b, 21c); -wherein the regulating valves (21a, 21b, 21c) are connected to a control system; wherein the supply of fuel to the internal swirler is regulated so that the air/fuel ratio is smaller than the air/fuel ratios of the intermediate swirler and of the external swirler. - a combustor provided with at least one burner unit; wherein the burner unit extends around a longitudinal axis and comprises: • an internal burner supplied with air and fuel, which extends around the longitudinal axis and is provided with at least one internal swirler; • an external burner supplied with air and fuel, which extends around the internal burner and is provided with at least one external swirler; • an intermediate burner supplied with air and fuel, which is arranged between the external burner and the internal burner around the internal burner and is provided with an intermediate swirler; • the outlet of the intermediate swirler being arranged upstream of the outlet of the internal swirler or aligned with the outlet of the internal swirler in the supply direction of the air and the fuel directed towards the inside of the combustor; the outlet of the external swirler is arranged upstream of the outlet of the intermediate swirler; • an internal burner supplied with air and fuel, which extends around the longitudinal axis and is provided with at least one internal swirler; • an external burner supplied with air and fuel, which extends around the internal burner and is provided with at least one external swirler; • an intermediate burner supplied with air and fuel, which is arranged between the external burner and the internal burner around the internal burner and is provided with an intermediate swirler; • the outlet of the intermediate swirler being arranged upstream of the outlet of the internal swirler or aligned with the outlet of the internal swirler in the supply direction of the air and the fuel directed towards the inside of the combustor; the outlet of the external swirler is arranged upstream of the outlet of the intermediate swirler; - a fuel supply unit provided with at least one first manifold configured to supply fuel to the internal burner of the at least one burner unit of the combustor, a second manifold configured to supply fuel to the external burner of the at least one burner unit of the combustor, and a third manifold configured to supply fuel to the intermediate burner of the at least one burner unit of the combustor; wherein the first manifold, the second manifold and the third manifold are connected to the same tank by respective supply lines provided with respective regulating valves (21a, 21b, 21c);