subject: Transmission Line In The Application Of Line Surge Arrester [print this page] Abstract: This paper introduces the principle of lightning arrester line, and after hanging on to run 2a arrester tracked statistics, lightning arresters on the line effect was evaluated.
Key words: transmission line lightning arrester failure
Introduction Recent years, due to the continuous deterioration of environmental conditions, lightning caused transmission line off Fault is also increasing, not only affect the normal operation of equipment, but also greatly affected the daily production and life. From the perspective of Shandong Province, Zibo are many minefields, lightning strikes occur every year off Fault Line. A few years ago, mainly concentrated in the southern mountain line, in recent years has the trend to shift the northern plains, stroke has become safe and reliable operation of transmission line the main factor.
Order to reduce the transmission line lightning faults, taking a variety of integrated lightning protection measures, such as lowering tower grounding resistance and improve the level of line insulation, protected by a negative angle, the construction of coupled ground, achieving a certain effect. But located in the part of high soil resistivity line, reduce the tower grounding resistance difficult, for the prevention and control around the mine attack on the line caused by the failure is still not a solution.
Present, foreign countries have been widely used line-based synthetic insulation MOA lightning protection for transmission lines, and achieved very good results. Since 1997, Zibo Electric Power Bureau and the former Ministry of Electric Power in the energy company Cooperation , Using the company's line surge arrester, and at 35kV, 110kV line running through two storm seasons have made the test of significant results.
1, a basic principle of lightning arrester line
Lightning towers, the part of the lightning current to flow through the grounding wire adjacent towers, the other part of the lightning passing through the pole into the ground, tower ground resistance showed a transient resistance characteristics, general use to characterize the impact of ground resistance. Towers of potential lightning tower
rapidly improved, and its potential value
Ut = iRd + L.di / dt (1)
Type in i?? Lightning current; Rd?? Impulse grounding resistance; Ldi / dt?? Transient components. When the top of the tower potential Ut and wire the difference in induction potential than U1 Insulator Series 50% of the discharge voltage will occur from the top of the tower to the conductor flashover. That Ut-U1> U50, if we consider line-frequency voltage amplitude Um effect was Ut-U1 + Um> U50. Therefore, the line of withstanding level with three major factors, namely, 50% of the line insulator discharge voltage, lightning current intensity and the impact of tower grounding resistance. In general, the line of 50% of the discharge voltage is certain, lightning current intensity associated with geographical location and atmospheric conditions, do not install surge arresters, increasing the level of transmission lines is often used Lightning lower tower grounding resistance, in the mountains, reducing grounding resistance is very difficult, which is why the reason transmission lines have been repeatedly struck by lightning.
After installing surge arresters, when the transmission line being struck by lightning, the lightning current diversion will change, part of the lightning current from the lightning spread of adjacent line towers, part of the body by the tower into the ground, when the lightning current exceeds a certain value, arrester moves into triage. Most of the lightning current flows from the arrester wire, spread to adjacent tower. Lightning current flows through the grounding wire and wire, because the role of electromagnetic induction between conductors, will produce in the conductor and lightning line coupling components. Because the arrester is far greater than from lightning diversion to divert the lightning current line, this streaming potential coupling will lead to improve, so that wire and the potential difference between the top of the tower is less than the flashover voltage of insulator string, insulators do not flashover occurs, therefore, has a good line arrester clamp potential, and this is a clear line arresters conduct mine characteristics.
Transmission Line In The Application Of Line Surge Arrester
