Control system retrofit guidelines

The Electric Power Research Institute statistics indicate that the average age of fossil power plants will reach 30 years in 1990. Many utilities are reviewing methods to extend the life of these units. The following are typical general objectives being pursued in plant upgrades: improved plant heat rate, lower generating cost, enhanced availability and reliability, and increased load change response. Upgrading instrument and control systems is one means to achieve these objectives. I C systems of these vintage plants are two to three generations old. As a result, spare parts are no longer available. Increasing calibration drift, increasing hysteresis, and decreasing sensitivity make maintenance difficult. Retrofit is the only viable solution. This volume of the guidelines describes the methodology for identifying, evaluating, and justifying the instrumentation and control retrofit projects. Control system, in the broadest sense of the term, refers to all devices and equipment that are used in an integrated manner to coordinate'' the total power plant operation and control function, utilizing hierachial and multilevel control methodologies. This all-encompassing definition covers the full spectrum of control systems--from the most basic, local loop controller to the futuristic plantwide distributed control and information network. The focus of this particular volume wasmore » toward boiler controls, burner management, and data acquisition systems; however, the guidelines described herein apply equally well to every I C system.« less