Lightning Warning System Composition

The lightning warning system consists of 3 parts: a lightning warning device, an automatic control unit, and remote monitoring. The structure of the lightning warning system is shown in Figure 1.

As can be seen from Figure 1, the lightning warning device is composed of an outdoor probe, mainframe, and UPS, whose function is to detect the change of lightning signal; the automatic control unit is to change the signal of the mainframe and control the opening/closing of the circuit breaker of the low-voltage power supply line, which is a self-developed product; the remote monitoring part is composed of the signal interface, network bridge, network switch, transmission line and PC terminal, whose function is to transmit the signal of lightning change and the opening/closing status of the circuit breaker of the low-voltage power supply line to the PC terminal of the communication monitoring room. At the same time, remote operation of the system is realized at the PC terminal of the communication monitoring room.

Lightning Warning System Working Principle Overview

10-30 min before the lightning flash (time adjustable), make the circuit breaker switch off through the lightning warning device alarm output control, to achieve isolation between 380 V low-voltage lines and the microwave station room; when the lightning flash disappears 10-30 min (time adjustable), make the circuit breaker switch closed through the lightning warning device alarm output control, to restore the AC power supply to the server room.

The overall working condition of the system is sent to the duty room of the regional communication center (communication dispatch) through remote monitoring. The battery discharge capacity of the alpine microwave communication station is generally configured for 48 h (2 groups of 500 Ah), and the power consumption of the lightning warning system is very small (direct current voltage -48 V, currently less than 1 A) and negligible relative to the total equipment load of the microwave station. When lightning flashes occur frequently, the microwave communication station will be in battery power supply for a long time (generally not more than 12 hours), so the battery can guarantee the normal operation of the equipment after the lightning warning system is installed in the microwave station.

Only when the lightning warning system circuit breaker has a fault that cannot be closed automatically or when the battery is in a critical state of discharge for some reason, it is possible to monitor the terminal through the communication center room system, The circuit breaker of the lightning warning system can be forced to close remotely to restore the AC power supply of the microwave station.

Lightning Warning System Technical Parameters And Functions

(1) Lightning Warning Device

Its detection radius should be greater than 15 km, the alarm threshold 2 to 4 kV/m adjustable (all-weather), the outdoor probe working temperature range is between -20 to +50 ℃, with a standard industrialized interface, data transmission in line with TCP/IP network protocol, and the system software is Windows system.

(2) Control Units

His role is when the atmospheric electric field exceeds the set value switch open; the atmospheric electric field below the set value switch closed. The neutral point insulation fault switch opens.

(3) Circuit Breaker

Rated voltage 600 V AC, rated current 80 A, short-circuit current 10 times rated current, 3 phases + neutral, control voltage DC 12/24 V, insulation withstand voltage 80 kV, insulation distance 100 mm, operation times > 50 000. 100 mm insulation distance, >50 000 operations.

Issues To Consider In Lightning Warning System Application

(1) Require circuit breakers in the open state, the withstand voltage level is greater than 80 kA or more, to ensure that the low-voltage power supply lines and microwave station room communication equipment really physical isolation, blocking lightning waves through the low-voltage power supply lines can not enter the room. The circuit breaker should be selected as an intelligent industrial-grade circuit breaker.

(2) The power supply requires that the lightning warning system can work normally under the loss of AC power in the microwave station, using the DC power supply of the microwave station battery and configuring the UPS power system to ensure the power supply of the system.

(3) Since the probe of the lightning warning system is installed outdoors and other equipment is installed in the communication room of the microwave station, the necessary lightning protection measures such as installation of lightning protectors, equipment grounding, and shielding are also taken for the equipment of the lightning warning protection system to ensure that the system itself is protected from lightning.

(4) In the event of lightning warning system equipment failure or other abnormal conditions, the system remote control terminal should have the ability to control the low-voltage power line circuit breaker to ensure that the communication duty center personnel control the low-voltage input power switch (circuit breaker) of the microwave station.

(5) For the circuit breaker open/close time point setting, should be adjusted according to the specific circumstances of different microwave stations. Generally set to open the circuit breaker contact about 20 min before the lightning comes; 20 min after the lightning disappears to close the circuit breaker contact.

If you have more ideas about lightning warning systems, welcome to discuss them.