Power Transformers
-
Technical committeeTypeAcronymIEC 60076-8CommitteePublished year1997Description
Provides information to users about certain fundamental service characteristics of different transformer connections and magnetic circuit designs; system fault currents; parallel operation of transformers, calculation of voltage drop or rise under load; selection of rated quantities and tapping quantities; application of transformers of conventional design to convertor loading; measuring techniques etc.... Cancels and replaces IEC 60606
-
Technical committeeTypeAcronymIEC 60076-7CommitteePublished year2005Description
IEC 60076-7:2018 RLV contains both the official IEC International Standard and its Redline version. The Redline version is available in English only and provides you with a quick and easy way to compare all the changes between the official IEC Standard and its previous edition.
IEC 60076-7:2018 is applicable to mineral-oil-immersed transformers. It describes the effect of operation under various ambient temperatures and load conditions on transformer life. This document provides guidance for the specification and loading of power transformers from the point of view of operating temperatures and thermal ageing. It provides recommendations for loading above the nameplate rating and guidance for the planner to choose appropriate rated quantities and loading conditions for new installations. This edition includes the following significant technical changes with respect to the previous edition:
a) title has been updated from "oil-immersed power transformers" to "mineral-oil-immersed transformers";
b) insulation life is updated by considering latest research findings;
c) temperature limits have been reviewed and maximum core temperature is recommended;
d) number of fibre optic sensors is recommended for temperature rise test;
e) Q, S and H factors are considered;
f) thermal models are revised and rewritten in generally applicable mathematical form;
g) geomagnetic induced currents are briefly discussed and corresponding temperature limits are suggested;
h) extensive literature review has been performed and a number of references added to bibliography. -
Technical committeeTypeAcronymIEC 60076-6:2007CommitteePublished year2007KeywordsDescription
Applies to the following types of reactors: shunt reactors; series reactors including current-limiting reactors, neutral-earthing reactors, power flow control reactors, motor starting reactors, arc-furnace series reactors; filter (tuning) reactors; capacitor damping reactors; capacitor discharge reactors; earthing transformers (neutral couplers); arc-suppression reactors; smoothing reactors for HVDC and industrial application.
Technology -
Technical committeeTypeAcronymIEC 60076-6CommitteePublished year2007Description
Applies to the following types of reactors: shunt reactors; series reactors including current-limiting reactors, neutral-earthing reactors, power flow control reactors, motor starting reactors, arc-furnace series reactors; filter (tuning) reactors; capacitor damping reactors; capacitor discharge reactors; earthing transformers (neutral couplers); arc-suppression reactors; smoothing reactors for HVDC and industrial application.
-
Technical committeeTypeAcronymIEC 60076-5CommitteePublished year2006Description
Identifies the requirements for power transformers to sustain without damage the effects of overcurrents originated by external short circuits. Describes the calculation procedures used to demonstrate the thermal ability of a power transformer to withstand such overcurrents and both the special test and the theoretical evaluation method used to demonstrate the ability to withstand the relevant dynamic effects.
-
Technical committeeTypeAcronymIEC 60076-4CommitteePublished year2002Description
Gives guidance and explanatory comments on the existing procedures for lightning and switching impulse testing of power transformers to supplement the requirements of IEC 60076-3. Also generally applicable to the testing of reactors (see IEC 60289), modifications to power transformer procedures being indicated where required. Information is given on waveshapes, test circuits including test connections, earthing practices, failure detection methods, test procedures, measuring techniques and interpretation of results.
-
Technical committeeTypeAcronymIEC 60076-3CommitteePublished year2013Description
IEC 60076-3:2013+A1:2018 specifies the insulation requirements and the corresponding insulation tests with reference to specific windings and their terminals. This International Standard applies to power transformers as defined by IEC 60076-1. It also recommends external clearances in air. It gives details of the applicable dielectric tests and minimum dielectric test levels. Recommended minimum external clearances in air between live parts and between live parts and earth are given for use when these clearances are not specified by the purchaser. For categories of power transformers and reactors which have their own IEC standards, this standard is applicable only to the extent in which it is specifically called up by cross reference in the other standards. This third edition of IEC 60076-3 cancels and replaces the second edition published in 2000, and constitutes a technical revision. The main changes from the previous edition are as follows:
- Three categories of transformer are clearly identified together with the relevant test requirements, these are summarised in Table 1.
- Switching impulse levels are defined for values of Um > 72,5 kV.
- The procedure for Induced voltage tests with PD has been revised to ensure adequate phase to phase test voltages.
- The AC withstand test has been redefined (LTAC instead of ACSD).
- Induced voltage tests are now based on Ur rather than Um. - New requirements for impulse waveshape (k factor) have been introduced.
- Tables of test levels have been merged and aligned with IEC 60071-1:2010.
- Additional test levels have been introduced for Um > 800 kV.
- A new Annex E has been introduced, which sets out the principles used in assigning the tests, test levels and clearances in air. This consolidated version consists of the third edition (2013) and its amendment 1 (2018). Therefore, no need to order amendment in addition to this publication. -
Technical committeeTypeAcronymIEC 60076-24CommitteePublished year2020Description
IEC 60076-24:2020 applies to medium power transformers from 25 kVA up to 3 150 kVA with highest voltage for equipment up to 36 kV, or in low voltage (LV) networks with highest voltage for equipment of up to 1,1 kV equipped with voltage regulating devices. Voltage regulating distribution transformers are transformers equipped with components to control primary or secondary voltage for on-load voltage regulation purposes. The main objective of the installation of a VRDT is to regulate the LV network voltage level (i.e. 400 V), to avoid violation of the limits defined by relevant standards or regulations. The VRDT must operate properly as a step down and step up transformer. Transformers covered by this document comply with the relevant requirements set out in IEC 60076 (all parts) and, unless otherwise stated in this document, they also comply with European Standards EN 50160 and EN 50588-1.
-
Technical committeeTypeAcronymIEC 60076-22-7CommitteePublished year2020Description
IEC 60076-22-7:2020 applies to a selection of accessories and fittings mounted on liquid immersed power transformers according to IEC 60076-1 and reactors according to IEC 600766 with or without conservator for indoor or outdoor installation. It outlines the service conditions and the mechanical requirements that are common to all the accessories and fittings. This document also outlines the operation requirements specific to each device as well as the preferred dimensions relevant for interchangeability and the type and routine test to be performed.This document covers an exhaustive selection of the accessories and fittings that are currently used on transformers or reactors.
-
Technical committeeTypeAcronymIEC 60076-22-6CommitteePublished year2021Description
IEC 60076-22-6:2021 covers the electric fans used in the cooling circuits of power transformers and reactors. It applies to electric fans mounted on liquid immersed power transformers according to IEC 60076-1 and reactors according to IEC 60076-6 with and without conservator for indoor or outdoor installation. It outlines the service conditions and the mechanical and electrical requirements that are common to all the equipment.
The electric fans concerned by this document are of the axially operating type and are for use on liquid to air coolers and for blowing out radiators.
This document also outlines the operation requirements specific to each equipment as well as the preferred dimensions relevant for interchangeability and uniform fan assembly and the type and routine tests to be performed.