TEL TAVRIDA ELECTRIC VCB15 LD, User Manual

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7.1 Primary circuits
Under normal operating conditions (see Table 1) the ISM is maintenance free for a period of at least 30 years or
until it has reached the permissible number of operating cycles.
However when maintenance is carried out on the switchgear then the commissioning tests should be repeated.
Check that the ISM is disconnected from all voltage sources before inspecting its insulating parts. Test results should
be treated as given in Table 16.
Operation description Required tool Approximate timing
Check for damage, remove any dirt or con-
tamination
Dry napless cloth or a napless cloth
soaked in alcohol to clean the insulation
5 minutes
Bolts and torques shall be according to
Figure 35 - Figure 38
Torque wrench according to torque value 2 minutes
Protective earthing shall be according to
subchapter 4.1.8
Wrench if required 1 minute
ISM operation check
Perform close and open operation of the
ISM. Modules shall be operable.
Otherwise, check the control circuit. If ne-
cessary, change the failed module.
Visual check, no tool is required 1 minute
Primary circuits insulation check
1)
Observe safety precautions listed in the dan-
ger and warning advisories. Construct the
proper barrier and warning light system Equipment to provide safety in test area 10 minutes
Ground each pole not under test Wires 2 minutes
Apply slowly rising 100%
2)
of test voltage
3)
(50 or 60 Hz) across each pole for one minu-
te
4)
. (ISM is open)
Power frequency withstand voltage test
set
2 minutes
If the pole sustains the test voltage for
that period, its vacuum integrity has been
verified
5)
Power frequency withstand voltage test
set
-
Repeat actions above to check each pole of
the ISM Power frequency withstand voltage test
set, wires
8 minutes
Close the ISM. Ground each pole not under
test Wires 1 minute
Apply slowly rising 80% of test voltage 2) (50
or 60 Hz) between a primary conductor of
the pole and ground for one minute, repeat
test for each pole of ISM
Power frequency withstand voltage test
set
12 minutes
If no disruptive discharge occurs, the
insulation system is satisfactory Power frequency withstand voltage test
set
-
After the test, ground all main circuit
terminals to dissipate any static charge Wires 2 minutes
Table 16 - List of tests and check-ups of ISM during maintenance
1) This test includes not only the vacuum interrupter test, but also the other insulation components tested in
parallel with the interrupter. These include the support insulators and the insulated drive links, as well as the
insulating (tension) struts between the upper and lower vacuum interrupter supports. If these insulation
components are contaminated or defective, the test voltage will not be sustained. If so, clean or replace the
affected components, and retest.
2) For test of separate VCB - 100% level of test voltage, for test of Switchgear with installed VCB - 80% level of
test voltage accroding to IEC 62271-200.
3) Rated test voltage levels (Ud) are given in Table 1 above.
4) To apply test voltage the single-core short cables should be used. Application of high voltage coaxial cables is
strictly prohibited. To coordinate the surge impedance between the test set and ISM extra resistor as shown in
Figure 80 shall be used.
5) During testing of vacuum interrupter, self-fading restrikes may appear. In case of restrikes, reduce the voltage
slightly until the restrikes disappear (for 10-15 seconds) and then increase again.