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We propose a high sensitivity optical fiber sensor for detecting the acoustic emission generated by the partial discharge in gas-insulated-switchgear (GIS). A model is established to investigate the effects of the cylinder coil on the sensitivity, the bandwidth, and the detection limit. After that, the proposed sensor was modified based on the effects. The average sensitivity of the optimized acoustic emission (AE) optical fiber sensor is 32 dB higher than that of the conventional lead zirconate titanate (PZT) in the frequency range from 20 kHz to 100 kHz. Moreover, the experimental results show that the detectable partial discharge initial voltage for the proposed optical system is 17.1% lower than that for the PZT system, and the amplitude of the signal detected by the proposed optical system is 525% higher than that detected by the PZT system.

Optical interferometer acoustic sensors for GIS partial discharge detection are proposed in recent years. However, the stability of the sensing system for actual apparatus PD detection is less of a concern, especially for actual GIS. In this paper, an optical fiber acoustic sensing system based on Michelson interferometer for GIS PD detection was developed. And the influence mechanism of environmental noise on the stability of the sensing system was analyzed. And then, a method of phase tracking feedback to resist noise interference was proposed. The Michelson optical fiber interferometer with the phase feedback system worked as a high-pass filter. And the cut off frequency was 1.8 kHz in the design. Lastly, the antiinterference performance of the optical fiber interferometer was tested in an actual 126kV GIS. With the designed phase feedback control system, the stability was ensured for the on-site application of the optical interferometric acoustic sensing system.

Flashover plasma across an epoxy sulfur hexafluoride interface in gas insulated switchgear (GIS) may induce blockage of power cut. However, characteristics of flashover plasma across an epoxy sulfur hexafluoride interface under the operation temperature of GIS (80°C) were less discussed previously. In this work, a high voltage experiment setup was built to investigate the temperature effect on the surface flashover plasma. The voltage, current, acoustic and ultra-high frequency signals were obtained with different kind of sensors. The experiments indicate that the flashover voltage reduced 11.74% when temperature increased from 20°C to 80°C. The distributions of electric field, temperature and the gas density were also simulated. A particle-in-cell model including field electron emission and temperature was developed to discuss the temperature effect. From the simulation results, it can be concluded that at higher temperature, it is more likely to develop flashover across an epoxy sulfur hexafluoride interface initiated by field electron emission. This work will give a reference for evaluation and design of epoxy sulfur hexafluoride interface for high-voltage GIS applications.

Optical fiber acoustic emission sensor was optimized to enhance the sensitivity of partial discharge detection in GIS. Amplitude of the signal detected by the proposed system was 525% higher than that of conventional system.

The pathophysiological changes in cells are mainly focusing on the ionic regulations like hyperpolarization, depolarization etc. The real-time monitoring of these changes in ionic behavior is one of the challenging areas in the biosensor field. A field-effect transistor (FET) based sensor system shows an exceptional advantage in noninvasive real-time monitoring of cellular changes. In this study, we monitored cell proliferation in real-time by using the FET biosensor. Cells were cultured on the FET sensing surface and the potential difference was monitored using the Electric-double-layer field-effect transistor (EDL-FET) biosensor system. Cell proliferation in the sensor surface was electrically measured as drain current change. The impedance measurement changes revealed the capacitive equivalent model of the FETs system. The most important factor in a cell-based system is to overcome the limited life span of cells in sensor platforms. This sensor platform was capable of monitoring cell growth and proliferation, compared with other conventional and current cell sensor platforms. Rapid electrical response corresponding to the cell growth and other functional changes associated with the cell can be used in many fields, including medicine, environmental monitoring and drug screening.

Weld lines are commonly present within injection-molded plastic components and generally reduce strength. In designing a plastic part, the designer can often vary the wall thicknesses, or move the gate locations to position the weld line, so that its structural loading is minimized. By altering such variables as melt temperature, mold temperature, and packing pressure, slight increases in weld-line integrity can be achieved. These approaches often do not increase the part strength or performance to an acceptable level, resulting in the exclusion of numerous applications for plastic conversion. This study investigated a hot runner system, sequential valve gates, and heat degree, to achieve economical methods for predicting weld-line properties. By calculating melt front temperatures with MoldFlow analysis, we can predict the strength of the weld line according to the definition of “heat degree”, which is the effective cross-sectional area of the melt front multiplied by the temperature gradient. An effective cross-sectional area of the melt front is defined as the area of the temperature above the melting point. In contrast to the test result, when the “sum of heat degree” is lower than 1150 mm2 °C for PA6 (Mitsubishi 1030J) and 500 mm2 °C for polypropylene (PP) (FCFC K1012), the molecules cannot bond adequately at the interface of the melt fronts. Therefore, the mechanical property declines significantly.