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This paper studies the influence of different parameters on the shielding failure of high voltage direct current (HVDC) transmission lines. A numerical of analysis model considering the developing process of the downward lightning leader based on electromagnetic field theory is used to estimate the lateral striking distance to the transmission line. The influences of these factors on the shielding...
Accurate evaluation of the direct-strike lightning protection is a key point in the design of transmission lines, while how to properly describe the propagating progress of lightning leader determines the accuracy of lightning protection evaluation. Fractal model of lightning is adopted by some researchers due to its similarity in appearance to natural lightning, however, as a result of the randomness...
Shielding failure of lightning is the key problem for safe operation of UHV transmission lines. Taking the feature of 1000KV AC double circuit transmission lines into account, the leader progression method with proper criterion was employed. The lightning shielding failure rate of top phase, middle phase and bottom phase of two different transmission line tower types were compute, in three different...
Based on the circuit theory, this paper adopts the analysis model for the impulse characteristics of grounding device considering the nonlinear soil ionization phenomena in the soil neighbouring the grounding conductors. The impulse characteristics of a typical independence grounding device for lightning protection of electronic and electrical systems inside structures is discussed and the impacts...
The electromagnetic transients of lightning protection system (LPS) under direct lightning strike is studied using NEC2. By employing antenna return-stroke model, lightning channelpsilas inducing effect and finite conductivity of ground are all taken into account. Results show that the lightning channelpsilas inducing effect tends to decrease the current flowing through horizontal conductors, and...
This paper studies the overvoltages on the low voltage power supply system caused by lightning surge. We use a 1/5 scale iron model to simulate a building's structure, a surge generator which can generate 1.2/50-8/20 mus waveform used as lightning surge, an SPD which constrain lightning surge under 1 kV, and some polyvinyl chloride cable. In this experiment, different load elements such as resistors,...
An electromagnetic model was constructed to study lightning leader striking distance to horizontal conductors. Two kind of horizontal conductors were investigated, which are horizontal conductor connected to ground and free standing horizontal conductor. A comparison had been done between these two cases. A case of the horizontal conductor stressed by a DC voltage was investigated
This paper aims to calculate step and touch voltages around transmission line tower foot due to lightning strike to the transmission line tower top and injecting the lightning current into resistive/capacitive ground. The transmission tower foot is modeled as hemisphere electrode impeded in the ground with specific conductivity and permittivity. The step and touch voltages are calculated for different...
Based on the latest electric arc model and the coupling of magnetic field and motion, this paper develops the procedure to simulate the movement process of three-phase short circuit arcs on distribution lines due to lightning stroke. The simulation results are in agreement with the experiment results. The study is very helpful to design the effective device to prevent the arcs from causing the wire...
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