What problems should be paid attention to in measuring absorption ratio polarization index

Conditions for measuring the absorption ratio

The absorption ratio and polarization index of the transformer with the voltage class of 10kv and the capacity of the distribution network transformer below 4000kvA can not be measured.

When the transformer voltage level is 220kv or above and the capacity is above 120MVA, the 5000V insulation resistance tester should be used to measure the absorption ratio. The absorption ratio should not be less than 1.5 at room temperature. When the insulation resistance value is greater than 10000MΩ at R60min, the polarization index is not required.

                                   GD3126A (GD3126B) Insulation Resistance Tester 5kV/10TΩ (10kV/20TΩ)

The following problems should be paid attention to in measuring the absorption ratio polarization index

(1) Each measurement should choose the same voltage level insulation resistance tester, different manufacturers have no impact;

(2) During measurement, the high voltage output line should be selected as a special high voltage shielding line, and the output line L and N can not be exchanged, the test line should not be wound and suspended as far as possible;

(3) To prevent the residual charge from affecting the test results, the tested substance should be fully discharged before the test;

(4) Before the test, remove the test wire, wipe the test joint clean and make sure that the ground is reliable;

(5) To prevent the influence of surface leakage current as far as possible in the air humidity is small test, when necessary to connect the shield ring;

The above are the problems that should be paid attention to when measuring the absorption ratio polarization index. It is necessary to pay attention to the selection of voltage for the power equipment. It should be in accordance with the test specifications.