Analysis And Optimization Of The600MW Supercritical Unit Coordinated Control System

This article comes from the production practice. With the ever-changing market, allof the power plants work hard to find ways to lower coal costs, lower unit powerconsumption rate, which results in many serious problems such as the polytropy of theunits burning coal, the significant deviation from design coal calorific value and the largeinertia of the flue gas system. The coordinated boiler-turbine control requirementspresent are very different from the ones in original fuel environment design which wasrelatively stable. It has been very difficult to meet the control requirements when thecalorific value of coal bunker dramatically changed for the original system. The plantoperation data during the past two years shows that the main steam pressure, temperatureand the reheat steam temperature changed significantly even out of stability when theunits burning coal deviate from the design coal significantly, with a great effect upon theunit load response rate and accuracy.In this paper, with operating characteristics of the unit studied, the in-depth researchand optimization of the unit coordinated control system (CCS in abbreviation) has beencarried out, and a new CCS has been established in the new case that the coal changedsignificantly and rapidly. The stability of the unit operation has been improved, and thefluctuation of the main steam pressure has been eliminated. Meanwhile the unit loadresponse rate and AGC regulation accuracy are increased, which creates good conditionsfor the system to adapt to the new scheduling requirements as soon as possible.