Accidents and Prevention of 10kv Overhead Insulated Conductor for Overhead Lines
According to operating experience, common accidents of 10kV overhead lines are as follows:
1. Lightning Accidents There are many kinds of accidents caused by lightning strikes on 10kV overhead lines. There are insulator breakdowns or bursts, broken wires, and transformers. Lightning strike accidents, although there is a major relationship with the objective causes of lightning strike lines, and equipment defects are also of great concern, the main reasons for the analysis of its equipment are:
(1) The quality of the insulator does not pass. In particular, there are defects in the quality of P-15 and P-20 pin insulators. In the past one or two years, lightning burst pin insulator bursts frequently occurred in this region, causing 10kV line grounding or phase short circuit.
(2) Insufficient lightning protection measures for 10kV lines. Since the end of 1998, zinc oxide surge arresters have been replaced in distribution transformers in many regions, but some of the longer 10 kV overhead lines do not have line zinc oxide arresters installed;
(3) Poor contact of the wire connector. In many areas, it has been customary to use a ditch clip as a connector for a 10 kV line. Even a parallel ditch clip does not have to be used to wind the cable. The ditch clip connection or winding connection is not the correct connection of the wire. The bad wire connection will withstand Can not withstand the impact of a powerful lightning current;
(4) Arrester grounding device failed. Unqualified grounding devices, grounding resistance greater than 10 ohms, low unloading capacity, lightning currents can not quickly flow into the earth.
2. The typhoon blows down tower tower accidents in accordance with the maximum designed wind speed of 25 meters per second designed to blow the typhoon 10 levels, the tower is no problem, the typhoon scraped tower due to:
(1) 10kV lines and towers were not constructed according to the design requirements, and the foundations of towers were not solid or were not deep enough;
(2) Typhoon wind speed exceeds the maximum design wind speed. Typhoon 10 has a wind speed of 25 m/s, typhoon 11 has a wind speed of 30 m/s, and typhoon 12 has a wind speed of 33 m/s.
3. External forces destroying accidents External damage is also one of the multiple accidents of 10 kV overhead lines. These types of accidents can be classified according to the forms of damage:
(1) Vehicle collision contact causes a 10kV overhead line reverse pole (tower);
(2) Kite touch causes 10kV overhead line short-circuit tripping tripping of overhead lines;
(3) Towers and towers are tilted or reversed when towers and fixtures are stolen;
(4) The base of the tower or the base of the cable is hollowed out and damaged, causing a reversed pole (tower);
(5) The tool or material of the illegal building touches the wire and causes a quick tripping of the phase-to-phase short circuit.
4. Line overload operation or poor contact of the wire connector causes heat or disconnection.
5. The line equipment is old, the service life is long, the equipment is flawed, and related accidents are caused.
The above analysis is about some common 10kV overhead line accidents. These accidents have great harm to the lines, causing great losses to local industrial and agricultural production, and inconveniencing the lives of local residents. The following measures on how to reduce accidents on 10kV lines and ensure safe operation of the lines will be discussed.
Anti-accident measures 1. Anti-lightning and anti-accident measures (1) Replacement, installation of post insulator or porcelain cross arm. Lightning strikes on stray insulators on 10 kV overhead lines are the most common equipment accidents. The reason for this type of accident is that, in addition to more thunderstorms in the region, the quality of needle insulators is also a major cause. The P used and installed in previous years was the main reason. -15. P-20 single-s******t, double-s******t and multi-s******t pin insulators have proved that the product is of low quality and low level of lightning resistance. It is possible to replace these insulators with pillar insulators or porcelain cross-arms and new 10kV lines. The pillar insulator or porcelain cross arm should also be selected. Operation experience shows that the lightning resistance level and the product quality of the pillar insulator and the porcelain cross arm are much better than the P-15 and P20 pin insulators.
(2) Install zinc oxide surge arresters. In open areas, because there is no high-rise buildings to attract lightning, lightning strikes the line is a common thing, so it is appropriate to install line type zinc oxide lightning arrester on the open 10kV overhead line, newly installed distribution equipment such as distribution transformer, column Zinc Oxide arresters must also be installed on switches and cables to enhance the lightning protection of 10kV lines and equipment;
(3) Use Amp clips. In the future 10kV line transformation and overhaul, we will gradually eliminate the wire connector as the wire connector, and strictly prohibit the use of wire clamps to wind the wires. We should use the Ampoule clamp with good connection performance.
(4) Check and correct the grounding device. Regularly check and measure the grounding resistance of the grounding device on the 10kV line, and rectify the failure to ensure that the grounding resistance value is not more than 10 ohms. The earth resistance of the newly installed 10kV line grounding device should not be greater than 10 ohms, and the grounding resistance of the grounding device that is shared with devices below 1kV is not more than 4 ohms.
2. Preventing accidents caused by typhoons (1) Regularly inspect 10kV transmission line towers, formulate a complete inspection system, and timely reinforce the foundations or add cables to towers that are not solid enough. The new tower should be constructed in strict accordance with the design requirements;
(2) Appropriately increase the maximum design wind speed. South China can design at a maximum wind speed of 30m/s.
3. Prevent external damage measures. According to the above-mentioned 10kV line external damage destruction type and reason, the following measures are taken:
(1) In order to prevent or reduce vehicle crashes and tower accidents, it is possible to apply a striking reflective paint to the poles on the side of traffic roads to attract the attention of vehicle drivers;
(2) Strengthen the publicity and education of primary and middle school students, set striking warning signs on the side of the 10kV line, and prohibit the kite flying within 300m on both sides of the 10kV line;
(3) Strengthen the crackdown on the theft and destruction of 10kV line materials and fittings, strive to get the cooperation of the local*, security protection departments, formulate effective measures and specific prevention plans, set up a special department responsible for implementation, and destroy and steal 10kV power facilities. Destructive elements attack severely;
(4) The operating department regularly inspects and inspects the tower and base of the 10kV line, the base of the cable and the illegal structures, timely repairs the base of the tower and the base of the string, repairs and repairs the defective equipment in time, and cleans the illegal buildings. Reorganize.
4. The technical operation department shall pay close attention to the load condition of each 10kV feeder, adjust the load of the cutover feeders in time, and strictly prohibit line overload operation.
5. Use an infrared thermometer to measure the temperature of the wire connector during the peak load period. Once the temperature is abnormal, perform immediate processing to avoid high temperature fuses.
6. Periodically derusting and oiling the electric pole interface, tower and distribution platform, strengthen the protection of towers and fittings, and improve the safety operation level of 10kV lines.
7. The short circuit fault indicator is installed on the 10kV line. Even if a short circuit fault occurs on the 10kV line, the fault point can be quickly detected and eliminated to reduce the accident loss.
The safe operation level of 10kV overhead lines will directly affect the economic benefits of power companies. It is a matter closely related to electricity customers. In addition to taking appropriate technical and management measures to prevent accidents and eliminate defects in a timely manner, power companies should also actively use local resources. The role of the government, the media, and the general public has increased their publicity, investigation, and crackdown. They have played a role in group prevention, reduced the occurrence of accidents, ensured the safe operation of the power grid, and better served the local economic construction.
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