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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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Low-voltage surge protectors was approved by IEC
Dec 07 , 2021
At the 2021 annual meeting of the International Electrotechnical Commission IEC/SC37A "Low-Voltage Surge Protector (SPD)" held a few days ago, my country’s first international standard proposal in the field of IEC low-voltage surge protectors was approved. The standard name and series number is: IEC TS 61643-05“Low voltage surge protective devices-Part 05: Monitoring device of Surge protecti...
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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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SPD backup protector
Dec 15 , 2021
As fuses and circuit breakers show insufficient surge current withstand capability when used in conjunction with SPD, it is necessary to improve the surge current withstand capability. Analyzing the influence of circuit breakers with different rated currents on the breaking capacity of the SSD power frequency short-circuit circuit, to summarize the selection points and coordination suggesti...
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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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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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How to reasonably select cables for photovoltaic system?
Jan 21 , 2022
In recent years, the technology of the photovoltaic industry has developed faster and faster, the power of a single module has become larger and larger, and the current of the string has become larger and larger, the current of high-power modules has reached more than 17A. Using high-power components and reasonable matching can reduce the initial investment cost and kWh cost of the sy...
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