Selection of insulation level of HVAC power lines operating in high altitude polluted area

A description is given of a method for choosing the insulation level of power lines operating in a high-altitude polluted area on the basis of an artificial pollution test. The test was carried out in a pressure chamber in which the air pressure could be controlled. The chamber was used to simulate air pressure for different altitudes. It was found that under the same degree of pollution the withstand voltage of insulators decreased as the altitude increased. For several kinds of test insulator, the withstand voltage was higher as the creepage distance is increased. The shape of the shed affects the withstand voltage. On the basis of the test results, recommendations are made for choosing insulation for lines operating in high-altitude polluted areas