EPRI is continuing to develop new manuals to guide outages for other natural gas turbines, including the GE 6FA, 7FA, and 9FA turbines and the Siemens/MHI 501G turbine. EPRI is also planning to produce more web applications. "It allows us to digitize the outage checklists that we developed and also input your own documentation, like photos of the condition of components, how measurements were taken, and some of the inspection forms," Angello said. Besides being an interactive tool, the web applications also build a repository of information about what repairs and inspections have been completed and the condition of components that can be easily referenced during future outages.
At Enel, the development of the manuals has resulted in greater accountability for OEMs performing outages. For example, one result of Enel's collaboration with EPRI was the development of non-conformity sheets that Enel staff can use to record and, if necessary, dispute activities performed and results of outages. The record can be used if future disputes emerge. "Additionally, this non-conformity form has to include the mitigation or correction plan to fix the non-conformity," Alvarez said.
The main change Enel has implemented as a result of the work is a detailed and thorough approach to outage activities and quality control. "The greatest benefit has been to increase the reliability and performance of each component and the whole gas turbine after the outage execution," Alvarez said. "And we have a greater quality control and knowledge of all the activities carried out during the outage."
The existence of the manual also means less experienced staff won't have to depend on seasoned TVA engineers to answer their outage-related questions. "If the answer is in the manual, don't call me," Lafferty said. "If a recommendation is in the OEM manual, it's approved. And the same thing goes for the EPRI documents." The benefits of the outage manual extend well beyond TVA. There are over 5,000 GE 7EA units globally and over 100 GT26 turbines. In addition, the knowledge gained by developing these instructional guides helps improve outage approaches to other gas turbines.
Since being published, the manuals and tools have made a difference in how outages are conducted. For example, TVA is in the process of starting a new round of hot gas path outages across its fleet. With the help of the manual, Lafferty sees an opportunity to improve the outages' effectiveness and reduce the utility's reliance on outside consultants to oversee them. "Why do we spend as much as we do on each outage when we have an engineer on-site?" Lafferty said. "We should bring the consultant in one more time and make sure the TVA engineer is paired with them and the outage guide. That engineer will then be ready for the outage the next time we do one, and we won't have to spend as much."
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