IEEE Std C57.13.5:2003 pdf free download

IEEE Std C57.13.5:2003 pdf free download.IEEE Standard of Performance and Test Requirements for Instrument Transformers of a Nominal System Voltage of 115 kV and Above.
a) No external disruptive discharge or collapse of voltage is observed, and
b) No internal insulation failure is found with the capacitance and dissipation factor measurement.
7.7 Partial discharge test
The pre-stress voltage shall be in accordance with Tablc 4.
At the discretion of the manufacturer, the power frequency voltage withstand and partial discharge test may be performed in accordance with 10.7.
The partial discharge test shall be performed within 30 minutes after the power frequency voltage withstand test, either in the same laboratory or in a different laboratory, as follows:
Before the test, the setup shall be calibrated for partial discharge measurement of 10 pU.
If necessary, external electrodes may be used for the primary terminal and the ground of the transformer. The test method shall be in accordance with llC 6027() (2000-12).
The pre-stress voltage shall be maintained in accordance with 4.1 .K. Subsequently the test voltage shall be reduced to the level of the prescribed extinction voltage which shall then be maintained for 60 ,t7 The partial discharge intensity shall be measured during this time.
If the intensity exceeds the limit of 10 pC after the 60-s duration, the test may be extended, at the manufacturer’s discretion, by up to 30 minutes at the prescribed extinction voltage level.
The test shall be terminated if the measured partial discharge intensity is less than or equal to 10 pC.
The transformer shall be considered as having met the requirements if the partial discharge intensity measured at the prescribed extinction voltage level is equal to or less than 10 pC.
7.8 Dissolved gas and water content analysis for oil-immersed transformers (of a nominal system voltage of 345 kV and above)
For oil-immersed transformers of a nominal system voltage of 345 kV and above, three days after the dielectric tests an oil sample shall be taken for dissolved gas and water content analysis.
The concentration of dissolved gas and water content shall be in accordance with the values provided in
Table 6. The oil sampling point shall be indicated in the test report.
NOTES
1—This standard recommends carrying out a dissolved gas and waler content analysis before the routine tests.
2—If the transftwmer is with a limited oil volume, the manufacturer should replenish the oil removed for the test before shipping thc transformcr.
7.9 Sealing test
The routine scaling test may be pertormed at any time at the convenience of the manufacturer.