IEC 61869-14 pdf free download
IEC 61869-14 pdf free download.Instrument transformers – Part 14: Additional requirements for current transformers for DC applications.
7.1 .3.1401 Sequence of type tests
The sequence of tests is not specified and may be agreed between the purchaser and the supplier.
Before starting the type test sequence, the following routine tests shall be performed:
• power-frequency voltage withstand test on primary terminals;
• partial discharge measurement.
NOTE The partial discharge measurement is generally performed together with the power-frequency voltage withstand test.
After the type test sequence, the current transformer shall be subjected to all routine tests detailed in 7.3.
The DC applied voltage test may be performed before the polarity reversal test. In this case, it does not need to be repeated after the type test sequence.
7.1 .3.1402 Sequence of routine tests
The sequence of tests is not specified, but the accuracy tests shall be performed after the dielectric tests.
7.2 Type tests
7.2.2 Temperature rise test
Subclause 7.2.2 of IEC 61869-6:2016 is applicable with the addition of 7.2.2.1401, 7.2.2.1402 and 7.2.2.1403.
7.2.2.1 401 Duration of test
Subclause 7.2.2.203 of IEC 61869-2:2012 is applicable.
7.2.2.1 402 Temperature and temperature rise
The purpose of the test is to determine the average temperature rise of the primary conductor, the secondary windings (if present), the primary and secondary converters and, for oil- immersed transformers, the temperature rise of the top oil, in steady-state conditions when the losses resulting from the specified service conditions are generated in the current transformer.
The average temperature of the secondary windings (if present) shall be determined by the resistance variation method.
Thermometers or thermocouples shall measure the temperature rise of parts other than the windings. The top-oil temperature shall be measured by sensors applied to the top of the metallic head directly in contact with the oil. The temperature rise shall be determined by the difference with respect to the ambient temperature.
7.2.2.1403 Test modalities
The current transformer shall be mounted in a manner representative of the mounting in service.
The current to be applied is the rated continuous thermal current ‘cth The test shall be continued until the steady-state temperature of the transformer has been reached in accordance with 7.2.2.1401.
The temperature rise test may be performed by applying only the long-time overload current up to the temperature stability state in accordance with 7.2.2.1401.
7.2.3 Impulse voltage withstand test on primary terminals
7.2.3.2 Lightning impulse voltage test on primary terminals
The subclause 7.2.3.2.1 of lEG 61869-1:2007 is applicable to current transformers having Urn equal to or above 20 kV.
7.2.3.3 Switching Impulse voltage test
The subclause 7.2.3.3 of lEG 61 869-1:2007 is applicable to current transformers having Urn equal to or above 100 kV.
7.2.4 Wet test for outdoor type transformers
The subclause 7.2.4 of IEC 61869-1:2007 is applicable with the following modifications:
For current transformers having Urn equal to or above 100 kV, the test shall be performed with switching impulse voltage test of both polarities, with the voltage corresponding to the insulation level.
For current transformers having Urn < 100 kV, the test shall be performed with power- frequency voltage defined in 7.3.1.
7.2.5 Electromagnetic compatibility (EM C) tests
7.2.5.1 RIV test
Subclause 7.2.5.1 of IEC 61869-1:2007 is applicable to current transformers having Urn equal to or above 100 kV, with the last three paragraphs replaced by the following ones:
The test shall be performed with AC power supply.
A pre-stress voltage of 1 ,25 x Urn / 2 shall be applied and maintained for 30 S.
The voltage shall then be decreased to 1,1 X Urn/ 2 in about 10 s and maintained at this value for 30 s before measuring the radio interference voltage.IEC 61869-14 pdf download.
