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TESTING OF MODELS OF EXPLOSION PROTECTION SYSTEM FOR HIGHVOLTAGE OIL-FILLED ELECTRICAL EQUIPMENT

Leonid A. Darian ; CJSC “Technical inspection UES”, Russia
Vladimir P. Polistchook ; JIHT of RAS, Russia
Alexey V. Shurupov ; JIHT of RAS, Russia

Sažetak

Explosions of high voltage oil-filled electrical equipment (OFEE) lead to a significant material
damage. These explosions occur under action of an arc discharge (AD) which arises after internal short
circuit. Modernization of OFEE design and protection systems is the possible way to achieve significant
reduction of potential explosion and substantial reduction of material losses. Examination of perspective
explosion-proof OFEE designs and new explosion protection systems demands the effective test
methods. In present work results of development and application of an arcless source of pulse pressure
(ASPP) are described. In ASPP the testing impulse is produced by the jet of powder gases (JPG) which
arises at the combustion of explosive materials.
In this work results of experimental researches of AD in transformer oil (TO) at conditions typical for
AD initial stage have been presented: current rise time was 3-5 ms, the maximum arc current was up to 30
kA, AD burning time was 3-20 ms. The energy released in AD amounted to 0.1 MJ. It was established, that
electric field strength in AD column was about 0.2 kV/сm, gas producing factor in AD was 110 l/MJ, growth
rate of pressure in TO was about 0.3 MPa/ms. These results allowed to create an ASPP with demanded
parameters. Experiments proved that TO flow under action of AD and JPG are similar given that the same
influence duration of the energy released in AD is equalled enthalpy of JPG at liquid inlet.
In this work the transformer fracturing behavior after explosion has been analyzed; and the
requirements for protection systems have been formulated. By means of ASPP the breadboard model
tests of two well-known OFEE explosion protection methods were carried out. In the first method it is
assumed that the protection is reached due to fast dump of pressure inside of OFEE case when special
membranes are opened. In the second protection method it is offered to establish porous coverings on
internal surfaces of OFEE cases. Experiments were carried out on OFEE model with the characteristic
size of 1 m at action energy up to 1.5 MJ. It was shown, that these systems cannot protect the
transformer body from significant damages.
The dynamic protection system of transformer (DPS) has been described. The efficiency of this
new system using ASPP has been verified in experiments with autotransformer of 25 MW. It was shown
that DPS protects the transformer from considerable damages at least at dynamic impulse of about 3 MJ.

Ključne riječi

transformer explosion; arc discharge; dynamic pressure

Hrčak ID:

199228

URI

https://hrcak.srce.hr/199228

Datum izdavanja:

15.8.2017.

Posjeta: 620 *