A method for controlling the overflow opening of steam turbine supplementary steam valve

Abstract

The invention relates to an overflow opening control method for a steam supplementation valve of a steam turbine. The method is characterized in that when primary frequency modulation control over thesteam turbine is carried out under the CTF coordination control, the actual value of the main steam pressure is collected in real time, whether the difference value between the actual value of the main steam pressure and the high limit value of the main steam pressure is within a set range or not is judged, the steam supplementing valve is automatically adjusted to be opened if the difference value is less than or equal to the minimum value of the set range, and the steam supplementing valve is automatically adjusted to be closed if the difference value is greater than or equal to the maximumvalue of the set range. Compared with the prior art, the method has the advantages that the main steam pressure can be maintained at the rated pressure for operation, and therefore the operating thermal efficiency of the steam turbine can be greatly improved.

Description

technical field [0001] The invention relates to a steam turbine control method, in particular to a steam turbine supplementary steam valve overflow opening control method. Background technique [0002] In recent years, in order to save energy and reduce emissions, more and more 1000MW units have been installed. The 1000MW ultra-supercritical unit includes an overload steam supplement valve, which is similar in structure to other steam inlet control valves. It is a single-seat valve located at the lower part of the high-pressure cylinder. The opening of the valve is adjusted by the electro-hydraulic control system, and it is closed safely by the spring. The steam sources of supplementary steam are drawn from the casings of the two main regulating valves (behind the main steam valve and in front of the valve core of the main regulating valve), connected to the overload supplementary steam valve, after passing through the overload supplementary steam valve, it is divided into ...

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Problems solved by technology

At present, the circulating cooling water temperature of the condenser is 29.7°C. If the cooling water temperature rises to 33°C (the highest temperature since it was put into operation), the unit will not be able to run at full load

[0006] 2. If the medium-pressure heat supply is 100t / h, the main steam pressure will increase by 0.6MPa, and it will not be able to supply heat under high-load conditions in summer

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