Post insulator is a unique insulation control that can play an important role in the overhead transmission line. In the early years, post insulators were mostly used for power poles. Slowly developed, many suspended insulators are hung at one end of the high-voltage wire connection tower. It increases the creepage distance, usually made of silica gel or ceramic, which is called an insulator. Insulators play two basic roles in overhead transmission lines: supporting conductors and preventing current from returning to the ground. These two roles must be guaranteed. The insulator shall not fail due to flashover and breakdown caused by changes in environmental and electrical load conditions. Otherwise, the insulator will lose its function and damage the service and operation life of the whole line. The insulator has high mechanical strength, low dispersion, and safe and reliable operation.
In order to test the low-temperature mechanical performance of the product, technicians simulated the change of outdoor temperature in winter and carried out a freezing test on the ZSW1-110/4 insulator. After several temperature cycles, the test crystal is subjected to a bending failure test at a low temperature. The test results show that the bending failure strength of the post insulator at -40 ℃ has no obvious change compared with room temperature.
The pollution resistance of insulators mainly depends on the product structure and the shape of the umbrella skirt. A lot of work has been done in this regard. Through design optimization, artificial pollution test optimization, and natural pollution test optimization, the insulator umbrella skirt with large and small umbrella phases and ribs under the umbrella is finally determined. The insulators with rated voltage of 126kV and 252kV, bending failure load of not less than 12kV, an insulator with creepage specific distance of 25mm / kV, under the equivalent salt density of 0.12mg/cm2, can withstand the maximum operating phase voltage for a long time. The creepage distance of line post insulator class III can fight level IV equivalent salt dense pollution. Insulators with a rated voltage of 550kV and creepage-specific distance of 25mm/kV can operate for a long time under the equivalent salt density of 0.06 mg/cm
Its equivalent salt density is one-third higher than similar products with the same climbing distance and equal diameter umbrella skirt.3. High seismic resistance level of post insulatorFor the post insulators with rated voltage of 252kV and 550kV, the technicians conducted a seismic performance test with the intensity of grade 9 in the Research Institute. The results showed that the test objects were intact.
For insulators with a rated voltage of 550kV, the radio interference generated under 1.1 times the maximum operating phase voltage shall not exceed 500 μV. There is no visible corona at night on sunny days, and the visible corona voltage is up to 450kv.
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