Optimizing Performance and Reliability with Plant Automation
By Albert Flowers, Plant Manager, Carolina Power & Light
Carolina Power & Light Co.`s (CP&L) Roxboro Plant utilizes integrated automation and information technologies in efforts to achieve the lowest possible production costs through optimizing performance and reliability while meeting environmental constraints. These efforts are part of an ongoing multiphase Electric Power Research Institute (EPRI) Integrated Automation Project at CP&L`s Roxboro Plant. The project began in 1991 with Phases 1 and 2 (1991-1994) as a joint alliance agreement with EPRI, CP&L, ABB and DEC. The project was expanded into Phase 3 (1995-1997) and includes integrated technologies from various vendors.
Phases 1 and 2 concentrated on developing new automation-based technologies on-top of existing software products, and on demonstrating the use and benefits of these technologies at the power plant. The project includes the following tasks: installing a plant information-management system for plant-wide distribution of real-time data, integrating performance monitoring and developing automated equipment testing, developing advanced controls on the DCS, developing and integrating a real-time operator advisory system, and implementing economic dispatch software, and development of a high-fidelity simulator. Phase 3 of this project (1995-1997) will result in further benefits achieved by transforming and integrating the vast amount of data at Roxboro into smarter applications such as plant advisory systems, integration of diagnostic data, equipment condition monitoring and emission optimization.
Roxboro is utilizing the integration of various Plant Information Network (PIN) products to provide continuous plant and corporate-wide desktop access and analysis of critical process, environmental, and business data. The applications installed have different focal areas but integrate to provide an overall plant business/process data source. This data is transported into a relational database or data warehouse. Plant optimizations are obtained by striving continuously to monitor, track and quantify critical variables that provide usable information that can be acted upon. Utilizing an integrated and distributed architecture enables the right people to have easy access to the information at the right moment and make intelligent, cost saving decisions.
Several products have been installed at the Roxboro Plant to support the optimization efforts. These products support process, maintenance diagnostics and business data. ABB has installed products (OPTIMAX/9000) that provide the base platform for process data and engineering applications for performance monitoring, automated equipment testing, operator expert advisories, plant simulations and advanced control techniques. Interfaces to various PC-based diagnostic systems also provide key information into the plant-wide network real-time database. The OPTIMAX/Inform PC software provides a desktop view of process and performance data for information awareness and analysis.
Roxboro`s PIN allows OPTIMAX to integrate with other products like EPRI`S O&M workstation to provide plant personnel a desktop view of equipment conditions to support condition-based and predictive maintenance. Integration with plant and corporate business-database applications (co-developed by CP&L and Power Vision Inc.) allows for business data and work-process data to be easily entered in the data warehouse and correlated and analyzed.
Roxboro has seen significant improvements in plant performance since 1990. These improvements are a result of many parallel plant-wide efforts that include equipment upgrades, improved maintenance and operation practices, and integration of information and automation technologies like OPTIMAX/9000. The following areas describe the continual efforts that revolve around the automation technology component of performance improvements.
Instrument Data Accuracy
Any power plant application`s integrity is based on the accuracy of the data provided. The Roxboro Plant has gone through an extensive effort to ensure that critical performance and control instrumentation is accurate. In many cases, this required upgrades to higher accuracy instruments. Roxboro has implemented a plant calibration reference center, which contains both primary and secondary standards for calibrating devices. These instruments are periodically certified and tracked for consistency. A database application program to track calibration histories has been developed to track instrument accuracy and drift. These values are uploaded into the OPTIMAX/Performance automated equipment testing to provide an instrument uncertainty value for the equipment test calculation.
OPTIMAX/Inform provides the interfaces to the plant distributed-control system (DCS). These values are available plant-wide for graphical views, statistics, history and trending. One of OPTIMAX`s software modules, OPTIMAX/Performance, provides on-line plant performance calculations for plant component performance, heat rate and operator-controllable losses.
An automated-equipment-test component enables engineers to configure and perform on-line equipment performance calculations more frequently.
Once the performance program calculates the numbers, the results are available plant-wide.
They are also sent back to the interface to the DCS to be integrated into the DCS`s operator interface. These values are graphically represented on the operator console as any other DCS parameter. The purpose of this system is to provide the operator with the current performance status of the unit, the optimal expected values and the cost of deviation from expected. The operator`s focus is on operations in the real-time and short-term future. Optimal real-time information results in immediate performance improvements.
The Roxboro Operators have access to an embedded monitor in the operator console that provides graphical causal diagrams of impending disturbances and deviations of process states from their defined normal behavior. The OPTIMAX/Expert system provides fault tree analysis to determine root causes. The system then provides a diagnosis and reasoning path and a recommended corrective action to clear the fault. The continuous monitoring of multiple heat-rate-effecting and load-effecting variables simultaneously is providing an excellent tool for the operator who is limited to how many issues he or she can focus on at one time. At Roxboro, one system requirement was for plant personnel to be able to configure and implement diagnostics to maintain the integrity and belief from operations. To date there are 30+ diagnostics that reside on the system and they have all been implemented with plant technicians and operators. This system has been installed at Roxboro for almost a year and is providing a significant benefit. Increased benefits are expected as more diagnostics are developed. The result will be a continuous, positive impact on heat rate and a reductions in forced outages.
Plant & Corporate Access and Analysis of Performance Data
Traditional means of data collection and analysis of plant-performance data is a labor-intensive and time-consuming process. Roxboro is utilizing OPTIMAX in conjunction with plant LAN and WAN capabilities to expedite this process and provide quicker feedback to operations for optimization of performance. Utilizing OPTIMAX/Inform allows for desktop access to all plant actual and calculated values for awareness and analysis. Continuous results and historical analysis from the performance package and automated-equipment-testing programs allow plant and corporate personnel to analyze performance effects of equipment conditions, load swings and emissions constraints. The automated-equipment-test component of OPTIMAX/Performance has proven valuable in allowing plant personnel to spend time analyzing data instead of collecting data. Tests can be run on-demand for current conditions or from any point in history where the unit stabilization and input criteria were met. The results of this data analysis is being provided to the plant-controls team to implement newer control strategies to automate optimal performance.
Having an accessible plant-wide information platform has provided a base foundation for improvements in performance and reliability. Utilizing the system is also playing a key role in Roxboro Plant`s plans for balancing emissions compliance against thermal efficiency. Having an integrated plant-wide database that has plant-process and performance data as well as data from the emissions monitoring system has enabled Roxboro to utilize data analysis from OPTIMAX to optimize heat rate while achieving NOx compliance on its 710-MW compliance unit (Unit 4). Currently, Roxboro is extracting historical data for development of models that represent performance-parameter relations with emission data. As the constraints become more difficult to achieve, Roxboro is planning a more intensive use and integration of OPTIMAX technologies with new adaptive-modeling techniques to provide closed-loop controls to the DCS to achieve the optimal balance of emissions and thermal efficiency.
Graphics provide engineers with continuous equipment testing status.
Screens use colors to highlight changes to boiler section cleanliness.