Generating electricity using geothermal sources has a number of advantages, not least the renewable nature of the energy source but ensuring a reliable and efficient output depends on a robust maintenance regime. While the more routine tasks are completed by the on-site engineers, repairing faults with larger pieces of equipment such as generators and turbines requires more specialist skills.
Sulzer has been working closely with energy producers in the Philippines for a number of years, providing planned outage and emergency breakdown on-site support as well as design and manufacturing assistance from facilities around the world. In particular, the Birmingham Service Center has been involved in the manufacture of new coils for the generator stators and rotors and also providing engineers in country to complete inspections and refurbishments.
The most recent projects have involved two generators that were found to require rotor refurbishments following a routine maintenance inspection that indicated a potential fault in the rotor windings.
With the scope of the project agreed, a team of specialists was dispatched and arrived in the Philippines to begin the strip down of the 20 MW generators to enable the rotors to be worked on site under controlled conditions. The rotors were inspected and measured to confirm the dimensions of the coils and uncover any other defects within the rotor that needed attention.
It is common in the repair of rotors to reuse the original copper bars, in order to minimize the repair time, provided all of the coils prove to be suitable for reuse. Having stripped and cleaned the coils, they were reinsulated and tested before being reinstalled in the rotor.
Consistent communication throughout the Project
While this process was being completed, the inspection process had identified a retaining ring on one of the rotors as being in need of replacement, which required the in-house machine shop in Birmingham to manufacture, from a blank forge, a new component. Data taken from the original retaining ring by on-site mechanical engineers helped to create engineering drawings using 3D CAD software. This enabled the new retaining ring to be manufactured from 18Mn-18Cr steel material, finish machined and delivered in time for the reassembly.
Working closely with the on-site Sulzer Project Manager and support from the UK Service Center allowed the client to maintain a consistent line of communication throughout the project with regular updates on the progress.
Keith Barbier, Head of International Contracts and Projects at Sulzer's Birmingham Service Center comments: "It is crucial to turn projects such as these around as efficiently as possible in order to minimize the downtime within the client's facility. The combined expertise of our on-site engineers and the team here in Birmingham ensures that the generators will continue to operate reliably for many years to come."
The most recent of these two generators was commissioned in 1993 and so it has seen over 20 years' service but as the insulation begins to age so it is likely that similar faults will start to occur. Sulzer provides a proactive maintenance and testing service that helps to identify potential issues before they develop into more serious concerns. This allows the engineers to develop a planned maintenance program that will enable repairs to be completed with minimal interruption.
Sulzer continues to offer a wide range of engineering services to the power generation industry, using the latest insulation technology to improve the durability and efficiency of generators. Working through a global network or repair facilities, the company can deliver a complete range of solutions, from on-site technical support to complete, turnkey projects, all to the highest standards in safety and quality.