Research On The Control Rule Of Combustion System In The DCS Of The Large Unit

With the tactics improvement of electric network dispatch real time control system, the implement of the open electric power market and the contest price, the award institution of the electric network in using AGC unit, there is an increase in using AGC unit. As an electricity enterprise , how to accelerate the speed of response and improve the quality of regulation becomes more and more important to increase AGC investment rate.The key in realizing automatic generation control (AGC) is to improve the combustion systemic quality which can meet the needs of the high-speed and stability in load transformation. The dynamic characteristics in boiler and turbine are quite different in the process of units. The boiler is the thermal inertia major controlled member. Compared with the turbine, the process of adjustment is more dilatoriness; In the combustion system , feeding air and induced air is small inertia and lag small governing system. However, main steam pressure regulation system of boiler is more inertia and more lingering .It is the limitation in realizing the unit load adjustment. In the real operation, the requirement of the load transformation rate must be fulfilled, so it demands that the coordinated control system changes quickly in the load response .Furthermore the requirement of main steam pressure must be fulfilled.After investing the mostly new build power plants of Shan Xi province, this paper firstly describes the common rule of the combustion control system. There are load control system and combustion control system. This paper secondly analyzes HIACS-5000M system of 200 MW unit of DA TONG second power plant, DIASYS-UP/V system of 350 MW unit of HE JIN power plant, TELEPERM-XP system of 350 MW unit of YANG CHENG power plant, OVATION system of 300 MW unit of GU JIAO power plant .After analyzing system logical figure of these power plants, the contents of load control system and combustion control system are concluded, and the difference and sameness of load control system and combustion control system are compared fully. At the end of this paper, the questions that the unit operates and debugs in present unit load control system and combustion control system are concluded. This part also contains the excellence of load control system and combustion control system, and their different features in every system .Including main steam pressure control, fuel quantity control, feeding air adjustment control and furnace pressure control. Some suggestions of technical improvements are put forward for the operation in future. In a short. After analyzing the logical structure of each control systems , the thought of design and the characteristic are got fully known, some suggestions in load control system and combustion control system for every power plant are put forward .In doing so, the stability in combustion adjustment is strengthened. In the long process of the unit, it can be more stable and economical.