Method and device for controlling feedwater flow during auxiliary machine failure and load reduction

Abstract

The embodiment of the invention provides a control method and device of feed water flow in the runback process. The method includes the steps of obtaining the deviation between the current main steam pressure value of a direct-current constant-pressure operation type coal-fired unit and the set main steam pressure value and obtaining the deviation between the current intermediate point temperature value of the direct-current constant-pressure operation type coal-fired unit and the set intermediate point temperature value after runback working conditions occur in the direct-current constant-pressure operation type coal-fired unit; and for the runback working conditions of different types, adjusting the preset rate of the feed water flow according to the deviation between the current main steam pressure value of the direct-current constant-pressure operation type coal-fired unit and the set main steam pressure value and the deviation between the current intermediate point temperature value of the direct-current constant-pressure operation type coal-fired unit and the set intermediate point temperature value. According to the scheme, the preset rate lowering the feed water flow is corrected in real time, and therefore the main steam pressure and the main steam temperature needed by operation can be accurately controlled, and the RB success rate can be increased.

Description

technical field [0001] The invention relates to the technical field of coal-fired units operating at constant pressure in direct current, in particular to a method and device for controlling feedwater flow in the process of auxiliary machine failure and load reduction. Background technique [0002] When the unit's main auxiliary equipment fault trips and the actual power of the unit is limited (the coordination control system is in the automatic state), in order to adapt to the output of the equipment, the coordination control system will forcefully reduce the load of the unit to the load target that the auxiliary equipment that is still in operation can bear This function of the coordinated control system is called RUNBACK, or RB for short. Generally, thermal power plants are typically designed with two induced draft fans, two supply fans, two primary fans and two feed water pumps. When one of the above equipment fails and stops running, RB will occur. The air volume, coal...

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Problems solved by technology

[0005] The embodiment of the present invention provides a method for controlling the feedwater flow in the process of load shedding due to auxiliary engine failure, so as to solve the technical problem in the prior art that affects the success rate of RB due to the inability to accurately control the hot spot temperature and main steam pressure

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