Calibration system for exhaust steam volume flow of steam turbine and safety early warning system

Abstract

The invention provides a calibration system for exhaust steam volume flow of a steam turbine. The system comprises a parameter collection module and a data processing module; the parameter collectionmodule obtains the steam inlet pressure and the exhaust steam pressure of a low-pressure cylinder of a current steam turbine, the obtained data are transmitted to the data processing module, the dataprocessing module obtains the exhaust steam volume flow on the basis of the steam inlet pressure and the steam exhaust pressure, a steam turbine last-stage blade safety early warning system is provided, and comprises the volume flow calibration system and a judging module, the data processing module transmits the exhaust steam volume flow to the judging module, and the judging module compares thecurrent exhaust steam volume flow with the rated exhaust steam volume flow and judges whether an early warning signal is sent out or not. The calibration system and the safety early warning system have the advantages that through measuring the steam inlet pressure and the exhaust steam pressure of the low-pressure cylinder, the exhaust steam volume flow can be portably and accurately calibrated, the factor influencing the last state blade safety can be subjected to early warning analysis essentially, and the influence of the frequent peak regulation on unit safety is reduced.

Description

technical field [0001] The invention relates to the technical field of steam turbine operation safety, in particular to a calibration system and a safety early warning system for steam turbine exhaust volume flow. Background technique [0002] The steam turbine exhaust volume flow rate directly affects the unit economy and the safety of the final stage blades. When the exhaust steam volume flow rate is too small, it will cause flutter in the steam turbine final stage blades. If the steam turbine operates under this condition for a long time, it will This leads to metal fatigue of the last stage blade, and eventually cracks or even breakage, which brings great hidden dangers to the safe operation of the unit. Refer to figure 1 . When the exhaust volume flow rate reaches around 20% of the design value of the rated working condition, the flutter stress reaches the peak value, so the safety warning system in the prior art requires the alarm before the exhaust volume flow rate d...

AI Technical Summary

Problems solved by technology

[0002] The steam turbine exhaust volume flow rate directly affects the unit economy and the safety of the final stage blades. When the exhaust steam volume flow rate is too small, it will cause flutter in the steam turbine final stage blades. If the steam turbine operates under this condition for a long time, it will This leads to metal fatigue of the last stage blade, and eventually cracks or even breakage, which brings great hidden dangers to the safe operation of the unit. Refer to figure 1

When the exhaust volume flow rate reaches around 20% of the design value of the rated working condition, the flutter stress reaches the peak value, so the safety warning system in the prior art requires the alarm before the exhaust volume flow rate drops to 20%, but due to the It is difficult to directly and accurately measure the volume flow rate, so at present, early warning and tripping protection are mainly set through the high back pressure of the steam turbine, but the protection value is set mainly considering the base load operating range of the unit in pure condensing state

[0003] With the increasing emphasis on environmental protection, thermal power plants need to carry out peak shaving operation more and more deeply. The current early warning method does not consider abnormal conditions such as low load rate under deep peak shaving, and reduction of steam turbine exhaust flow after heating transformation. Therefore, this early warning method cannot accurately judge the working status of the final blade, and cannot meet the requirements of safe operation of steam turbines under the new situation.

Images