(1) The Role Of High-Voltage Line Arrester
High-voltage line arrester for 6 ~ 220kV AC transmission lines, is a new type of lightning arrester suspended and installed on the transmission tower.
Transmission line arrester: mainly insulated zinc oxide arrester.
Distribution line arrester: valve type arrester, tube type arrester, zinc oxide arrester, etc.
The main role of the high-voltage line arrester is
Limit high-voltage line lightning overvoltage.
Improve the level of high-voltage line lightning resistance.
Reduce the tripping rate caused by lightning faults in the system.
(2) The Principle Of High-Voltage Line Arrester
A high-voltage line arrester has two forms.
One is usually installed in parallel with the line insulator string, the arrester can be connected in series to form a gap. And make the breakdown voltage is lower than the insulator string flashover voltage.
So that the high-voltage line arrester in the insulator string before the flashover breakdown, its installation is as follows.
Another is the gapless arrester directly into the system, the use of arrester resistance nonlinear this characteristic to protect the insulator string. Both can improve the level of lightning resistance of transmission lines, and thus reduce the rate of lightning tripping, increase the reliability of transmission line operation.
High-voltage line arrester and high-voltage line insulators in parallel. When the lightning strike arrester action, the residual voltage of the arrester is lower than 50% of the insulator string discharge voltage. Even if the lightning current increases, the residual voltage of the arrester only slightly increased, the insulator still does not occur flashover. After the lightning flow, the frequency continuation current flowing through the arrester is only milliampere, the frequency continuation current flowing through the arrester extinguishes at the first time over zero, will not trip, the system returns to normal.
The following figure illustrates the high-voltage line arrester and high-voltage line insulator volt-seconds characteristics of the cooperation relationship. The volt-second characteristics of the arrester than the insulator volt-second characteristics of more than 15% lower, when the backlash, can be lower than 20%.
