| Popis: |
The performance of 11 kV suspension type porcelain (in-serviced and fresh) and polymeric composite insulators, energized by HVAC (High Voltage Alternating Current), are investigated in the present study. To characterize the electrical performance of the samples, artificial pollution tests have been conducted. Fly ash, mixture of soluble and partially soluble salts, cement, and agricultural sand have been used as contaminants to simulate the different pollution conditions of field operative HV insulators. The solid layer method (IEC-60507) is used for artificial pollution and wetting is done by natural fog. Equivalent Salt Deposit Density (ESDD) and Non-soluble Deposit Density (NSDD) approaches were used for classifying pollution severity on the insulators. Flashover voltage and surface conductivity were also measured to compare the pollution flashover characteristic. The results indicate that, under the same pollution conditions the in-serviced porcelain insulator attains poorest performance, while polymeric-composite insulator achieve relatively good performance. It is also found that the difference in the flashover values is basically due to the roughness of the insulator surfaces and ionic properties of the contaminants. |
