Applied Mechanics and Materials Vols. 347-350

Abstract: This paper designs a universal intelligent wiring harness tester with the Cortex-A8 processor and embedded ARM-Linux operating system as the core, which is able to detect and diagnose the fault of harness including dislocation, short circuit, open circuit quickly and accurately. It also can achieve the test function of on-state resistance, insulation resistance and withstand voltage level and other additional features of the test data analysis, storage and network communication, which can be widely used in various occasions where harness are tested automatically.

Abstract: The 75 m/1.5 kA AC high-temperature superconducting cable(75 m HTS cable) and the 360 m/10 kA DC HTS power cable (10 kA HTS cable), which are supported by Chinese State 863 projects, are both of the demonstration projects facing to industrialization application. The characteristic in structure of warm dielectric (WD) insulated HTS cable is introduced. The electric field distribution characteristic at the cryogenic envelope body, the end-point of metallic shield layer at the end of the HTS cable and the connection sections are analyzed; the controlling method for electric field stress is introduced; there is serious concentration of electric field both in the termination and the connection sections between the termination and the cryogenic envelope. It is difficult to calculate the electric field of the part with irregular or special structure by resolution analytical methods, and the numerical analysis method is effective to analyze the electric field of the shaped structural part for HTS cable. The electric analysis, simulation, the design and processing of insulation for the two cables are finished based upon these two cables run well by now.

Abstract: The Multi-objective Optimal AlgorithmNSGA-II for Network reconfiguration of the shipboard power system is proposed to overcome the shortcomings of single objective optimal algorithm. This paper chooses the least of lost loads and cost of switch operation as objective function, uses capacity and structure as constraints, codes two-dimensional gene with switch and uses NSGA-II to solve the multi-objective and multi-restriction network reconfiguration problem. The test results of a typical integrated power system show that the model can balance each objective to avoid extreme results, which make restoration schemes more practical.

Abstract: The reactive power optimization control of grid voltage is the important measures of lowering the net loss and improving the voltage quality. The paper reviews the situation of voltage reactive power control in our country, putting forward implementation program of AVC system. The system can collect and dispatch the real-time data of automotive nodal voltage, active power and reactive power and so on. The objection is minimum net loss and voltage excursion. After optimization of the system we can form a set of commands about the position of the shunt capacitor and adjust the tap of load and OLTC.These commands can be carried out through dispatching automatic four remote control system.The control system can effectively improve the voltage quality, reduce grid power loss, and make reactive power compensation equipment fully utilized, so have a strong broad application value.

Abstract: Under-frequency load shedding (UFLS) and under-voltage load shedding (UVLS) as the last defense of the power system to maintain its stability are of great significance, especially for the current development of large-scale interconnected power system. At first, this paper presents the existing methods of load shedding and analyses their drawbacks. Then, a brief overview of the application of wide area measurement system (WAMS) in UFLS and UVLS is provided. Finally, a novel intelligent load shedding scheme which realizes load adjustment instead of load shedding based on the characteristics of smart grid and smart home is proposed.

Abstract: With the deepening of global energy crisis, looking for the new energy to replace traditional energy become the only way for the development of energy. This paper designs a new oscillating buoy ocean wave power generation device. It introduces the basic composition of the device and its structure, and its working principle and process. Combining the wave theory and calculation principle, wave power conversion efficiency theory, analysis and calculate the energy conversion efficiency of the device. Suppose the device is under the action of linear wave, through the theoretical calculation, the theoretical efficiency of this device is up to 0.383 when the wave period is 4 s, wave height is 0.5 m, buoy Side length is 0.3m, wind pipe diameter is 0.05. Compared with common wave power generation device, this device has higher power generation efficiency.

Abstract: With the increase of the power demand and reduction of land resources, it is imperative to increase AC transmission line capacity. Tri-pole HVDC is proposed as a new technique to solve this problem. This paper presents the basic principle of tri-pole HVDC, including its schematic and current modulation strategy. Based on the platform of PSCAD/EMTDC a tri-pole simulation model is built to carry out the simulation on deblock startup and block shun down. Besides, a cooperation mode of the controller with the protection under emergency outage of single converter station or under fault occurred in DC transmission line is put forward, and simulation results show that the proposed control and protection strategies are effective.

Abstract: Based on Support Vector Machines (SVM) and S-transform, a novel approach to detect and classify various types of high voltage direct current (HVDC) converter faults is presented. An electro-magnetic transient state simulation software PSCAD/EMTDC was used to set up a simulation model of HVDC system to investigate the typical converter faults. For the good time-frequency characteristic of S-transform, S-transform is applied to obtain useful features of the non-stationary fault signals. Then fault types are identified through the pattern recognition classifier based on SVM classification tree. Numerical results show that the proposed classification method is an effective technique for building up a pattern recognition system for converter fault signals.

Abstract: This paper proposes an effective way to optimization of the PI parameters of controllers in emergency power support. Transient simulation is used to evaluate the optimization objective function, an optimization algorithm based on the Particle Swarm Optimization method is used as the engine for producing new candidate points. The ITAE index is used to evaluate the dynamic response of AC system, the objective is to minimize the weighed sum of ITAE associated with different simulation states. The usefulness of the approach is demonstrated by a simulation of multiline HVDC-AC transmission in parallel in PSCAD.

Abstract: Accurate phase information on three-phase grid voltage and currents which are supplied by PLL are needed in power system operation. Conventional three-phase synchronous reference frame-based phase locked loop is generally sufficient during balanced operation conditions. But unbalanced in input signal set causes a double-frequency ripple. The output signal is not ideal. There are lots of improved SRF-PLL methods, aiming at removing the double-frequency ripple such as DSC-PLL,MAF-PLL, but these methods may causes a certain time delay. DIF-PLL method is based on adding another signal, which has reverse polarity ripple. It may amplify the harmonic signal. In this paper, an INT-PLL method based on integral is proposed, which wont amplify the harmonics. The comparison of these methods and simulation results are given in this paper.