Main steam pressure variable rate control method for assisting RB process steam drum water level control

Abstract

The invention relates to a main steam pressure variable rate control method for assisting RB process steam drum water level control. The main steam pressure variable rate control method comprises the following steps of performing differential calculation on a steam drum water level value to obtain a variable rate of a steam drum water level, respectively designing model functions of a main steam pressure rate and steam pressure instruction generation inertia time corresponding to the steam drum water level variable rate in a water feeding pump RB and a non-water feeding pump RB, and correcting the main steam pressure rate and the steam pressure instruction generation inertia time through the model functions. The method has the beneficial effects that the sliding pressure rate and the inertia time in the RB process are corrected in real time in allusion to a subcritical unit by combining the RB propulsion time, the load before RB action and the dynamic characteristics of the steam drum water level on the basis that the sliding pressure rate and the inertia time are corrected by the RB process propulsion time, the steam drum water level is controlled and assisted to be stabilized by utilizing the main steam pressure variable rate, and therefore fluctuation of the steam drum water level in the RB process of various auxiliary machines is effectively reduced, and running safety and running state recovery of a unit are ensured.

Description

technical field [0001] The invention belongs to the field of equipment faults of thermal power units, and in particular relates to a main steam pressure variable rate control method for auxiliary RB process steam drum water level control. Background technique [0002] When the important auxiliary equipment of the thermal power unit fails, the rapid load reduction control strategy adopted is called RUNBACK, or RB for short. The thermal power unit has corresponding main steam pressure parameters according to the design capacity. When the unit is in normal operation, the main steam pressure setting value is automatically controlled according to the unit load value, the designed speed and the inertia time. The purpose of the inertia time setting is to simulate the actual main steam pressure. In the pressure start-up process, in the current RB control strategy design of the unit, in order to quickly balance the unit load and the auxiliary engine load capacity, the steam pressure ...

AI Technical Summary

Problems solved by technology

[0007] However, in the current RB control, the setting method of constant rate and constant inertia time, which is generally used for the main steam pressure setting value, does not fit well with the changes of actual parameters, which not only affects the control of some important parameters of the unit during the RB process, It is also unfavorable for the recovery of the operation state of the follow-up unit, especially the control of the drum water level in the RB process of the subcritical unit; the inventor of the present application only considered the main steam pressure in the RB process in the auxiliary machine RB method of variable speed control of the steam-water system. Variable rate control (sliding pressure rate), and according to the advancement steps of the RB process, the speed of each stage is consistent with the actual trend, but does not consider the mechanism relationship between the associated operating parameters, and only designs the speed of each stage according to the advancement of the RB time. The sliding pressure rate and inertia time cannot accurately adapt to the real-time working condition changes of the unit, especially without considering the influence of steam pressure on other operating parameters of the unit

Images