This part of IEC applies to three-phase and single-phase power transformers (including auto-transformers) with the exception of certain categories of. NORME CE1 INTERNATIONALE IEC INTERNATIONAL STANDARD Edition Edition consolidée par l’amendement Edition . Buy IEC Ed. Power transformers Part 1: General from SAI Global.
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Whenathree-phasetransformer is tested,thevoltagesshall be measuredbetweenline terminals, if a delta-connected winding is energized, and between phase and neutral terminals if a YN or ZN connected winding is energized. Enter the exact number of the standard: This applied voltage is referred to as the short-circuit voltage [IEV of the pair of windings.
Direct current shall be used for the measurement. Theobject of theIECistopromote international co-operation on all questions concerning standardization in the electrical and electronic fields. Single or three-phase unit. In addition the short-circuit impedance values for the principal tapping and at least the extreme tappings shall be given, preferably in ohms per phase referred to a specific winding.
Skip to main content. Matters of special tolerances shall be brought to attention at the tender stage, and revised tolerances agreed upon between manufacturer and purchaser.
NOTE 3 Thezero-sequence impedance may also beexpressed as a relative value inthe same way as the positive sequence short-circuit impedance see 3. Any divergencebetweentheIECStandardandthecorrespondingnational or regionalstandardshallbeclearly indicated in the latter.
NOTE On multi-winding transformers, supplementary information will generally be required. Such a detailed specification should therefore not be issued without good reason. Iiec figure l a illustrates,thisappliesfor minus tappings, on the tapped winding, under CFVV, and for plus tappings on 60076-1 untapped winding underVFVV figurelb. See definitions of these terms below. Whether a generator transformer is to be connected to the generator directly or through switchgear, and 60076-1 it will be subjected to load rejection conditions.
General 1 Scope and service conditions 1. Diagrams,withterminalmarkings,andwithindication of built-in current transformers when used, may be presented on the rating plate together with the text information that is specified in clause 7. The second purpose normally requires the ‘maximum current tapping’ to be selected for the test.
06076-1 Measured values may deviate from guaranteed values within the tolerances according to clause 9, but shall not fall outside the boundaries, which are limits without tolerance. A temperature-rise type test, if specified, shall be carried out on one tapping only.
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In measuring the cold resistance for the purpose of temperature-rise determination, special efforts shallbe made to determinetheaveragewindingtemperatureaccurately.
The phasors are assumed to rotate in a iex sense [IEVmodified] NOTE The high-voltage jec is taken as reference,and the displacement for any otherwinding is conventionally expressed by the ‘clock notation’, that is, the hour indicated by the winding phasor when the H. Formulti-winding transformers, any impedances that are specified for particular pairs of windings together with relevant reference ratings if percentage values are given.
Example of specification of short-circuit impedance by boundaries If winding balancing ampere-turns are missing in the zero-sequence system, for example, in a star-star-connected transformer without delta winding, the applied voltage shall not exceed the phase-to-neutral voltage at normal operation.
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I made the wrong choice D I agent purchasing librarian D D other NOTE 6076-1 definition is not appropriate in relation to a series winding of a booster transformer see 3. Enter the email address you signed up with and we’ll email you a reset link. Thebushings,tap-changersandotherauxiliaryequipmentshallbeselected so as not to restrict the loading capability of the transformer. From this tapping onwards the tapping current values for the winding are then specified to be constant.
I Specified load current for loss determination rated current, tapping current, other specified value related to a particular loading case.
The temperature correction procedure is detailed in annex E. The LV winding lags the HV by “. A further winding in the transformer, usually with lower value of rated power than the secondary winding, is then often referred to as ‘tertiary winding’, see also definition 3.
Thesedeviationsshould be subject to agreement between themanufacturerand the purchaser. S Any special tests not referred to above which may be required. If different values of apparent power are assigned under different circumstances, for example, with different methods of cooling, the highest of these values is the rated power.
Totallosses for specifiedloadingcasesinvolvingall these windings are determined accordingly. The matters should preferably beraised at an earlystage and the agreementsincluded in thecontract specification. Dyn1 1 Example 2 A three-windingtransformer: