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Pin type insulator is used up to _________ because beyond that it becomes bulky and uneconomical.
415 kV
11 kV
33 kV
66 kV
33 kV
Pin type insulators are designed for overhead power distribution and transmission lines. They are used up to 33 kV because, beyond this voltage level, the size and weight of the porcelain or glass required to maintain the necessary creepage distance and insulation strength become economically and mechanically unfeasible.
Pin type insulators are designed for overhead power distribution and transmission lines. They are used up to 33 kV because, beyond this voltage level, the size and weight of the porcelain or glass required to maintain the necessary creepage distance and insulation strength become economically and mechanically unfeasible.
LcreepageтАЛтИЭVoperatingтАЛ тАФ Creepage distance is directly proportional to operating voltage
CostтЙИkтЛЕVn тАФ Cost increases exponentially with voltage due to material volume
The insulating property depends on the creepage distance (the shortest path over the surface between the conductor and the tower). As voltage increases, the required creepage distance grows proportionally. For pin-type insulators, this necessitates a larger, multi-petticoat structure, which leads to excessive bulk, high manufacturing costs, and potential structural instability on the cross-arm.
Pin type insulators are limited by their design to moderate voltage applications.
Higher voltages require suspension-type insulators to manage mechanical stress and insulation levels.
The 33 kV limit is an industry-standard economic threshold in India for distribution networks.
Simple design and easy maintenance
Cost-effective for low and medium voltage levels
Low installation labor
Becomes heavy and bulky at high voltages
Prone to failure due to tracking at higher potentials
Cannot be easily upgraded for higher voltage transmission
Primary distribution lines
Urban and rural electrical networks
Sub-transmission up to 33 kV
For voltages above 33 kV (e.g., 66 kV, 132 kV, 400 kV), suspension string insulators are used instead of pin insulators.
Option A (415 kV) is a transmission level voltage where pin insulators are physically impossible to implement.
C is correct тАФ Pin type insulators are restricted to 33 kV because their size and weight make them uneconomical and mechanically inefficient for higher voltages.
In power systems, always associate pin insulators with distribution levels (up to 33 kV) and suspension/string insulators with transmission levels (above 33 kV).