A Direct Measurement Method of Efficiency of Low Pressure Cylinder of Steam Turbine

Abstract

The invention discloses a direct measurement method for turbine low pressure cylinder efficiency. The direct measurement method comprises the following steps that 1, test measuring points and a data acquisition system are arranged and installed; 2, a unit is stabilized at 40%-60% of rated load, the reheating steam temperature is adjusted to 5-10 DEG higher than rated temperature or above, and thebackpressure of the unit is adjusted to rated summer backpressure of the unit; 3, the unit runs stably for 30 minutes, the backpressure of the unit is increased by 1-2kPa, and step 4 is entered; 4, the unit runs stably for 30 minutes, it is judged whether or not the exhaust temperature of a low pressure cylinder is greater than 15 DEG C or above of saturation temperature corresponding to low pressure cylinder exhaust pressure, if yes, step 5 is entered, and if no, step 3 is entered; 5, test timing is started, and 30 minutes of test data is collected; and 6, the test data is collated and calculated to obtain low pressure cylinder etaL. According to the direct measurement method for the turbine low pressure cylinder efficiency, direct test is carried out to obtain the low pressure cylinder efficiency under the premises that the cost is lower, a few of test instruments are used, and the safety risk is low.

Description

technical field [0001] The invention relates to an engineering thermodynamic method for the efficiency of a steam turbine, in particular to a method for directly measuring the efficiency of a low-pressure cylinder of a steam turbine. Background technique [0002] At present, my country's thermal power units account for more than 60% of the total installed capacity of power generation. Steam turbines are important devices for converting thermal energy into mechanical energy in thermal power plants. With the advancement of technology, steam turbines are developing towards high parameters and large capacity. The units are 1000MW ultra-supercritical, 600MM ultra-supercritical, supercritical, subcritical, and 300MW supercritical and subcritical units. Regardless of the capacity, the basic structure of the steam turbine is: high, medium and low pressure cylinder structure, in which the high and medium pressure cylinder steam of the above-mentioned large-scale steam turbine works in...

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Problems solved by technology

[0013] (2) The experimental uncertainty of this method is relatively large. From the perspective of energy and flow balance, all measurement errors and system errors (including internal and external leakage of the thermal system) in the system are all accumulated in the calculation of energy or flow balance. In this way, it is accumulated into the calculated value of the exhaust enthalpy of the low-pressure cylinder, which affects the uncertainty of the efficiency result of the low-pressure cylinder;

[0014] (3) Due to the large number of test instruments and meters used, the test cost of this method is relatively high

[0015] (4) During the test, the thermal system needs to be isolated according to the design of the heat balance diagram. In the low-pressure cylinder efficiency test for a 300MW unit, there are about 200 to 300 valves that need to be checked for isolation status on site, and isolation operations are required There are about 60 to 100 valves, so the workload of system isolation is large, and there is a certain risk to the normal operation of the unit

[0016] From the above description, it can be seen that the conventional low-pressure cylinder efficiency measurement method needs to collect a lot of data, requires a large amount of instruments, a large workload, complex calculation methods, and brings certain safety risks to the operation of the unit during the test.

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