An experimental study of air breakdown voltage and its effects on solid insulation

الملخص EN

Recent increasing in industrial and economic development in the present world, demands the use of more and more electrical energy which has to be transferred over long distances in large quantities efficiently.

This is made possible by introducing the higher transmission voltage level in the power system.

Rapid growing this demand for use of higher voltage has given the opportunity to power engineers to develop the insulation of high quality for sustain high voltage (HV) tress over a long period.

Presently, in high voltage electrical power system, variety of materials (solid, liquid and gaseous) is used for insulation purpose to protect the incipient failure in HV power equipment.

The insulation design for such HV power equipment is one of the important challenging tasks to the power engineers as the HV equipments are involved with huge cost.

To protect such equipments different types of conducting electrodes having protective gap are used widely throughout the world.

Standard sphere electrodes are commonly used for this purpose among those all electrodes configuration.

Normally, air medium is widely used as an insulating medium in different electrical power equipments as its breakdown strength is 30 kV / cm.

Therefore electrical breakdown characteristic of small air gap under the different applied voltage has its great significance for the designing of various air insulated HV equipment.

In this study to simulate the air breakdown voltage experimentally in high voltage laboratory, standard diameter of 25 cm spheres are used for measurement of air breakdown voltages at NTP.

In addition, the air breakdown voltage with insulation barrier and without insulation barrier is investigated inside the high voltage test laboratory.

The effects of the breakdown voltage on paper insulation have been investigated in this work for quality assessment.

The comparison of microstructure before and after the breakdown test reveals the information about the effects of electrical stress on the insulating paper.