F-class gas turbines reliability solutions FAQ

Trips are often linked to four main challenges: flame scanner cooling water leakage, false high exhaust spreads, compressor bleed valve sticking, and false loss of flame. These issues can result in failed starts, trips, forced outages, and extended downtime.

• Flame scanner cooling water leakage: Increases the risk of turbine rubs due to potential tubing cracks or disconnections, which can lead to compressor rubbing, irreparable damage, and extended downtime.
• High exhaust spread: Uneven or excessive temperature variation across the turbine exhaust, which can be caused by inaccurate thermocouple readings or premature sensor issues.
• Compressor bleed valve issues: Occurs when a valve that extracts air from the gas turbine compressor during key operating points in startup or shutdown gets stuck open or closed and does not respond to commands. This issue can be caused by a corroded internal part.
• Loss of flame: An indication of sudden loss or instability of the combustion flame in the combustor. A malfunctioning flame scanner may cause false loss of flame.

Upgrading to non-optical flame detectors (NOFD) or fiber-optic dry flame detectors eliminates the need for water-cooled scanners, removing the risk of casing damage from leaks while providing reliable flame detection.

Start-reliability solutions are critical for plants operating in peaking or daily cycling modes, and for those transitioning to these profiles. GE Vernova offers a comprehensive suite of start reliability upgrades, including OpFlex controls, operability enhancements, and instrumentation and hardware improvements.

Key examples of these solutions are:

• OpFlex* Start Agility portfolio, with solutions including Start Assurance, can help improve both simple cycle and combined-cycle start reliability. Fast Start, Purge Credit, and Start-up NOx are other start-related solutions in the portfolio.
• OpFlex variable peak solution enhances control and operability by increasing the firing temperature to a specified level based on the gas turbine’s hardware and combustion system configuration.
• Instrumentation upgrades such as advanced compressor bleed valves, flame scanners, and gas valves.
• Flange-to-flange upgrade replaces the existing turbine from inlet to exhaust.

The recommended upgrades depend on each unit’s condition and operating profile. Each plant has site-specific needs. Contact us or your GE Vernova account manager to learn which upgrades are right for your plant.

For seasonal or intermittent operations, we recommend following the GEK28156Q (available in the GE Vernova Customer Portal) procedure, which is included in the plant’s Operation and Maintenance documentation. This document outlines protection and preservation measures for gas turbines and their associated equipment under various conditions, including:

• Short-term storage: For periods up to one year, beginning when the equipment ships from the factory to storage.
• Long-term storage: For storage periods exceeding one year.
• Pre-commissioning and installation: When the unit has arrived on-site but is still in the installation phase.
• Post-commissioning: When the unit is commercially operational but remains offline for extended periods (e.g., two weeks or more).

By following the GEK28156Q guidelines, users can reduce the risk of reliability challenges when units cycle between operational and preservation states. Contact us or your GE Vernova account manager for more details.

GE Vernova control systems use redundancy and diagnostics, including Triplex Metrics controllers, dual networks, and redundant sensors. This approach helps reduce unnecessary trips and helps protect the unit without relying on a single point of failure.

Users should review all published TILs as they become available, with priority given to those related to safety, compliance, and alert notifications. These carry the highest criticality and should be acted upon first.

Are you unsure if you have any unread TILs? Visit the customer portal to see any unread TILS or contact your account manager.

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GE Vernova is constantly seeking opportunities to enhance and improve our reliability upgrades. We apply learnings and technologies from H-class turbines (9HA and 7HA gas turbines) and utilize F-class fleet data from our engineering teams and customer support cases to develop upgrades that can help improve the reliability and efficiency of the overall F-class fleet.