A steam study begins by building a dynamic model of the existing plant using ProTRAX, our proprietary software. ProTRAX is a modular, dynamic simulation system based on first principles of mass, energy and momentum conservation. All ProTRAX models built by TRAX with this software meet or exceed the ISA Standard for accuracy of Fossil-Fuel Power Plant Simulators (ISA-S77.20).
The balance of plant model is comprised of a process model and a control system model. TRAX builds the model using design and plant operating data to match the specific plant. Individual components such as steam turbines, pumps, valves and heat exchangers are dropped onto a page and connected to one another to represent the plant configuration. The resulting schematics closely resemble piping and instrumentation diagrams (P&IDs), with individual pieces of equipment, equipment numbers and line numbers.
A complete set of SAMA modules, included with ProTRAX, are used to simulate control loops for the process systems. Control parameters (such as proportional or integral gains, high and low limits, etc.) are all built into the model.
TRAX then verifies the accuracy of the model at multiple steady-state conditions, as well as through a dynamic event to validate the models match the operating conditions of the actual plant. Once the existing configuration plant model is validated, the model is modified to reflect the proposed equipment and controls changes that will occur at the plant.
Next, transient testing begins, and the model is subjected to different scenarios, such as pump trips, turbine trip, mis operation or catastrophic equipment failure. Through these transient events, pressures, flows and temperatures are monitored throughout the system. The transients allow investigation of plant dynamics caused by actuator stroke time, control system gains or plant runbacks. The analysis done during the dynamic events can provide information that cannot be obtained with normal steady-state analysis. A full review of proposed controls changes performed as part of a steam study can also confirm control compliance with industry guidelines.
Once transient tests are complete, the results are analyzed to identify excessive pressure, flow, temperature, electrical current excursions or other undesirable behaviors. TRAX will develop and test process or control logic changes to prevent or remediate excessive conditions. Process and control modifications can be tested individually or in combination to determine what works best.
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