毕业设计（论文）300MW的机组过热汽温控制系统的设计.docVIP

爱爱爱 摘 要 300MW单元机组过热汽温控制通常采用分段控制系统，由二段相对独立的串级控制构成，串级控制系统对改善控制过程品质极为有效。过热汽温的控制系统对于电厂的安全经济运行都非常重要，整个系统是维持过热器出口蒸汽温度保持在允许的范围内，并且保护过热器是管壁温度不超过允许的工作温度。 在电厂整个控制系统中，影响过热汽温的因素很多，主要有蒸汽流量扰动、烟汽流量扰动、减温水量扰动三方面。而喷水减温对过热器的安全运行比较有利是目前广泛采用的方法。 在串级控制系统中副调节器所在的内回路能快速消除减温水量的自发性扰动和其他进入内回路的各种扰动，而主调节器所在的外回路保持过热汽温等于给定植。并且系统实现了自动跟踪和无扰切换，保证机组安全经济的运行。对于过热蒸汽的采集实现了二冗余，提高了系统的可靠性。 整个过热汽温控制系统是用N—90实现的，且系统切换和逻辑报警线路全面，具有较高的可靠性。 关键词： 电力系统，过热汽温，串级控制 Abstract In this paper, The 300 MW unit machine set leads the hot air the control usually adopts a control system, constituting from two opposite and independent string classes control, string class control the system controls the process quality to the improvement extremely effective .Lead the control system of the hot air for the power station of safe economy circulate all count for much, the whole system is to maintained the hot machine to export the steam temperature to keep within the scope of allow of, and protected the hot machine is a work temperature that takes care of the wall temperature not to exceed to allow. In the whole control system of power station, affected the factor of the hot air a lot of, mainly have the steam discharge to move, the smoke current of air quantity move, reduces the water to move three aspects .But spray the water to reduce to lead the safe movement of the hot machine more beneficial is an extensive adoptive method currently. In string class control system vice- modulator place of inside the back track can remove the self-moving sex of reduce to move quickly and other enter inside the back track of various move, but the outside back track of the main modulator place kept the hot air to be equal to plant certainly .And the system carried out to follow automatically and have no the cut over, guarantee the machine set safety economy of movement .For led the hot steam to collect to carry out two redundancies, raise dependable sex of the system. Whole lead what the hot air control system is to use the N-90 to carry