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Characteristic of switching impulse discharge plays an important role during the external insulation design of transmission and transformation project. For the determination of calculation method of switching impulse discharge strength, this paper introduces a new elasticity coefficient mathematical model based on the test research of rod-plane air gaps under 50% standard switching impulse voltage...
Servo motors have been widely used in medical equipment, but servo motors have the large torque and flux linkage ripple in the conventional direct torque control (DTC). The stator flux linkage estimation in the conventional DTC also needs the integration of the back electromotive force (back-emf), and is largely affected by the value of the stator resistance. The application of the extended Kalman...
In order to investigate the high altitude effect on dc corona inception voltage of power transmission lines, a mobile corona cage test system was constructed. The experiments were carried in Wuhan, Xining, Geermu, and Nachitai, respectively. Photons released as a result of corona discharge on the conductors were detected by the ultraviolet image detector. Both positive and negative corona inception...
Energy loss, radio interference, and audible noise interference caused by corona discharge bring many special problems to the design and operation of the transmission lines. The smooth conductor is adopted in the traditional calculation model. The electric field intensity of stranded conductor which is used in practice is larger than that of smooth conductor. Therefore, a computation model is adopted...
The transmission lines pass by the high altitude region with low air pressure, which brings many special problems to the design and operation of the transmission lines. The corona cage is widely used to study the corona performance of conductors for its good economy and maneuverability. A computation model is adopted for evaluating the corona inception voltages of conductors in the corona cage, which...
In order to obtain the altitude correction factor of corona inception voltage of HVDC transmission lines within the range 23 to 4000 meters, a mobile corona test cage was used to research the influence of altitude changes on positive DC corona characteristics of several kinds of conductors. Photons released as a result of corona discharge on the conductors were detected by the ultraviolet detection...
The electrical performance of porcelain insulators will be degraded by the accumulation of the airborne pollutants. In this paper, anti-pollution TiO2 coatings were prepared on the surface of the ceramic substrate through a simple hydrothermal method without high-temperature treatment. The morphology and structure of the coatings were characterized by X-ray diffractometer and scanning electron microscope...
In order to accurately obtain the working performance of the grounding grid, the soil structure must be analyzed precisely. In this paper, the objective function is set up based on the difference square of the estimated value and analyzed value. The genetic algorithm is introduced to get the optimum solution of the objective function.
1000 kV ultra-high voltage (UHV) AC power transmission system is being constructed in China. UHV corona cage is an indispensable testing facility for the research of the electromagnetic environment problem caused by the corona effects of UHV transmission lines. In this paper, the principles for the selection of the key parameters of the UHV corona cage are analyzed in detail. According to the calculation...
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