Online Peracetic Acid Sensor, Peracetic Acid Probe, peracetic acid electrode Suzhou Delfino Environmental Technology Co., Ltd. , https://www.daruifuno.com
Test of all individual components in the secondary scheduling (current, voltage, time, differential, balance, negative sequence, distance, power direction, inverse time limit, frequency, synchronization, reclosing, etc.).
In general, there are four ways to avoid lightning strikes in buildings: 1) to divert the earth from the charge in the thunderclouds, thus avoiding direct lightning strikes or inductive lightning currents flowing through the protected buildings or equipment. Objects or equipment are protected from lightning strikes. 2) Isolation, which is to isolate the lightning signal from the protected object to avoid lightning strikes. 3) Equivalent, that is, the same potential as the public place of the tower, the work place, and the building. 4) Dissipation, that is, the release of the opposite charge and the charge in the thundercloud for neutralization, thereby preventing the formation of lightning. According to the above four lightning protection methods, specifically for the lightning protection design of a radio communication project, the main lightning protection measures are as follows.
1. Installation of lightning protection devices for lightning protection devices or lightning protection devices. The lightning protection pins are mainly installed on the communication tower. This method is economical and simple, but it must be installed in strict accordance with the following requirements.
a. The lightning rod should be installed a few meters above the tip of the antenna. There should be a certain interval between the lightning rod and the antenna to prevent the radiation pattern of the antenna from being damaged due to the presence of the lightning rod. The general practice is that the lightning rod becomes the main pole of the antenna tower, and the communication antenna is installed at about 1.5 wavelengths outside the lightning rod.
b. The resistance of the DC path of the lightning protection ground wire is low enough, generally 10-50Ω. Due to the large lightning surge current, wide spectrum and short duration, it is required to have as small an inductance as possible.
c. The ground wire cannot be used with flat wire or stranded wire, because this wire has a large inductance, which is not good for discharging lightning current and is easily corroded. Try to use solid wires of 3 mm or more as much as possible, and it is the same metal material.
d. In order to increase the drainage area of ​​the ground surface, a plurality of grounding bodies buried at a certain interval may be used and welded to each other. For example, bury 10 copper pipes around the building at intervals of 1 to 2 meters and weld them together.
Although the lightning rod is installed on the communication tower, although the economy is simple, it is difficult to be foolproof. For some important communication projects, it is considered to install a radioactive lightning protection device. The radioactive lightning protection device can be said to be one of the world's advanced lightning protection devices.
A key part of the radioactive lightning protection device is the radioactive source, which can continuously emit particles by itself, so that the surrounding air is ionized to generate a large amount of electrons. Under the action of the lightning electric field, these electrons are accelerating, generating multi-level ionization or avalanche ionization of the air, forming an electron flow proportional to the electric field strength. At this time, the ionization guide directed by the radiation source to the thundercloud will never be Intermittently neutralizing and releasing space charge, eliminating the existing low electric field, reducing the possible high electric field to a low electric field, thereby effectively preventing lightning from occurring and playing a significant lightning-preventing effect. The radiation protection device has a large protection area, and its radius is about 260 meters. It is safe and reliable, and it has no harm to the human body. 2. In addition to installing a lightning rod or lightning protection device on the communication tower, it is also necessary to eliminate the lightning strike. Inductive lightning strikes, the usual practice is to install lightning arresters in the antenna feeder system.
Pay attention to the following aspects when installing the lightning arrester in the antenna feeder system. First, the grounding end of the arrester must be reliably connected to the ground. The grounding resistance must not exceed 5Ω, otherwise the lightning protection effect will be affected. Second, due to the certain insertion loss of the arrester, it has a certain influence on the intensity of the radiated signal of the antenna, and also pay attention to the change of the standing wave ratio. Generally, the standing wave ratio of the antenna feeder system is less than or equal to 1.5. Third, when the communication antenna is installed, the antenna stay is reliably connected to the tower, and the connection resistance is equal to 0 Ω. The feeder should be suspended from the inside of the tower and fixed with copper wire and iron tower at intervals.
For important communication projects, in addition to installing lightning arresters in the antenna feeder system, attention should also be paid to the lightning protection of the power supply system. The general practice is to install lightning protection devices in transformers and power distribution rooms. All of the above contents are the experience of experts from Zhengzhou Leidi Electronic Engineering Co., Ltd. If you need more information, please contact us directly.
The natural weather phenomenon of lightning from ancient times to the present has caused great impact on the development of human beings. If we do not pay attention to protection, it will cause serious harm to life and property. For lightning protection of radio communication equipment, lightning protection design is especially important for engineering work. In this article, Zhengzhou Leidi Electronic Engineering Co., Ltd. technicians will analyze the lightning protection related information of the radio.