DECS-450, Digital Excitation Control System

The DECS-450 is a microprocessor based, high performance, extremely reliable excitation controller for both positive and positive/negative forcing excitation systems. The DECS-450 controls and monitors the output of a synchronous machine. It supplies control voltage to an external power converter, which supplies dc energy to the main field or to the exciter field of the synchronous machine, making it compatible with any size synchronous machine. The DECS-450 can be provided in many configurations to meet specific requirements and redundancy needs. Basler offers customized and standard solutions engineered to meet a wide variety of applications.


  • Reduce your setup time with Basler's intuitive BESTCOMSPlus® software that simplifies complex setup with simple drag-and-drop programmable logic, visual real-time strip chart capabilities, innovative auto PID selection capabilities, and configurable protection.
  • The revolutionary auto tuning function automatically establishes optimum gain settings, taking the guesswork out of system setup, reducing commissioning time and cost while maximizing overall system performance.
  • A wide variety of redundancy options increases system reliability.
  • An available suite of limiters coordinates with protective functions to help maintain safe operating parameters and avoid system downtime.
  • Avoid system damage by utilizing various protection functions integrated into the controller.
  • Maximize excitation system performance with dual gain settings based on load conditions.
  • Improve system reliability and stability by coordinating dual settings groups for limiters and protection to match generation system conditions.
  • Prevents undesired overshoots using the soft-start feature to maintain generator voltage control during system startup.
  • Time-synchronizing provisions facilitate event analysis with a common chronological reference to aid in coordination efforts when comparing oscillography files from other devices.
  • Simplify system testing and commissioning with real-time monitoring and built-in test provisions.
  • Entering settings with confidence is easy with BESTCOMSPlus®. Software provides intuitive settings with graphs, built-in error checking, and summary screens.
  • The Offline Simulator in BESTlogic™Plus helps test and troubleshoot logic without the need for expensive hardware.
  • Sequence of Events and Oscillography Recording provisions collect valuable system data triggered by disturbances for event analysis.
  • Avoid costly generator damage and improve overall system stability with Basler Electric's integrated Power System Stabilizer (optional) that utilizes the "integral of accelerating power" to safely dampen local mode, inter-area and inter-unit power oscillations, white noise generator, and phase plot compensation.
  • Basler's in-house engineering, fabrication, manufacturing, and test capabilities provide maximum control of processes and product design, resulting in the highest quality and maximum reliability while offering shorter lead times.


Technical Resources


Case Studies

  • Case Study

    • One Good DECS Deserves Another (616.8KB)
      Throughout Taiwan’s history, many government-owned power plants were built to supply power for the main island of Taiwan and its outlying islands. Basler excitation systems and protective relays are widely used in these plants.