Research On The Key Technics During Installation And Commission Process Of Large Combined Cycle Units

With the adjustment of power supply policy, more attention has been paid to the large combined cycle generator units. How to improve the installation techniques and the safe and reliable operation of these units are very important.The paper introduces the structure of the large gas turbine and steam turbine combined cycle generator units.Key techniques during installation process are summarized such as: fixator installation, gas turbine landing checking, load coupling installation, coupling alignment, gas turbine tie rod installation and adjustment, LP casing installation, connection of LP casing with condenser, HP casing load distribution, connection guide steam pipe with cylinder, generator rotor locating, and end cap closing, etc.Elevation is the main factor which influences bearing load distribution. The multi-rotor-bearing system elevation curve calculation model is set up using transfer matrix method. The paper discusses factors which influence multi-bearing load distribution. Influence of elevation on vibration is also analyzed and summarized in detail.For the efficient vibration fault diagnosis of large gas turbine symptoms of rotor imbalance, rub, oil whirl, thermal bend, steam induced whirl, rotor misalignment are analyzed and summarized. Vibration measurement method is also illustrated..Fault diagnosis examples of a 6B gas turbine unit and a 9FA unit are given.The installation technique, elevation analysis model, vibration and fault diagnosis method discussed in the paper,are important to the safe and reliable operation of large gas steam combined cycle units.