Breaking News: GE Frame 5PA Upgrade Motivated by Forced Outage Also Works for 6B and 7B-EA

TTS Successfully Converts a Mark V Fuel Control to Electronic Valves

A paper products plant in the Southeast was planning for a major spring 2017 inspection for their Frame 5 with preparations were well underway in October 2016 when suddenly, the unit tripped on high vibration, just as day shift arrived at the facility.

An original Row 2 bucket failed, causing considerable downstream damage. Management decided to begin necessary repairs immediately and to conduct the machine’s third major inspection at the same time.

The Frame 5 cogen unit had accumulated nearly 115,000 total fired hours and 1,500 starts since its commission in 1997. The 24.5-MW (on gas) MS5001PA engine was equipped with a DLN-1 combustion system and capable of dual-fuel firing. It was one of the most advanced Frame 5s in the fleet when it was first installed.

Since its commissioning, the 12 combustion, six hot-gas-path (HGP) and three major inspections typically revealed little beyond normal wear and tear. In fact, few significant modifications had been made to the basic engine in its two decades of service and plant personnel told the editors that the bucket failure was the first major issue suffered by the gas turbine in its lifetime.

Chris Mancini of Mechanical Dynamics & Analysis Ltd was informed of the unit trip and its likely damage shortly after it occurred. He and a superintendent were onsite within two days to assist in damage assessment.

Field service personnel arrived one day after Mancini and the following day, the day shift completed its site and safety orientation, organized tools and work areas and ran power and compressed-air lines as needed. The night shift received its site orientation, set up lighting and began disassembling the unit. The project proceeded at an aggressive pace from that point forward given the black-start cogen unit’s importance to mill production.

MD&A was awarded a turnkey contract for repairs, the major inspections of the turbine and generator, as well as some additional projects including the removal of the liquid-fuel and trip-oil systems.

Because the mill never had success operating on liquid fuel, the most practical solution was to not burn liquid fuel. That decision, made years ago by plant management, was easy given the ready availability of quality gas.

However, oil infrastructure eventually ran afoul of the company’s goal for continuous improvement. It took three shifts to remove liquid-fuel components to conduct a combustion inspection and three to reinstall it before engine restart.

The facility has been performing CIs at 8000-hr intervals so the cost, in terms of labor and outage schedule impact, added up quickly.

The plant engineer was guardedly optimistic about doubling that interval, as promised by the more robust coating applied by ACT Independent Turbo Services Inc, on hot-section parts in its Texan LaPorte shop during the outage. However, this doubling required approval by the facility’s insurer and the coating’s merit would need to be considered.

MD&A was credited with developing a plan to eliminate oil capability, including the fuel-nozzle mods, at less than half the cost estimated by an alternative supplier. It should also be noted that by eliminating the parasitic power associated with the liquid-fuel system, unit output increases by 280 kW.

Issues with fuel valves equipped with hydraulic actuators motivated the mill to replace that equipment with electrically actuated valves when the change to gas-only firing was made. With this upgrade, less gas is burned to produce a given amount of power than with hydraulic valves in the circuit.

Replacing the mechanical overspeed bolt and trip-oil system with an electronic overspeed trip enables operators to now verify trip functionality at 500 rpm without stressing the unit.

 

Converting from Dual Fuel to Gas-Only

The liquid fuel system (LFS) for this Frame 5 included the following subsystems: primary and secondary liquid fuel and purge, atomizing air, and water injection and purge. LFS decommissioning, a first step in the conversion of the unit to gas-only operation included deactivation or removal of all hardware associated with oil supply as well as of equipment in the subsystems noted.

During the forced outage, key components of the LFS were removed, but because of schedule constraints and the physical location of some hardware, it was not feasible to remove everything at that time. Others who have performed similar conversions told the editors it’s important to disconnect/remove components that would consume power when inactive—such as the fuel pump and atomizing air compressor—and simply abandon in place piping that would have no adverse impact on gas-only operations.

The end covers and piping inside the turbine compartment were modified during the outage to reflect elimination of the LFS; Mark V controls software was reconfigured to accommodate the changes made.

 

Checklist of LFS Hardware Removed

  • Accessory-gearbox oil-vapor eductor; a desiccant breather cap was installed in its place.
  • Atomizing-air booster compressor driven by the starting diesel, along with related piping and valves.
  • Atomizing-air pre-cooler and its cooling-water supply piping. Source-air piping from the atomizing-air pre-cooler inside the turbine compartment also was removed.
  • Extraction piping from the compressor to the atomizing- and purge-air subsystems.
  • Gas-fuel purge system hardware.
  • Primary liquid-fuel lines from the flow divider to the fuel nozzles.
  • The accessory-gear-driven atomizing air compressor—together with its drive gear and associated bearings.
  • The accessory-gear-driven fuel pump—together with the electric clutch, coupling, bypass valve, and gear and its bearings.
  • Water-injection piping to the fuel nozzles.

 

Fuel Valve Upgrades

The mill’s Frame 5 was equipped with a combined, hydraulically actuated gas stop speed/ratio (SRV) and control valve (GCV) and gas fuel splitter valve. Recall that the SRV and GCV are independent valves. Gas flows through the SRV to the GCV, which regulates the amount of fuel flowing to the ring manifold serving the 10 combustion chambers. The splitter valve serving on DLN machines divides gas flow between the primary and secondary fuel systems.

Turbine Technology Services Corp was retained to remove the liquid fuel system, as described above, and to replace the existing hydraulically actuated, 3-in. SRV/GCV and splitter valves with new electronic valves from Young & Franklin Inc. Existing gas supply strainers and valves were retained inside the compartment. A 3-in. stop valve was required in addition to electronic primary- and secondary-fuel control valves.

 

The company’s Dave Simmons told the editors TTS has deep experience in this work, having removed liquid-fuel capability on about 50 GE Frame 5s through EAs over the years and retrofitted electronic valves from different suppliers on perhaps 20 machines.

Simmons said elimination of liquid-fuel capability on a non-DLN gas turbine is relatively easy, but experience counts when a DLN engine is involved. This project was unique: It was the first time that a Mark V-equipped DLN-1 machine was converted to electronic valves for fuel control—and it took only four weeks from initial request to startup.

TTS proved it could satisfy project goals by running tests on its reconfigured Mark V simulator. No empirical testing was involved. There were no surprises, Simmons said. The Y&F valves performed the way the company said they would.

He added that an increasing number of plants are investigating conversion to electronic valves and most projects can be justified based on opportunity costs. One of the first things to do, Simmons continued, is to determine the availability of physical space to accommodate the new equipment. This shouldn’t be challenging for non-DLN machines, he said.

Some demolition and installation of the new valves and electrical conduit and wiring are key elements of the physical project. The editors were told that most wiring generally can be reused, excepting old non-DLN units. Otherwise, shielded cable is strongly recommended for use with electronic valves.

Finally, if considering electronic fuel valves for your plant, don’t forget to audit the control system logic file to see if it can accommodate the switch from hydraulics to electric. There was no such issue on this project because of all the liquid-fuel infrastructure removed.

TTS modified the gas control software in the Mark V panel and HMI operator screens and then performed functional and operational tests of the new gas control system.

 

Other Activities Required to Complete the Project

  • Disable piping to the gas control valve for the existing hydraulic- and trip-oil systems. Note that the mechanical overspeed trip was disabled when trip-oil supply to the gas control valve was terminated.
  • Install an emergency-stop pushbutton inside the accessory compartment.
  • Install two magnetic speed pickups and independently connect to the Mark V overspeed “hardware” trip.

To convert the dual-fuel end covers to gas only, the liquid-fuel and water-injection distributors were removed. The tubing runs connecting the distributors to the corresponding five primary-fuel nozzles on each end cover also were removed and caps installed in their place at the openings created. Secondary-fuel nozzles attach to the center of each end cover—their liquid-fuel and water-injection connections were also removed and capped.

 

To learn more about TTS’ dual fuel experience and capabilities for fuel conversions or upgrades, visit our website.

TMOS Provides a Path to Compliance with the Recent GE Power Product Service Information Bulletin Regarding Mark V Communication Interface Overload

By Scott Muster, Turbine Technology Services

A recent article published on a popular online media site highlighted a catastrophic failure on a GE F-Class unit using Mark V controls and discussed the events leading up to the failure. While the root cause of this failure was not identified, it was associated with an apparent overloading of instructions to the Mark V system which then behaved abnormally precipitating the failure. The article suggested possible actions to protect against the failure but did not suggest steps to prevent the failure from occurring in the first place.

Subsequently GE Energy published a technical bulletin which referred to the article. The bulletin described the events surrounding the failure in detail and provided specific communication management criteria which if adhered to would likely preclude a failure of this type. It also recommended against implementing the protective measures suggested in the original article.

For many users, modifying their existing <HMI>, DCS and other interconnected systems to comply with these communication limitation requirements may represent a significant engineering exercise and may alter or limit the functionality of their overall DCS, SCADA and PLC systems. In addition, it may still be difficult to guarantee that a communication overload is not possible under every set of circumstances for each and every possible system configuration.

One solution to this problem is the Turbine Monitoring System (TMOS), available through Turbine Technology Services (TTS). The TMOS is a direct replacement for existing Mark V <I> and <HMI> systems and one of its main features is that it actively manages and regulates the transfer of instructions from all site devices (BOP, DCS, SCADA, Operator Stations) to the Mark V ensuring that the type of communication overload associated with the recent failure is not possible.

TMOS has been in the field since 2001 and has maintained an outstanding record for safety and reliability for more than 60 million operating hours. TMOS is typically a simple and quick “plug and play” replacement for single Mark V systems and can be used to dramatically simplify multi-unit systems. TMOS is an established product and there are already hundreds of machines around the globe that have been upgraded to this system.

We asked the TMOS’ developer Thomas Finstermann, CEO, of Industrial Turbine Services to comment on how TMOS addresses the recommendations in GE’s Bulletin Advisory. He highlighted the following points:

  • TMOS has a built-in traffic control algorithm that buffers the command traffic from all connected clients (operator stations, DCS systems, SCADA systems, etc.) and sends them to each MKV with a delay which ensures compliance with GE’s Advisory requirement. Operator Display command push buttons are given priority over Modbus, OPC, or other 3rd party clients.
  • The traffic control algorithm consolidates identical commands arriving simultaneously at TMOS from multiple devices into a single command which is then forwarded to the Mark V.
  • The TMOS communication architecture ensures that the number of TMOS (HMI) Servers on any Mark V ARCNET system does not exceed two (2) while providing full server and HMI system redundancy in a “hot backup” configuration.
  • TMOS Servers act as a historian and online site monitoring system. There are no additional read requests issued to the Mark V panel.
  • The TMOS traffic control will only allow a predefined number of sessions and it is safe to use them during unit operation.
  • The traffic control algorithm will not allow the same signal to be requested from the Mark V twice. If a signal is required for a fast trending operation, but the same signal is already used in a slow updating display, the signal will be moved from the slower to the faster task.
  • There is no screen cache limitation in TMOS. If two or more operator displays or other devices are requesting the same signal at the same time, the Mark V will receive only one request.

Neither the original article nor the GE bulletin discusses or identifies a root cause mechanism for the failure and while it is important to ensure that each Mark V system complies with the GE advisory recommendations, it remains possible that other factors could have contributed to this specific failure.

TMOS provides the most established, rigorous and predictable solution to the issue of managing traffic to a Mark V system and ensuring system compliance with the fundamental GE recommendations in the bulletin. TMOS will also simplify the overall Mark V system communication architecture while allowing users to maintain all their existing SCADA, DCS, PLC and other communication interfaces intact and without modification.

For additional information on the TMOS system and its capabilities please visit our website or contact Scott Muster at smuster@turbinetech.com.

Discover the Full Capabilities of Turbine Technology Services on Expanded Website

Industry-leading gas turbine technology company launches intuitive site

turbine-technology-services-logo (1)

Orlando, Fla. (September 1, 2016) – Turbine Technology Services (TTS) recently launched a new, user-friendly website. With more than 30 years of experience in the power generation industry, TTS’ new site expands upon its innovative gas turbine technology, as well as emphasizes the company’s capabilities as an original equipment manufacturer (OEM) alternative, including delivery of industry-leading aftermarket parts, gas turbine installation and modernization, and exceptional customer service, worldwide.

“The gas industry is constantly changing, and TTS is changing with it,” said Scott Muster, TTS Marketing Director. “Our customers require information needed to make complex decisions and solve power generation problems. The new site explains how we can help. More content is in the works including detailed technical data, explanation videos and valuable case studies.”

On top of featuring the company’s broad portfolio of products and services, TTS made the new website easier to access. Developed using the latest technology, the website is compatible with today’s internet browsers and mobile devices.

Pat Begley, TTS Vice President said, “TTS is and will always be a technology company; gas turbine engineering is our product. This website puts our innovative technologies and expertise in the spotlight.”

Tony Thornton, TTS President commented, “The gas industry and the turbine business is our world. We hope visitors come to the website and learn our world is much bigger than they knew.”

Explore the in-depth capabilities of TTS by visiting http://turbinetech.com/.

Check the website often for the latest industry news, trainings and seminars, and company announcements.

CyberSecurity: “The single biggest threat out there is cyber.”

7F Users Group Conference: CyberSecurity… Options for Gas Turbine Control Systems

Turbine Technology Services (TTS)  is delivering a presentation at the 7F Users Group Annual Conference being held in Orlando, FL, May 9-13 that is focused on the compliance and threat issues that gas turbine control systems face. “In the past, many owners and operators haven’t focused very much on security and staying current with their cyber assets.” Said David Donnaruma, Project Engineer, TTS. … [Read More]

TTS Enterprises Expands Industry Capabilities with Launch of Reciprocating Technology Services

Reciprocating Technology Services will provide comprehensive solutions for oil and gas reciprocating engines and compressors.

TTS Enterprises is excited to announce the launch of our new company, Reciprocating Technology Services (RTS). RTS joins Turbine Technology Services Corporation (TTS) to solidify our worldwide engineering capabilities for the power generation, oil and gas industry. … [Read More]

Establishing Cybersecurity Compliance Position to Support Power Plant Customer NERC/FERC Requirements

Turbine Technology Services adds cybersecurity compliance support to its existing suite of plant control system design and support services. 

(ORLANDO, FLORIDA) —Turbine Technology Services (TTS), a full-service turbine engineering firm based in Orlando, Florida, is solidifying its focus on supporting customer cybersecurity compliance efforts by appointing Mark Ring as its Senior Compliance Coordinator. … [Read More]

Exhibiting Turbine Monitoring System at 2015 7F Users Group Annual Conference

Turbine Technology Services will showcase their comprehensive products and services at this year’s conference in Denver, Colorado.

(Orlando, Florida) —Turbine Technology Services (TTS), a full-service gas turbine engineering services firm based in Orlando, Florida, will attend the 2015 7F Users Group Annual Conference in Denver, Colorado. The 7F Users Group Annual Conference is of key importance to the power industry, with over 2,000 7F gas turbines currently in operation worldwide in power plants and other facilities. At this conference, TTS will be able to connect with and educate users about how they can maximize the performance and reliability of GE 7F gas turbines. … [Read More]

Turbine Technology Services Expands its Operation to Houston, Texas

A booming oil and gas sector and continuing company growth lead to a permanent office for TTS in Houston.

(Orlando, Florida) — Power generation service provider, Turbine Technology Services (TTS), opened a new office in Houston, Texas this fall. TTS’ headquarters will remain in Orlando, Florida with the new Houston office located at 6721 Portwest Drive, Suite 140 on the west side of the city. … [Read More]

Turbine Technology Services Announces Oil and Gas Initiative with New Business Development Manager, Rick Woody

Our technical expertise in turbomachinery is enhanced by Woody’s experience in oil and gas to bring quality customer support to the market.

Turbine Technology Services recently expanded our expertise and customer support to the oil and gas market and selected Rick Woody as the new Business and Development Manager for the oil and gas segment.

We’ve been serving a diverse network of rotating equipment customers for over 30 years in the marketplace worldwide. … [Read More]

Presenting on Gas Turbine Fuel Flexibility at 2014 7EA Users Group Annual Conference

TTS will speak on the needs and applications of gas turbine fuel flexibility at the upcoming conference in Nashville, Tennessee.

Our Senior Combustion Engineer, Mitch Cohen, will present at the 2014 7EA Users Group Annual Conference. The conference takes place in Murfreesboro, Tennessee (in the greater Nashville area) from October 21 through October 23 at the Embassy Suites Nashville SE-Murfreesboro. Cohen will speak to users and select vendors about “Operational Versatility for your Gas Turbine with Fuel Flexibility” the morning of Thursday, October 23 at 8:00 a.m.

… [Read More]