| Jiangmen city is on the edge of the South China Sea with the coast line as long as 680 kilometers. The annual thunderstorm days of the city are above 90 days. The 220kV TongTangJIA, 220kV TongTangYI, 220kV TongShui and 220kV TongNeng four overhead transmission lines with total power load of 1150MW along the coast are important power supply lines in Jiangmen, and even in the Pearl River Delta. Once the line fault occurs, the accident influence scope is of great power.As the line towers are mainly located in coastal hills and the microclimate regions of complex landform, therefore the line towers are easily suffer from dual effects of typhoon invasion and lightning impulse. Since it was very difficult to search the fault location, therefore it was easy to form a hidden danger of the equipments which was difficult to find out. It was a great threat to the safe and stable operation of the power grid of Jiangmen. According to the survey, the maximum instantaneous wind speed was up to 51 m/s with strong convection thunderstorm weather when the typhoon was landing, and the magnitude of the lightning current was up to hundreds of kiloampere. The wind deviation and arc discharge phenomenon occurred after the transmission lines were attacked by strong wind and lightning, which usually caused clearance decreased on the top of the tower to the high voltage wires, conducting line tripping, or other serious defects such as the wire to be burned and broken by electric arc when seriously. Even the blackout accident would happen, so as to threaten the safe and stable operation of the power grid. Therefore, to study the implementation of windproof reinforcement project, find out the economic, effective lightning protection measures, carry out comprehensive analysis and comparison to its popularization and application, is of great significance to improve the reliability of coastal power supply lines and the ability of power grid to resist natural disasters.In order to reduce the tripping phenomenon which caused by strong wind and lightning of the overhead transmission line, this paper combined with the practical operation of power grid in Jiangmen, through methods of collecting basic data, establishing computation model, developing testing calculation of the wind yaw angle of the tower and lightning over voltage, etc., to make judgment of line fault reasons by undertaking thorough and careful analysis of trip fault reasons of the four overhead transmission lines as 220kV TongTangJIA, 220 kV TongTangYI, 220kV TongShui and 220kV TongNeng, which suffered from frontal attack by the thunder storm weather as well as strong typhoon as "Hagupit" and "crater".This paper studies and formulates relevant windproof and lightning protection reinforcement measures, analyzed and discussed specific prevention measures such as increasing the size of the top of the tangent tower, increasing wind declination of the transmission line, reinforcing tension resistance tower with cross arm insulator as well as reasonably adjusting the length of the jumper as well as far sighted the lighting protection measures of transmission lines which set up on the same tower. Simultaneously, this paper put forward that it should be closely combined with the local climate conditions and carried the required pre degree on size of the top of the tower to meet the needs of operation in the process of designing the overhead transmission line. In addition, through engineering practice of the transformation of windproof and lighting protection of the overhead transmission line, possible line fault which may be caused by typhoon and the thunderstorm weather would be reduced, thereby improving the power supply reliability of the transmission line, of which obtained apparent effect in actual operation and should have a certain value of popularization and application in the future. |
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