Correct use and selection of lightning protectors
The harm of lightning to various buildings and equipment is self-evident. In China, many effective protective measures have been taken against direct lightning strikes, but the destructiveness of induced lightning has only begun to attract attention in the near future. In fact, the destruction of induced mines also caused a considerable loss of each system every year. At present, the information of the meteorological system is transmitted through the computer network. Once induced lightning damage occurs, the consequences are very serious.
To achieve the most effective and complete lightning protection function, to protect electronic equipment from instantaneous overvoltage caused by lightning or switching, various types of transmission lines must be considered, including: power input and output, data, signals and telephone lines In addition, program-controlled switches should also be equipped with appropriate lightning protection devices.
To play a good lightning protection function, a lightning protection device must have the following points:
(i) Compatibility An ideal SPD should not cause any interference or disruption to the equipment or lines it protects.
The following specifications must be provided by the manufacturer to ensure that the lightning protector does not interfere with the performance of the protected equipment at all:
(B) can withstand high currents Although the lightning current can be as high as 200,000 amps, but the general secondary induction current will not exceed 10000 amps, so the SPD must be able to withstand at least 10000 amps of instantaneous current through.
(3) The low “pass†voltage surge arrester must be able to reduce the transient spike voltage to the range that a typical electronic device can withstand, that is, less than twice the peak voltage of the device (about 700V).
(4) Full protection The power surge protectors must provide the following protection functions: Relatively, Medium to Ground, and Relatively Medium.
(5) The display of operating status shall be clearly displayed on the panel whether it is in the normal working state, degraded state or failure.
(6) Telemetering function When the SPD malfunctions, the remote monitoring center can be notified of the fault status through the telemetry dry contact.
(7) Repeated use and long lifespan Under normal conditions of use, multiple lightning strikes can be used repeatedly, and their working life must be more than 20 years.
The above is the basic theory of lightning protection technology. At home and abroad, there are nearly 40 manufacturers that manufacture and develop lightning protection products, but many of them are “eliminators.†They have not really played an effective role because of their simple design ideas and low cost. How to improve the level of mine prevention work in China and synchronize it with international research standards and world-accepted standards is the direction that all departments need to work together.
In addition, at present, most regions in China have gradually approached thunderstorm season. How to make mine arresters work in practical work and reduce the economic losses caused by thunderstorms is an urgent task for meteorological departments and other organizations.