Testing
Following are several tests that can be performed to
determine if a recloser is operating properly. For a more
detailed explanation of testing procedures, refer to
Reference Data R280-90-2, Low Voltage AC Testing of
Hydraulic Recloser.
Minimum-trip-current test
To perform the minimum-trip-current test:
1. Connect a low-voltage variable-current source to the
recloser terminals as shown in Figure 1.
230 Vac
VARIABLE
AUTO TRANSFORMER
T1
SERIES
TRIP COIL
MAIN
CONTACT
RECLOSER
A AMMETER
CT
Figure 1 . Test-circuit diagram
otee:
N
Ratio and kVA rating of transformer T1 will depend
upon size of recloser trip coil. Short time rating
of T1 must be sufficient to accommodate load of
trip solenoid.
2. Close the recloser by moving the yellow operating
handle to CLOSE. Wait at least three minutes to make
sure the trip piston is completely reset.
3. Slowly raise the variable-autotransformer voltage from
zero, note the current needed to trip the recloser.
otee:
N
As the trip-solenoid plunger moves downward,
into the trip-coil, coil impedance will increase; the
increased coil impedance will cause current flow to
decrease. The maximum current reading, the peak
observed just before current begins to decrease, is
the minimum-trip current.
Insulation level withstand tests
High-potential withstand tests provide information on
the dielectric condition of the recloser. Perform the
high-pot test in a suitable test cage at 75% of the rated
low frequency withstand voltage (V4L 37.5 kV ac-rms,
V4E 45 kV ac-rms). Table 1 shows the dry, one minute,
60 Hz withstand voltage rating for each recloser. Test
reclosers at the applicable voltage for 60 seconds in each of
the following configurations:
CAUTION
Radiation . At voltages up to the specified test voltages,
the radiation emitted by the vacuum interrupter is
negligible . However, above these voltages, radiation
injurious to personnel can be emitted . See Service
Information S280-90-1, Vacuum Interrupter Withstand
Test Voltage Ratings Information, for further
information .
G109 .2
CAUTION
Equipment damage . Never operate a vacuum recloser with
a dc test source . The vacuum interrupters will be severely
damaged if a dc arc interruption is attempted .
T229 .1
TEST 1e:
Proceed as follows:
1. Manually close main contacts.
2. Ground recloser tank and head.
3. Apply test voltage to one bushing.
TEST 2e:
Proceed as follows:
1. Open main contacts.
2. Ground recloser tank, head, and one bushing.
3. Apply test voltage to opposite bushing.
4. Reverse connections and apply test voltage.
FAILURE MODESe:
The recloser has failed the test if any
one of the following occurs:
1. Breaker opens on high potential tester.
2. External arcing is seen (from bushing terminal to head
or terminal to terminal).
3. A sharp “
popping
” noise is heard (indicating an
internal failure).
TEST RESULTSe:
The high potential withstand tests provide
information on the dielectric condition of the recloser and
the integrity of the vacuum interrupter.
1. If the recloser fails the closed-contact test (Test 1), the
cause may be a diminished electrical clearance, low
oil dielectric strength, or failed insulation. Inspect the
recloser to identify and correct the problem. Repeat
the test.
2. Failure in either open contact test may be caused by
a deterioration of the vacuum interrupter. Replace
interrupter assembly and repeat test.
Types V4L and V4E single-phase maintenance instructions
5
MAINTENANCE INSTRUCTIONS
MN280055EN May 2017
