چكيده به لاتين
In this thesis, an online insulation condition assessment will be studied based on aging of partial discharge source(i.e. cavity). Insulation condition assessment is important because of three reasons which is protection and maintenance of cable, prevention from wasting expense and unplanned downtime.
For insulation condition assessment, first an index is introduced that in all cases including change in supply voltage, change in length of cable, change in location, size and depth of cavity, change in temperature and different periods of aging cavity can be used. In fact, it has specifications including having identical values for different cavity location, showing concept of aging of PD source, corresponding relationship with increase of temperature and inversely with increase of depth(from conductor) and low sensitivity to number of pulses.
After specifing the index, an by employing it determination of decision making thresholds about insulation condition of cables based on partial discharge is done. Selected thresholds should have specifications for determining repair or replacement of cable and/or smaller periodic inspection, showing concept of aging and being constant with change of cavity location.
In sequel, rate of changes of the index is calculated and then, by introducing a method for determination of reference ratio, rules of decision making have been presented for inspection and maintenance operations.
Keywords : High voltage cables, Partial discharge, Aging, Insulation condition, Decision making thresholds
