4 Conclusions
The methodology presented in this paper caused some
degradation in four non-ceramic apparatus aged in a saltfog
chamber. Different degradation types were observed
for each type of non-ceramic insulation. Tracking was
observed on the samples evaluated without pollutant layer
and/or with small arcing distance. In contrast, the samples
tested with pollutant layer developed erosion and
punctures on the surface. According to the obtained
results, it is theorised that damages in the insulation were
caused by surface discharges and/or corona activity as it
was observed with the corona camera. The worst
degradation was developed on the surge arrester with
pollutant layer, which was subjected to the highest activity
of surface discharges in the range from 120 to 260 mA, as
it was shown by the replica technique, but it did not
severely damage the insulation.
According to the replica technique, erosion was identified
on the insulating material of the surge arresters, and this
erosion was more severe on their sheaths.
The developed test allows the evaluation of the accelerated
ageing of different polymeric insulation materials and
profiles. The cycles considered in the test help to know the
effect of the hydrophobic property of the polymeric material
on the performance under wetting and pollution conditions.
The results show that a good hydrophobic property does not
always means a good performance to the ageing resistance,
but it also depends on the material composition. The
application of a pollutant layer on the insulation surface in
the beginning and in the middle of the test is an important
factor to ageing the insulating material. The pollutant layer
causes a high electric activity close to the insulation surface
which may age the insulation in a short time.
The hydrophobic property of the insulating surface can
decrease the degradation caused by the surface discharges
(dry bands) if it is maintained, as it happened with the SiR
surge arrester (sample 4). However, if the arcing distance is
not longer than 1 m, the electric field could damage the
insulating surface. Therefore the arcing distance must also
be selected accordingly to avoid that the electric field
strength magnitude be higher than values that may cause
surface degradation.
Non-ceramic components of breakers bushings and surge
arresters in service can suffer damage under heavily polluted
4 Conclusions
The methodology presented in this paper caused some
degradation in four non-ceramic apparatus aged in a saltfog
chamber. Different degradation types were observed
for each type of non-ceramic insulation. Tracking was
observed on the samples evaluated without pollutant layer
and/or with small arcing distance. In contrast, the samples
tested with pollutant layer developed erosion and
punctures on the surface. According to the obtained
results, it is theorised that damages in the insulation were
caused by surface discharges and/or corona activity as it
was observed with the corona camera. The worst
degradation was developed on the surge arrester with
pollutant layer, which was subjected to the highest activity
of surface discharges in the range from 120 to 260 mA, as
it was shown by the replica technique, but it did not
severely damage the insulation.
According to the replica technique, erosion was identified
on the insulating material of the surge arresters, and this
erosion was more severe on their sheaths.
The developed test allows the evaluation of the accelerated
ageing of different polymeric insulation materials and
profiles. The cycles considered in the test help to know the
effect of the hydrophobic property of the polymeric material
on the performance under wetting and pollution conditions.
The results show that a good hydrophobic property does not
always means a good performance to the ageing resistance,
but it also depends on the material composition. The
application of a pollutant layer on the insulation surface in
the beginning and in the middle of the test is an important
factor to ageing the insulating material. The pollutant layer
causes a high electric activity close to the insulation surface
which may age the insulation in a short time.
The hydrophobic property of the insulating surface can
decrease the degradation caused by the surface discharges
(dry bands) if it is maintained, as it happened with the SiR
surge arrester (sample 4). However, if the arcing distance is
not longer than 1 m, the electric field could damage the
insulating surface. Therefore the arcing distance must also
be selected accordingly to avoid that the electric field
strength magnitude be higher than values that may cause
surface degradation.
Non-ceramic components of breakers bushings and surge
arresters in service can suffer damage under heavily polluted
การแปล กรุณารอสักครู่..
4 Conclusions
The methodology presented in this paper caused some
degradation in four non-ceramic apparatus aged in a saltfog
chamber. Different degradation types were observed
for each type of non-ceramic insulation. Tracking was
observed on the samples evaluated without pollutant layer
and/or with small arcing distance. In contrast, the samples
tested with pollutant layer developed erosion and
punctures on the surface. According to the obtained
results, it is theorised that damages in the insulation were
caused by surface discharges and/or corona activity as it
was observed with the corona camera. The worst
degradation was developed on the surge arrester with
pollutant layer, which was subjected to the highest activity
of surface discharges in the range from 120 to 260 mA, as
it was shown by the replica technique, but it did not
severely damage the insulation.
According to the replica technique, erosion was identified
on the insulating material of the surge arresters, and this
erosion was more severe on their sheaths.
The developed test allows the evaluation of the accelerated
ageing of different polymeric insulation materials and
profiles. The cycles considered in the test help to know the
effect of the hydrophobic property of the polymeric material
on the performance under wetting and pollution conditions.
The results show that a good hydrophobic property does not
always means a good performance to the ageing resistance,
but it also depends on the material composition. The
application of a pollutant layer on the insulation surface in
the beginning and in the middle of the test is an important
factor to ageing the insulating material. The pollutant layer
causes a high electric activity close to the insulation surface
which may age the insulation in a short time.
The hydrophobic property of the insulating surface can
decrease the degradation caused by the surface discharges
(dry bands) if it is maintained, as it happened with the SiR
surge arrester (sample 4). However, if the arcing distance is
not longer than 1 m, the electric field could damage the
insulating surface. Therefore the arcing distance must also
be selected accordingly to avoid that the electric field
strength magnitude be higher than values that may cause
surface degradation.
Non-ceramic components of breakers bushings and surge
arresters in service can suffer damage under heavily polluted
การแปล กรุณารอสักครู่..