BS EN IEC 60230:2018 pdf free download Impulse tests on cables and their accessories
8.2 Test setup
Some possibilities are given to apply an impulse voltage to a test object which is at the same time energized by a DC voltage; Annex C illustrates the possible superimposed impulse test circuit arrangements.
8.3 Time parameters
The time parameters shall meet the requirements of Clause 6 or Clause 7 and shall be determined with the DC voltage source set to zero output or disconnected, i.e. without energizing the test object by a DC voltage and with the spark gap (as applicable) short-circuited. Once the time parameters have been determined, there shall be no changes to the test setup other than connecting the DC voltage source and removing the short-circuit across the spark gap
The time parameters are to be determined in this way because a base level around 0 kV is required by IEC 60060-1 .
8.4 Application of the DC voltage
Before the impulses are applied to the test object, if required, the test object shall be energized by a DC voltage with a level and duration and polarity as specified in the product standard.
The application of the impulses is given in Clause 1 0.
9 Measuring system
The preferred method to measure the impulse voltage is by using an approved measuring system according to IEC 60060-2.
Alternatively, the method described in Annex B may be used at the discretion of the manufacturer.
10 Application of the impulses
Both ends of the test object shall be connected to the impulse generator (via the spark gap or blocking capacitor in the case of a superimposed impulse test).
For an impulse test, the test object shall be subjected to a series of 1 0 positive impulses and 1 0 negative impulses at the voltage and shape as specified. For a superimposed impulse test the polarity, method of application of impulses and rest periods between DC polarity changes shall be as given in the relevant product standard.
As a means of conditioning the test object when using an approved measuring system, each series of 1 0 impulses may be preceded by one or more impulses of the same polarity at a level of approximately 50 %, 65 % and 80 % of the voltage and shape specified.
At least the first and tenth impulses at the voltage and shape specified shall be recorded, in each series.
The impulses at the lower level may be recorded.
The ambient temperature, the cable temperature and, where applicable, the gas or oil pressure shall be recorded.
When, for research purposes, lightning-impulse tests to levels above the withstand level are made, the procedure according to Annex A is recommended.
BS EN IEC 60230:2018 pdf free download
