±800-kV UHVDC demonstration project passed live line test

On December 26, 2009, in the main control room of Shanghai Fengxian Converter Station, the voltage value on the screen rose from zero to 800 kV. This represented the demonstrative ±800-kV

The Mechanical Characteristics and Experimental Study of the Stratospheric Airship

Stratospheric airship is a special near-space air vehicle which has lots of advantages than other traditional flying aircrafts, such as long endurance, strong survival ability, low cost, excellent resolution detector etc. In addition, the stratospheric airship can be an ideal stratospheric bearing platform. This paper firstly gave an overview describing some technical differences between the stratospheric airship and the traditional airship, including the working environment, design specifications, structure characteristics, energy system, flying modes, and so on. Some technical difficulties including the materials, power system which apply to the stratospheric airship and deformation of the huge hull, super-heating effect, and station-keeping were discussed. Furthermore, technical target, technical specifications, design concept, and overview of flying tested about two stratospheric demonstration airships which were representative achievements of the research on the stratospheric airship in China were introduced. Finally, the predictions about the progress and direction of development were discussed.

Design of 1000-kV AC Single-Circuit Overhead Transmission Line

The UHVAC 1 000-kV transmission system is so far the one with the most advanced transmission technique applied and highest operation voltage.There are no guidelines or standards available for the design of 1 000-kV overhead transmission line in China.Study on key technologies and design schemes shall be carried out to ascertain the technical principles and construction standards for project construction,which are presented in this paper based on the Southeast Shanxi-Nanyang-Jingmen test and demonstration transmission line.A comparison and analysis of technical data and economic indices between UHV line and other lines are also described.

A Fault Sample Simulation Approach for Virtual Testability Demonstration Test

Virtual testability demonstration test has many advantages,such as low cost,high efficiency,low risk and few restrictions.It brings new requirements to the fault sample generation.A fault sample simulation approach for virtual testability demonstration test based on stochastic process theory is proposed.First,the similarities and differences of fault sample generation between physical testability demonstration test and virtual testability demonstration test are discussed.Second,it is pointed out that the fault occurrence process subject to perfect repair is renewal process.Third,the interarrival time distribution function of the next fault event is given.Steps and flowcharts of fault sample generation are introduced.The number of faults and their occurrence time are obtained by statistical simulation.Finally,experiments are carried out on a stable tracking platform.Because a variety of types of life distributions and maintenance modes are considered and some assumptions are removed,the sample size and structure of fault sample simulation results are more similar to the actual results and more reasonable.The proposed method can effectively guide the fault injection in virtual testability demonstration test.

Multiple hierarchy risk assessment with hybrid model for safety enhancing of unmanned subscale BWB demonstrator flight test

To explore the low-speed characteristics of the Blended-Wing-Body(BWB)configuration for future civil aircraft,a series of unmanned subscale demonstrators have been developed and tested by our research team.During this process,specific safety risks deriving from uncertain design features,system unreliability,and insufficient personnel experience caused continuous flight test mishaps and the risk mechanism was not clear.Local and trial-and-error learning driven safety improvements took few effects on mishap prevention,so our focus was turned to look for systematic safety strategies.This paper establishes a systems theory based hybrid model to integrate the physical system reliability analysis techniques with the system dynamics method for illustrating the multiple risk interactions of the demonstrator flight test involving organizational,human resource and technical system factors.Using the prior BB-5 demonstrator as a case,the hybrid model simulation represents its historical risk evolution process,which verifies the model rationality.Derived risk control strategies reduced the mishap rate of a new demonstrator called BB-6 Sprit.The paper also shows the extended hybrid model can be applied on safety management of unmanned aerial vehicles from the initial period of vehicle development.