No.5 Development of the "G" series gas turbine

MHI developed and put into operation the 1,200°C class M701D gas turbine and the 1,400°C class M501F/M701F gas turbines. Their high efficiency and reliability for combined cycle applications have been proven in field operations.
Based on the fact that combined cycle efficiency is highly dependent on the turbine inlet temperature, MHI newly developed the 1,500°C class M501G/M701G gas turbines, which MHI calls its G-series.
Development of the G-series gas turbine was started in the early 1990s, and the design was based on the following concepts.
First, proven features from the F-series were maintained. Second, the most advanced technologies in aerodynamic design, heat transfer design and new materials were introduced into the G-series. Third, our conventional design, critical for industrial gas turbines, was applied. Fourth, the turbine inlet temperature was increased to the extent where the NOx level and the metal temperature could be maintained at the same level as the F-series.

M501G rotor

Finally, verification tests were carried out prior to the production of the M501G gas turbine to ensure its high reliability. The trial operation of the M501G was conducted in 1997 in the combined cycle verification plant in MHI Takasago, Japan. After its successful trial operation was completed, commercial operation of the M501G started in June 1997.

M501G combined cycle
verifacition plant of MHl
Takasago Machinery Works

Also, the availability, defined as the actual power supply hours over the demanded power supply hours excluding scheduled shutdowns such as periodical inspections, during the commercial operation reached 98.8% as of March, 2002, which demonstrates the M501Gs high reliability. In addition, the trial operation of the first combined cycle system applying the M501G was started in 2002 in KEPCO Ilijian Co., Philippines.

Complete view of HigashiNiigata
Thermal Power Station
Tohoku Electric Power Co.

As for the 50Hz unit, two M701G Gas turbines started commercial operation in July 1999 in Tohoku Electric Power Co., Inc.