The Overview of Turbine’s Rotor Repair Methodology in 55 MW Geothermal Powerplant

The 55 MW Geothermal power plant located in West Java, suffered a Turbine's broken into 2 parts in the workshop during processing of crack relieved from the turbine rotor. The root cause assessment indicates that the severely damage on turbine crack is due to harsh operational environment, highly acid geo-fluid from the reservoir.The standard procedure to relieve the crack is by machining deep in to the crack and re-welding to the original size, and further machining to meet the original size of the rotor. Therefore, since the crack was depth enough close to the center of the rotor, during machining the rotor was broken, there is no standard procedure available for rotor turbin's repairement. Considering take or pay of supplying steam the immediate and prudent action shall be taken to reduce a high operation loss, while to avoiding sluggish purchasing of the new rotor option.Development of new methodology for the broken rotor repairing procedure is highly concern on technical aspect that qualify to pass an approved quality assurance based on international standard available. The proposed repairing methodology is by using a procedure of stub-weld method with a comprehensive quality check to assure quality process in each repair stage. Finally, the success rotor stub-weld method within 8 months, has return the powerplant's performance, and much faster recovery duration compared with procure a new purchasing turbine's rotor option.