Transformer
bushings play a vital role in electrical power systems. They enable
high-voltage conductors to pass safely through the transformer's high-voltage
side and directly into its grounded tank. But the failure of the bushing can
cause costly power outages.
This makes it essential for the operators to understand the standard modes of
failure in transformer bushings. This blog will discuss the leading causes of
bushing failure and prevention measures.
Let us explore!
1. Moisture ingress and
insulation deterioration
Moisture can destroy
transformer bushings by slowly weakening them. Water or moisture can come into
contact with the insulation due to damage. This erodes the dielectric strength
and heightens the chances of partial discharges or flashovers.
Tips on how to stay one step ahead:
·
Inspect the seals regularly, especially after a temperature
swing.
·
Use only top-notch gaskets and sealants.
·
Fit an online moisture monitoring system to detect problems
early doors.
Keeping a tight seal on
moisture is crucial for maintaining insulation in good condition and preventing
nasty breakdowns inside.
2. Thermal overload and overheating
Bushings are under
constant barrage from electrical and mechanical stress, so it's only a matter
of time before excessive heat starts causing the insulation to break down and
increase the oil's temperature, resulting in that unsightly bulge or even tear.
Things to look out for to avoid a blow-up:
·
Keep an eye on transformer loading levels so you're not pushing
it too hard.
·
Sort out your oil circulation and cooling so it can do its job.
·
Check temperature readings and infrared thermography reports
regularly.
Thermal stress is bound
to set in at some point, but with some proactive management, you can limit the
damage & make sure it doesn't get out of control.
3. Partial discharges and electrical breakdown
Partial discharges (PDs)
happen when small areas of insulation break down because of gaps, cracks, or
dirt. If left alone, PDs weaken insulation until it fails.
Prevention Tips:
·
Tests for PDs often use sound or electrical detection tools.
·
Switch out old bushings before PD levels get too high.
·
Make sure the area around the transformer stays clean and free
of dust.
Keeping an eye on
partial discharge activity gives you a head start in stopping bushing failures.
4. Mechanical stress and vibration damage
Forces from
short-circuits, shaking during transport, or wrong setup can cause cracks,
misalignment, and loose bushing connections.
Prevention Tips:
·
Use tools to reduce shaking when moving and setting up.
·
Tighten connections as much as the maker says.
·
Check the physical condition.
Even small vibrations
can lead to significant failures if mechanical stresses are not controlled.
5. Ageing and material degradation
Like all
components, transformer bushings have a finite lifespan. Over
time, insulation paper becomes brittle, oil oxidizes, and the overall
dielectric performance declines.
Prevention Tips:
·
Follow manufacturer-recommended service life guidelines.
·
Conduct periodic Dissolved Gas Analysis (DGA) and insulation
resistance tests.
·
Plan timely replacements as part of preventive maintenance
schedules.
Replacing bushings
before they reach their end-of-life stage ensures consistent transformer
reliability.
Conclusion
Transformer
bushings, the small components, play a vital role in high-voltage
reliability. To control deteriorations, operators must know the usual failure
modes, like water getting in, overheating, mechanical stress, and wear and
tear. Monitor the system, perform regular maintenance, and replace parts when
needed to avoid such mishaps. This not only makes transformers last longer but
also keeps operations safe.
Are you looking to boost your transformer performance and reduce the failure
risk? Partner with Ador Powertron, a
trusted name for dependable power and transformer solutions. With decades of
experience, Ador delivers solutions for electrical systems to keep them safe,
productive, and built to meet international standards.
