Communication Base Station (Independent Station) Lightning Protection Solution
I. Introduction
For a long time, the protection work of the communication base station (independent station) has separated the lightning protection and grounding engineering and completed it by different departments, which has resulted in high investment and maintenance costs for the entire project, increased difficulties in the construction of the project, and difficulty in coordinating the relationship between the parties. The lightning protection effect is far from satisfactory. This is a long-standing problem for the construction and maintenance departments of communication operators.
Shenzhen Yuanzheng Technology Co., Ltd. and Beijing University of Posts and Telecommunications began investigating a large number of damages to base station equipment caused by lightning accidents since 2000. After four years of theoretical exploration and five years of practical application, improvements have been made in conjunction with the latest protection technology concepts. A new solution for lightning protection and grounding one-stop protection of the new communication base station was proposed.
This solution simplifies the complex base station ground network engineering by using the equipment method, and completely isolates the impact between lightning protection grounding, working grounding, and protection grounding. At the same time, it combines isolation and leakage flow for each channel of a lightning current invading a base station. The method realizes the reliable protection of the entire communication base station equipment. The joint grounding system adopting the "isolated group grounding technology" standardizes the grounding method. In the project, the "simple ground net" combined with the "earth system lightning current high-frequency suppressor" method is used to ground the communication base station (stand alone station). The design, construction, and maintenance of lightning protection projects are more standardized and simpler, eliminating the confusion of the original wiring. The simple equipment and wiring methods have standardized the equipment room, eliminated the work of the engine room in the maintenance work, and reduced the lightning damage. Probability, improve the quality of network operation, and at the same time significantly reduce the construction and maintenance costs of base stations (independent exhibitions), with significant reliability and economic indicators.
Second, the technical principle
The basic idea of ​​the “Easy Networkâ€+ “Isolation Protection Technology†program is to take isolation measures on each lightning current intruding into the channel of the system to be protected, to block the lightning current out of the system, and also to discharge the lightning current. Provides a good effusion channel; at the same time, by grouping all grounding systems by function and using equipment to standardize the grounding method, it not only guarantees the normal operation of the entire system, but also includes the standardization of engine room construction in the design and construction projects; Grounding grounding scheme saves people, money, goods and time.
Isolated group grounding technology: Based on the traditional joint grounding network of an independent station, all grounding cables are divided into two types according to their functions, namely, lightning protection grounding wires and protection grounding wires, and connecting the protection grounding wire and the joint grounding network in series. "Ground system high-frequency suppressor", when there is a lightning current on the local network, the "grounding system high-frequency suppressor" starts to work, and the connection channel between the joint grounding grid and the protective grounding line is isolated and the lightning current on the ground is blocked. It is not possible to enter the communication system in reverse string through the protective earth. In this way, the grounding resistance value of the grounding grid can be relaxed, and the grounding with a large grounding resistance can be realized. In the project, the “simple network†is used to replace the traditional complex grounding grid.
Channel protection technology: The following figure is a schematic diagram of a lightning current invading a base station (stand alone station). The lightning current enters into the communication system mainly through AC lines, metal cores of optical cables, and the ground network ground potential counterattack. By installing a “series-type lightning current high-frequency suppressor†in the AC power supply line, cut off or isolate the propagation path of the inrush current power channel. At the same time, the ground lines will be grouped to protect the ground and lightning protection with "leakage current high frequency suppressor" classification wiring to prevent ground potential counterattack.
III. "Isolation Protection Technology" Application Plan
"Wireless communication base station lightning intrusion channel isolation protection technology" in the practical application of the project, the use of "simple network" with Shenzhen Expeditionary Communications company developed "grounding system lightning current high frequency suppressor", that is to achieve a large grounding resistance grounding, and The protection of all equipment and networks of communication base stations (standalone stations) is realized.
Single-phase power supply integrated protection box: installed in series at the power supply into the lower pole, two sets of "high-frequency suppressors for lightning currents" are connected in series in the line, and provide Class B 100KA lightning current discharge channels and C-class 40KA Overvoltage protection, blocking the inrush current from the AC power supply system into the communication base station (independent station); adding a "grounding system lightning current high frequency suppressor" between the lightning protection ground and the protection ground to prevent ground potential counterattack Overvoltage stringing in the system.
Fourth, system protection solution
It is recommended to install a "single-phase power supply integrated protection box" at the input of the AC power supply of the mobile station (stand alone station).
The AC power system is the high point of lightning intrusion. The switching power supply equipment is the equipment with the most lightning failures. The traditional methods are “adding power line lightning protection lines, armored cable insertion pipes, and installing multi-level parallel SPDsâ€. , but the actual effect is not ideal.
For this purpose, we propose to use the “YZ(O)AC/JD25KV-100KA(10A)†“YZ(O)AC/JD25KV-100KA(10A)†to install a “single-phase power comprehensive protection box†at the lower pole of the AC power supply. This device can effectively block the lightning current from entering the power supply. The system also provides access to lightning currents into the ground. Because the device adopts the “AC power high-frequency suppressorâ€, it has a strong inhibitory effect on the lightning current and can exceed the attenuation effect of the lightning current by the “lightning conductor and armored cable through the pipeâ€. Exempt from the investment in these two projects. At the same time, the device has built-in B-level 100KA lightning current drain channels and C-level 40KA overvoltage protection to block inrush currents from the AC power supply system into the communication base station (stand alone); in lightning protection and protection areas A set of "grounding system lightning current high-frequency suppressors" was added to prevent counter-attack of ground potential and over-voltage stringing in the system.
Therefore, the installation of a "single-phase power integrated protection box" in the system can reduce the investment in the construction and maintenance of traditional lightning protection methods such as the installation of power line lightning protection lines, installation of multi-stage parallel SPDs, and armored cable penetration pipes. Get better protection.
Fifth, the proposed configuration
According to the characteristics of climatic and geographical geology of each place, and the different conditions of network construction and post-maintenance, according to the intensity of actual protection effect of independent stations in urban areas and independent stations in mountains, we propose independent stations (single station) through the system's protection effect and cost considerations. Only need to install a comprehensive protection box, can carry on the overall overall protection to the power system, the grounding system.
Configuration reference table:
Select device name
Quantity
Single-phase power protection box
1 set
Simple network
Grounding resistance can be relaxed up to 100 ohms, available in building or civil steel construction