外文翻譯---三坐標(biāo)測(cè)量機(jī)測(cè)頭的誤差校準(zhǔn)-其他專(zhuān)業(yè)-全文預(yù)覽
【正文】 from the System Point of View Function of Automation Control System of the Power unit At first the thermal power unit as the controlled object is deeply studied before its automation control system is studied and designed .The thermal power unit is a huge group of equipments ,which is posed of generator, ,steam turbine ,boiler and many auxiliary equipments. Its process flow is plex and pipelines intervenient .Especially the largescale power unit is a typical coupling ,nonlinear ,varying plex controlled object with multiinput and multioutput .Thousands of parameters are measured ,operated and controlled .The character of object is changeful because of many different operating modes and switch relation .With enlarging of industry production scale and the raising of people’s living standard ,the required quantity of power energy is increasing and the difference of apex and vale of power load is increasing .So the new and higher require is put forward for automation control system of the power unit . （ 1.） Load control :Along with the increase of the unit capacity ,early load control mode of “boiler follows steam turbine ”or “steam turbine follows boiler ” has not already satisfied the requirements so we must adopt more suitable load control scheme ,which is the unit coordinate control . （ 2.） Reliability: The design of system must be reliable, ensuring safe and economic operation of the unit .In addition, The tolerance fault, redundant technology ,selfdiagnosis of software and hardware must be adopted to improve the reliability of system . （ 3.） Communication and manmachine interface: Because there are many parameters need to be measured and controlled and its varying speed is quick when the large scale unit is running , munication system must have quick realtime response and high reliability 。 . Basic function of coordinate control system. Coordinate control system of the thermal power unit should usually have following function:(l) select different load instruction according to the unit operating condition and the requirement of power work for the unit.(2) restrict the change rate of load instruction.(3). Calculate the biggest possible output of the unit and restrict the biggest and minimum amplitude of load.(4). Have the function of RUNBACK.(5). Select different running mode according to the unit operating condition.(6). Calculate actual unit output.(7). Let automation control system have enough steady abundant quantity and better wholeness.(8). Have necessary safe measures such as starting bypass system and preventing steam turbine from exceeding the speed limit etc…, when the unit and power work unite suddenly because of accident. Basic position of coordinate control system of the unit. Now the coordinate control system of the unit is posed of two parts, which are load instruction process and coordinate control of boiler and steam turbine, shown as . Unit Coordinate Control System In which, load instruction process is posed of unit calculation loop, unit Allowed load calculation loop and load restriction loop. Coordinate and steam turbine controller. . Implementation of coordinate control system of the thermal power unit Modern largescale thermal power unit adopts distributed control system to realize
法律信息相關(guān)推薦
鄂ICP備17016276號(hào)-1