1. Test Method
1) Breather separated from main body, body clean by Air.
2) Nitrogen(Dry air) through the transformer to the body's respiratory system piping at a pressure of 0.35kg/㎠ injection.
3) Pressurized leakage area and then left in place for 12 hours after the inspection.
4) Record the start of the test, the injection pressure and oil temperature(ambient temperature) will vary depending on the oil temperature and the pressure of nitrogen(N2).
5) If the leakage area in case of a fastening portion and gasket area and re-check the pressure(leaks) to restart the test. (In this case, the pressure holding time is restarted.)
The no load losses are the losses caused by energizing the transformer. These are constant losses, regardless of loading. This in effect tells you the efficiency of the transformer. (Power in) - (no load losses) = (Power out)
No. A megger's output voltage is not high enough to test the insulation of a high-voltage transformer if, by 'high-voltage transformer ', you mean a distribution transformer or power transformer. Instead, a high-voltage test set or 'pressure tester' (e.g. a 'HiPot' tester) must be used, as these produce far higher voltages.
The open/short-circuit test on a transformer isn't 'needed'. It's only used if you want to find out the efficiency of a transformer.
1st make sure the power is turned offDisconnect one lead on primary side of transformer and using an ohm meter check for continuity. You will probably get a low ohm reading if you get no reading the windings are broken and transformer is no good2nd test using ohm meter again check for winding to ground you should get no reading. If you get a ohm value the transformer is shorted to groundRepeat these tests on secondary sideWith power on and fuse removed with a voltage meter check for power on secondary sideIf it is okay turn off power and install fuseIf fuse blows again check for shorts in circuitRemember to be careful when power is turned on
A transformer this size will usually come with a test report which will give this information. Depending on the configuration, it may give zero seqence and positive sequence impedances.
Short circuit test and open circuit test are widely used to test the efficiency of the transformer.
These two tests are performed on a transformer to determine (i) equivalent circuit of transformer(ii)voltage regulation of transformer(iii) efficiency of transformer. The power required for theseOpen Circuit test and Short Circuit test on transformeris equal to the power loss occurring in the transformer.
why need dielectric test for transformer
The no load losses are the losses caused by energizing the transformer. These are constant losses, regardless of loading. This in effect tells you the efficiency of the transformer. (Power in) - (no load losses) = (Power out)
A no-load test is done with the normal supply connected in the way the transformer is intended to be used. It is also known as an open-circuit test to distinguish it from a short-circuit test, and its purpose is to measure the power loss in the iron core of the transformer and the no-load current drawn from the supply.
The short-circuit test runs the rated current through the windings of the transformer to measure the copper-loss, or power lost in the winding resistances. Because the transformer is run at low voltage for this test, there is very little additional power loss in the iron core of the transformer.
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A test done on a transformer. The voltage at the power frequency is ramped up to verify the transformer is capable of handling the stresses due to switching and natural phenomena (lighting strikes).Withstand Voltage:The voltage which has to be applied to a test object under specified conditions in a "withstand test" is called the "withstand voltage".
No. A megger's output voltage is not high enough to test the insulation of a high-voltage transformer if, by 'high-voltage transformer ', you mean a distribution transformer or power transformer. Instead, a high-voltage test set or 'pressure tester' (e.g. a 'HiPot' tester) must be used, as these produce far higher voltages.
A short-circuit test is done to determine the power lost in the resistance of the primary and secondary windings of the transformer. It is done at full load current but with only enough voltage to give the required current with the secondary short circuited. An open-circuit test is done at full load voltage but no current is taken from the secondary, and this enables the power lost in the magnetic core of the transformer to be measured. As well a power, the tests also allow the inductances to be measured as well as the resistances, in order ot characterise the transformer fully.
If, by 'upf', you mean 'unity power factor', then allwattmeters measure the in-phase component of the load current, so the term is quiet unnecessary.A short-circuit test is used to determine the (true) power loss in the transformer, which is exactly what a wattmeter measures
The point pressure leak test, also known as the Valsalva leak test