The Advanced Pulsation Control Logic (APCL)

A new technogy on logic side to control the Gas Turbine's pulsation concept. Another post will describe the definition on pulsation it self. 

The Advanced Pulsation Control Logic (APCL) is a combustion closed-loop-control-concept for premix operation. The engine’s fuel to air ratio is varied as a function of low range frequency (8-35Hz) RMS pulsation signal to achieve both a required flame stability and a specified NOx emission level, independent of changing boundary conditions such as rapid weather changes or unforeseen variation in fired fuel composition.

The APCL is activated if necessary after Premix/Pilot switch over, normally between 60% and 65% Prel. Activation and deactivation of APCL is done through a ramp to the set points. The ramp generator is used to limit the speed of change of the controller, achieving stable controller behaviour (no oscillating). During transient operation i.e. loading / deloading, the controller parameter are set to faster values to meet the increased requirements.