Launching a gas turbine control upgrade project
Given the constant pressure today for cost savings and near-immediate return on investment, it’s tempting to look at project costs in initial bids as the heaviest factor when determining who will support your gas turbine control retrofit. Project cost is critical, but it’s never the whole story. It’s important to know what questions to ask when you consider this purchase and what risks are taken if due diligence is not completed.
Simply requesting proposals from multiple vendors and then selecting the lowest bid can expose your company to additional risk by overlooking critical variables, namely, those that affect reliability, availability, short- and long-term support, and of course, return on and protection of your investment. In addition, the experience level of the control system provider, its application knowledge, execution references on similar projects, installation services, aftermarket support, and many other elements must be carefully considered.
How can you be sure you’ve understood the full scope of conditions and variables, and are armed with the factual knowledge that will enable you to make the right decision? What are the critical factors?
Experience is key to application knowledge – Is it important that your system retrofit partner understand specific turbine control functions such as combustor dynamics, emissions control, or cyber asset protection standards implementation? The right system, properly engineered, with clear understanding of your particular application will result in integrated control that allows your turbine and generator to produce as much power as possible and do so while protecting the compressor, hot gas path, and other critical components. It’s important to avoid engineering by trial and error, which significantly increases your risk and can reduce reliability and availability. You don’t want your site to be a science experiment or practice field for your control system provider. Make sure you ask for proven references on similar projects, and make sure you are specific about the applications. An experienced supplier will be able to verify a track record of successful projects with proven results, including references you can contact or visit. If time permits, it’s a good idea to contact other companies and plants. What are they saying about this company’s product, its ability to hit deadlines, expertise with your applications, and ability to stay on budget?
Understanding the system – Turbine field devices can be very unconventional. They may include bi-polar electrohydraulic servovalves, flame detectors that require 335 Vdc power, or LVDTs (linear variable differential transformers) that require an excitation source of 3 KHz at approximately 7.0 Vac RMS. An effective partner should have a proven system that integrates with existing field devices and instruments without requiring third-party I/O module converters. Such converters add points of failure to the system, plus they require spare parts inventory, maintenance, and sometimes even operator training. An experienced turbine control provider will have hardware that directly connects to all turbine field devices and will support the level of redundancy (simplex, dual, or triple modular redundancy) that best suits your reliability and availability goals.
Installation and operation services – A history of strong experience with your specific turbine operation, performance, and safety devices is critical. This will not only help you avoid an unsafe condition during commissioning and start-up, but will also ensure that you maintain or improve performance, today and in the future. Be sure the supplier not only has the ability to meet the current operating profile of the turbine, but can also address changes to the duty cycle that may occur in the future. In your RFQ (request for quote), specify that the company must demonstrate the capability to provide for future requirements, including lower emissions, faster starting, combustion dynamics monitoring, fuel flexibility, lower turndown, and so on. In addition, request demonstrated knowledge of any other systems that communicate with your control system, such as vibration monitoring, safety, combustion dynamics, and others.
Find out whether the company is willing to share some risk related to installation and operation. A good way to test this is to include a separate line requiring outage commitments, as well as long-term service contracts on parts availability, technical support, and post-retrofit turbine performance. Ask peers who have worked with this company whether initial outage duration and budget were met. Did frequent or significant change orders increase the price?
Aftermarket support, lifecycle cost, and ROI – Does each supplier under consideration have a robust parts, repair, and services offering, including a dedicated aftermarket sales and services team? This should include new and refurbished parts as well as repair, test, and certification services. Be sure to gain an understanding of the company’s history of supporting older control systems. Ask for references and information on its long-term control system support agreements. Consider whether the company has the capability to troubleshoot your control system remotely, reducing mean-time-to-repair and thus increasing uptime.
There are many questions and issues to consider when determining your best partner for a turbine and/or generator control retrofit. Understanding what questions to ask in your RFQ and what elements to consider can help streamline the decision making process. These guidelines can help you understand the complexities of this decision, identify the correct supplier, and lower your risk.
Checklist to help design your RFQ
1. Company background:
- Years in business and number of employees help establish history of success as a control system supplier and scope of resources available after installation and commissioning.
- Find the locations of headquarters and branch offices, local and international, with personnel available for engineering and field service support.
- Get the names, titles, and contact information of the commercial team responding to your RFQ.
- Ask for installations/projects completed that are of similar size and scope to your project.
- Call several of them, asking for measurable results, including whether deadline and budget commitments were met. Proof of a history of success is critical.
- Does the company have experience with your equipment, specific turbine operation, performance, and critical safety devices? Which specific projects are similar to yours, and which are different?
- Ask for measured results to back up reliability claims.
- Is the supplier the OEM of your equipment? Confirm its knowledge of the product as well as its ability to install today and support tomorrow.
- Ask for data sheets for all components used in the proposed solution.
- Probe into capability details, including high-level engineering, project management, and commissioning processes.
- Identify roles and responsibilities of all subcontractors to be used in your project.
5. Services and aftermarket support:
- While you may focus on critical installation factors and budget now, the ability to service and support your control system long after installation affects maintenance costs and return on investment.
- What aftermarket parts and repair services are available, including new parts, refurbished parts, repair services, test, and certification services?
- Is the company willing to support older control systems?
- Is a dedicated aftermarket sales and service team available?
- Does the company provide long-term control system support agreements?
- Is there capability to troubleshoot and monitor the control system remotely, thereby reducing mean-time-to-repair?
- Research details of outage duration commitments as well as maintenance and services commitments, including new and refurbished parts, repair, test, and certification services.
6. On-time delivery history:
- How easily can you afford missing an outage deadline by a day or two? Ask for references where schedule commitments were met or exceeded, including complicated short- and long-outage instances.
7. Long-term support:
- Ask about availability of long-term performance commitments, extended services warranties, and other commitments to ensure your ongoing unit uptime.
- Will you be able to maintain the system yourself when necessary using in-house resources, cost effectively, over its full lifetime?
8. Partner support:
- Can the supplier provide the type of consulting or contract engineering that your company requires for day-to-day operation and future improvements?
- Ask about the supplier’s roadmap for product improvements.
- Do product developments reflect customer input? Ask references if the company listens to their requests.
9. Installation and operation services:
- You know how you want to operate today, but can your supplier develop strategies to address changes to the duty cycle that may occur in the future?
- Can the company address future requirements, such as lower emissions, faster starting, combustion dynamics monitoring, fuel flexibility, lower turndown, and so forth?
- What other systems are there in your plant that may need to communicate with the control system? Request demonstrated knowledge of other systems such as vibration monitoring, safety, combustion dynamics, and so on.
10. Share risk:
- Is the company is willing to share some risk related to installation and operation?
- Include a separate line in the RFQ requiring outage commitments as well as long-term service contracts on parts availability, technical support, and post-retrofit turbine performance.
Carlos Scott is product line leader, power generation, for GE Energy.