The high-voltage lightning arrester is connected in series and parallel with the insulators of the power transmission line to protect the insulator string, improve the lightning resistance level of the line, reduce the lightning tripping rate, and achieve the purpose of lightning protection. Linear high-voltage arresters mainly have two structural forms: series type and non-series type. This series of gap-type high-voltage arresters are connected with conductors using an air gap, and their impact on the breakdown voltage is smaller than the insulator string lightning voltage. Under normal circumstances, the high-voltage arrester is in a "sleeping" state and does not withstand power frequency voltage. Only when the lightning overvoltage reaches a certain amplitude, the high-voltage arrester body can work normally when connected in series, so that the charge ratio of the band resistor is large, the residual lightning voltage is reduced, the reliability is improved, and the service life is extended. The high-voltage arrester without series joints is directly connected to the wire, and uses the nonlinear characteristics of the high-voltage arrester resistance to protect the insulator. Compared with the type with series gaps, it has the advantages of reliable impact energy absorption and no leakage delay. In addition, in order to prevent the high-voltage arrester itself from malfunctioning and affecting the normal operation of the line, gapless high-voltage arresters are generally equipped with a fault tripping device.
Since the 1980s, the United States and Japan have begun to use high-voltage arresters on transmission lines and have achieved good results. In the mid-to-late 1990s, my country's power transmission lines began to use high-voltage arresters to improve lightning resistance and reduce the line's lightning tripping rate. High-voltage lines use high-voltage arresters, which can achieve better results. Both theory and engineering tests have shown that it is feasible and effective to install high-voltage arresters for lightning protection on transmission lines.
Lightning arrester manufacturer
Line high voltage arrester and its installation location selection
The power line high-voltage arrester is a line-type metal zinc oxide gapless high-voltage arrester with a series gap and a disconnect device. The voltage stability, electricity resistance, corrosion resistance, pollution resistance and sealing, corrosion resistance, pollution resistance and corrosion resistance of the two types of wire-type zinc oxide high-voltage arresters can meet the requirements of 110kV line operation and lightning protection. The gapless high-voltage arrester has better operating characteristics, current impact resistance and operating load capacity under power frequency fault current, which can ensure that the high-voltage arrester does not affect the normal operation of the line when a fault occurs, and is maintenance-free. The selection of zinc oxide arrester installation points is mainly for lightning-prone towers and sections. Through the analysis of the distribution of lightning strike fault points on two lines in recent years, it was found that lightning strike towers mainly fall into two areas. Among them, the right side of the line is a mountain peak. The left side is an empty valley or a reservoir. The fault points are on the left side and the middle phase. The left phase and middle phase of Tower No. 84 near the top of the mountain occurred 4 and 3 times respectively, and the left phase of Tower 85 and the middle tower both failed. The leachate fault points are widely distributed, but more than half of the No. 7 to 21 tower sections have faults. The fault points are mainly in the phase insulators on both sides, and there are very few insulators in the middle phase. The topography of the vulnerable area is characterized by continuously spanning multiple mountain peaks, with a large span, with the largest one reaching 879m. Therefore, these two lightning-prone areas should be used as the installation locations of line high-voltage arresters, and the pole towers for installing high-voltage arresters should be determined based on the fault points. Therefore, high-voltage arresters are also considered to be installed on both sides of the 82.86 tower. Due to the large range of easy-to-contact sections of the asphalt line, the failure of the high-voltage arrester installed on the No. 7 pole tower was taken into account. At the same time, for the mountainside on both sides of the mountain top, No. 13.17 tower, which is prone to lightning strikes based on topographic analysis, determined a total of 14 base towers to install high-voltage arresters for the second line. In view of the installation cost and the characteristics of negative angle protection of lines, high-voltage arresters are usually only installed on both sides of each tower, and based on the differences in lightning strike faults, high-voltage arresters are installed on each phase of the four base towers to prevent shielding strikes. According to the installation point tower structure, in order to accumulate operating experience, gap-type and gapless high-voltage arresters with disconnection devices are respectively used. In the actual installation, gap-type high-voltage arresters and gap-free high-voltage arresters were mainly used, and 32 zinc oxide high-voltage arresters were installed, 12 phases with gaps and 20 phases without gaps. The clamping bracket is used to pick out the high-voltage arrester. The bracket with a series gap type is used to pick out the high-voltage arrester and lift it, and then connect it in series and parallel with the insulator.
(1) For the middle phase of the tower, use a bracket to directly fix the high-voltage arrester between the conductor and the tower.
(2) For the side phase of the tension tower, use the method of fixing high-voltage arresters on the beams and jumper wires. In addition, the installation of line high-voltage arresters must fully consider the influence of wind speed, and the support structure must be calculated accordingly according to line design requirements.
Metal oxide arrester
The use and effect of line high voltage lightning protection devices
After the phase line zinc oxide high-voltage arrester was put into use, it has been operating in good condition since it was put into operation. The high-voltage arrester has a cumulative operation record of 39 times, and the lightning protection effect is relatively ideal. After the high-voltage arrester was installed, no lightning tripping occurred, and the line high-voltage arrester recorded a total of 20 operations.
The 110kV lines in the same area have experienced lightning tripping many times, among which the lightning tripping phenomenon of the 35kV line is still relatively serious. The line lightning resistance level calculation parameters of the DL/T8l5-2000 standard are used to determine the line lightning resistance level is low. Due to the use of synthetic insulators, lightning protection wires, tower types and other factors, its lightning resistance level is obviously low. In addition, tower No. 84.85 has a large ground resistance and extremely low lightning resistance level, which causes frequent lightning flashovers in specific terrain and climate environments. The overall lightning resistance level is acceptable. Some towers, such as tower 11.15, exceed 100kA. The main reason for lightning tripping of the line should be poor terrain and local climate conditions, and extremely strong lightning activity. For example, the lightning resistance level of Tower 15 has reached 169kA, but due to the special terrain conditions of the tower, it still suffered lightning flashover. After installing a high-voltage arrester, the lightning-strike resistance level of the line is greatly improved. Generally, the lightning-strike resistance level of a three-phase high-voltage arrester will be increased by 3 to 3.6 times, and the two sides connected on both sides will increase by 1.6 to 2 times. When high-voltage arresters are installed on three phases, the lightning resistance strength is increased by 3 times. When high-voltage arresters are installed on both sides of the phase, the lightning resistance strength is increased by 1.8 times, and the lightning resistance strength reaches more than 100kA, which greatly improves the lightning protection ability of the line. Comparing the lightning resistance levels of the high-voltage arresters of the two transmission lines before and after. The action conditions of the high-voltage arresters and the actual operating effects of the lines. It can be seen that after the high-voltage arresters are used on the lines, the lightning protection level of the lines has been improved, and the lightning tripping of the lines has been greatly reduced, achieving the expected results.
Conclusion
(1) Judging from the engineering application results of two 110kV lines in the power grid, the effect of applying line high-voltage arresters on 110kV transmission lines is ideal and is an effective lightning protection measure.
(2) Due to price and cost issues, the technical and economic comparison of using line-type high-voltage arrester models for power transmission lines has yet to be demonstrated. For lines with high lightning tripping rates, it is completely feasible in terms of technical and economic benefits to use high-voltage arresters to improve the lightning resistance level of the line and reduce the lightning tripping rate based on topography, geology, and meteorological conditions, in locations prone to lightning strikes or on poles with frequent lightning strikes.
(3) Because linear zinc oxide high-voltage arresters have gaps or no gaps, special attention must be paid to the insulation coordination between the high-voltage arrester and the insulator string. For example, the coordination margin between the comprehensive insulator string and the series gap high-voltage arrester means that the lightning discharge voltage of the high-voltage line arrester is connected to the insulator U.
(4) The application of high-voltage surge arresters on 110kV power transmission lines has achieved good results, accumulated experience for the promotion and use of other high-voltage power transmission lines with high lightning tripping, and played a positive role in reducing the fault trip rate of power transmission lines and improving power supply reliability.
High voltage arrester
