Recommissioning Legacy Turbine Control Systems for Enhanced Reliability
Increases in renewable energy on the power grid have increased the need for reliable peaking power. In many cases, these assets are available but less reliable than they once were due to the age and neglect of their control systems. In most cases, refurbishment of digital systems from the last 30 years is a viable alternative to costly upgrades which can have long lead times and require extensive outages to install.
Mechanical Dynamics & Analysis (MD&A) Control Systems Division can recommission legacy gas turbine power generation control systems at a fraction of the cost of system replacement and can enhance these systems with a modern human-machine interface (HMI).
This recommissioning process can alert owner/operators to safety concerns, detect current and future nuisances or erroneous alarms, and build renewed confidence in asset operation through optimized control systems, alarms, and indications.
Recommissioning services and calibrations were recently completed, for example, on two GE® Frame 7EA heavy-duty gas turbines with DLN-1 combustors, burning natural gas and used for peaking service. Both units utilize the Mark V turbine control system. Calibration check line-item pass/fail listings on these units showed device failure ratios of up to 30 percent.
The key to such work is focused precision along with full knowledge of the OEM system’s operations, hardware, and components.
Primary tasks are I/O loop-checking, function testing, and running checks while investigating all field devices, connections, and operating conditions. Improper equipment is either recalibrated or replaced.
Plant personnel offer input into the recommissioning and both their experience, efficiency, and safety are of utmost concern to MD&A. In a recent example, personnel expressed concerns over high turbine compartment temperatures. During recommissioning, MD&A’s investigators found non-working gravity-operated dampers and potentially high temperatures in the accessory compartment and around the turbine.
Both site personnel and MD&A also noticed loud buzzing in the 125 VDC battery chargers, indicating possible problems with the output filter capacitors and/or the main transformer. Loop-checking also uncovered numerous junction box issues that could severely impact the fire protection system.
This was in addition to the background that site personnel offered on nuisance and false alarms. Some field devices were found to be non-working and were replaced or readjusted, several inputs had not been originally connected to the Mark system, and general issues and long-term concerns were uncovered regarding conduits and circuit connections. Selected incorrect wiring was also discovered.
The key descriptors for MD&A’s Recommissioning Legacy Turbine Control Systems are meticulous attention to detail, pinpoint examination, in-depth problem solving, precise record-keeping and reporting, and full use of MD&A’s gas turbine knowledge and experience. And as a result, any alarms articulated during startup and operation should be reduced to only those that require attention.
MD&A recommissioning projects can be completed for as little as 10 percent of the cost of new or retrofit equipment with significantly less site and downtime and are available for any unit capable of being operated on cooldown, cranking, and starting and loading.
We are your full-service, OEM-alternative! MD&A Control Systems maintains a staff of OEM experienced field engineers who know and efficiently plan and execute the process, identify any issues and work with plant personnel on optimum resolutions. We provide installation, technical support, advanced troubleshooting, training, and consulting services globally for gas and steam turbine controls, generators, and auxiliary systems.
Contact our Control Systems Division to recommission your legacy turbine control systems at +1 (970) 224-2223 or use our contact form.
Tags: Recommissioning, Turbine Control Systems, controls
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