IEEE 957-1995 pdf download IEEE Guide for Cleaning Insulators
1. Overview
1.1 Scope
This guide for cleaning insulators documents the procedures used for cleaning contaminated electrical insu-ators (excluding nuclear, toxic, and hazardous chemical contaminants) of all types, using various equipmentand techniques.
Because of the great variety of conditions, practices, electrical system designs, and contamination possibilitiesthis guide describes a number of approaches to insulator cleaning on power systems. The IEEE makes no representation or warranty as to the adequacy, accuracy, economy, or safety of this guide, When determiningwhether or not, and/or how, to use the information in this guide, all factors shall be considered with regard tothe specific situation(s).
1.2 Purpose
This guide presents inforation on the equipment needed and the methods that can be used when cleaningcontaminated insulators. The methods or equipment, or both, presented are not intended to prescribe specificprocedures, but to show the successful experience of many individuals who have safely cleaned contaminated insulators. The guide is intended to serve as a reference source for a company or persons seeking infor.mation on insulator cleaning procedures so that they may consider the experience of others in modifying orformulating insulator eleaning programs and practices
2.References
This guide shall be used in conjunction with the following publications:
IEEE Std 4-1995.IEEE Standard Techniques for High-Voltage Testing.
IEEE Std 516-1995, IEEE Guide for Maintenance Methods on Energized Power Lines.2
IEC 479-2 (1987), Effects of current on human beings and livestock, part 2: Special aspects. Chapter 4:Efects of alternating current with frequencies above 100 Hz. Chapter 5: Effects of special waveforms of cur-rent, Chapter 6: Effects of unidirectional single impulse currents of short duration.
3. Definitions
3.1 Terms
3.1.1 ceramic insulator: Insulators made from porcelain or glass or a general class of rigid material.
3.1.2 cubic meters per second (m-/s): Volume of water or liquid discharged per second under standardconditions.
3.1.3 equivalent salt-deposit density (ESDD): A measure of contamination level.
3.14 kilopascal (kPa): Metric unit for water or air pressure.
3.1.5 line worker: A person qualified to perform various work operations on electric transmission or distri-bution. including on the ground or from aerial devices.
3.1.6 nonceramic insulator: Insulators made from polymer materials.
3.1.7 nonconducting: Made of a material of high dielectric strength.
3.1.8 nonconductive: See: nonconducting
3.1.9 overspray: A portion of the water stream that is unintentionally directed away from the device beingwashed.
3.1.10 polyplastic: A synonym for polyethylene-coated, nylon-reinforced hose, usually considered to benonconductive. (In terms of this guide, the hose is used to carry water.)
3.1.11 skiving: 1) The process of assembling a fitting to a hose. 2) The process of trimming outside of a hoseto fit the inside dimensions of a fitting.
3.1.12 system voltage: Phase-to-phase voltage of the circuit(s). When phase-to-ground voltage is the inten.
tion, it should be so noted.
3.1.13 water resistivity: Resistance of water is expressed in cm or Qin.
3.2 Acronyms and symbols
3.2.1 ESDD: Acronym for equivalent salt-deposit density. See also: 3.1.3.
3.22 gal/min: Symbol for gallons per minute
3.2.3 gal/s: Symbol for gallons per second
3.24 id: Acronym for inside diameter
3.2.5 kPa: Symbol for kilopascals. See also: 3.1.4.
IEEE 957-1995 pdf download
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