Applied Mechanics and Materials Vols. 536-537

Abstract: For problems of zero sequence current and negative sequence current of traction transformer in Electrified Railway, a novel balance transformer with asymmetrical windings was presented. By a systematic analysis method based on the magnetic force balance equations, winding connection equations, output-port equations and voltage transfer equations, the current relationships of the primary windings and secondary windings, the balance condition and the short circuit impedances (when the neutral current in the primary side is zero) were deduced, and the electric characteristics of the balance transformer was analyzed. Through the experimental model of balance transformer in simulation platform based on Matlab/Simulink, the electric characteristics of balance transformer and change law of zero sequence current and negative sequence current in different mode were researched. Correctness and feasibility of the theoretical analysis are verified through the simulation experiment.

Abstract: The Series Dynamic Voltage Regulator can compensate the harmonics distortion caused by voltage type harmonic source This paper presents a new approach of detecting harmonic voltage in dq0 coordinates, based on the generalized instantaneous reactive power ,and used in the series dynamic voltage regulator successfully. It is demonstrated by theoretical analysis and simulation results that the proposed detecting method of harmonic voltage is correct and valid.

Abstract: This paper describes the generation of low frequency oscillations and suppression methods briefly. Observing a phenomenon of low frequency oscillation of Gansu Grid Power and analysis its actual situation. Therefore, we need establish simplified simulation model in MATLAB environment, then do the simulation with the dual power system simulation model which add to power system stabilizer. Simulation results show that: PSS can solve the problem of low frequency oscillations in a region of Gansu steel caused rapid and effective.

Abstract: A marine DC uninterruptible power supply is designed. The UPS adopts PIC16C73 single-chip microcomputer to realize the battery management. Both AC power and battery power, the output voltage stability in 23 to 24 v.Via advanced battery management, two sections of charging, equalized charging and floating charging can automatic convert and the DCUPS has many functions of protection, such as over-voltage protection ,under voltage protection and short circuit protection.The actual use on the ship and other occasions showed that the DCUPS is convenient and practical,and is more simple, reliable and longer emergency power supply than the traditional AC-DC uninterruptible power supply management scheme.

Abstract: A phenomenon that the damping ratio will decrease when the power flows from both sides to the primary power grid is summarized and analyzed in the paper. Based on analysis of the damping ratio change of West Inner Mongolia-Shandong oscillation under the sequential operation mode and the hedge operation mode, a three-machine equivalent system is established to study edge to edge (ETE) oscillation mode under hedge operating mode of the power system. The influence of magnitudes and trends of power flow on damping ratio is analyzed, and the reason that why damping ratios decreases when both sides send power to the mid-side power grid is explained.

Abstract: Aiming at the problem of electromagnetic interference in design and application of electronic rectifier and inverter system, introduces the electromagnetic interference and electromagnetic compatibility characteristics of common circuit, the interference test of rectifier and inverter system, puts forward the products it has produced inhibition method of interference. The test results show that the method can reduce electromagnetic interference system greatly.

Abstract: A new hybrid technique based on ADALINE (Adaptive linear element neuron) associated with Prony algorithm is presented for harmonics and interharmonics estimation in power system. The Prony algorithm can detect the accurate frequencies of harmonics and interharmonics, and the ADALINE can get the amplitudes and phase angles. If the noise is present, the Prony algorithm can get less accurately frequencies to reduce convergence time of the ADALINE, and the ADALINE will obtain higher accurately frequencies, amplitudes and phase angles by adjusting the weights. The validity and feasibility of the proposed algorithm is demonstrated by numerical simulations.

Abstract: Photovoltaic system because of the complexity of the circuit functions, prone to failure. In this paper, according to the fault characteristics, established the HAZOP method combined with the method of fault tree model, combined with a service building of Tianjin to analyze the fault and gives countermeasures.

Abstract: This paper introduces a robust high-gain observer based state of charge (SOC) estimator for lithium-ion batteries of automated guided vehicles (AGV) . The proposed observer scheme enhances the transient response speed and diminishes the effect of uncertainties. Furthermore, it overcomes the perturbation problem, which is caused by high gains since the proposed observer scheme adopts sliding mode control technique. In order to verify the effectiveness of the propose method, the linear RC battery model in ADVISOR is used.

Abstract: Gap-type conductor stringing and currently existing conventional tension stringing construction technology are not identical, explore two old wires with a new gap-type conductor, which is two-pulling-one wire stringing construction technology. In this paper two-pulling-one running board is designed and manufactured to meet the stringing construction technology. The experiment results show that the system greatly improves the efficiency of the stringing, at the same time reduces construction costs, saves a lot of manpower and time, ensures the construction period, safely and efficiently completes the construction task.