Optimum Design Of A Load Control System For Power Unit Based On "Two Documents"

Along with our country electric power industry’s rapid development and the numberof large capacity units increasing, operation mode is changing, so power grid needspower plants to improve their load controlling ability of unit. As the background of No.7unit in Datong2nd Power Plant, to satisfy the “Two Documents” of North China GridCompany Limited, the optimization of load control system under Automatic GenerationControl (AGC) Mode for600MW Suberitical Power Unit is investgated.The unit control system of No.7unit in Datong2nd Power Plant is a kind ofcomprehensive coordination control system, the paper introduces the basic situation ofthe unit, and the load instruction processing circuit, turbine master control, boiler mastercontrol, primary air pressure control system and fuel quantity control system. Combiningtheory with practice research, before optimization of No.7unit, the coordinated controlsystem has been analyzed the control strategy, points out its problems existing in the loadcontrol system and a series of factors to influence the control effect. The problemsexisting at No.7unit are the slow response ability to load etc. The main optimizationstrategies are as follows: to largely rais the speed of response by comprehensivelyoptimizing the boiler master control dynamic feed forward unit and load instruction logic,optimizing primary air pressure controlling loop, adding the loop of caloricity calibrationto adapt to coal quality variation, and designing condensate throttling and parametersadaptive method of key parameters in boiler and turbine. After optimization of the No.7unit, the regulation performance index k1is worth to significantly improve, k3valueslightly raises, k2value due to grid calculation method critical than before, the value fallsslightly, kp value is on the rise and has improved significantly. Finally the unit canquickly response to the rise and fall of electric load requirements, maintain stableoperation, and adjust the performance index to meet the requirements of the "two rules",effectively improved the quality of AGC system.