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DC transmission has a lot of merits compared with AC transmission. For example, the cost of the construction and the equipment is less than that of the AC transmission system. Besides, more energy can be transmitted in DC transmission lines. Recently, multi-terminal transmission lines are required urgently. For that purpose, the reliable DC transmission circuit breakers must be developed. As we all...
Insulating liquid, because of high breakdown strength and superior self-recovery property, is widely applied to intense electron beam accelerator, transformer, and superconducting fault current limiters, etc. However, the formation of bubbles caused by heat transfer in power equipment seriously hurts the performance of the insulating strength in liquid. The objective of this paper is to study the...
Hybrid DC circuit breakers have the advantages of fast fault current interruption with the solid-state semiconductor devices and low conducting loss with the mechanical switches. Therefore it is suitable to be used in the multi-terminal DC transmission system. The objective of this paper is to determine a voltage sharing between the mechanical switch and the IGBTs in a proposed topology of hybrid...
In order to achieve the unmanned live cleaning operation in the substation, and ensure the running trajectory and control precision fulfil requirements, a hydraulic pan-tilt control system based on hydraulic actuator model is designed. The pantilt reaches a certain location with a certain speed is the main purpose of control. In this paper, the movement of the pan-tilt is based on the model of the...
There are few investigations of DC self-excited oscillation interruption under transverse magnetic field (TMF). The objective of this paper is to understand the effects of transverse magnetic field on DC interruption characteristics of CO2 and SF6 gases based on the self-excited oscillation principle. The DC self-excited oscillation interrupting characteristics of CO2 and SF6 at 0.5 Mpa absolute atmospheric...
The objective of this paper is to propose a quenching recovery time measurement method for superconducting fault current limiter used in DC circuit. The proposed measurement method includes an experiment circuit, in which there is a L-C discharging current source and a DC circuit breaker. The L-C current source can produce a high DC current which quenches the superconducting coil. Then the DC circuit...
DC resistive type superconducting fault current limiters (SFCL) can be used in multi-terminal DC systems for fault current limiting. They help DC circuit breakers interrupt fault current with lower interruption overvoltage and they improve the interruption reliability. Insulation design is necessary for the application of SFCLs. The objective of this paper is to design the insulation of DC resistive...
Liquid Nitrogen Insulated metal enclosed Switchgear (LNIS) is an alternative to the conventionally used Gas Insulated Switchgear (GIS), so all the components of GIS must be considered for LNIS as well. The principle research is however required to examine the behavior of arc plasma in Liquid Nitrogen (LN2). Until now, no one has ever investigated the arcing time in LN2. The objective of this work...
Data and energy integrated communication networks (DEINs) have emerged for simultaneously realising both of wireless energy transfer and wireless data transfer by exploiting radio-frequency signals. A heterogeneous DEIN is studied, which consists of both indoor and outdoor user equipments (UEs). In order to characterise the diverse data and energy requirements of UEs, a utility function is defined...
We present a new point set registration method with global-local correspondence and transformation estimation (GL-CATE). The geometric structures of point sets are exploited by combining the global feature, the point-to-point Euclidean distance, with the local feature, the shape distance (SD) which is based on the histograms generated by an elliptical Gaussian soft count strategy. By using a bidirectional...
Flooding DDoS and Flash Crowds (FC) are difficult to be discriminated from network layer because both of them have too many statistical similarities. If attacker learnt those statistical difference and could produce some mimicking traffic which have little difference from traffic produced by legitimate uses in FC, which means existing methods will uselessness. In order to verify the existence of this...
At present, most of the researches on friction and wear of bearing are focused on rubber bearing and Babbitt bearing. Study on characteristics of bearing that is made of Polytetrafluoroethylene (PTFE) composite material is less reported. This paper mainly carried out the calculation and experimental research on the rule of wearing between PTFE composited bearing and steel shaft. A correct model was...
It is critical for the well running of electricity factory to monitor and predict the statues of turbine oil used by turbine generator. However, there are a lot of monitoring parameters for turbine oil and the statues trend is hard to predict. So the principle component analysis method was used to research 7 groups and monitor data for 10 months. The two principle components obtained from analysis...
Discriminating Distributed Denial of Service (DDoS) from Flash Crowds (FC) is a tough and challenging problem, because there are many similarities between each other existed in network layer. In this paper, according to an extensive analysis of user traffic behavior of DDoS and FC, it can be found that some traffic abnormalities are existed between Bots and legitimate users. So a behavior-based method...
In order to realize the matching design of screw propeller and diesel engine conveniently and accurately, and feedback measurement data to calculation model on shore to guide the ship propulsion system design, a web based remote interactive platform for screw propeller and diesel engine matching calculation was designed as an interface, which combined .NET platform with MATLAB platform. And this platform...
Particulate matter 2.5 (PM2.5) pollution has become one of the most urgent issues to be addressed in China. The anthropogenic reasons of PM2.5 formation have considered to be highly related to local economic development model, industrial structure, energy structure and fast urbanization. The aim of this study is to explore the quantitative relationship between PM2.5 and anthropogenic factors in China...
This letter puts forward weak FBGs Fabry-Perot (FP) structures with copper coating for quasi-distributed temperature measurement. The weak FBGs (−33dB) are fabricated by on-line draw tower. The sensors system exhibits the superiorities of high signal to noise ratio (SNR). At the same time, wavelength/frequency/time multiplexing immensely increases the capacity of the sensing system. In the experiment,...
A distributed vibration sensing system with Michelson interferometer based on width-band ultra-weak fiber Bragg grating (UWFBG) arrays in Draw Tower Grating (DTG) is proposed and experimentally demonstrated. The precise of the space between adjacent UWFBG is less than 1mm, which is conducive to precise positioning and rapid demodulation. The system is capable of measuring vibrations of up to 1 kHz...
Rainfall is one of the key drivers of hydrological and land surface models. Satellite remote sensing is able to provide regional and global rainfall estimates. However, there is still room to improve the accuracy of satellite rainfall products in areas where no/less rain gauges available, such as the Tibetan Plateau. In this study, the satellite rainfall product obtained from the Tropical Rain Measurement...
With the loss of the L-band radar, the NASA SMAP satellite lost the capability to directly provide high resolution global soil moisture data products after July 7th, 2015. However, the SMAP L-band radiometer has been successfully and continuously providing high quality coarse resolution observations with the best RFI mitigation since April 2015. These coarse resolution soil moisture observations could...
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