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Transmission line insulators are made of
Porcelain
Glass
Composite Polymer
Any of the above
Any of the above
Transmission line insulators are critical components used to isolate the high-voltage conductor from the grounded tower structure. They must possess high dielectric strength, high mechanical strength to support conductor weight, and high resistivity to leakage currents, qualities found in materials like porcelain, tempered glass, and composite polymers.
Transmission line insulators are critical components used to isolate the high-voltage conductor from the grounded tower structure. They must possess high dielectric strength, high mechanical strength to support conductor weight, and high resistivity to leakage currents, qualities found in materials like porcelain, tempered glass, and composite polymers.
R=╧БAlтАЛ тАФ Where R is resistance, ╧Б is resistivity, l is length, and A is cross-sectional area; high resistivity is essential for insulators.
VstressтАЛ=dVтАЛ тАФ Electrical stress where V is voltage and d is insulation distance.
The primary role of an insulator is to provide a high-resistance path to prevent leakage current (IlтАЛ=V/RinsтАЛ) from reaching the earthed tower. They must withstand electrical stresses (lightning, switching surges) and environmental conditions (pollution, humidity) without undergoing electrical breakdown or mechanical failure.
Porcelain is the traditional material; it is reliable but heavy and brittle.
Glass insulators offer visual inspection benefits as they shatter if faulty.
Composite insulators (silicone rubber) are lightweight and hydrophobic, excellent for polluted environments.
Mechanical strength is just as important as dielectric strength for line stability.
High dielectric strength prevents flashovers
Durability against harsh weather conditions
Chemical inertness prevents degradation over long lifespans
Porcelain/Glass are heavy and fragile
Composite insulators can suffer from tracking or erosion over time
Porcelain attracts dirt/pollution leading to tracking
Overhead transmission lines (11kV to 765kV+)
Distribution lines
Substation busbar support
Standard insulators must meet IS 731 standards for porcelain types.
Glass insulators are typically made of toughened glass to resist thermal shock.
D is correct тАФ All listed materials are standard industry choices for transmission insulators depending on cost, environmental requirements, and mechanical load specifications.
Always remember that while porcelain is classic, composite insulators are the preferred choice for modern high-voltage DC (HVDC) lines due to superior performance in polluted zones.