Understanding Arresters

Surge Protection Educational Series

If you are ever involved in the application, purchasing, or specification you will find this NEMA-sponsored video series informative. The series consists of six interrelated videos and supporting papers of the same name. The videos are a quick look at the topics covered in each of the papers on Arrester Quality and Arrester Application.
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What to Look for in a Good Quality Arrester

View in PDF Format All good quality arresters have much in common. This first in a series of articles, sponsored by NEMA Surge Arrester Section members, covers what to look for in that quality arrester. Introduction We’ve all been there before. Which product offers the best quality? Quality is an important factor for the surge arresters that perform the important task of keeping the...
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What to Look for in a Good Quality MOV Disk

View in PDF Format The Metal-Oxide Varistor (MOV) A quality arrester starts with a quality disk. A quality disk starts with quality raw materials and a solid design. The size of a disk does not indicate quality in any way if it is applied correctly. The disk in Figure 1 is a distribution class disk rated about 4kV MCOV. It consists of the following components: an aluminum top and bottom...
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What to Look for in a Good Quality Supplier

This is the third in a series of four guidance documents on quality and arresters. The first is “What to Look for in a Good Quality Arrester,” followed by “What to Look for in a Good Quality Disk.” The final document is “Understanding Arrester Datasheets.”
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Understanding the Arrester Datasheet

Part of selecting a good quality arrester is understanding the published data. A good quality supplier will fully disclose the relevant data in a format that is comprehensible and user-friendly. This article is a guide to understanding the arrester datasheet and what is behind it.
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The Many Uses of Transmission Line Arresters

It was not realized at the time, but the 1992 introduction of the polymer-housed transmission line arrester (TLA) was clearly a game changer in the practice of lightning protection of transmission lines. Overhead shield wires had been the only cost-effective means of mitigating the effects of lightning until that moment. Since then, the TLA has shown its value not only in reducing lightning...
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The Lightning-Proof Distribution Line

In the U.S., the distribution transformer is effectively lightning-proof when protected by a tank-mounted metal-oxide varistor (MOV) arrester. Even if the arrester fails, the transformer will have been protected in the arresters last action. In the U.S., the power transformers found in substations are effectively lightning- and switching surge–proof and have been so for many years. The...
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