Generation loss avoided:  catching bearing vibration issues in gas turbines  

Detecting bearing vibration issues in gas turbines is notoriously challenging, particularly in the early stages. These turbines function at exceptionally high speeds and temperatures, which can obscure the subtle indicators of bearing wear or damage. Complicating matters further, issues further, issues, such as spalling or lubrication degradation, may generate intermittent vibration signals, further complicating the detection process before they escalate.

To prevent unexpected failures, a power generation site operating a GE Vernova 6B gas turbine in the Asia Pacific region utilizsed GE Vernova Monitoring & Diagnostics (M&D) services with Asset Performance Management (APM) SmartSignal. APM SmartSignal is an AI/ML driven predictive analytics platform designed to support critical equipment availability. With this advanced solution, the site received an early alert indicating abnormal behavior in gas turbine bearing #2.

Using digital twin technology, which creates a virtual model of the turbine, the APM SmartSignal software identified that the vibrations in gas turbine bearing #2 had exceeded the high threshold value set for journal bearing vibration. An increase in vibration levels at this threshold may indicate potential mechanical issues requiring immediate attention.

In response to this alert, GE Vernova's engineering services team initiated a comprehensive analysis. Upon detection of a high-potential issue, the assigned engineer collaborated with subject matter experts (SMEs) to further evaluate a the issue and understand the risk urgency. In this example , the assigned engineer escalated the issue to an SME, who confirmed the concern and initiated a dedicated case. The findings were included in the customer’s weekly report, a key tool for strategic planning and operational decision-making.

To identify the underlying cause, the first step was to assess the integrity of the gas turbine’s sensors. The customer was informed about the deviation and adhered to the suggestion to examine the mechanical integrity of the sensors, including probes, wiring, controller card, and configuration. No abnormalities were found.

Due to the complexity of the situation, once the sensor issue was ruled out, the assigned GE Vernova engineer raised an Engineering Request (ER) case and collaborated with GE Vernova Gas Power experts for a comprehensive review. After a thorough analysis, several recommendations for further investigation were provided to the customer.

Based on the recommendations, the customer strategically scheduled a hot gas path inspection (HGPI) shutdown to delve deeper into the issue. This specific shutdown refers to a planned outage during which key components in the hot section of a gas turbine such as combustion liners, fuel nozzles, turbine blades, and shrouds, are inspected, maintained, or replaced . These parts are subject to extreme thermal and mechanical loads, making them prone to wear and cracking.

During the inspection, upon removal of the gas turbine casing, the team discovered several components were either missing, damaged, or deformed. This critical finding necessitated replacement or repair of the affected parts of the hot gas path (HGP).

Following these corrective actions, the vibrations in bearing #2 returned to levels similar to those observed before the anomaly occurred.

With early notification and expert evaluation from GE Vernova, the customer was able to strategically plan a controlled unit shutdown mitigating the risks associated with prolonged operation under elevated vibration conditions. This proactive approach prevented potential catastrophic failures in critical components such as HGP section and fuel nozzles.

Upon completion of maintenance, vibration values returned to expected levels, providing the customer with confidence in the health of their equipment and the effectiveness of the corrective actions taken. implemented.

This case exemplifies the importance of proactive monitoring and close collaboration between GE Vernova and its customers. It highlights how early alerts, expert insights, and timely interventions can enhance safeguard asset reliability, minimize downtime, and extend asset life.

Ultimately, this comprehensive approach helped to prevent operational downtime and extensive equipment damage. It is estimated to have saved the customer approximately $1,076,064 in potential costs.

*Avoided costs are based on North American average production loss.