A steam path audit is a physical inspection of the turbine steampath, conducted while the rotor is on the half-shell. The purpose is to identify and quantify performance problems due to the deterioration of steampath components. Engineers and maintenance personnel use the results of audits to identify the most cost-effective repairs and to justify repair recommendations.
MD&A offers both thermodynamic and structural audits. Audits are also an excellent way to predict the return to service performance of your machine, following repairs.
Data taken during a steampath audit can also help to:
- Measure the efficiency effects of deposits
- Assess recoverable leakage losses following repairs
- Determine losses due to surface roughness changes
- Provide quantifiable data for the review repair recommendations
- Evaluate the effects of solid particle erosion
- Calculate losses associated with foreign object damage
- Integrate decisions with alignment recommendations
- Provide historical records for future outages
Photographic Record
During an audit, photographs are taken of the damage and are included in each unit’s audit report. Photographs provide a convenient method for recording and confirming the history of repairs and the extent of the damage. Steam path audits are also a useful method to quantify and isolate the performance of new parts. OEMs often guarantee that certain steampath upgrades will contribute a specific percentage to improve turbine performance. A steampath audit is an accepted and repeatable method for quantifying the contribution of these parts, while also determining the performance gained as a result of other maintenance that was performed during the outage.
