A. across the center disc is minimum
B. across the centered disc is maximum
C. across the top disc is minimum
D. across the top disc is maximum
Answer: C. across the top disc is minimum
Explanation:
The following points may be noted regarding the potential distribution over a string of suspension insulators:
- The voltage impressed on a string of suspension insulators does not distribute itself uniformly across the individual discs due to the presence of shunt capacitance.
- The disc nearest to the conductor has a maximum voltage across it. As we move towards the cross-arm, the voltage across each disc goes on decreasing.
- The unit nearest to the conductor is under maximum electrical stress and is likely to be punctured. Therefore, means must be provided to equalize the potential across each unit.