IMPROVEMENT OF OPERATIONAL RELIABILITY OF AIR-COOLED TURBOGENERATORS FOR A GAS TURBINE PLANT

Modern mobile power plants driven by gas turbines traditionally use air-cooled turbogenerators, the levels of operational impacts of which are quit high. The system of electrical insulation of stator windings is a structural element that largely determines the reliable operation of turbogenerators, especially those with air cooling, taking into account the coupled impact of increased thermal, mechanical and electrical loads. An urgent task is to ensure high reliability of such turbogenerators. JSC Power Machines used the technology of vacuum pressure impregnation of the stator (Global VPI) for the production of air-cooled turbogenerators with a capacity of up to 225 MW. However, this technical solution cannot be viewed as successful, since during operation, a number of generators manufactured in recent years had malfunctions that led to unscheduled repairs. The production of a line of air-cooled turbogenerators, including a new turbogenerator for the GTE-170 project, was transferred to the technology of pre-impregnated tapes (Resin Rich). Such a transfer made it possible to ensure a commensurate level of influencing temperatures, modernize the system of slot seals and corona protection layers based on the use of elastic radial and lateral sealing of the rod in the slot. The existing problems of discharge activity, thermomechanical displacements and maintainability of stators were solved, which makes it possible to predict an increase in the operational reliability of such turbogenerators. In the design of the turbogenerator insulation system for the Resin Rich technology, only domestic materials were used, which is an important advantage in the current conditions.