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Introduction In modern medium-voltage power systems, vacuum circuit breakers play a dominant role in safe and efficient current interruption. Engineers prefer these breakers for their robustness, low maintenance requirements, and high dielectric recovery strength. A vacuum circuit breaker, also known as VCB, uses the unique properties of a vacuum to quench electrical arcs. Unlike SF6 … Read more
Before discussing the actual comparison, let’s look at the different media used in circuit breakers. These are air, oil, and SF6 gas. Nowadays, engineers have also developed some other gaseous media like compressed air, C4-FN mixtures (C4-FN/CO2 or C4-FN/N2), C5-FK mixtures (C4-FK/air or C4-FK/CO2), and pure N2 or N2/CO2 mixtures as insulating mediums. Certainly, some … Read more
We shall cover the constructional details of a vacuum interrupter along with its function, how it facilitates arc quenching, etc. Introduction to Vacuum Circuit Breakers Before entering into the detailed discussion about the vacuum interrupter, let us have a look at the basic concept of vacuum circuit breakers. A vacuum interrupter, which we also call … Read more
A lightning arrester is a protective device used in electrical power systems, buildings, communication systems, and other infrastructure to safely divert high-voltage surges caused by lightning strikes or switching events to the ground for preventing damage to equipment. Actually, a lightning arrester is a device connected between the line and ground. It remains non-conductive under … Read more
Here, we will 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 effectively and non-effectively earthed conditions. Effectively … 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