Question

Which of the following statements relevant to pin insulators is INCORRECT?
1. They can be of single piece or multipiece.
2. Pin insulators are commonly used on rural and urban 11 kV primary distribution lines.
3. They can take conductor load in tension which often occurs at angles and at dead ends.
4. Pin insulators can be used upto 33 kV.

Answer 1

Correct Answer - Option 3 : They can take conductor load in tension which often occurs at angles and at dead ends.

Pin Insulator:

• The pin insulator is used in power distribution for the voltage up to 33 kV
• Pin insulators are commonly used on rural and urban 11 kV primary distribution lines.
• Pin-type insulators are not economical at operating voltages greater than 33 kV.
• It is placed on the cross arm of the supporting tower.
• They can be of a single piece or multipiece.
• The pin insulator has grooves on the upper end for keeping the conductor
• The conductor is tied to the insulator on the top groove on straight line positions and the side groove in angle positions by annealed binding wire of the same material as that of the conductor
• A lead thimble is cemented into the insulator body to receive the pin

Advantages:

• It has high mechanical strength
• The pin type insulator has a good creepage distance
• It is used on the high voltage distribution line
• The construction of the pin type insulator is simple and requires less maintenance
• It can be used vertically as well as horizontally

Disadvantages

• It should be used with the spindle
• It is only used in the distribution line
• The voltage rating is limited, i.e., up to 33kV
• The pin of the insulator damaged the insulator thread