Study of geothermal power plant electricial and control system with emphasis on reliability aspects

Abstract

The main aim when constructing and installing electrical and control systems for a power plant is to have continuous and trouble free operation of the plant. Geothermal power plants are very different from hydro power plants. It is difficult to restart a geothermal power plant after shutdown and it is exposed to H2S corrosion. This report emphasizes plants using the binary process. The electrical system of a geothermal power plant is described, including generator, power transformer, different alternatives for switchgear configuration, protective relaying, auxiliary power supply and instrumentation. The control system configuration is described along with its effect on reliability. Operation and maintenance aspects are discussed, and both the reliability and H2S corrosion prevention aspects are discussed. Finally, the electrical and control systems in the Aluto-Langano geothermal pilot power plant are included as an example.