Secondary temperature-decreasing water valve position self-optimizing method in main steam temperature control

Abstract

The invention discloses a secondary temperature-decreasing water valve position self-optimizing method in main steam temperature control. For the existing main steam temperature closed-loop control process, the improper temperature setting value of a secondary inlet regularly causes a too low or too high working point of the secondary temperature-decreasing water valve, so that the secondary temperature-decreasing water valve loses the adjusting capacity in the subsequent time. The secondary temperature-decreasing water valve position self-optimizing method overcomes the existing disadvantages through the following steps of: (1) setting upper limit and the lower limit for the optimization of the secondary temperature-decreasing water valve; (2) setting the filter time for the secondary temperature-decreasing water valve; (3) setting the automatic steam temperature adjusting condition for the secondary inlet; and (4) setting a maximum offset of the automatic steam temperature adjustment for the secondary inlet. According to the method provided by the invention, the secondary temperature-decreasing water valve is enabled to be always in a proper position so as to ensure enough adjusting margin on the up stroke and the down stroke, and sufficient adjusting means are guaranteed in case of unexpected disturbance; in a varying load process, the function can more easily enable the main steam temperature to be stable.

Description

technical field [0001] The invention belongs to the field of thermal automatic control, in particular to a method for self-optimizing the position of a secondary desuperheating water valve in main steam temperature control. Background technique [0002] The main steam temperature in the superheated main steam temperature control system is an important parameter in the operation process of the power plant unit. High main steam temperature can improve the thermal efficiency of the power plant, but too high steam temperature will cause overheating of metals, accelerated aging of pipes, and excessive stress. Eventually lead to pipe leaks. Therefore, the purpose of adjusting the main steam temperature is to maintain a small fluctuation range under various working conditions, so as to increase the set value of the main steam temperature to achieve higher thermal efficiency. Usually, the adjustment of the main steam is carried out by spraying water to reduce temperature. Generally...

AI Technical Summary

Problems solved by technology

[0003] In the process of closed-loop control of the main steam temperature, if the set value of the secondary inlet temperature is not appropriate, the working point of the secondary desuperheating water valve will often be too low or too high, that is, the secondary desuperheating water valve is at or close to fully open or fully closed , so that it loses its ability to adjust in the subsequent time

[0004] At present, the temperature setting value of the secondary inlet is manually controlled by the operator based on experience. It is difficult to continuously fine-tune the conventional manual control method to ensure the adjustment ability of the secondary desuperheating water.

When a special working condition occurs, the original automatic adjustment can only be withdrawn, and the primary and secondary valves need to be manually adjusted in a large range, resulting in excessive fluctuations in the main steam temperature

In this way, on the one hand, during routine control, the set value of the main steam temperature should not be too high to prevent overheating in special working conditions; The thermal stress fluctuates greatly, which causes the aging of the pipeline

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