EN IEC 60230-2018 pdf free.Impulse tests on cables and their accessories.
lf not specified in the reference lEC product standards, the following conditions shall bemaintained:
lf the test object is not intended to include any other accessory, the length of the sample taken shall be such that the length of free cable between the terminations is at least 5 m.Where one joint is included in the test object, the minimum length of free cable,betweenthe joint and terminations shall be 5 m. Where more than one joint is included, the samerequirement shall be observed and in addition there shall be a minimum length of 3 m offree cable between successive joints.
5 State of the test object to be subjected to the test
The test object shall be maintained under the following conditions.. Pressure conditions, if any:
For gas-pressure and oil-filled cables, the pressure shall be adjusted in accordance withthe relevant lEC standard.
Temperature conditions:
The temperature conditions and the method of temperature measurement shall be asdescribed in the relevant lEC standard,but other methods of temperature measurementmay be used by agreement between the purchaser and the manufacturer.
6 Lightning impulse voltage
The peak voltage level of the lightning impulse is specified in the relevant product standard orcontractual agreements.The lightning impulse voltage to be applied shall be a standardlightning-impulse voltage as specified in lEC 60060-1 with the exception that the front time T,shall be between 1 us and 5 us.
7 Switching impulse voltage
The peak voltage level of the switching impulse is specified in the relevant product standard.
The switching impulse voltage to be applied shall be a standard switching impulse voltage asspecified in lEC 6o060-1.
8 superimposed impulse voltage test
8.1 General
The superimposed impulse voltage test shall be carried out on HVDC cable systems. Thepeak voltage level of the switching impulse is specified in the relevant product standard.
When a superimposed impulse voltage test is required,Clause 8 shall be applied in additionto the other clauses of this document.
8.2Test 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.
8.3Time parameters
The time parameters shall meet the requirements of Clause 6 or Clause 7 and shall bedetermined with the DC voltage source set to zero output or disconnected,i.e. withoutenergizing 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 changesto the test setup other than connecting the DC voltage source and removing the short-circuitacross the spark gap.
The time parameters are to be determined in this way because a base level around 0 kV isrequired by lEC 60060-1.
8.4Application of the Dc voltage
Before the impulses are applied to the test object,if required, the test object shall beenergized by a DC voltage with a level and duration and polarity as specified in the productstandard.
The application of the impulses is given in Clause 10.
Measuring system
The preferred method to measure the impulse voltage is by using an approved measuringsystem according to lEC 60060-2.
Alternatively,the method described in Annex B may be used at the discretion of themanufacturer.
10 Application of the impulses
Both ends of the test object shall be connected to the impulse generator (via the spark gap orblocking capacitor in the case of a superimposed impulse test).
For an impulse test, the test object shall be subjected to a series of 10 positive impulses and10 negative impulses at the voltage and shape as specified.For a superimposed impulse testthe polarity, method of application of impulses and rest periods between DC polarity changesshall be as given in the relevant product standard.
As a means of conditioning the test object when using an approved measuring system, eachseries of 10 impulses may be preceded by one or more impulses of the same polarity at alevel 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, ineach 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.EN IEC 60230 pdf download.