Table 1. - Bushing troubles
Trouble Possible Methods of
results detection
results detection
Cracked porcelain
Moisture enters.
Visual inspection.
Oil and/or gas
Power factor test.
leaks.
Hot collar test
Filler leaks out.
Deterioration of
Moisture enters,
Visual inspection.
cemented joints
Oil and/or gas
Power factor test.
leaks.
Hot collar test.
Filler leaks out.
Gasket leaks
Moisture enters.
Visual inspection.
Oil and/or gas
Power factor test.
leaks.
Hot collar test.
Filler leaks out.
Hot-wire test for
moisture.
Insulation resis-
tance.
moisture.
Insulation resis-
tance.
Moisture in
Moisture enters.
Power factor test,
insulation
Hot collar test.
Solder seal leak
Moisture enters.
Visual inspection.
Filler leaks out.
Power factor test.
Hot collar test.
Hot-wire test for
moisture.
Leak detector.
Hot collar test.
Hot-wire test for
moisture.
Leak detector.
Broken connection
Sparking in appa-
Power factor test.
between ground
ratus tank or
sleeve and flange
within bushing.
Discolored oil.
Discolored oil.
Voids in compound Internal corona.
Hot collar test.
Power factor tip-
up test.
Power factor tip-
up test.
Oil migration
Filler contamina-
Visual inspection.
tion.
Power factor test.
Hot collar test.
Hot collar test.
No oil
Oil leaks out.
Visual inspection,
Moisture enters.
Power factor test.
Hot collar test.
Hot collar test.
Displaced grading
Internal sparking
Hot collar test.
shield
discolors oil.
Electrical fiashover Cracked or bro-
Visual inspection.
ken porcelain.
Hot collar test.
Complete failure.
Lightning
Cracked or bro-
Visual inspection.
ken porcelain.
Test lightning
Complete failure.
arrestors.
(FIST 3-2 11/91) 2
Table 1. - Bushing troubles - Continued
Trouble
Possible
Methods of
results
detection
Corona
Internal break-
Power factor test
down.
Hot collar test.
Radio interfer-
Hot-wire test.
ence.
RRIV
Treeing along sur-
face of paper or
internal sur-
faces.
face of paper or
internal sur-
faces.
Short-circuited
Increased capaci-
Power factor test.
condenser sections
tance.
Voltage test at
Reduced voltage
capacitance tap.
at capacitance
Capacitance test.
tap terminal.
Adds internal
stress to insula-
tion.
Adds internal
stress to insula-
tion.
Darkened oil
Radio interfer-
Power factor test.
ence,
Hot collar test.
Poor test results.
following are minimum suggestions for safety
and are not intended to supersede safety prac-
tices established by individual regions or the
ROMSS.
and are not intended to supersede safety prac-
tices established by individual regions or the
ROMSS.
A. Handling. - When handling bushings,
care must be taken to be sure that rigging is
applied properly to prevent damage to the
bushing and/or to adjacent equipment and
personnel.
care must be taken to be sure that rigging is
applied properly to prevent damage to the
bushing and/or to adjacent equipment and
personnel.
Cracked or chipped porcelain produce sharp
edges which can result in severe cuts on the
hands and arms of personnel working around
them.
edges which can result in severe cuts on the
hands and arms of personnel working around
them.
B. Static Charges. - Static charges induced
by test potentials provide a source for serious
accidents through falls caused by reflex action,
High- static voltages may be encountered at
the bushings installed in apparatus during cold
weather and oil-handling operations. Protective
or safety grounds should be used to bleed off
static charges. High-static charges may also be
encountered at the bushing capacitance
by test potentials provide a source for serious
accidents through falls caused by reflex action,
High- static voltages may be encountered at
the bushings installed in apparatus during cold
weather and oil-handling operations. Protective
or safety grounds should be used to bleed off
static charges. High-static charges may also be
encountered at the bushing capacitance
taps if