Control and Excitation Recommissioning Services

MD&A offers Control and Excitation Recommissioning Services for gas and steam turbines. Many OEMs, consultants, and companies will tell you your turbine control system is old and needs to be updated in order to achieve enhanced reliability. There are many turbines around the world running with 30+ year-old turbine control systems, which can be highly reliable when properly maintained. Generally, all that needs to be done to improve reliability is to ensure that all the I/O are properly connected, sending and receiving the proper signals, and that nuisance alarms are investigated and resolved.

Recommissioning involves performing I/0 loop-checks to ensure that all I/0 are working properly; sending & receiving the proper signals to & from the existing turbine control system just as was performed when the unit was first commissioned. The recommissioning difference is: It doesn't take two or three months like the original installation—MD&A’s experienced controls personnel can accomplish the recommissioning in a matter of weeks.

Nuisance and/or erroneous alarms can be the cause of many perceived operational problems. Most can easily be resolved and made to only alarm when the condition actually exists and requires resolution. This helps to reduce the number of alarms annunciated during starting and operation to only those which are real and require attention.

The recommissioning process allows you to keep your existing equipment, including turbine control and HMI systems, which your personnel is already familiar with. If needed, MD&A can help with sourcing Mark* turbine control system hardware, in addition to providing services.

MD&A can provide high-quality personnel to verify calibration of all devices on the unit and auxiliaries if requested--which ensures all devices are operating properly and per specification.

By working with your plant personnel to identify recurring issues MD&A can also help to explain and understand sequences and control philosophies critical to reliability, operation, and troubleshooting. MD&A uses OEM P&IDs and documents to help understand and explain systems when necessary.

Timeline and Cost

So, how long does recommissioning require? It can be completed in as little as two-and-a-half to three weeks on a unit that is capable of being operated on cooldown, cranking/starting and loading. For single fuel units, that can be in as little as 100 to 110 hours. (This assumes the plant is not scheduled to run during this time, except for final testing the last day or two.)

Curious about the potential cost of a new turbine control and HMI system? Retrofit control systems can typically cost in the range of USD $750,000, but can easily run as high as USD $2 Million depending on the level of hardware requested (say, for updating instrumentation, actuation, or other auxiliaries). And, then there's that learning curve that must be taken into account for operators and technicians.

A recommissioning could be performed for as little as $70,000 and in less than half the time of a retrofit. Talk to MD&A about recommissioning your existing turbine control system and restoring your faith in a trusted and proven system and improving operational reliability.

Potential Additional Points and Benefits

• Water- or Steam Injection for NOx emissions reduction? MD&A personnel can conduct those, helping with system reliability and tuning, if necessary. DLN tuning? MD&A can perform that, as well.
• Liquid fuel operation issues? MD&A Personnel can diagnose those and determine corrective action. (Many times this requires new or refurbished devices and components (specifically check valves or solenoid, or pneumatic-operated valves). Up-front discussions with plant personnel can help identify possible problems and have suspected items on-site for the recommissioning. And, MD&A can assist with sourcing the components, as well.)
• Have issues with Motor Control Center equipment? MD&A can help with that, too, in some cases sourcing legacy parts.
• Need help with compressor water washing (off-line or on-line)? MD&A can provide guidance, working with plant personnel to identify valves to be operated and using water wash auxiliary equipment, as well as determining if washing was effective and how to anticipate when it's necessary to water wash.
• MD&A can photograph each device and each device's location and include them in the final report so they can easily be found in the future, The final report will detail any issues found and resolved, any issues which could not be resolved during the recommissioning, and the results of operational testing, including alarm resolution to eliminate any nuisance and erroneous alarms.

Check out our case study:

Recommissioning Legacy Turbine Control Systems for Enhanced Reliability

Learn more about the other Gas Turbine Services that MD&A offers.