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《Journal of Hydroelectric Engineering》 2018-09
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Methods comparison for calculating peak-to-peak amplitudes of vibrations and pressure pulsations in hydropower units

ZHANG Fei;LIU Shiqi;XUE Xiaobing;DENG Lei;Technology Center of State Grid Xinyuan Company Ltd.;Harbin Institute of Large Electrical Machinery;Operation and Maintenance Department of East China Yixing Pumped Storage Power Co.,Ltd.;  
Collecting accurate data of stability parameters is a key to monitoring and fault diagnosis of hydropower units, particularly the core stability parameters: peak-to-peak amplitudes of vibrations and pressure pulsations. First, this paper examines different methods for calculating peak-to-peak values specified in different standards and discusses the concept of confidence interval from the two viewpoints of statistics and engineering application. Then, considering signal collection in a complicated field environment, we verify each method using both numerically simulated signals with normally distributed noises and field measurements. Results show that for low frequency dominated signals, the ±1.96σ method produces large errors and thus is not applicable, while for signals with high frequency components, different methods often result in great differences. This study recommends the method of 95% confidence interval for calculation of peak-to-peak values of the signals, which is conservative but robust and insensitive to noises. These results would help the revision of GB/T 17189, IEC 60994 and other related ISO specifications.
【Fund】: 国家电网公司科技项目(52573016001G; 52573015000J);; 国家自然科学基金(51309258);; 中国水利水电科学研究院基本科研业务费专项项目(HM0145B222018)
【CateGory Index】: TV734
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