In order to make the performance of externally gapped line arrester (EGLA) meet the requirements of national standards better, the discharge voltage of its gap becomes the most important parameter so ...that the study on the relationship between discharge voltage of gap and other factors is considered as a critical project. Generally, before the gap discharging, the distribution of voltage between the gap and the arrester unit is mainly affected by equivalent capacitance. As a result, there is a close relevance between discharge voltage of the gap and the capacitance of arrester unit as well as the gap capacitance. In this paper, capacitances of gaps and voltage distribution in different structures with different arrester unit parameters were calculated under 35kV and 110kV with ANSYS. Experiments under power frequency as well as impulse voltage were conducted on EGLA under different configurations. Results of calculations and experiments were compared and preliminary conclusions were deduced. It indicates that arrester unit parameter and the gap structure affect the discharge voltage of EGLA, and the influence of the former is larger.
Unmanned aerial vehicles, bustling autonomously over the sky above our heads, demand a high level of intellectual ability to avoid possible collision. An early warning radar is proposed for such a ...purpose. The radar uses a far-reaching signal to detect the existence of another UAV maneuvering in vicinity, and then uses a second near-reaching signal to validate the detection. A safe distance is defined as a threshold below which collision will happen and thus a warning should be triggered. Instead of being measured, the distance between the UAVs is assumed to be random under the rationale that the UAVs are highly maneuverable. With the safe distance given, an arbitrarily high hit-rate of warning and an arbitrarily small false-alarm rate can be achieved by adjusting the strengths of probing signals.
Due to the influence of various factors such as gain, observation distance and discharge voltage of UV detector, the number of photons measured by different instruments or the same instrument when ...discharging electrical equipment has different degrees. How do the various factors in UV charging detection? The in-depth analysis of the photon number measurement problem was carried out. The laboratory corona discharge test and OFIL's SUPERB UV image detector were used to analyze the influence of the gain, observation distance and discharge voltage of the UV detector on the photon number measurement. The corresponding conclusions provide a reference for the actual measurement of the project.
Link budget based on quality of service Rumin Yang; Chengbo Yu
2014 14th International Symposium on Communications and Information Technologies (ISCIT),
2014-Sept.
Conference Proceeding
This paper proposes a link budgeting approach to address the quality of service (QOS) for wireless communication links. The measures for the QOS include the coverage radius, line-of-sight occurring ...rate, and confidence level. The QOS-based link budget analysis can significantly reduce transmission powers in situations where more line-of-sight paths exist and lower confidence level is allowed. In comparison to traditional link budgeting methods, the QOS-based budgeting method can lead to significant energy saving.
In order to improve the load-following ability of nuclear reactors, an advanced load-following controller based on L 1 adaptive control theory is proposed in this paper. First, the state estimator, ...which is used to reconstruct the unmeasured state, is built according to the reactor core uncertain model. Then, an adaptive control law is structured to estimate the core uncertainty online while ensuring the global asymptotic stability of the closed-loop system. Finally, L 1 adaptive control law is designed to compensate for system uncertainties and ensure that the system realizes load-following control. Considering the high gain problem caused by adaptive control, the low pass filter is added to suppress high frequency oscillation effectively. The simulation results show that the proposed controller is not only adaptive to the system uncertainty, but also effectively completes the load-following control.
Currently, some necessary material performance parameters and accurate numerical simulation boundary can hardly be obtained via numerical analysis of the ablation laws of the solid rocket motor ...throat. Based on throat diameter dynamic identification and micron-CT 3D scanning reconstruction technique, the nozzle throat diameters of three types of SRM during the operating phase were dynamically identified, the throat before and after the test was reconstructed via 3D scanning and the static throat diameter change was analyzed. The results demonstrate that throat diameter dynamic identification technique in this study exhibits higher precision than micron-CT three-dimensional reconstruction, with a maximum error of only 0.327%. The negative ablation phenomenon appeared in the test can be attributed to the deposition of Al2O3 particulate-phase. Overall, the proposed method exhibits remarkable engineering application values and promotion significance.
Solar Ring (SOR) is a proposed space science mission to monitor and study the Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic plane. It will deploy three ...120{\deg}-separated spacecraft on the 1-AU orbit. The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second, S2, 90{\deg} downstream, and the third, S3, completes the configuration. This design with necessary science instruments, e.g., the Doppler-velocity and vector magnetic field imager, wide-angle coronagraph, and in-situ instruments, will allow us to establish many unprecedented capabilities: (1) provide simultaneous Doppler-velocity observations of the whole solar surface to understand the deep interior, (2) provide vector magnetograms of the whole photosphere - the inner boundary of the solar atmosphere and heliosphere, (3) provide the information of the whole lifetime evolution of solar featured structures, and (4) provide the whole view of solar transients and space weather in the inner heliosphere. With these capabilities, Solar Ring mission aims to address outstanding questions about the origin of solar cycle, the origin of solar eruptions and the origin of extreme space weather events. The successful accomplishment of the mission will construct a panorama of the Sun and inner-heliosphere, and therefore advance our understanding of the star and the space environment that holds our life.
This paper addresses the anti-disturbance tracking control problem of robotic systems with exogenous disturbances. In order to obtain the favourable tracking performance, the ...disturbance-observer-based-control (DOBC) method is established to monitor the value of unknown disturbances in real time and the PID controller is designed to implement dynamical tracing for the displacement of typical second-order robotic systems. By using the Lyapunov analytical method, the controller gain and the observer gain can be computed so that the dynamical tracking error of the displacement tend to zero. Finally, the second-order model of robotic system is built to simulate. The satisfactory stability and the attitude tracking of the robotic system can be obtained via the designed algorithm.
The load-following control is a very important technology to ensure the safe and stable operation of nuclear reactors. In this paper, a guaranteed cost control system based on T-S fuzzy model is ...presented to improve the nuclear reactor load-following capability. First, the nonlinear reactor core model is transformed into a T-S fuzzy model based on the division of five relative initial power points. Then, combining the Lyapunov stability theory, a state observer is introduced to solve the problem that some state variables cannot be measured. Finally, a guaranteed cost load-following controller is obtained by solving linear matrix inequalities. The simulation results demonstrate that the proposed controller can effectively complete the load-following control and the coolant temperature also complies with the operating requirements.
This paper presents the design of microwave bandpass filters with frequency-dependent (FDC) coupling for power wireless private network communication. The filters are composed of four resonators ...arranged in the in-line and folded topology using substrate integrated waveguide (SIW) technology. The frequency-dependent coupling is implemented bya magnetic coupling iris and a balanced microstrip line with a pair of metallized via-holes, which produces an extra zero in comparison to classical approaches. To verify the characteristics of the proposed FDC, an in-line fourth-order substrate integrated waveguide bandpassfilter (BPF) with one transmission zero and a folded configuration BPF with one small negative slope for independently controlled transmission zero are designed.
