Reliability Enhancement of Power Transmission Under Sulfuric Corrosive Conditions - Case Study at Geodipa Dieng Geothermal Plant

Abstract

The Dieng Geothermal Power Plant (PLTP), operated by Geodipa Energi, plays a strategic role in supporting Indonesia’s transition toward renewable energy. The 150 kV Dieng Substation is responsible for transmitting electrical energy from the PLTP to the national grid. However, recent inspections have revealed corrosion-related damage to several transmission equipment units, including substation components and 150 kV overhead lines (SUTT), likely caused by exposure to sulfur compounds emitted from geothermal activity. Such corrosion poses a serious threat to the operational reliability and service life of transmission infrastructure. This study employs a failure analysis and risk-based approach to investigate the corrosion mechanisms affecting transmission assets. The methodology includes material identification and a series of diagnostic tests such as visual inspection using a stereo microscope, Optical Emission Spectroscopy (OES), hardness testing, tensile strength evaluation, metallographic analysis, and Energy Dispersive Spectroscopy (EDS). These analyses are used to determine the extent of degradation, assess the impact on equipment performance, and formulate mitigation strategies. Risk-based recommendations are developed to enhance system reliability under corrosive geothermal environmental conditions. The results of this study provide a comprehensive framework that can be used as a reference for corrosion management in geothermal-based transmission systems or other high-corrosion zones in Indonesia.