Wood Pole Overhead Lines
Concentrating on the mechanical aspects of distribution wood pole lines, this informative text includes coverage of live line working, environmental influences, climate change and international standards.
TABLE OF CONTENTS Wood Pole Overhead Lines
Chapter 18: Lightning and Lightning Protection
18.1 Introduction
In dealing with system outages the utility can often take some pro-active steps by dealing with the original source of the fault, e.g. improving line construction, tree cutting etc. With lightning, the utility has no choice there is no control over the lightning storm. The only solution is to protect the network to the economic limit of available techniques.
However, in order to protect the network, there is a need first of all to understand the lightning process and how damage occurs. Otherwise, a protection policy may end up as a set of vague or meaningless instructions that can be open to misinterpretation or malpractice in application, as the reasons for them are not fully understood.
This chapter briefly explains what lightning is, how to decide risk levels and how to protect against it. Details of component damage have been provided in chapter 16. This chapter is thus not intended to be a comprehensive guide and more detailed information can be obtained from Cooray [ [1]].
[1]COORAY, V.: The lightning flash (IEE Publishing, 2003)
18.2 Lightning effects on overhead lines
18.2.1 General
It is perhaps unfortunate that lightning is not the same all over the world. Although it is extremely common at any one time there will be around 2000 thunderstorms [ [2]] active somewhere in the world it is essentially a random process in the short term. In equatorial regions such as Singapore, there are 180 200 days each year when lightning storms occur. This is based on...
Copyright The Institution of Electrical Engineers 2005 under license agreement with Books24x7
