TOS93 Series User’s Manual 329
Appendix | Example of partial discharge test
Performing an alternative test
The test complying with EN50178 is inefficient because it must be performed manually. Here, we propose
an alternative test method. This method makes the criteria for passing more stringent, but for EUTs with
more than enough insulation performance, the test time can be reduced.
1
Estimate the start voltage by using a method described in “Performing tests”
(p.328) or the like.
2
Set the following test conditions.
For the procedure to set test conditions, see “Set test conditions” (p.108).
3
Press START.
The test starts.
4
After the test is complete, check that the discharge inception voltage is no more
than 90 % of the voltage applied during the test.
If the discharge inception voltage exceeds 90 % of the applied voltage, increase Test Voltage in
the test conditions by about 5 %, and perform the test again.
If step 4 is confirmed, and the judgment result is pass, the test is successful.
Test condition Setting
Test Voltage
Estimated start voltage × 1.15
Limit Voltage
The voltage determined in “Maximum application voltage” (p.326).
Voltage Pattern Ramp
Frequency 50 Hz
Upper Coulomb OFF
Upper Pulse Count OFF
Test Time 2 s
Rise Time 10 s
Fall Time 10 s
Range 100 pC
Inception Voltage 10 pC (≤ 100.0 pC)
Extinction Voltage 10 pC (≤ 100.0 pC)
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