Advanced Materials Research Vols. 986-987

Abstract: In order to analyze the partial discharge of void defect discharge in solid insulator, for the PD problems that at home and abroad simulation model can’t objectively reflect the physical process of partial discharge. Based on classical three capacitor equivalent-circuit model, the change of the electric field intensity and the voltage as size of the air void differs is studied. The influence of the air void geometry properties of partial discharge is analyzed. By comparing the results of the simulation model and its results and existing research results, the correctness of the circuit simulation model is verified.

Abstract: In order to quickly determine the performance of a transient voltage suppressor (TVS), improve time domain identification capability of Elman network, the simulation of electromagnetic pulse (EMP) inject effects based on improved Elman network is proposed. Derivation proved that improved Elman network trained by standard BP algorithm has a similar form with the basic Elman network trained dynamic BP algorithm. We establish and improve its Elman network predictive modeling based on the measured parameters of TVS and then demonstrate that improved Elman network has the characteristics of quick speed, high precision, good performance and strong generalization ability, and broad use of prospects.

Abstract: In this paper, the numerical analysis methods of electromagnetic field is used and by establishing the computer model of 110kV high-voltage power line and medium wave amplitude modulated broadcasting (AM) stations, the impact on the electromagnetic environment of medium wave broadcasting stations caused by 110kV high-voltage power lines is analyzed.

Abstract: Based on the theory and mathematical treatment for the photovoltaic cell, a simple and accurate PV array model of external characteristics is developed with PSIM. Output simulation results for different Temperature and Light intensity. The simulation results show that I-V and power simulation result of the Photovoltaic array model, and experimental result are in close agreement with each other. This verifies the accuracy and suitability of the developed PSIM model.

Abstract: The transformer model is one of the most needed to improving components of the modern transient simulation software. A new nonlinear broadband frequency (50Hz-10MHz) model of power transformer is proposed in this paper. The model is divided into a linear block and a nonlinear block by a reasonable equivalent transformation. The linear block is set up through measuring and synthesizing. And the nonlinear block is derived by the impendence of iron core. The final circuit model is built in Simulink, and the comparisons between the simulation and measurement results verify the feasibility and validity of the model.

Abstract: In order to calculate the two-port wide frequency parameters of a large transformer quickly and accurately, parameter calculation of multi-conductor transmission lines model is proposed based on the sparse matrix operation. It solved the problem caused by the large matrix. Firstly, multi-conductor transmission lines model of the transformer windings is established. Secondly, matrix characteristics of Y and Z is analyzed, based on which the block storage and computation method is applied. Then the frequency-domain model is solved based on sparse matrix operation. At last, taking a SS11-20000/110 transformer as an example, the correctness of this method has been verified by comparing calculation results with measurement results.

Abstract: In this letter, an optimal power allocation in the two-way relay channel of four transmission nodes employing the physical-layer network coding (PNC) protocol is proposed to improve the network sum-rate of the two-way relay system. The optimal power allocation is obtained by maximizing the network sum-rate of the PNC protocol under a sum-power constraint in a Rayleigh fading channel environment. Analytical and simulation results show that the proposed power allocation can improve the network sum-rate. Furthermore, compared with the equal power allocation scheme, the proposed power allocation scheme can achieve much higher network sum-rate performance.

Abstract: The static signal is collected through the experiment, and the probability density function model is established. The static random signal noise is analyzed by frequency spectrum, power spectrum and high order spectrum analysis. It is found that the third order spectrum of the laser static signal is zero by the high order spectrum analysis. Noise signal is only to analyze on the frequency spectrum and power spectrum. The results show that the static laser signal has the characteristics of stationary Gauss random signal.

Abstract: The standard OFDM signal requires a cyclic prefix (CP) of length larger than the channel impulse response. This paper investigates the effect of CP length to the capacity of OFDM system. We have found that full CP or none CP may not be optimal in the sense of capacity. Specifically, the capacity is a monotonic function of CP length in the low and high SNR regime and is approximately concave down when SNR is about 3dB.

Abstract: This paper discusses the application of wavelet transform in signal compression and signal recombination detailedly. This paper briefly introduces the principle of wavelet transform in signal compression and signal recombination, this paper also introduces the wavelet MATLAB simulation experiments. This paper researches the differences the wavelet transform and wavelet packet transform in signal compression, this paper also briefly discusses the influence factors of signal compression.