Dielectric behaviour of polluted porcelain insulators

Abstract

The dielectric behaviour of polluted porcelain insulators is investigated by means of experimental tests and simulation methods. The elaboration of the experimental results, using well known mathematical models of polluted insulators, leads to the identification of the arc constants. It was found out that the arc constants are independent of the insulator type and of the experimental pollution procedure (salt fog or solid layer cool fog method). This allows the formulation of a generalised simulation model of polluted insulators. The critical parameters for the flashover (voltage, current and gradient) are computed by means of the developed model, using only the geometric dimensions of the insulator, the pollution severity and the arc constants. Different types of porcelain insulators are investigated and the variation of the critical parameters upon the density of the pollution layer is determined. The influence of the geometrical dimensions and of the shape of the insulator to the critical parameters is also investigated. Furthermore, analytical relations are defined, between the computed critical parameters and the salt deposit density as well as the dimensions, the shape and the type of the insulator.

Analytical Model to Predict Pollution Flashover Voltages of Porcealin Disc Insulators

“…From the figure 3 it can be observed that present model predicts the flashover voltages with a deviation of less than 10% in comparison with experimentally [15] obtained flashover voltages for Type A, B and C insulators except for Type B insulator the prediction is having a maximum deviation of 21% at lower ESDD levels. Figure 5 shows a comparison of flashover voltages as a function of pollution severity in terms of ESDD (mg/cm 2 ) between experimental [15,38] and proposed model for Type D, E and F Insulators.…”

“…The proposed model is verified for its validity by comparing the model results with previous researchers experimental and model results [14,15,37,38]. The dimensional details of the insulators considered in the study are given Table 3 Figure 4 shows a comparison of flashover voltages Vs ESDD for Type A, B and C insulators between proposed model and experimental [14].…”

“…The comparison shows clearly that the deviation between experimental [15,38] and proposed model results is within 10% for the above three insulators under varying pollution conditions. …”

“…The accuracy of such prediction may be confined to only to the insulators which have been used in the prediction of flashover voltages. There are models developed [14,15] based on the real insulators, but in such models the number of parameters involved are more hence increasing the complexity of the model.…”

Mathematical Modeling on AC Pollution Flashover Performance of Glass and Composite Insulator

“…These are typically composed of a central rod made of fibre reinforced plastic and an outer weather shed made of silicone rubber or Ethylene Propylene Diene Monomer rubber (EPDM). The composite insulators replace porcelain insulators because of its excellent anti-pollution performance, economical maintenance, light weight and suitable for highly polluted areas [1][2][3]. To ensure the safe and reliable operation of ac transmission lines, a great number of research on ac flashover performance of polluted insulators have been conducted [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”