The Development And Application Of Steam Turbine Performance Test System Based On Virtual Instrument

Steam turbine performance test is an important means to evaluate the economic and safety of steam turbine unit, and it is of great significance to the energy saving of coal-fired units. However, at present, data acquisition of steam turbine performance test has the characteristics of poor real-time performance and weak communication reliability, and intelligence level of data preprocessing is low, and the calculation of test data is still in the off-line processing stage. So realize the function of real time data acquisition, intelligent data preprocessing and data online computing capabilities for turbine performance test will further deepen the guiding significance of steam turbine performance test in the unit energy-saving work.Virtual instrument is the product of the combination of instrument technology and computer technology, and the hardware device complete signal measurement, acquisition, and software complete the signal analysis and processing. Based on virtual instrument technology, this article developed a steam turbine performance test system. The hardware of the system realizes real time data acquisition, and the software realizes the intelligent data processing and on-line data analysis.In design of hardware, because the data acquisition component is the core of the system hardware, this article select NI data acquisition products-NI Compact DAQ chassis and NI C series NI 9203 data acquisition boards to achieve the original signal measurement of the scene after the election among a variety of data acquisition equipment, which has a higher module hardware index, a stronger real-time communication, and easier programming in data acquisition. Then the signal is transmitted by the data exchange components to the computer.In design of software, system software is programmed by the virtual instrument software, including three parts of test data acquisition, preprocessing and computational analysis. Test data acquisition software including test data acquisition and control, signal analysis and noise reduction, developing data acquisition module by the application of graphical programming software Lab VIEW and driver software NI-DAQmx to control data acquisition; analyzing the signal spectrum to determine the frequency range of test data noise by Fourier transform; achieving the noise reduction processing of signals by using Butterworth low-pass filters. Taking the thermal test of Xibaipo #5 unit as an example, completing the pretreatment of test data rely on Fisher Ordered Clustering, which can extracted "steady state test data" that used in test data calculation from the data acquisition system. Test data calculation mainly include calculations of water flow and thermal parameters correction, and in the article, calculating water flow according to the water flow display matrix calculation equation, then complete thermal performance economic indicators calculation, such as heat rate, using conventional heat balance method; and complete parameter modification by the use of correction curve, and complete system correction according to the generalized steam-water distribution matrix equation.In this article, turbine performance test system collects real-time operating data that included in the scope of monitoring the plant by using the data acquisition system, which is based on virtual instruments. Through application of virtual instrument,this System can achieve online processing of test data and real-time monitoring of energy consumption indicators. To maximize real-time guidance role of energy consumption monitoring in the unit operation and maintenance work, and further realize unit energy consumption diagnostic and energy assessment.