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Thunder and lightning
Nov 25 , 2021
As we all know, when the charge in a thunderstorm cloud reaches a certain amount, a strong electric field is formed between different parts of the cloud or between the cloud and the ground. When the charge accumulates to a certain degree,discharge occurs between the cloud and the cloud or between the cloud and the ground. The occurrence of thunder and lightning comes from the acc...
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Grounding resistance of lightning protection for urban rail transit
Dec 02 , 2021
In order to formulate relevant standards for the lightning protection grounding resistance of urban rail transit, it is necessary to further carry out actual measurement research on the grounding resistance of urban rail transit lines, count more test samples, deepen theoretical analysis, and summarize the test methods and test limits requirements for urban rail transit. W...
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Lightning protection to Railway Power Lines
Dec 09 , 2021
To the railway power transmission lines, they are narrow and long, with long distance power supply,bad environment, and frequent accidents, especially in mountainous areas, jungles and river networks, and inconvenient traffic. Once the line fails, it is very difficult to find the fault point and maintain, with high labor intensity and long time to restore power sup...
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Brief introduction to MOV of SPD
Dec 21 , 2021
Metal oxide varistor (MOV) is a semiconductor element with a unique grain boundary structure. Its resistance value decreases sharply with the increase of voltage. It has excellent nonlinear volt-ampere characteristics, as well as high current capacity, the lower residual voltage, no freewheeling and lower cost. That’s why mov has been the first choice to be used in power and signal ports as over-v...
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The hazards of electrostatic discharge
Dec 22 , 2021
Electrostatic discharge (ESD) and electrical fast transients (EFT) cause different hazards to instrumentation systems. Electrostatic discharge produces strong radio frequency radiation in the frequency range of 5 to 200 MHz.The peak of this radiated energy often occurs between 35MHz and 45MHz, and self-oscillation occurs. The resonant frequency of many information transmission cables is usually wi...
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Is it safe in a car during thunderstorm
Dec 23 , 2021
It's safer to sit in the car during thunder Reminder: all windows should be closed When thunder and lightning strikes, some drivers may have questions like: The car is made of metal. If it is struck by lightning, is it safe to sit in the car? Should you stay in the car or get out of the car to avoid it? It is understood that as a metal shell, the car body is equivalent to a shielded room. Even if ...
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“Thunder and Snow”
Dec 23 , 2021
Thunder is common in summer, because the ground temperature is high, and convective clouds are more likely to form when warm and humid air rises, which creates conditions for lightning. In areas with relatively large undulations, thunder and rain are more common. This is because the warm air is blocked by mountains during the horizontal movement to form convection. In winter, the ground temperatur...
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Concept of neutral and grounding
Dec 29 , 2021
Neutral connection: The neutral point of generators and distribution transformers is called the zero point, and the line drawn from the neutral point is called the neutral line. The metal shell of electrical equipment connected to the neutral line is called Neutral connection. Working grounding: The neutral point of the transformer of the power supply system is directly grounded as the w...
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