IEC IEEE 65700-19-03 pdf free download
IEC IEEE 65700-19-03 pdf free download.Bushings for DC application.
7 Test requirements
7.1 General requirements
The tests shall be made in accordance with Clause 7 of IEC 60137:2008 (Test requirements), except where described differently below. Where applicable, reference shall also be made to IEC 61378-2, IEC 61462 and to IEC 62155.
• Most of the dielectric routine and type tests can be carried out with the bushing axis at any inclination, regardless of its intended service angle where appropriate.
• The wet switching impulse voltage withstand test and the thermal, mechanical and special tests shall be carried out with the bushing mounted at its intended service angle, unless other arrangements have been agreed and if shown compatible and sufficient.
• DC tests on converter transformer and reactor bushings shall be carried out with external insulation (barriers) and ground planes surrounding the lower end of the bushing in a position as similar as possible to that of the intended service condition. The simulation of the insulation arrangement may be agreed between the manufacturer and the purchaser.
• In cases where a bushing is exposed to DC applied voltage withstand and Polarity Reversal tests and it is tested with a temporary insulating barrier system in oil, it is recommended that the conductivity and fibre content of the oil are recorded.
• DC tests on wall (roof) bushings shall be carried out with wall ground plane and mounting arrangements as similar as possible to that of the intended service condition.
• Except for mechanical tests, all tests shall be carried out with the bushing mounted on a supporting structure with their ends in the media of the type in which they are intended to operate.
7.2 Test Conditions
7.2.1 Air temperature
The ambient temperature at the time of test shall be between 10 °C and 40 °C.
7.2.2 HumIdity
The absolute humidity at the time of test shall be between I ,0 g/m3 and 15,0 g/m3.
7.2.3 CorrectIon factors
Correction factors shall be in accordance with IEC 60137:2008, Table 7. In addition the following may be applied
• DC voltage withstand test: correction factors k1 x k2.
• Polarity reversal test: no correction.
For cases where the maximum specified valve hail ambient air temperature exceeds 40 °C, test voltages shall be corrected for the high ambient temperature and specified minimum ambient air humidity. Equivalent “reference ambient air” test voltages shall be calculated by dividing test voltages by calculated k1 and/or k2 where applicable. Reference ambient air is considered to be 20°C, a relative humidity of 60% (hg/rn3) and atmospheric air pressure of 101,3 kPa. Test voltages shall be further corrected for differences between atmospheric conditions within the test bay and reference ambient air conditions.
7.3 Test classification
7.3.1 Type (or design) tests
Type tests are those made to determine the adequacy of the design of a particular type, style, or model of power apparatus bushing: to meet its assigned ratings, to operate satisfactorily under usual service conditions or under special conditions if specified, and to demonstrate compliance with appropriate standards of the industry.
Type tests are made only on representative bushings to substantiate the ratings assigned to all bushings of the same design. These tests are not intended to be made as a part of normal production. The applicable portions of these tests may also be used to evaluate modifications of a previous design and to assure that performance has not been adversely affected. Test data from previous designs may be used for current designs where appropriate. Once made, the tests need not be repeated unless the design is changed so as to modify performance.
During the type tests, the bushing will be stressed higher than usually encountered in service and must withstand these tests without evidence of partial or complete failure. Hidden damage that may occur during type testing can usually be detected by comparing initial and final values of capacitance, dissipation factor and partial discharge quantity.
Type tests are included in Table 2; applicability to particular bushing types is detailed in the relevant clause.IEC IEEE 65700-19-03 pdf download.
