Introduction  The by-pass system of Zhuhai Power Station is designed by BTG company whose upgrade plan has been the prime focus of our group, since its function control by electric element using analog signal which leads to low reliability and regulation performance.

  Method  In this investigation we measured the localize redundancy control method which was using a innovative structure mixed with XDC800B and ATOS, including the Xinhua DCS/DEH control system XDC800, the high and low pressure turbine by-pass valves and their spray control valves are controlled by xSV valve control card of XDC800 system and ATOS digital power amplifier card.In order to further improve the stability of by-pass control system, the undisturbed automatic switching function of high and low pressure by-pass valves and their spray control valves is realized by using self-developed redundant switching control board.

  Result  The results shows that the function of new system is completely identical with the original imported equipment which also achieving higher data control precision and make the unit runs more stable, while the requirements of unit start and shutdown, pressure control and FCB function under complex operating conditions are fully meet.

  Conclusion  Thus, we demonstrate the feasibility of the localize redundancy control method, and this this is a successful project suits to Zhuhai Power Station with small construction area, short period and high economic benefit; This work provides some guidance for further study on by-pass system upgrade in the field of power generation.