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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On theother hand, forexample, when atransformer is to becombined with previously existing units, it may be justified to specify and agree on narrower impedance tolerances. NOTE 2 The zero-sequence impedance is dependent upon thephysicaldisposition of the windings and the magnetic parts and measurements on different windings may not, therefore, agree. Variable flux voltage variation VFVV NOTE It is recognized that the most severeloading conditions for testvoltagesourceaccuracy are usually imposed by large single-phase transformers.
In measuring the cold resistance for the purpose of temperature-rise determination, special efforts shallbe made to determinetheaveragewindingtemperatureaccurately. I specialist marketing 13 1 unacceptable, other Atransformerwithatapped kV windinghavingaltogether21tappings, symmetrically 6006-1, is designated: Thetransformershallbecapable of carrying, in continuous service, the rated power for a multi-windingtransformer: The transformer shall be approximately at factory ambient temperature.
Particulars of the specifications to which the transformer shall comply. Matters of special tolerances shall be brought to attention at the tender stage, and revised tolerances agreed upon between manufacturer and purchaser. The rated power refers to continuous loading.
Forsuch transformers,thetappingparticularsaresubject to agreement. This may be done with the aid of a graph or irc table. NOTE This quantity may be expressed in relative, dimensionless form, as a fraction z of the reference impedance Zret,of the same winding of the pair. Index 2 Indicates conditions during measurement of load loss Instead of items c and dtabulation of the same type as used on the rating plate may be used to advantage see example in annex B.
If the delta winding is not taken out to three line terminals but only provided as a stabilizing winding, the 06076-1 would indicate this by a plus sign.
NOTE 2 The no-load current of a winding is often expressed as a percentage of the rated current of that winding. These may be factors such as high altitude, extreme high or lowtemperature,tropical humidity, seismicactivity, severe contamination, unusual voltage or load current wave shapes and intermittent loading.
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. Toobtainthis result more rapidly, the oil may be circulated by a pump. Direct current shall be used for 600761- measurement.
Wherea tolerance in one direction is omitted, there is no restriction on the value in that direction. Thereby,the series winding and the common winding together form one measuring circuit, and the common winding alone forms the other.
It bears the edition number 2. P Any peculiarities of installation, assembly, transport and handling. The test basis for all characteristics other than insulation is the rated condition, unless the test clause states otherwise.
Further windings, if existing, are open-circuited NOTE 1 Idc a two-winding transformer there is only one winding combination and one value of load loss. They are defined as follows: Enter the email address you signed up with and we’ll email you iiec reset link.
Also note the importance of current harmonics for load loss and temperature rise. Indoor or outdoor type.
IEC 1 Power transformers General | Duy Nguyen –
When the tapping factor deviates from unity, the tapping current for full-power tappings may riseaboveratedcurrentonone of the windings. Whether a stabilizing winding is required and, if so, the method of earthing.
NOTE 3 Thezero-sequence impedance may also beexpressed as a relative value inthe same ic as the positive sequence short-circuit impedance see 3. Tests shall be made at any ambient temperature between 10 “C and 40 “C and with cooling water if required at any temperature not exceeding 25 “C.
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Other tappings are identified by their tapping factors. The total loss for the selected tapping is the test power for determination of oiltemperatureriseduringthetemperaturerisetest, and thetapping current for that tapping is the reference current for determination of winding temperature rise above oil.
Whethertransformerswillbesubjectedtofrequentovercurrents,forexample,furnace transformers and traction feeding transformers. The 60076-11 winding lags the HV by “.
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Thebushings,tap-changersandotherauxiliaryequipmentshallbeselected so as not to restrict the loading capability of the transformer. The phase I phasor of the low-voltage winding is oriented according to the induced voltage relation which results for the connection ifc.
Terminal marking on the transformer follows national practice.