Design of a New Gas Turbine-Generator System
1. INTRODUCTION :
Gas Turbine-Generator system has proximity to zero level due to absence of condenser. Therefore, Generator should have Terminal Bushings at the top of the Stator Frame. This avoids digging of tunnel / trench for routing Bus Duct and also avoids accumulation of gases from safety point of view. It was decided to develop a module THRI 108/44 for application with Gas Turbine. 2. DESIGN CHALLENGES : Since, bar type design of THRI 108/44 module for GTG application is not available. Hence the same had to be designed afresh taking the following major design challenges into consideration:
2.1. Shifting Terminal bushings for tapping power from bottom to top.
2.2. Location, number and size of coolers and cooler ducts in stator Frame to accommodate connections between Bus Bar and Terminal Bushings.
2.3. Proven ventilation scheme inside stator frame for cooling of stator core, windings and its overhangs.
2.4. Provision of static excitation system by providing slip ring shaft.
2.5. Position of Barring Gear on Exciter End (non drive end) requiring Slip Ring shaft rotor having a matching coupling with generator rotor on one side and barring gear on other side.
2.6. Provision of routing of piping emanating from bottom of stator and end shield in the foundation.
2.7. Routing of connections between bus bar and terminal bushings maintaining required electrical connections
2.8. Use of existing components as far as possible for inventory and variety reduction.
2.9. Mechanical and Electrical calculations for soundness of design.
3. ACTION PLAN :
3.1. Identification of assemblies for fresh designing - 34 numbers design groups out of 125 groups were identified to be designed afresh. (Annexure-1)
3.2. Carrying out Exhaustive Electromagnetic, Mechanical, Ventilation & Heat Transfer calculations.
3.3. Development of detailed design documents, scrutiny by technology, incorporating the changes suggested and release of
Gas Turbine-Generator system has proximity to zero level due to absence of condenser. Therefore, Generator should have Terminal Bushings at the top of the Stator Frame. This avoids digging of tunnel / trench for routing Bus Duct and also avoids accumulation of gases from safety point of view. It was decided to develop a module THRI 108/44 for application with Gas Turbine. 2. DESIGN CHALLENGES : Since, bar type design of THRI 108/44 module for GTG application is not available. Hence the same had to be designed afresh taking the following major design challenges into consideration:
2.1. Shifting Terminal bushings for tapping power from bottom to top.
2.2. Location, number and size of coolers and cooler ducts in stator Frame to accommodate connections between Bus Bar and Terminal Bushings.
2.3. Proven ventilation scheme inside stator frame for cooling of stator core, windings and its overhangs.
2.4. Provision of static excitation system by providing slip ring shaft.
2.5. Position of Barring Gear on Exciter End (non drive end) requiring Slip Ring shaft rotor having a matching coupling with generator rotor on one side and barring gear on other side.
2.6. Provision of routing of piping emanating from bottom of stator and end shield in the foundation.
2.7. Routing of connections between bus bar and terminal bushings maintaining required electrical connections
2.8. Use of existing components as far as possible for inventory and variety reduction.
2.9. Mechanical and Electrical calculations for soundness of design.
3. ACTION PLAN :
3.1. Identification of assemblies for fresh designing - 34 numbers design groups out of 125 groups were identified to be designed afresh. (Annexure-1)
3.2. Carrying out Exhaustive Electromagnetic, Mechanical, Ventilation & Heat Transfer calculations.
3.3. Development of detailed design documents, scrutiny by technology, incorporating the changes suggested and release of