Odd Harmonics in the Current Circuit

The edition 2 of the IEC62052-11 has introduced two additional tests for odd harmonics. We all know from the previous releases the odd harmonic test with a phase fired waveform of 90°.

The harmonics distribution for this wave form looks like this:

harmonics-distribution-for-phase-fired-wave-form-90

Now additionally is mandatory a test with a phase fired waveform of 45° and a test with a 135° waveform. See graphics below or refer to section 9.4.2.4 of the standard.

Test criteria

Voltage circuits shall be energized with their highest specified nominal voltages.
The nominal currents have to follow the graphics. The IEC is not separating between I_b and I_n any more. To make it simple: I_b is now I_n.
So we use for this test the nominal current I_n.

The meter is Pass when the error measurement is within the limits given for its accuracy class and the load relay doesn't operate unexpected.
Of course always the original IEC62052-11 wording is valid. This is a summary for practical use.

Thank you for reading and share your thoughts with us.

Editor's note: This article was originally published in July 2020 and has been updated for comprehensiveness.