BS IEC IEEE 65700-19-03-2014 pdf free download – Bushings for DC application.
6.1 Electrical requirements
• Voltage withstand tests
• Partial discharge
• Dissipation factor and capacitance
• Bushing voltage tap. Capacitance graded bushings may be provided with a voltage tap.
This tap is normally intended for use as a voltage divider during normal operation and may require the use of additional capacitance to limit the output voltage and protective devices.
These additional components may be mounted directly to the bushing or in the transformer control cubicle.
• Bushing test tap. Capacitance graded bushings may be provided with a bushing test tap.
This tap is normally grounded and is intended for measurement of dissipation factor,capacitance from conductor to tap, and partial discharge. Since the capacitance from tap to ground is not controlled, the tap is not intended for use as a voltage divider during normal operation. Bushing test tap functionalities may be integrated in voltage tap.
• When not in use the voltage tap and test tap shall be effectively grounded throughout the life of the bushing
• Creepage distance
6.2 Mechanical requirements
• Dimensions
• Cantilever strength
• Internal pressure and vacuum
• Apparatus bushings shall be designed to withstand full vacuum when mounted in the apparatus tank
• Draw lead bushing cap pressure
The liquid or gas for internal insulation of the bushing shall comply with their relevant material standards:
• IEC 60376 for new SF 6 or IEC 60480 for used SF 6 .
• IEC 60296 for oil, or
• IEC 60836 or IEC 60867 for synthetic fluid.
6.3 Nameplate markings
The following information shall appear on all bushing nameplates:
• Manufacturer’s name, identification number, type, year of manufacture and serial number.
• Rated continuous DC voltage (for bushings for pure DC application, see 4.1 .1 ).
• Rated peak voltage (for bushings for combined voltage applications, see 4.1 .2).
• Rated continuous DC current, where applicable.
• Rated continuous AC current, where applicable.
• Dry lightning impulse voltage withstand.
• Dry/wet switching impulse voltage withstand or dry power-frequency voltage withstand.
• Capacitance, C 1 and C 2 , on all bushings equipped with voltage taps, and C 1 on all bushings equipped with test taps.
• Dissipation factor measured from conductor to tap, where applicable.
• Type of insulating gas, and minimum pressure, where applicable.
• Mass if greater than 1 00 kg.
• Maximum angle of mounting if exceeding 30° from vertical.
7 Test requirements
7.1 General requirements
The tests shall be made in accordance with Clause 7 of IEC 601 37:2008 (Test requirements), except where described differently below. Where applicable, reference shall also be made to IEC 61 378-2, IEC 61 462 and to IEC 621 55.
• 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.BS IEC IEEE 65700-19-03 pdf download.