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Customer Information
Introduction
Products
Thermal Advisory
Event Background
Société Tunisienne de l'Electricité et du Gaz (STEG) uses APM Performance Intelligence as part of their performance monitoring strategy. On June 27, 2024, the software indicated that Gas Turbine 5 at Bouchemma Power Station was experiencing a degradation of 4 MW.
"This event is a show case on the added value of GE Vernova digital solution APM PI, wich is a facility to maintain our fleet reliable and efficient. This is aligned with STEG road map to deploy advanced technology, using digital solution to monitor STEG’s Assets."
Recommendations & Actions
Utilizing APM Performance Intelligence, the STEG M&D team could see which section of the gas turbine the losses were coming from (Figure 1). They requested that the operations team check for observations that could be related to any abnormal operation or change in sensor behavior.

APM Performance Intelligence trend showing increased degradation on June 27, 2024 in Turbine Efficiency and Misc.
Image credit: GE Vernova
"Daily, we, STEG and GE M&D team, are reviewing and analyzing any deviation observed in the performance trend, KPI’s and asset health. We anticipate to do proactive actions to avoid any unplanned unavailability, this is totally in coordination with site team."
The site team requested to inspect a purge valve, and it was found not to be opening as per the opening purge order. The site performed 20VG3 purge valve maintenance, which restored the machine performance. The initial site recommendation, extended lean leanoperation of the machine, would have caused significant mechanical damagewithout resolving this issue. Fuel nozzle inspection has beenscheduled in the next BI inspection.
There was a similar history in the past on this machine in 2016 which caused damage to SFN1 and SFN2(Figures 2-3).
There was a similar history in the past on this machine in 2016 which caused damage to SFN1 and SFN2(Figures 2-3).
Customer Impact
4MW recovery was confirmed by APM Performance Intelligence over the course of the next few days(Figure 1).
Fuel nozzle mechanical damage was avoided, and the total financial impact was estimated to be$351,300 USD (~ 1,068,000 TND) and 96 saved hours (Figure 4).
Fuel nozzle mechanical damage was avoided, and the total financial impact was estimated to be$351,300 USD (~ 1,068,000 TND) and 96 saved hours (Figure 4).

2016 fuel nozzle damage; significant mechanical damage avoided in 2024
Image credit: GE Vernova

Cost benefit analysis
Image credit: GE Vernova