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In this article, we shall explore the lightning arrester ratings. The article includes rated voltage, MCOV, discharge current, residual voltage, energy absorption, and many more. Lightning Arrester Ratings based on Voltage How to Select the Lightning Arrester Ratings based on Voltage? For that, we have to consider two conditions. These are the effectively earthed condition … Read more
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
Zinc oxide has a semiconducting nature. Zinc oxide (ZnO) is an n-type semiconductor. An n-type semiconductor is a material in which loosely bound electrons are available. However, zinc oxide (ZnO) is not like conventional semiconductors such as germanium or silicon. In germanium or silicon semiconductors, these extra electrons come from dopants. But in ZnO, no … Read more
We also refer to a Gas Insulated Switchgear (GIS) as a Gas Insulated Substation. Why is GIS the Future of High-Voltage Power Systems? There are several reasons for preferring a Gas-Insulated System (GIS) over an Air Insulated System (AIS). Constructional Details of Gas Insulated Substation (GIS) A GIS consists of several key modules, each performing … Read more
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
Engineers prefer to use silicone rubber composite insulators for transmission lines in areas with high pollution levels. In other words, these areas are among the most heavily polluted. These insulators normally have a creepage distance of 31 mm/ kV. The disc insulators used in heavily polluted areas also have a creepage distance of 31 mm/kV. … Read more
Power stations generate electric power. Electrical power transmission lines transmit the generated power to far places. The resistance and reactance of the line cause a voltage drop in the power. The Voltage Regulation of Transmission Line is the change in voltage between the sending and receiving ends. What is Voltage Regulation? We express the Voltage … Read more
Skin effect is a phenomenon that occurs in conductors. It mainly occurs while a conductor carries alternating current. Actually, an alternating current always tries to flow through the outer layer of a conductor. As a result, the current distribution across the cross-section of the conductor becomes uneven. Alternating current flows through the conductor at 50 … Read more
A valve-type lightning arrester is an effective type of lightning arrester for high voltage surges. Here, we shall explore how valve-type lightning arresters work and why they were revolutionary in their time. What Is a Valve-Type Lightning Arrester? As stated, a valve-type lightning arrester is a high-voltage surge protection device. It was widely used in … Read more
The corona effect is a natural electrical phenomenon. It occurs on EHV and UHV transmission lines. It may also occur inside substations on the live parts of high-voltage equipment. Cause of the Corona Effect The voltage level of transmission lines and live equipment is very high in EHV systems. Therefore, the electric field intensity surrounding … Read more