Advanced Materials Research Vols. 986-987

Abstract: According to the problem that the existing data interpolation algorithm has low efficiency when handling high-speed data, this paper proposes a FPGA-based FIR sine interpolation algorithm based on pipeline and parallel technology. The algorithm not only reduces the critical path so that improve the system working clock effectively, but also increases the speed of data processing to improve the speed of interpolation process significantly. Finally, according to the experiment based on FPGA, the result shows that the proposed algorithm improves the speed of data interpolation process, and reduces the system power consumption effectively. It can realize the real-time interpolation process of high-speed or hyper-speed data stream.

Abstract: As an important part of pipeline safety, pipeline leak detection is usually done by extracting feature vectors of leakage signal. Many researchers used wavelet packet algorithm to extract feature vector, but because of mixing effects of wavelet packet, the acquired feature vector may be not accurate. To solve this problem, the authors propose an improved wavelet packet algorithm to extract the feature vector. The improved algorithm is different from the traditional algorithm in decomposition and reconstruction and the feature vector is constituted by three time-frequency domain parameters. A lot of experiments have been performed to extract feature vector based on the proposed algorithm, with the results showing that the proposed algorithm can overcome the mixing effects and accurately extract the feature vector.

Abstract: To improve accuracy and speed of recognising and classifying grid power quality disturbances, this paper presents a new method which combines complex wavelet transform and particle swarm optimization (PSO) neural network to identify and classify the disturbance . This method extract both amplitude-frequency and phase frequency information of the interference signal to make up for the lack of traditional wavelet transform which only extract the amplitude-frequency information. And on this basis, using particle swarm optimization, we seek the optimal solution of neural network weights and thresholds for the identification and classification of power quality. The MATLAB simulation result has verified the accuracy and rapidity of this method compared with the traditional method .

Abstract: By using the advantages of C-type of traveling wave fault location method in distance measuring and the pattern recognition function of support vector machines (SVM),a new fault location method is presented.The first step of the method is determining the fault distance by C-type of traveling wave location method; the second one is locating the fault section by SVM. It also adopts the wavelet to reduce the noise of fault signal,and the accuracy can be more precise when the parameters of SVM are optimized.The simulation results of ATP and MATLAB show that the method can determine the single phase grounding fault point in 10kv distribution networks with branches accurately.

Abstract: In order to achieve aims of rapid real-time monitoring iron grade during sales process or mineral processing for the iron ores, a quick detection approach to magnetic iron grade of magnetite based on electromagnetic induction is explored in the paper. Information acquisition head is focused on an iron grade sensor, and the iron grade sensor is made up of coil-windings with magnetite core. Information acquisition circuits are given adapting mode of the transformer bridge type rectifier, and construction of the head is designed and machined. Testing mechanism is analyzed from the angle of magnetic field analysis, and the magnetic field model is also built up. Furthermore, magnetic iron grade of some testing samples are measured by the detection device above. It is showed that when the grade range of the magnetic iron of magnetite is varied from 20% to 65.3%, deviation is lower than 1.0%. By research above, it is shown that the detection method of iron grade based on electromagnetic induction is feasible, and it is also significant for improving the total testing level of mineral processing fields.

Abstract: Positive displacement flowmeters (PDFs) are highly accurate flowmeters that are relatively insensitive to the upstream velocity distribution and fluid viscosity. Rotor speed sensors are the key components of a PDF. This paper presents the structure of a non-contact rotor speed ​​sensor which can be used in cycloid rotor flowmeter and other PDFs. The sensor outputs a square wave which contains the speed information of the rotors. The key parameters of the rotor speed sensor are analyzed in this paper and a prototype was fabricated to confirm the rotor speed sensor work well.

Abstract: To detect interharmonics whose amplitudes are often small, a detection method based on ANF and interpolated FFT is proposed. In the method, the parallel structure of the ANF (adaptive notch filter) is firstly used to detect the fundamental and harmonic components, in which the fundamental frequency signal with high amplitude is detected with the main ANF and then the measured base frequency is output to sub-parallel ANF structure so as to extract the harmonic components. Then a separated interpolated fast Fourier transformation (FFT) analysis of interharmonic components will be effectively completed without the influence of the fundamental and harmonic components. A detection platform based on the proposed method is implemented in LabVIEW. The results of simulation and experiments show the effectiveness of the method.

Abstract: Fluids in the heat-supply pipelines have a small amount of impurities. Impurities can easily settle down on the ultrasonic heat meters’ reflecting faces. It caused measurement inaccuracy. Vortex generator is placed in ultrasonic heat meter in this paper, which can generate vortex in the reflect fields. Vortex toke away impurities on the bottom of heat meter. Reflecting surface keeps clean. A v-shaped ultrasonic heat meter is taken for example. Numerical study of the flow field near the Reflecting surface vortex generator is carried out. Results show certain strength of vortex is caused in the reflective surface, while other palaces influenced little.

Abstract: Eddy current testing is one of the five major routine nondestructive testing methods and it is convenient, fast and suitable for online detecting of the surface fatigue crack of bolt holes. However, the signals of eddy current testing are so weak that it is difficult to identify the signals. So more effective signal processing method must be adopted to deal with the weak signals. This paper used the wavelet analysis to process signals of the eddy current testing for the surface flaw of bolt holes. It can inhibit the noise and reinforce signal and make qualitative testing possible for quality evaluation of the surface fatigue crack of bolt holes.

Abstract: In order to research high level harmonic wave of six bundle conductors corona current, a measurement system was developed, and a series of wave data was obtained. Corona current is one of important corona characteristic research contents. The corona current measurement system can be used to measure the wide frequency band corona current. Six-bundle conductors was tested, and corona current was obtained. And the current signal collected in this way is safe and reliable. To research the six-bundle conductors’ corona current characteristic, conductor corona current harmonic wave was analyzed, by advanced Hanning windowed interpolation FFT algorithm was adopted. Corona current harmonic characteristics before and after corona onset were compared. Research results show that, after corona onset, corona current odd harmonic increases in evidence, and even-order harmonic increase less relatively. Triple-frequency harmonics and quintuple harmonics increase obviously very much.