3 Park Avenue. New York, NY USA. IEEE Power and Energy Society. IEEE Std C™/Cor (Corrigendum to. The definition of constant k in Equation 2 (in ) and line terminal rated voltage in the last paragraph of are corrected in this corrigendum. Define IEEE Standard C means the IEEE Standard Test Code for Liquid – Immersed Distribution, Power, and Regulating Transformers, ;.
|Published (Last):||5 September 2015|
|PDF File Size:||5.51 Mb|
|ePub File Size:||9.31 Mb|
|Price:||Free* [*Free Regsitration Required]|
Line terminals, including ieew of autotransformers and regulating transformers, shall be either solidly grounded or grounded through a resistor with an ohmic value not in excess of the values given in Table 3.
The methods described in this standard are applicable to distribution and power ieed of present-day design that are immersed in an insulating liquid. The input or output terminals are shorted, and voltage at rated frequency is applied to the other terminals. Short the line terminals and neutral of winding 1.
Also, other excitation conditions may occur in service leading to lower, or higher, no-load audible sound levels. NOTE 1—The insulation resistance of electrical apparatus is of doubtful significance compared to the dielectric strength.
Definition of IEEE Standard C57.12.90
When a delta winding is present, the applied voltage should be such that the rated phase current of any delta winding is not exceeded. The post-set method does not demonstrate that the transformer would be able to withstand energizing the transformer on a short-circuit, i. The frequency spectrum of core sound consists primarily of the even harmonics of the power frequency; thus, for a 60 Hz power system, the main frequency components are,and Hz.
No-load losses include core loss, dielectric loss, conductor loss in the winding due to excitation current, and conductor loss due to circulating current in parallel windings. Automatic recording of the resistance data is recommended so that the time to saturation and the variability of the resistance readings after stabilization can be documented.
The following test sequence shall be performed: When choosing the test voltage, the possibility of over excitation and high inrush current shall be considered. Otherwise, the tests shall be repeated with other voltmeters.
IEEE Standard C | legal definition of IEEE Standard C by
The following alternatives exist: Radio-frequency chokes or tuned filters may be used to isolate the transformer under test and the partial-discharge-measuring circuit from the remainder of the test circuit, including its energy source.
When the transformer has taps, the turns ratio shall be determined for all taps and for the full winding. IEEE is a registered trademark in the U. A thermocouple is the preferred method of measuring surface temperature.
Implementers of IEEE Standards documents are responsible for determining and complying with all appropriate safety, security, environmental, health, and interference protection practices and all applicable laws and regulations. Only a range is proposed because the threshold operating level of the nonlinear devices is transformer design dependent. However, assembly of items that do not affect dielectric tests, such as radiators and cabinets, is not necessary.
For Categories I and II, calculate ISC using transformer impedance only; except for Category I, the symmetrical current magnitude shall not exceed the values listed in 7. When the measurements are made and the requirements of If corrections are required with apparent power factor or system phase error outside this range, the following exact formulas in Equation 11 apply: Correction of load loss measurement due to phase-angle errors in the wattmeters, voltage-measuring circuit, and current-measuring circuit shall be applied in accordance with Table 1 using the correction formula in Equation For three-phase transformers a three- phase supply is preferable, as long as the fault current requirements defined in IEEE Std C The dc source should be selected such that it can also provide sufficient current to keep the core saturated without causing excessive heating of windings.
Included are methods for: When other- than-rated winding current is used, the average liquid rise method shall be used to determine winding rises. Autotransformers and split-coil transformers require special precautions and it may be required to use the post-set method instead of the preferred pre-set method. After being held for the c57.1.90 specified in No-load losses also vary with temperature and are particularly sensitive to differences in waveform; therefore, no-load loss measurements will vary markedly with the waveform of the test voltage.
The ste of the no-load losses and the load losses. All values shall be included in the certified test report. The extent of the visual inspection shall be established sgd the basis of combined evidence obtained from the measurements described in Comments on standards should be submitted to the following address: C557.12.90 the current constant for 1 h. Typical phasor and zero-sequence impedance diagrams are shown in Figure 28 a and Figure 28 b. To verify that switching the bridge from phase to phase does not affect the result on the remaining phases and to demonstrate that the time involved in switching the bridge does not result in undue heating of the transformer windings during the test, the losses can be monitored for stable readings by wattmeters in all phases.