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Copyright of Electric Power is the property of Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jiangsu University (Natural Science Edition) / Jiangsu Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Jiangsu University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Residual current devices (RCDs), a type of protective equipment in low-voltage systems, are widely used to prevent and avoid leakage accident of power grid and protect the safety of life and property. At present, the operation of an RCD is based on sensing the root mean square value of residual current in an electrical circuit. The circuit will be interrupted on the action of a relay when the residual current exceeds a predetermined level (30 mA for human safety), known as the tripping current. Although such devices offer a large degree of protection, they are prone to nuisance tripping or maloperation in the actual operation of the grid due to the lack of the ability to diagnose electric shock type and identify touch current, which reduces the reliability and the rate of proper commissioning for RCDs. Thus, aiming at the problem that the measured electric shock signals are non-stationary and difficult to diagnose the type of electric shock, a new method of fault diagnosis of electric shock signal based on time-frequency singular spectrum of leakage current and fuzzy clustering is proposed. First of all, a simulation signal is used to compare and analyze the time-frequency analysis performance of short-time Fourier transformation (STFT), wigner-ville distribution (WVD) and smoothed pseudo Wigner-Ville distribution (SPWVD). The simulation results show that the STFT presents a lower time-frequency resolution because of the fixed window function, the WVD has serious crosstalk terms and it is difficult to determine the frequency components of the signal, and the SPWVD suppresses the crosstalk of WVD and reflects the distribution of signal frequency components with time through the smoothing of time-frequency window function. Therefore, SPWVD is chosen as the time-frequency analysis method in this paper. Then, numerous groups of total leakage current signals were measured using a recorder on the electric shock experiment platform of RCDs. We select a total of 0.04 s of data (one cycle before the electric shock and one cycle after the electric shock) as electric shock sample data. The SPWVD is used to analyze the total leakage current signal to obtain the time-frequency matrix, and the frequency band width of the main spectrum energy is 0-150 Hz, which can be divided into 13 sub-bands. The singular value decomposition (SVD) is adopted to decompose the time-frequency matrix formed by 13 sub-bands, and the singular values corresponding to the respective sub-frequency band are obtained as the feature vectors of the electric shock signal. And then the fuzzy C means (FCM) algorithm is applied to perform the clustering of extracted feature vectors to get the electric shock signal type. Finally, a total of 400 groups of animals and plants shock data are used as the research object. Among them, 140 groups of animal electric shock samples and 140 groups of plant electric shock samples are taken as known samples, and 60 groups of animal electric shock samples and 60 groups of plant electric shock samples are used as test samples. The experimental results show that there are 3 groups of samples in 120 groups of test samples which are wrongly identified and the recognition accuracy rate is 97.50%. Among them, the accuracy rate of plant electric shock test sample is 100%, and there are 3 samples in animal electric shock test samples, which are identified incorrectly and the recognition accuracy rate is 95.00%. The above results verify the correctness and validity of diagnosing the type of the electric shock fault signal by the extracted characteristic value of the total leakage current, which can lay a solid theoretical and technical foundation for developing new generations of adaptive residual current protection devices. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jiangsu University (Natural Science Edition) / Jiangsu Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Jiangsu University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to quickly and accurately extract the electrical parameters in the transient signal of the electric shock caused by organisms, an instantaneous amplitude and frequency extraction method based on local mean decomposition (LMD) for the total leakage current signal of biological electric shock was proposed. The de-noising total leakage current signal was decomposed into a linear combination of a finite set of product functions (PF) and the amplitude modulated (AM) signal, and frequency modulated (FM) signal of each PF also could be obtained. The amplitude modulated signal was utilized to calculate the instantaneous amplitude and damping, while the frequency modulated signal was used to determine the instantaneous frequency. By using the method, compared with the Hilbert-Huang Transformation (HHT), the curves of the instantaneous amplitude had less distortion in wave head and the instantaneous frequency had shorter swings. The method of HHT consisted of separation of the series data to components with different time scale (e.g. intrinsic mode function (IMF)), and empirical mode decomposition (EMD), and application of the Hilbert Transformation to obtain the instantaneous amplitude and frequency of the signal from the IMF. The results of simulation signal showed that LMD and EMD were carried out on the test signal which was three PF components and five IMF components, respectively. The energy change values of LMD and EMD before and after decomposition was 0.2851, 0.5633, and the decomposition time of LMD was shorter than the EMD. Moreover, the instantaneous amplitude frequency based on the calculation of HT and integrated algorithm of PF appear the phenomenon of flying wings, but compared with the Hilbert transform, the proposed method to calculate the result was more smooth which can restrain endpoint effect to a certain extent and extract the instantaneous amplitude and frequency better. Experimental signal analysis results showed that LMD and EMD were carried out on the de-noising total leakage current signal which received five PF components and six IMF components, respectively, and the energy change values of LMD and EMD before and after decomposition were 0.5574, 0.8896, and the use of decomposition time were 0.0835s, 0.2479s, respectively. In calculating the instantaneous frequency aspects, the moment of electric shock can be determined by the LMD, while the instantaneous frequency was calculated by using the Hilbert transform not only unable to determine the electric shock time, but also the negative frequency values appeared, which had no physical meaning. In calculating the instantaneous amplitude aspects, the average instantaneous amplitude of the total leakage current signal before the electric shock was 11.3240 mA, compared with the real amplitude, the absolute error was 0.0298 mA, while the error was obtained by using Hilbert transform was 1.0190 mA. In addition, the absolute errors between the average instantaneous amplitude of total leakage current signal after electric shock was computed by LMD and Hilbert Transform methods and real amplitude were 0.4340 mA, 0.6643 mA, respectively. Therefore, it can be seen that the simulation and experimental results prove the feasibility and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]