Case Study B: How can we help with your under-performing single-shaft unit.
Single-shaft CCGT plant with general decreased performance. Customer unsure if GT or HRSG or ST is to blame, neither where to start looking.
Scenario:
- 400 MW 1×1 Single-Shaft CCGT power plant.
- Coming out of an annual GT and ST maintenance event.
- Upon start-up, plant net efficiency is lower than expected.
- Without knowing the MW contribution of GT vs. ST, troubleshooting efforts cannot be efficiently applied.
- Vacuum level is not a concern.
Recommended Services:
- Detailed Performance Assessment.
- Total Plant.
Resolution
Audits & Testing
- Pre-mobilization historian data review.
- Transmitter checks on GT, ST and HRSG.
- IGV measurement & verification.
- Power & fuel flow validation.
- GT and WSC isolation audit.
- GT & ST control constant check.
- Condenser audit.
- Baseload, 80% and 60% load data collection.
Analysis
- Load split calculations.
- GT characterization: airflow, compr. efficiency, turb. efficiency, ISO Tfire.
- ST thermal characterization: Swallowing capacities, P-ratio and section efficiency analysis.
- HRSG characterization: flows & temperatures, full controls validation, section-by-section analysis.
Findings
+0.5%
CC EFFICIENCY
recoverable from GT valve leaks and erroneous Tfire control.
+0.2%
CC POWER & EFFICIENCY
recoverable from HRSG control deficiencies.
1%pts
PLANT TURNDOWN
improvable from recovered
GT performance.
How to Prevent: Delta Tracker can help monitor performance changes across outages.