Generally, the whole line of UHV line is protected by ground wire, or a ground wire and an OPGW optical cable, which has certain effects of lightning protection for UHV transmission lines. The specific lightning protection measures are as follows:
GDCR2000G Earth Resistance Tester
1. Reduce the value of grounding resistance. Whether the grounding resistance is good or not will directly affect the lightning resistance level of the line directly hitting the seedlings. Ensure the reliable connection between the tower and the ground down conductor. In daily maintenance, increase the patrol and strictly follow the pre-test period of the line to measure the ground resistance. It is also necessary in special areas. Shorten the pre-test period. In mountainous power transmission lines, some poles are on the peak and ridge of the mountain. These poles are equivalent to high poles and should be treated as extra-high towers. They often become vulnerable points for falling wealth, and should focus on reducing grounding resistance. Therefore, it is recommended to use HV HIPOT GDCR2000G Earth Resistance Tester to measure the ground resistance value of the tower on a regular basis. Suitable for ground leads of various shapes (round steel, flat steel and angle steel). Clamp-on ground resistance tester is widely used in the ground resistance measurement of electric power, telecommunications, meteorology, oil field, construction and industrial electrical equipment.
2. Set up a coupling ground wire. Set up a coupling line under (or near) the wire, which can play a role of shunting and coupling when the tower is struck by lightning, and then the voltage that the tower insulator bears will improve the lightning resistance level of the line.
3. It is better to increase the number or length of the insulators to increase the impact strength of the insulators while ensuring the wind deviation of the insulator string.
4. Install a controllable discharge lightning rod on the top of the mountain tower or the tower head in areas where lightning strikes are frequent.
5. In order to prevent power frequency arc burns and lead money caused by lightning strikes, fast relay protection should be used as much as possible to shorten the trip time. Most lightning strikes are single-phase flashovers, so single-phase automatic reclosing should be used as much as possible.
6. The new transmission line changes the structure of the tower head during the tower design stage, so as to reduce the protection angle of the ground wire to the conductor. It is to use a negative protection angle in key lightning protection areas to reduce the lightning shielding rate.
7. When selecting the route for the initial setting of the overhead line, avoid the urban areas prone to thunder and lightning.
Post time: Dec-03-2021