Premix burner and method of operation

The invention describes a premix burner, in which fuel and air can be mixed to form a fuel/air mixture, for forming at least one stable flame front within a downstream combustion chamber for driving a gas turbine which follows the combustion chamber, having a premix burner casing which is formed in the manner of a tube open at the upstream end, is connected in the downstream direction to the combustion chamber via a transition contour and through which air can flow, a burner lance, which is designed as an inner tube, projects into the interior of the premix burner casing on the upstream side, encloses a flow passage which is annular in cross section together with the premix burner casing, and has an inner tube wall which surrounds an inner flow passage and in which there is at least one fuel-addition unit for feeding fuel into the inner flow passage and at least one further fuel-addition unit for feeding fuel into the annular flow passage is provided in such a manner that downstream of the inner tube the fuel/air mixture ignites within the flame front in the region of the combustion chamber.