IEC 60815: Guide for the selection and dimensioning of high-voltage
insulators for polluted conditions
Part 1 - : Definitions, information and general principles
Introduction from the Project Leader
What’s new ?
This draft takes into account the decisions taken at our Stockholm meeting.
It integrates the work submitted by RM on figure 2/Table 3.
It also integrates the work submitted by WV on definitions, figure 1, rapid
pollution, dust deposit gauges. Note that there is a suggested Figure 2b
showing the applicability of the approaches and the influence of simple profile
parameters.
I have left the schedule/content and orientation below so that we can keep
them in mind and update as necessary.
I have included both RS and WV ESDD/NSDD measurement procedures in
Annex B – we need to select the best from both.
Tasks, notes etc. arising from Renardières are outlined in yellow
Schedule
The following table shows the planned progress of the revision work. This schedule is based
on the availability of resources within Working Group 11 and an average of two meeting per
year. Since much of the content of the revision is based on the work of CIGRE TF 33.13.01,
the schedule also takes into account the project plans of this Task Force.
The dates are by no means fixed, since the progress of work on the successive parts of IEC
60815 will depend on the degree of acceptance of the first drafts of parts 1 and 2.
availability
Part Expected
May 2001
1st complete draft Part I (1CD) – Guide for the choice of insulators
under polluted conditions – Part 1: Definitions, information and
general principles
December 2001
1st complete draft Part II (1CD) – Part 2: Porcelain and glass
insulators systems
1st complete draft Part III (1CD) ) – Part 3: Polymer insulators for
April 2002
< systems
1st complete draft Part IV (1CD) ) – Part 4: Porcelain and glass
End 2002 ?
insulators systems
1st complete draft Part V (1CD) ) – Part 5: Polymer insulators for
End 2003 ?
< systems
Content and orientation
In addition to the strategy and layout given by the task in 36/157/RVN, the orientation of the work on the revision of IEC 60815 is also based largely on the following list of areas where IEC 815 was perceived to be weak by CIGRE [1]:
• Performance of polymeric insulators
• Insulator orientation
• Extension of applicability to voltages above 525
• Design application
• Insulators with semi-conducting glaze
• Surge arrester housing performance, particularly with reference to polymeric materials • Longitudinal breaks in interrupter equipment
• Radio interference, television interference, and audible noise of polluted insulators
• Effect of altitude
• Effect of heavy wetting
The revision of 60815 to take into account current experience, knowledge and practice related to polluted insulators in general, and specifically to include polymer insulators and to systems r
equires subdivision of the guide into the following five parts:
Part 1: Definitions, information and general principles
Part 2: Porcelain and glass insulators systems
Part 3: Polymer insulators systems
Part 4: Porcelain and glass insulators systems
Part 5: Polymer insulators systems
So far the work on parts 1 and 2 has concentrated on the elaboration of the requirements for evaluation and measurement of site severity along with study of the relative applicability of profile parameters to different insulators, materials and technologies.
In addition to the aforementioned aspects, the following major changes have been made or are foreseen:
• Encouragement of the use of site pollution severity measurements, preferably over at least a year, in
order to classify a site instead of the previous qualitative assessment; • Addition of the influence of non-soluble deposit density (NSDD) as a parameter of severity;
• Use of the results of natural and artificial pollution tests to help with dimensioning;
• Recognition that creepage length is not always the sole determining parameter;
• Recognition of the influence other geometry parameters (e.g. large or small diameters, non-linearity …).
IEC 60815: Guide for the selection and dimensioning of high-voltage
insulators for polluted conditions
Part 1 - : Definitions, information and general principles
1. Scope and object
This guide is applicable to the selection of insulators, and the determination of their relevant dimensions, to be used in high voltage systems with respect to pollution. For the purposes of this guide the insulators are divided into the following broad categories:
• Ceramic insulators systems;
• Polymeric insulators systems;
• Ceramic insulators systems;
• Polymeric insulators systems.
Ceramic insulators have an insulating part manufactured either of glass or porcelain, whereas polymeric insulators have an insulating body consisting of one or more organic materials. More precise definitions are given below.
This part of IEC 60815 gives general definitions and principles to arrive at an informed judgement on the probable behaviour of a given insulator in certain pollution environments. It also provides methods for the evaluation of pollution severity. The specific guidelines for each of the types of insulator mentioned above are given in the further parts of IEC 60815, as follows:
60815-2 - Ceramic insulators systems;
60815-3 - Polymeric insulators systems;
60815-4 - Ceramic insulators systems;
60815-5 - Polymeric insulators systems.
This structure is the same as that used in CIGRE 33.13 TF 01 documents [1, 2], which form a useful complement to this guide for those wishing to study the performance of insulators under pollution in greater depth.
This guide does not deal with the effects of snow or ice on polluted insulators. Although this subject is dealt with by CIGRE [3], current knowledge is very limited and practice is too diverse.
The aim of this guide is to give the user means to :
• Characterise the type and severity of the pollution at a site;
• Determine the nominal creepage distance for a "standard" insulator;
• Determine the corrections to the creepage distance to take into account the specific properties of the "candidate" insulators for the site, application and system type;
• Determine the relative advantages and disadvantages of the possible solutions;
• Asses the need and merits of "hybrid" solutions or palliative measures.
references
2. Normative
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 60507
IEC 61245
List to be updated
3. Definitions
For the purpose of this publication, the following definitions apply.
3.1. Line Post Insulator
A rigid insulator consisting of one or more pieces of insulating material permanently assembled with or without a metal base cap intended to be mounted rigidly on a supporting structure by means of a central stud or one or more bolts.
3.2. Cap and Pin (Disc) Insulator
An insulator comprising an insulating part having t he form of a disk or bell and fixing devices consisting of an outside cap and an inside pin attached axially.
3.3. Long Rod Insulator
An insulator comprising an insulating part having a cylindrical shank provided with sheds, and equipped at the ends with external or internal metal fittings.
3.4. Station Post Insulator
A rigid insulator consisting of one or more pieces of insulating material permanently assembled and equipped at the ends with external metal fittings intended to be mounted rigidly on a supporting structure by means of one or more bolts.
Insulator
3.5. Polymer
A polymer insulator is one made of at least two insulating parts, namely a shank and housing, and equipped with metal fittings. Polymer insulators can consist either of individual sheds mounted on the shank, with or without an intermediate sheath, or alternatively, of a housing directly moulded or cast in one or several pieces on the shank. Polymer insulators can be of the long rod, line post or station post type.
3.6. Insulator Shank (Ceramic Insulators)
The shank refers to the main body of the insulator and is designed to provide the required mechanical characteristics.
3.7. Insulator Shank (Polymer Insulators)
The shank is the internal insulating part of a polymer insulator and is designed to provide the required mechanical characteristics. It usually consists of continuous glass fibres which are positioned in a resin-based matrix in such a manner as to achieve maximum tensile strength. CE to combine
3.8. Sheds
The sheds are the projections from the shank of an insulator intended to increase the creepage distan
ce. Various typical types of shed and shed profiles are illustrated below.
characteriseNormal Shed Alternating Shed Under ribbed Shed Drawings of shed profiles to be updated, SN for ceramic posts/long rods/hollws, CL/KK for cap & pin, RM/FS for composites.
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