HD 588.1 S1:1991

SLOVENSKI STANDARD
SIST HD 588.1 S1:1998
01-januar-1998
High-voltage test techniques - Part 1: General definitions and test requirements
(IEC 60060-1:1989 + corrigendum March 1990)

High-voltage test techniques -- Part 1: General definitions and test requirements

Techniques des essais à haute tension -- Partie 1: Définitions et prescriptions générales

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Figure 1 - Distance minimale D des objets sous tension ou A la terre A I'6lectrode

Characteristics related to disruptive discharge and test voltages ................... 17

4.4 Statistical characteristics of disruptive discharge voltages .................. 19

4.6 Assured disruptive discharge voltage of a test object ..................... 21

9.2 Traditional procedures for wet tests with alternating voltages ................ 31

11.3 Wet tests. tests under artificial pollution and combined tests ................. 39

11.4 Conflicting requirements for testing internal and external insulation ............ 41

15 Definitions for alternating voltage tests ................................. 51

Measurement of the test voltage and determination of impulse shape ............ 67

22.5 Measurement of test voltage and determination of impulse shape ..............

24.7 Total duration of a rectangular impulse current T. ....................... 83

25.4 Measurement of voltage during tests with impulse current .................. 85

Appendix A: Statistical Treatment of Test Results .............................. 91

A.2 Statistical Behaviour of Disruptive Discharge ............................. 93

B.2 Pre-deposition of pollution. coating and wetting procedure .....................

B.3.1 Surface conductivity of the insulating surface ........................ 107

B.3.2 Equivalent amount of sodium chloride per square centimetre of the insulating surface

Appendix C: Calibration of a Non-Approved Measurement Device with a Rodmod Gap ....... 111

The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on

which all the National Committees having a special interest therein are represented, express, as nearly as

They have the form of recommendations for international use and they are accepted by the National Committees

In order to promote international unification, the IEC expresses the wish that all National Committees should

adopt the text of the IEC recommendation for their national rules in so far as national conditions will permit.

Any divergence between the IEC recommendation and the corresponding national rules should. as far as

This standard has been prepared by IEC Technical Committee 42: High Voltage testing techniques .

Full information on the voting for the approval of this standard can be found in the Voting Report indicated

This standard is applicable only to tests on equipment having its highest voltage for equipment U, above

This standard is not intended to be used for electromagnetic compatibility tests on electric or electronic

- to describe methods for generation and measurement of test voltages and currents;

- to describe methods for the evaluation of test results and to indicate criteria for acceptance or

Definitions and requirements concerning approved measuring devices and checking methods are given in

Alternative test procedures may be required to obtain reproducible and significant results. The choice of

An impulse is an intentionally applied aperiodic transient voltage or current which usually rises rapidly

For special purposes, impulses having approximately linearly rising fronts or transients of oscillating or

The term "impulse" is to be distinguished from the term "surge" which refers to transients occurring in

A distinction is made between lightning and switching impulses on the basis of duration of the front.

Impulses with front duration up to 20 p are defined as lightning impulses and those with longer fronts

Generally, switching impulses are also characterized by total durations considerably longer than those of

In this standard, the term "disruptive discharge" (sometimes referred to as "electrical breakdown") relates

to phenomena associated with the failure of insulation under electrical stress, in which the discharge

completely bridges the insulation under test, reducing the voltage between the electrodes practically to

zero. It applies to electrical breakdown in solid, liquid and gaseous dielectrics and combinations of these.

Non-sustained disruptive discharge in which the test object is momentarily bridged by a spark or arc may

occur. During these events the voltage across the test object is momentarily reduced to zero or to a very

small value. Depending on the characteristics of the test circuit and the test object, a recovery of dielectric

strength may occur and may even permit the test voltage to reach a higher value. Such an event should

be interpreted as a disruptive discharge unless otherwise specified by the relevant Technical Committee.

Non-disruptive discharges such as those between intermediate electrodes or conductors may also occur

without reduction of the test voltage to zero. Such an event should not be interpreted as a disruptive

Some non-disruptive discharges are termed "partial discharges" and are dealt with in IEC Publication 270:

The term "sparkover" is used when a disruptive discharge occurs in a gaseous or liquid medium.

The term "flashover" is used when a disruptive discharge occurs over the surface of a dielecmc in a

The term "puncture" is used when a disruptive discharge occurs through a solid dielectric.

A disruptive discharge in a solid dielecmc produces permanent loss of dielecmc strength; in a liquid or

The characteristics of a test voltage are those characteristics specified in this standard for designating the

The prospective characteristics of a test voltage causing disruptive discharge are the characteristics which

would have been obtained if no disruptive discharge had occurred. When a prospective characteristic is

The actual characteristics of a test voltage are those which occur during the test at the terminals of the

The value of the test voltage is defined in the relevant Clauses of the present standard.

The disruptive discharge voltage of a test object is the value of the test voltage causing disruptive

discharge, as specified, for the various tests, in the relevant Clauses of the present standard.

Disruptive discharge voltages are subject to random variations and, usually, a number of observations must

be made in order to obtain a statistically significant value of the voltage. The test procedures, described

in the present standard, are generally based on statistical considerations. Information on the statistical

The disruptive discharge probability p of a test object is the probability that one application of a certain

prospective voltage value of a given shape will cause disruptive discharge in the test object. The parameter

The withstand probability q of a test object is the probability that one application of a certain prospective

voltage value of a given shape does not cause a disruptive discharge on the test object. If the disruptive

The 50% disruptive discharge voltage is the prospective voltage value which has a 50% probability of

The p% disruptive discharge voltage of a test object is the prospective voltage value which has p%

4.4.5 Conventional deviation z of the disruptive discharge voltage of a test object

The conventional deviation z of the disruptive discharge voltage of a test object is the difference between

its 50% and 16% disruptive discharge voltages. It is often expressed in per unit or percentage value,

NOTE - If the disruptive-discharge probability function (see Appendix A) is close to a Gaussian function, 2

The withstand voltage of a test object is a specified prospective voltage value which characterizes the

Unless otherwise specified, withstand voltages are referred to standard reference atmospheric conditions

The assured disruptive discharge voltage of a test object is a specified prospective voltage value which

Insulation systems of apparatus and high voltage structures must basically be classified into self-restoring

and non-self-restoring insulation and may consist of external and/or internal insulation.

External insulation is the air insulation and the exposed surfaces of solid insulation of the equipment,

which are subject both to dielectric stresses and to the effects of aunospheric and other external conditions

Internal insulation comprises the internal solid, liquid or gaseous elements of the insulation of equipment,

which are protected from the effects of atmospheric and other external conditions such as pollution,

Self-restoring insulation is the insulation which completely recovers its insulating properties after a

Non-self-restoring insulation is insulation which loses its insulating properties, or does not recover them

completely, after a disruptive discharge caused by the application of a test voltage.

NOTE - In high voltage apparatus, parts of both self-restoring and non-self-restoring insulation are always

operating in combination and some parts may be degraded by repeated or continued voltage applications. The

behaviour of the insulation in this respect shall be taken into account by the relevant Technical Committee when

The test procedures applicable to particular types of test objects, for example, the polarity to be used, the

preferred order if both polarities are to be used, the number of applications and the interval between

applications shall be specified by the relevant Technical Committee, having regard to such factors as:

- the random nature of the observed phenomenon and any polarity dependence of the measured

- the possibility of progressive deterioration with repeated voltage applications.

At the time of a test, the test object shall be complete in all essential details, and it should have been

The disruptive discharge characteristics of an object may he affected by its general arrangement (for

example, by its clearance from other live or grounded structures, its height above ground level and the

arrangement of its high voltage lead). The general arrangement should be specified by the relevant

A clearance to extraneous structures not less than 1.5 times the length of the shortest possible discharge

path on the test object usually makes such proximity effects negligible. In wet or pollution tests, or

wherever the voltage distribution along the test object and the electric field around its energized electrode

are sufficiently independent of external influences, smaller clearances may be acceptable, provided that

In the case of a.c. or positive switching impulse tests above 750 kV (peak) the influence of an extraneous

structure may be considered as negligible if its distance from the energized electrode is also not less than

the height of this electrode above the ground plane. A practical lower limit to this clearance is given in

A withstand test may be acceptable when successfully performed with shorter distances to earthed objects.

The test object shall be dry and clean. If not otherwise specified by the relevant Technical Committee, the

test should be made at ambient temperature and the procedure for voltage application shall be as specified

The preferred wet test procedure, described in 9.1, is intended to simulate the effect of natural rain on

external insulation and is a revision of earlier test methods. It is recommended for tests with all types of

test voltages and on all types of apparatus, but either of the alternative test methods given below are

Two earlier test methods, not intended to simulate natural rain, are described in 9.2. They have been in

use for many years for tests with alternating voltages on apparatus having U, up to 420 kV and many test

For a.c. apparatus of large dimensions, such as those having U, higher than 800 kV, no appropriate wet

The relevant Technical Committee shall specify the arrangement of the test object during the test proce-

The test object shall be sprayed with water of prescribed resistivity and temperature (see table 1) falling

on it as droplets (avoiding fog and mist) and directed so that the vertical and horizontal components of

the spray intensity are approximately equal. These intensities are measured with a divided collecting vessel

having openings of 100 cm2 to 750 cm2, one. horizontal and one vertical, the vertical opening facing the

The position of the test object relative to the vertical and horizontal rain components shall be specified