Electrical Insulation

Disc Insulators in High Voltage Transmission Lines 

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Before we discuss the use of disc insulators in high-voltage transmission lines, let’s understand the need for such insulators.  Transmission lines operate at very high voltages such as 66 kV, 132 kV, 220kV, 400 kV, even 765 kV and more. So, the conductors used in these systems are also very heavy. To maintain proper ground clearance, we suspend these … Read more

Lightning Arrester – Gapless Metal Oxide (ZnO) Arrester

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Why was the gapless ZnO lightning arrester developed over the valve-type lightning arrester? In a valve-type lightning arrester, we connect spark gaps in series with non-linear resistors. This is necessary because silicon carbide (SiC) has a relatively low non-linearity coefficient (α ≈ 5–7). As a result, the knee point in the V–I characteristic of an … Read more