Application of zinc oxide arrester manufacturers on transmission lines
The application of zinc oxide arresters on transmission lines has two aspects:
One is for lightning protection of transmission lines;
The second is to limit the operating overvoltage along the transmission lines of 330kV and above (especially on lines where the circuit breaker cancels the closing resistance).
Different applications require different determinations of zinc oxide arrester models, zinc oxide arrester parameters and installation locations.
Compared with the traditional lightning protection of transmission lines, zinc oxide arresters are connected in parallel at both ends of line insulators (strings) to protect sections with frequent lightning activity and difficulty in reducing tower grounding resistance. At the same time, with the rapid development of composite jacketed arresters and the continuous improvement of the performance of resistive sheets, zinc oxide arresters are increasingly used in power systems, and research on arresters for line lightning protection is gradually being carried out.
Line arresters are divided into series gap type (air gap or fixed gap) and gapless type. They are connected in parallel at both ends of the insulator (string). The main difference is that the zinc oxide arrester body of the former type basically does not bear the system operating voltage, and the failure of the body will not affect the normal operation of the line. The latter type of arrester can withstand the effects of operating voltage for a long time.
Discussion on issues related to lightning current through zinc oxide arresters, cold shrink cable terminals
When lightning strikes the top of the tower, part of the lightning current propagates along the lightning protection line to both sides of the lightning strike point; part of it enters the ground through the tower; and part of it flows through the zinc oxide arrester. The proportion of each part of the current to the total current depends on the geometric arrangement of the lightning protection wire and wires, the height of the tower and the grounding resistance. Taking a line arrester with a rated voltage of 108kV installed on a 110kV single pole and single lightning protection line cement tower as an example, the electromagnetic transient calculation program (EMTP) calculation shows that under extremely harsh conditions, the lightning current amplitude is 300kA, and the tower grounding resistance is 60SZ. When lightning strikes the tower directly, the current flowing through the zinc oxide arrester does not exceed 20kkA.
In terms of field tests, in order to summarize methods for preventing winter lightning damage to transmission lines in coastal areas, technicians have carried out artificial lightning triggering and actual measurement of lightning current flowing through line arresters.
Yichang Hengyuan Technology Co., Ltd. specializes in the production of European-style cable joints, plug-and-pull heads, cable branch boxes, American-style elbow joints, high-voltage vacuum circuit breakers, high-voltage load switches, arresters, zinc oxide arresters, tank arresters, over-voltage protectors, counters, monitors, heat-shrinkable cable accessories, Manufacturer of cold shrink cable accessories, T-heads, wall bushings, European cable accessories, American cable joints, transformer neutral point protection devices, fuses, isolating switches, PT cable heads, elbow cable joints, 10kV outdoor terminals, switch cabinets, cable intermediate joints, cable accessories and other products
