Stalks Turbine Problems

  

 

Stalks Turbine Problems

 

Reliable and efficient operation of gas turbines is essential for the profitable operation of today’s power generation and processing facilities.

To maximize the availability and reliability of a gas turbine, while at the same time minimize maintenance costs, it is necessary to continually monitor and assess the unit’s condition.   Typically, turbine operators have performed this function manually or semi-automatically - two methods that can be prone to error.

The Tiger™ monitoring and diagnostic system provides turbine operators with continuous expert analysis and diagnosis by gathering performance data once per second every second of the day.

By taking more than 600 measurements directly from the controller of a gas turbine, or the distributed control system, Tiger automatically makes an assessment of the condition of the gas turbine and a diagnosis of any problems that have occurred or are developing.   The system uses a variety of specialized fault detection mechanisms in combination with traditional knowledge based systems and advanced techniques for reasoning about sequences of events over time.

Virtually all Tiger users have become members of the ‘Tiger $150K Club’, which represents the combined cost savings and benefits that are accrued through operating the system.

The following examples describe real incidents of ‘Tiger $150K Club’ members and give a sampling of the wide range of areas in which Tiger can provide assistance and cost savings.

Chemical Processing Facility

A chemical plant customer operates a Frame 5 gas turbine in a two-shaft configuration as the prime driver of its key compressors.  The machine had a number of enhancements to increase the power output.  During maximum power output, the second stage nozzles appeared to stick, and failed to control the speed of the gas turbine within its target.  To prevent an overspeed trip, the customer was forced to reduce power, limiting the production capacity of the entire plant.  The plant continued to operate with this problem for more than one year prior to the installation of Tiger.  Concurrently, the customer attempted to identify the root cause of the problem, but given the data acquisition systems available, was unable to do so. 

Using the information acquired by Tiger, the customer easily identified the intermittent times when the fault occurred, enabling the engineering staff to investigate the incident in more detail.  The staff quickly demonstrated that the sticking of the second stage nozzles was not a mechanical problem, but was due to the hydraulic actuator not being strong enough to override the increased airflow due to the higher power levels.  During the next outage, the customer upgraded the hydraulic actuator.   Having resolved this problem, the turbine was then able to run effectively at a higher power level.

In the month after this outage the chemical plant set its first production record in over four years, generating an increase in product output valued at over $1.5 million per year. 

Independent Power Producer

When an IPP customer’s gas turbine operated on temperature control, it showed load oscillations of approximately 1.2 MW every 3 seconds.

The problem had existed for some time before Tiger was installed at the site.  However it was only when the Tiger information was available that the problem was quickly and easily identified.  Earlier installation of Tiger would have aided in eliminating the problem and avoided premature and costly first stage nozzle repair/replacement on each of three turbines displaying a similar problem.