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Simulation and Optimization of Embedded Voltage Sensor in High Voltage Insulator
Sports have great benefits for human health, and monitoring the intensity of sports operation can help adjust the state of human health. However, there are certain shortcomings in the current methods for monitoring sports intensity. Therefore, this paper designs an intelligent sports intensity monitoring method based on embedded web sensors. By analyzing the changes in the human body state during sports, the monitoring data of intelligent sports intensity are determined, including heart rate intensity, blood oxygen saturation, body temperature during exercise, and tilt angle changes during exercise. Such data are used as the object for monitoring exercise intensity, and by adopting a nonintegrated approach, changes in the monitoring environment are determined, designing a dedicated embedded network system with web server functionality, and completing the design of an embedded web sensor monitoring system. Based on the embedded web sensor monitoring system, periodic and nonperiodic key points during human sports are determined, the peak and valley values of acceleration changes during human sports are calculated, and a first-order autoregressive model is established to determine the relationship between monitoring data during human sports. The monitoring data are input into the embedded web sensor monitoring system to complete the monitoring. The experimental results show that the method proposed in this paper has good performance in monitoring sports intensity.
In order to improve the teaching effect of public physical education courses to the greatest extent and lay the foundation for the process of teaching reform, this paper puts forward the design of a public physical education course quality evaluation system based on the “5V” characteristics of computer big data. Analyze the characteristics of big data “5V” and study its application in public physical education courses; analyze the action estimation, prior, and update, failure recovery of public physical education course teaching, and get the three-dimensional visual positioning result of public physical education course teaching; collect the upper arm action image, extract the upper arm action image contour feature through edge contour detection, analyze the contour feature error characteristics, obtain the pixel component weighted value of the contour feature, further obtain the fuzzy error value of the upper arm action image contour feature through calculation, and according to the fuzzy error value, the design of public physical education course quality evaluation system is completed. The experimental results show that the average error recognition accuracy of the research method is 99.63%. The class hours are adjusted according to the proportion of disciplines, and the corresponding teaching plan is formulated. The accuracy of recommending internship posts for students is relatively high.
We have developed a system of differential-output monitors that diagnose current and voltage in the vacuum section of a 20-MA 3-MV pulsed-power accelerator. The system includes 62 gauges: 3 current and 6 voltage monitors that are fielded on each of the accelerator's 4 vacuum-insulator stacks, 6 current monitors on each of the accelerator's 4 outer magnetically insulated transmission lines (MITLs), and 2 current monitors on the accelerator's inner MITL. The inner-MITL monitors are located 6 cm from the axis of the load. Each of the stack and outer-MITL current monitors comprises two separate B-dot sensors, each of which consists of four 3-mm-diameter wire loops wound in series. The two sensors are separately located within adjacent cavities machined out of a single piece of copper. The high electrical conductivity of copper minimizes penetration of magnetic flux into the cavity walls, which minimizes changes in the sensitivity of the sensors on the 100-ns time scale of the accelerator's power pulse. A model of flux penetration has been developed and is used to correct (to first order) the B-dot signals for the penetration that does occur. The two sensors are designed to produce signals with opposite polarities; hence, each current monitor may be regarded as a single detector with differential outputs. Common-mode-noise rejection is achieved by combining these signals in a 50-Omega balun. The signal cables that connect the B-dot monitors to the balun are chosen to provide reasonable bandwidth and acceptable levels of Compton drive in the bremsstrahlung field of the accelerator. A single 50-Omega cable transmits the output signal of each balun to a double-wall screen room, where the signals are attenuated, digitized (0.5-ns/sample), numerically compensated for cable losses, and numerically integrated. By contrast, each inner-MITL current monitor contains only a single B-dot sensor. These monitors are fielded in opposite-polarity pairs. The two signals from a pair are not combined in a balun; they are instead numerically processed for common-mode-noise rejection after digitization. All the current monitors are calibrated on a 76-cm-diameter axisymmetric radial transmission line that is driven by a 10-kA current pulse. The reference current is measured by a current-viewing resistor (CVR). The stack voltage monitors are also differential-output gauges, consisting of one 1.8-cm-diameter D-dot sensor and one null sensor. Hence, each voltage monitor is also a differential detector with two output signals, processed as described above. The voltage monitors are calibrated in situ at 1.5 MV on dedicated accelerator shots with a short-circuit load. Faraday's law of induction is used to generate the reference voltage: currents are obtained from calibrated outer-MITL B-dot monitors, and inductances from the system geometry. In this way, both current and voltage measurements are traceable to a single CVR. Dependable and consistent measurements are thus obtained with this system of calibrated diagnostics. On accelerator shots that deliver 22 MA to a low-impedance z-pinch load, the peak lineal current densities at the stack, outer-MITL, and inner-MITL monitor locations are 0.5, 1, and 58MA/m, respectively. On such shots the peak currents measured at these three locations agree to within 1%.
The measurement of the power system voltage is of important significance for energy measurement, the correct action of relay protection device and the monitoring of transmission line over voltage. We summarized several methods of on-line measurement for high voltage at present, compared and analyzed the working principle and characteristics of various measurement methods, and pointed out the existing problems of various methods. It can be seen from the analyses that the optical voltage measurement method has become a research hotspot due to its advantages of good insulation, small sensor volume, and good transient performance. The non-contact measurement method based on the D-dot principle has good development prospect due to its advantages of good insulation property, simple switching operation and being able to be replaced with electricity. However, the long-term stability of these two measurement methods still needs to be tested. At last, the development direction of high voltage measurement is prospected, which is beneficial to the practical process of the high voltage measurement methods. © 2018, High Voltage Engineering Editorial Department of CEPRI. All right reserved.
Condition-based maintenance (CBM) is a maintenance program that recommends maintenance decisions based on the information collected through condition monitoring. It consists of three main steps: data acquisition, data processing and maintenance decision-making. Diagnostics and prognostics are two important aspects of a CBM program. Research in the CBM area grows rapidly. Hundreds of papers in this area, including theory and practical applications, appear every year in academic journals, conference proceedings and technical reports. This paper attempts to summarise and review the recent research and developments in diagnostics and prognostics of mechanical systems implementing CBM with emphasis on models, algorithms and technologies for data processing and maintenance decision-making. Realising the increasing trend of using multiple sensors in condition monitoring, the authors also discuss different techniques for multiple sensor data fusion. The paper concludes with a brief discussion on current practices and possible future trends of CBM.
In order to clarify the response of overhead distribution lines to
direct lightning hits, experimental facilities were installed at the UHV
Shiobara Testing Laboratory of CRIEPI. A lightning impulse current with
a crest value of 18 kA and a waveform of (2/11) μs was generated
through the impulse current generator with a high internal resistance of
400 Ω. This impulse current is not easily affected by the
conditions of a distribution line side. Protective effects of surge
arresters and an overhead ground wire against direct strokes to the pole
of a distribution line were clarified experimentally. Experimental
results showed a better protective effect than earlier calculated
results. Overvoltages between a line conductor and the earth are
inclined to have a short wavetail. The 50% flashover voltage of an
insulator against overvoltages with a short wavetail is higher than that
against overvoltages with a standard wavetail
For pt.II see ibid., vol.6, no.5, p.35 et seq. (1990). The question of how to relate the magnitude of the measured, effective, partial discharge (PD) to the size, shape, and position of the cavity within a solid dielectric system is addressed. The causes of cavities are examined, and a brief review of gas breakdown is given. It is then shown that for a range of geometries, such as parallel plate and coaxial, one can develop analytic solutions (i.e. formulas), and that for any system the solution can be found using computer-based methods for calculating the electric field throughout a sample. Scaling rules are derived from the physical model.< >
Many electromagnetic measurements of electromagnetic pulse (EMP)
interactions with electronic systems use B -dot and
D -dot probes. The effects of the measurement probe on the field
distribution being measured is considered. An infrared measurement
technique is used to determine the field distributions with and without
the presence of electric- or magnetic-field probes. Two-dimensional
thermogram images of the scattered field patterns are measured. The
scattering effects of various probes in the frequency range from 1 to 10
GHz are presented. This frequency range can be used to scale-model many
EMP and high-power microwave (HPM) effects. It is shown that wide
variations in the response of a probe can occur due to resonant
frequency and mutual-coupling effects. These effects are due, in part,
to the different measurement configurations of the probe relative to the
direction of propagation and polarization of the incident
electromagnetic wave to be measured. These differences can be
significant at certain frequencies and separation distances for the
various probe measurement configurations
- Siada A. A.