浪涌保护器 - 第5部分：选择和应用建议 - 第1节：总则

6.1.6.1.2 Resistive leakage current

There is no evidence that the capacitive current would change significantly due to deterioration of the voltage-current characteristic of the non-linear metal-oxide resistors. Therefore, it is unlikely that measurements of capacitive current can reliably indicate the condition of metal-oxide arresters.

At given values of voltage and temperature, the resistive component of the leakage current is a sensitive indicator of changes in the voltage-current characteristic of non-linear metal-oxide resistors. The resistive current can, therefore, be used as a tool for diagnostic indication of changes in the condition of metal-oxide arresters in service. Typical resistive and capacitive voltage-current characteristics for a.c. voltages are shown in figure 5. For comparison, typical characteristics for d.c. voltages are also shown in figure 5.

Figure 5 – Typical voltage-current characteristics for non-linear metal-oxide resistors

The resistive component under a.c. voltage is defined as the current level at the instant of voltage maximum (dU/dt = 0), as indicated in figure 3. The resistive leakage current of a non-linear metal-oxide resistor is in the order of 5 % to 20 % of the capacitive current under normal operating conditions, corresponding to about 10 µA to 600 µA peak resistive current at a temperature of +20 °C.

In the leakage current region, the resistive current depends on the voltage and temperature. Typical values of voltage and temperature dependencies under a.c. voltage are indicated in figures 6 and 7, normalized to Uc and at +20 °C, respectively.

6

2 Scope

2

NORME INTERNATIONALE INTERNATIONAL STANDARD МЕЖДУНАРОДНЫЙ СТАНДАРТ

NORME INTERNATIONALE INTERNATIONAL STANDARD МЕЖДУНАРОДНЫЙ СТАНДАРТ

CEI IEC 50(426) Première édition First edition 1990-10 Vocabulaire Electrotechnique International Chapitre 426 : Matériel électrique pour atmosphères explosives International Electrotechnical Vocabulary Chapter 426 : Electrical apparatus for explosive atmospheres Международный Электротехнический Словарь Глава 426 : Электрооборудование для взрывоопасных сред © CEI 1990 Droits de reproduction réservés - Copyright - all rights reserved - Право издания охраняется законом Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l'éditeur. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. Запрещается Без письменного разрешения издателя воспроизведение или копирование этой публикации или ее части в любой форме или любыми средствами — электронными или механическими, включая фотоконю и микрофильм. Bureau central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève Suisse Commission Electrotechnique Internationale International Electrotechnical Commission Международная Электротехническая Комиссия Code prix Price code Код цены S Pour prix, voir catalogue en vigueur For price, see current catalogue Цена указана в действующем каталоге 3

50(715) © IEC:1996

CONTENTS

FOREWORD	VII
PREFACE	VII
Sections
715-01	Basic terms	1
715-02	Resources	10
715-03	Calls	17
715-04	Times and delays	22
715-05	Traffic	24
715-06	Circuit groups	32
715-07	Traffic engineering	34
715-08	Networks	41
715-09	Circuit switched networks	46
715-10	Message switched networks	51
715-11	Packet switched networks	52
Index	53

:current

Foreword

This document (EN 10216-3:2002) has been prepared by Technical Committee EC/TC 29, "Steel tubes and fittings for steel tubes", the secretariat of which is held by UNI.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2002, and conflicting national standards shall be withdrawn at the latest by November 2002.

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s).

For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document.

Other Parts of EN 10216 are:

Part 1:	Non-alloy steel tubes with specified room temperature properties
Part 2:	Non-alloy and alloy steel tubes with specified elevated temperature properties
Part 4:	Non-alloy and alloy steel tubes with specified low temperature properties
Part 5:	Stainless steel tubes

Another European Standard series covering tubes for pressure purposes is:

EN 10217:

Welded steel tubes for pressure purposes

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

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1 Scope

This Part of EN 10216 specifies the technical delivery conditions in two test categories for seamless tubes of circular cross section, made of weldable alloyed fine grained steel.

2 Normative references

This European Standard incorporates by date or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For date references, subsequent amendments to or revisions of, any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).

The requirements of this European Standard rule when they differ from those in the standards and documents referred to below:

EN 10002-1, Metallic materials - Tensile testing - Part 1: Method of test (at ambient temperature).

EN 10002-5, Metallic materials - Tensile testing - Part 5: Method of testing (at elevated temperature).

EN 10020, Definitions and classification of grades of steel.

EN 10021, General technical delivery requirements for steel and iron products.

EN 10045-1, Metallic materials - Charpy impact test - Part 1: Test method.

EN 10052, Vocabulary of heat treatment terms for ferrous products.

EN 10204, Metallic products - Types of inspection documents.

EN 10027-1, Designation systems for steels - Part 1: Steel names, principle symbols.

EN 10027-2, Designation systems for steels Part 2: Numerical systems.

ENV 10220, Seamless and welded steel tubes - Dimensions and masses per unit length

EN 10233, Metallic materials - Tubes - Flattening test.

EN 10234, Metallic materials - Tubes - Drift expanding test.

EN 10236, Metallic materials - Tubes - Ring expanding test.

EN 10237, Metallic materials - Tubes - Ring tensile test.

EN 10246-1, Non-Destructive Testing of steel tubes Part 1: Automatic electromagnetic testing of seamless and welded (except submerged arc welded) ferromagnetic steel tubes for verification of hydraulic leak-tightness.

EN 10246-5, Non-Destructive Testing of steel tubes - Part 5: Automatic full peripheral magnetic transducer/flux leakage testing of seamless and welded (except submerged arc-welded) ferromagnetic steel tubes for the detection of longitudinal imperfections.

EN 10246-6, Non-Destructive Testing of steel tubes - Part 6: Automatic full peripheral ultrasonic testing of seamless steel tubes for the detection of transverse imperfections.

EN 10246-7, Non-Destructive Testing of steel tubes - Part 7: Automatic full peripheral ultrasonic testing of seamless and welded (except submerged arc welded) steel tubes for the detection of longitudinal imperfections.

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