Domestic 200MW Power Generation Unit Collaborative Control System's Design And Implementation

Thermodynamic system is composed of three main equipments: steam-wheel machine, boiler and dynamo, and some other ancillary equipments. The auto-control system of the Thermodynamic System includes some subsystems, which has their own adjusting instruments and adjusting objects. All the subsystems are independent from each other, but as the parts of the whole system, they are also correlative and interactive to be strong coupling, large retardation and nonlinear. So to adapt to the change of the load of the electrical system, a system should be designed, which can harmonize the control functions of all subsystems based on the warp of the main parameters to ensure the system to run safely. Such system is called Harmony and Control System of equipment group unit.Harmony and Control System of equipment group unit is developed with the manufacture of equipment group unit with large capacity and the development of the computer auto control technology, especially the development of dispersive control system. Harmony and Control System is applied on some imported equipment group at the beginning of 90's. And at that time the control strategy is also imported. At the end of 90's, Harmony and Control System is widely used on the 200MW equipment group unit of our country. But restricted by the developing level of the electric power, the condition was not very perfect, and the function was not very consummate. There were still some problems, and it need to be improved and developed.The main functions of Harmony and Control System of equipment group unit is to harmonize the steam-wheel machine, boiler, dynamo and inner control subsystem after receiving the load command or the control center command, adopt some technical measures to make the main parameters approach the max working curve but within the permission region and increase the response speed of the system to make the system more efficient and safe to adopt to the change of the load of the electrical system. And at the same time, it also should harmonize the load command and the real capability of the equipment group. When the capability of the equipment group is restricted, the control system should limit or change the load of the equipment group to implement the interlocking protect function.So, Harmony and Control System is helpful to enhance the auto control system of the equipment group unit, increase the adopt ability to the load change, perfect the emergency measures when trouble happens, decrease manual operations and lighten the manual work, thus make the equipment group unit more safe and economical, and also provide condition for equipment group unit to implement AGC control.Harmony and Control System of equipment group unit has four running modes: harmony and control mode, machine-based mode, boiler-based mode and manual mode. The switch between different modes should be smoothly. The principle of the machine-based mode is that the load commands are received by the steam controller, and the boiler controller receives the pressure enactment and control the steam pressure. The principle of the boiler-based mode is that the boiler controller receives the load commands, and the steam controller receives the pressure enactment and controls the stem pressure. The principle of the harmony and control mode is that the load command and the pressure command are sent to the steam controller and boiler controller, and then steam controller change the open degree of the steam clique, and boiler controller change the fuel quantity, so that to change the steam quantity to meet the requirements of load command and the pressure command. Manual mode is to set the steam controller and the boiler controller as manual mode, and the worker control the system manually. It is the mode when some problems occur in the steam system, boiler or control system.The No1 equipment group of the ChangChun No2 Thermoelectricity Ltd. is 200MW double pumps thermoelectricity equipment group. The unit control mode is used in the system. To improve the level of the auto control...