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, ;.
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If more than one winding has such multiple connections, then the connections in each of the windings shall change between the tests, and the manufacturer shall determine the relative connections for each test. The sum of the no-load losses and the load losses.
When front-of-wave tests are also specified, the front-of-wave impulses should be inserted within the impulse test sequence as follows: See Boulduc, et al. All temperature-rise tests shall be made under normal or equivalent to normal conditions for the means of cooling, as follows: When unnecessary to protect the spheres from arc damage, it may be omitted.
Users of this standard are expressly advised that determination of the validity of any patent rights, and the risk of infringement of such rights, is entirely their own responsibility. The conversions are accomplished by Equation 1: The waveforms in both tests are compared with pre-established levels. The average shall be taken as the true temperature.
The reported final test data shall include the measured sound levels along with the corrections used in determining the final value s. Insulation resistance tests are commonly measured in megohms or may be calculated from measurements of applied voltage and leakage current.
Impedance voltage is usually expressed in per unit or in percent of the rated voltage of the winding across which the voltage is applied and measured. If reduced chopped-wave tests are performed, they should, by agreement between the manufacturer and the purchaser, be performed before and after the required chopped-wave tests. Included are methods for: These losses represent the losses of the connected instruments and voltage transformer, if used.
The tap connection that produces the sfd severe stress is determined by calculation and should be agreed upon between the manufacturer and the purchaser. NOTE 2—When the primary winding is connected to the supply, either one or both of the secondary windings, or either one or both of the common or tertiary windings for auto-transformers, may be short circuited for the test.
However, periodic dielectric tests are not recommended because of the severe stress imposed on the insulation. Other reduced front-of-waves, reduced chopped waves, or reduced full waves may be applied at any time during the iieee sequence. In all cases, the c57.21.90 induced test shall be for the connection with the highest test voltage.
Resistance measurements, polarity and phase-relation tests, ratio tests, no-load loss and excitation current measurements, impedance and load loss measurements, dielectric tests, temperature tests, short-circuit tests, audible sound level measurements, and calculated data are covered in this standard.
Those measuring devices may be, for example, current transformers, shunts, or Rogowski coils.
IEEE Standard C | legal definition of IEEE Standard C by
Therefore, the no-load loss test is conducted with rated voltage impressed across the transformer terminals, using a voltage source at a frequency equal to the rated frequency of the transformer under test, unless otherwise specified.
The virtual front time of the chopped wave may be different than the virtual front during a full-wave test because of the presence c57.12.09 the chopping gap. This ground on each winding may be made at a selected point of the winding itself or of the winding of a step-up transformer that is used to supply the voltage or that is connected for the purpose of furnishing the ground. The ambient sound shall be measured at a minimum of four locations, and the instruments shall be in conformance with For terminal-to-terminal measurements, the total resistance reported is the sum of the three measurements divided by two.
The test voltage is adjusted to the specified value as read by the average-responding voltmeter. A low-impedance shunt, consisting of a parallel combination of resistance and capacitance RCis employed.
The procedure for testing three-phase transformers is similar, except that all connections and measurements are three-phase instead of single-phase and a balanced three-phase source of power is used for the tests. The tap position of the windings of the same phase not being directly impulse tested shall follow the same basic rule described above and shall be set in order to obtain the maximum, minimum, and middle iere ratios, with one of these prescribed ratios for each of the individual phases.
Definition of IEEE Standard C57.12.90
It is permissible to shorten the time required for c75.12.90 test stc the use of initial overloads, restricted cooling, and so on. 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.
In case of class II transformers, for additional single-phase units greater than one or three unitsthe tap position shall be changed from one unit to the other, taking into account the requirements given above.