Buy BIS IS (R) SPECIFICATION FOR DRY-TYPE POWER TRANSFORMERS from SAI Global. Since dry-type power transformers are not made for such high voltages and ratings as oil-immersed transformers, a large portion of IS: * serves no purpose. pdf – Download as PDF File .pdf), Text File .txt) or read online. SPECIFICATION FOR DRY-TYPE POWER TRANSFORMERS Transformers Chairman.

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Part 3 Protective current transformers jfirst revision. Thegas in a gas-immersed transformer NOTEthroughout the range of transformer operations. Oblique strokes shall be used to separate the group of symbols for different cooling methods for the same piece of equipment.

IS (): Dry-Type Power Transformers

Cl Wave-shape of supply uoltage – A supply voltage shape is approximately sinusoidal. Letter symbols for use in connection shall be as given in Table 2. The provisions out by mutual 18 ; of acoustic sound level 19 ; and test Documents Flashcards Grammar checker. Trqnsformers is carried out as described in Appendix A of IS: Part 3 Insulation levels second revision.

All other transformers shall be identified by four symbols for each cooling method for which a rating is assigned by the manufacturer.

Dey number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

These ratings shall be such that the transformer can deliver its rated current tdansformers steady loading conditions without exceeding the limits of temperature-rise specified in Section 3, assuming that the applied voltage is equal to the rated voltage and that the supply is at rated frequency. For greater altitudes, see 3.

While such conditions may have transfrmers or no effect on a sealed, dry-type transformer, they may have serious effects on other kinds of dry-type txansfbrmer. For the purpose of determining when constant temperature conditions have been achieved, thermocouples, thermistors, RTDs or thermometers shall be applied to the following surfaces: Information on the gas, if required, to fill the drt g h 3 k 4 Method Indoor of cooling; or outdoor installation; Rated power in LVA ; Rated voltage for each winding ; State whether tappings are required, and circuit tap-changers transformres links are required; 20 if SO, whether off- 4 Highest voltage for equipment, U, for each winding ; P Insulation level, that is, values of test voltage at power frequency and, if required, lightning 1111 ,for which each winding is to be designed [see IS: Afo NOTE – necessary.


When the test frequency duration of the test shall be: NOTE – In view of the fact that the transtormers will be operated at two different taps the winding temperature-rise of two transformer may be slightly different. Where the excess temperature exceeds one of the values specified in 3. Thus, for convenience sake, this separate and concise standard has been prepared to set out specific requirements for drytype power transformers.

The test sequence per line terminal shall be one calibration impulse at a voltage between 50 and 75 percent of the full transforkers followed by three impulses at full voltage.

NOTE- When a trsnsformer has windings of different insulation system temt peratures class of insulationonly one reference temperature is, the one relating to the winding having the higher inrulation Part 4 Terminal markings, tappings and connections Jirst revision. NOTE – Insulating materials may be used separately or tranxformers a combination providing that, in any application, each system will not be continuously subjected to a temperature in excess of that for which it is suitable when operating under rated conditions.

Part 1 General requirements first revision. While interpreting transformerz results, appropriate corrections to the temperature-rise should be made in accordance with It may be performed on all kinds of dry-type transformers, but is especially applicable to transformers having encapsulated windings. By agreement between the manufacturer and the purchaser at the time of the enquiry, tests may be made with positive polarity, but in this case sudden changes of polarity have to be avoided.


By means of different voltage ratios or an injected voltage, the rated current is made to flow in the transformer under test. This test shall be repeated with another line terminal earthed. Introduction to Power Generation and Transmission.

NOTE – The cooling of a dry-type or forced circulation. Temperature tests are made by utilizing the rises obtained tests, one with no-load loss only, and one with load losses only, short-circuit run.

IS 11171 (1985): Dry-Type Power Transformers

Enclosed or non-enclosed non-encapsulated-winding dry-type transformers are normally designed for installation indoors in dry locations. Part tranxformers Temperature-rise 14 Jirst rctisioh. Any site conditions which may either impose restrictions on the cooling air or produce high ambient air temperatures should be stated by the ipurchaser.

Details of conditions, under which a licence for the use of the IS1 Certification Mark may be granted to manufacturers or processors, may be obtained from the Indian Standards Institution. In addition to high or low ambient temperature and high altitude, other environment conditions which may affect design and application can exist and are not necessarily covered by this standard. Part 2 Measuring current transformers jirst revision.

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