In this paper, a 1000 kV gas insulated transmission line (GIL) prototype with a basin insulator and a three-post insulator structure was designed and developed to study the particle motion behavior in an ultra high voltage (UHV) GIL. Particle traps were arranged on the convex side of the basin insulator and near the three-post insulator. Aluminum and copper particles were arranged in front of and on the surface of the traps. A short-time voltage application procedure and a graded long-time voltage application procedure were designed to investigate the difference in the capture effect of the traps on the two types of particles when the test voltage was applied to the prototype through these two voltage application procedures. The results of the study show that the particle motion behavior is complex under AC voltage. The placement of the particles, their own properties and the voltage application procedure all affect the motion behavior of the particles. The trap with the grid structure is effective in capturing particles near both the convex side of the basin insulator and the three-post insulator. At the end of the test, some of the particles went inside the trap and some of them gathered at the edge of the trap. The graded long-time voltage application procedure with a small voltage application gradient and a long duration enables the particles to move sufficiently at a lower voltage to be trapped.
With the qualities of smooth operation, high efficiency and small size, the planetary gear box was widely used in transmission field. In this paper, a 2-stage planetary gear box was studied. CAXA and Pro/E were used for modeling. The FEA analysis results were obtained by ANSYS, both the contact stress and the bending stress of the gear tooth root. The results showed that with the continuous action of cyclic loads, the excessive contact stress is the direct reason of the failure. Then, the system reliability evaluation was made, which can provide guidance for engineering practice.
In order to accurately assess the risk of the hybrid AC/DC network under fault, a risk assessment method for the hybrid AC/DC system based on transient energy function is proposed. First, based on the energy transfer relationship of the hybrid AC/DC power system, the transient energy function model of the hybrid AC/DC system is established. Based on the operating data of the power grid, the energy function is used as an efficiency variable, and the efficiency variable is integrated into the prior risk probability calculation of nodes in the network, and a Bayesian network-based risk assessment model of hybrid AC/DC system is established. Considering the dynamic update model of network cascading failures, the clique tree propagation algorithm is used to dynamically calculate the posterior risk probability of the node to realize the dynamic assessment of the network risk. Finally, the improved IEEE-39 node hybrid AC/DC system is taken as an example for analysis. The results show that the proposed model can not only effectively evaluate the overall safety of the network, but also has feasibility in predicting faults, which can provide a theoretical basis for the stability control of the hybrid AC/DC system.
The active academic basic of the shape tolerance and shape error assessment is a geometrical problem which is based on the shape tolerance zone. The research puts forward the probability distribution of the statistical roundness error on the condition of the researching about roundness error of rotor parts and does experimental measurement and data collection. In order to prove that it complies with certain probability distribution law, the fitted roundness error should gain the statistical distribution result by using mathematical statistics.
Herein, burdock polysaccharide (BP) and modified burdock polysaccharide (MBP) were prepared, followed by the fabrication of chlorogenic acid (CA)-BP, CA-MBP, isochlorogenic acid A (ICA)-BP, and ICA-MBP nanoparticles. Afterward, the structural characteristics, physical stability, digestive characteristics, and antioxidant activity of hydrogen peroxide (H2O2)-damaged HepaRG cells were evaluated. The result indicated that the loading capacities of CA in BP-CA and MBP-CA were 0.14 and 0.53 μg/mg, respectively. Conversely, the loading capacities of ICA in BP-ICA and MBP-ICA were 0.36 and 0.60 μg/mg, respectively. Four complex nanoparticles exhibited excellent physical stability under different pH values, temperatures, and ionic concentrations, especially MBP-CA and MBP-ICA. Moreover, four complex nanoparticles could protect caffeoylquinic acid from being released in gastric fluid. All six samples exhibited high antioxidant activity in H2O2-induced HepaRG cells, especially BP and MBP-CA. These findings indicated that caffeoylquinic acid–polysaccharide complexes were successfully prepared and highlighted the potential of polysaccharides as natural carriers for hydrophobic bioactive molecules.
Based on decreasing the flexibility of the power grid through the integration of large-scale renewable energy, a multi-energy storage system architectural model and its coordination operational strategy with the same flexibility as in the pumped storage power station and battery energy storage system (BESS) are studied. According to the new energy fluctuation characteristics and the different peak valley parameters in the power grid, this paper proposes a electricity heat hydrogen multienergy storage system (EHH-MESS) and its coordination and optimization operational model to reduce the curtailment of wind power and photovoltaic (PV) to the power grid and improve the flexibility of the power grid. Finally, this paper studied the simulation model of an energy storage optimization control strategy after the multi-energy storage system is connected to the distribution networks, and analyzed three operational modes of the multi-energy storage system. The simulation results show that the EHH-MESS proposed in this paper has a better power grid regulation flexibility and economy, and can be used to replace the battery energy storage system based on MATLAB.
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