Boiler Drum Level Control

Problem in Boiler Drum Level Control with YS170 and SLPC:

  • In the YS170 and SLPC, single-element control needs to be configured within the user program.
  • The YS1700, however, offers the primary direct mode so that the user program can switch on and off single-element control by changing a parameter.

Three-element Control:

  • Disturbances in drum level are caused by fluctuations in main steam flow.
  • Figure 1 shows a typical drum level controller, which measures the drum level (1), main steam flow (2), and feedwater flow (3) and manipulates the feedwater control valve to regulate the drum level. This is three-element control.
  • This three-element controller is a so-called cascade controller in which a drum level control unit is cascaded into a feedwater flow control unit.

Single-element Control:

  • During startup of a boiler, both the feedwater and main steam flow rates remain below the measurable ranges, and this makes the three-element control with a level controller and flow controller unstable.
  • In such cases, it is effective to use single-element control in which the feedwater controller is bypassed and the drum level controller directly controls the feedwater control valve.

Cascade function(CSC)


Related Products & Solutions


YS1700 프로그램 조절계는 사용자 프로그램을 통해 다양한 어플리케이션을 지원하는 단일 루프 컨트롤러입니다. Yokogawa 독점 기술의 높은 신뢰성과 사용의 용이성 및 확장성을 갖추고 있습니다.


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