Advanced Materials Research Vols. 860-863

Abstract: Electrostatic discharge is a familiar interfere. Repeatability of discharge current is poor. Transmission line pulse (TLP) is used in study of immunity of a microcontroller. A TLP generator is first manufactured with the rise time of output pulse less than 1ns. Then couplings by electric field probe, magnetic field probe and direct injection are presented. And immunity test of a microcontroller is done by using the TLP generator and probes. Results show that the tested microcontroller is more sensitive to magnetic field interference; reset pin and crystal oscillator pin of the chip are more sensitive than other pins under action of direct injection interference.

Abstract: The application of Ultraviolet Imaging Technology (UVIT) in the electric equipment Partial Discharge (PD) was proposed and the operating principle of Ultraviolet Imaging Technology Instrument (UVITI) was analyzed in the paper. By describing the current development trend of UV imaging technology in China and foreign country, the several factors influencing the detect accuracy of the UVITI was analyzed. The results show that: the environment temperature, the back light, the air humidity, the instrument gain level, the wind level and the measurement distance will influence the accurate measurement of PD level and location seriously. In order to detecting the PD level and locating the fault position accurately, electric equipment PD measurement should be taken in low environment temperature and humidity, short measurement distance and avoiding big wind. For the disturbing of environment noise on measurement signal, the instrument gain level should be improved.

Abstract: This paper presents a new digital potential transformer (PT) model. Due to the effect of hysteresis and saturation phenomenon, the magnetization curve of iron core has a strong nonlinear. From the perspective of hysteresis effect of iron core, this article presents a PT core model using the theory of fractional calculus, then propose a new PT circuit model. The model simulates the nonlinear part of iron core using the fractional order expressions and can reflect the feature of saturation. Finally it shows the correctness and validity of the model through the theoretical analysis and simulation results.

Abstract: Fractional calculus theory has gained more and more applications in numerous fields. In many cases, using fractional reactance element model can describe the properties of objects more accurately and simply. This paper studies the sensitivity of networks with fractional order reactance, puts forward the adjoint network sensitivity formulas and the incremental network models of fractional order capacitor and inductor, which will further develop the adjoint network and Incremental network theory. The simulation verification is also given.

Abstract: For studying the environment of power frequency electric field near the transmission line, the electric field model of 220kV transmission line was made in charge simulation method. Using the model, the electric field strength nearby the ground that under the lines was calculated and the distribute curves were drew in MATLAB language. The results showed that increasing the height of the conductors to ground, the electric field strength at the same point becomes lower.

Abstract: The frequency speed control system in flow control based on SENLAN SB60 frequency converter is made up of input set value and actual value which is the feedback voltage signal given by flow sensor, then adjusted by process PID automatic control, changes output frequency to regulate the speed of three-phase asynchronous motor to achieve the purpose of speed regulation, thus the tank's flow control can be obtained.

Abstract: One of the most widespread method of redevelopment of wet masonry is additional creating of hydroinsulating screen in the material. This method has many advantages. The biggest advantage is fact, that building can be repaired from inside without damaging its statics and saving it from being demolished, thus sparing the environment. In comparison to other procedures its application is quick, easy and has excellent final efficiency. Main object of this article is testing of application and total functionality of individual screens in masonry.

Abstract: Compared with traditional voltage-source converter (VSC) in low level topology, modular multilevel converter (MMC) is suitable for supplying passive networks. A stable and well controller is important to ensure the high quality power supply to passive network connecting to MMC. In this paper, a double closed-loop controller containing an inner current loop and an outer voltage loop is designed for the rectifier station. The feedback linearization controller is adopted in the inner current loop, which is much simpler and better than the traditional PI controller. And a constant AC voltage controller is designed for the inverter station. The performance of the proposed controllers under different operation conditions are simulated in PSCAD/EMTDC. The simulation results show that the proposed controllers can ensure MMC-HVDC system provide highquality power supply to passive networks.

Abstract: When using a remote networked control system, a network-induced time-delay is generated, which causes advert effects on the closed-loop networked control system such as performance degradation and system destabilization. For solving the time-delay in remote control system, intelligent fuzzy logic compensator is introduced in this paper to improve the traditional networked PI control system. In the full adaptive fuzzy parameter adjustment, off-line optimization and on-line adaptation are applied to the design of the controller, So that the consequent parameters can be tuned adaptively, As well as the membership functions in the antecedent part Simulation results of a networked controlled Brushless DC motor is used to illustrate the effectiveness and feasibility of the proposed fuzzy PI control scheme.

Abstract: The mathematical model of grid-connected wave power generation system based on modular multilevel converter (MMC) is deduced with topology structure and the operation principle of the MMC analyzed in this paper. Then the corresponding current decoupling control strategy is obtained in dq coordinates. Simultaneously, averaging voltage control and voltage balancing control are used to control the MMC to solve the imbalance and the ripple of the capacitor voltage of sub-modules. Moreover, the double closed-loop control strategy is used to control the grid-side MMC. Finally, the simulation model of grid-connected wave power generation system based on MMC is built in Matlab/Simulink. The simulation is carried out to verify the effectiveness and feasibility of the proposed control strategy.