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The article will focus on the contact design of vacuum interrupters. Before discussing the subject, let us consider why a specific design of contacts is required. The simplest form of contact is the butt-type contact, which has a plain and flat surface. This type of contact is suitable for vacuum circuit breakers with a rated … Read more
Formation of Arc in Medium Before discussing the vacuum arc, let us recall the concept of arc formation in a medium like air, gas, or any other similar medium. Arc during closing contacts Let us switch on a circuit breaker online. Closing of this circuit breaker connects a load to a source. During closing, the … 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
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
A High Voltage Circuit Breaker (HVCB) is a crucial component in power transmission and distribution networks. Its primary role is to protect electrical equipment by interrupting fault currents within the system. Beyond safeguarding equipment, HVCBs are vital for maintaining the integrity of the power grid. They isolate faults effectively, ensuring that adjacent systems remain unaffected … 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
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
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
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