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For equipment not mentioned in Annex C, emission tests shall be conducted with the user's operation controls or automatic programs set to the mode expected to produce the maximum total harmonic current (THC) under normal operating conditions. This defines the equipment set-up during emission tests and not a requirement to measure THC or to conduct searches for worst-case emissions.

The harmonic current limits specified in Clause 7 apply to line currents and not to currents in the neutral conductor. Nevertheless, for single-phase equipment, it is permissible to measure the currents in the neutral conductor instead of the currents in the line.

The equipment is tested as presented by, and in accordance with information provided by, the manufacturer. Preliminary operation of motor drives by the manufacturer may be needed before the tests are undertaken to ensure that results correspond with normal use.

The test shall be conducted according to the general requirements given in 6.2.3. The test duration shall be as defined in 6.2.4.

The measurement of harmonic currents shall be performed as follows:

• for each harmonic order, measure the 1,5 s smoothed r.m.s. harmonic current in each DFT time window as defined in Annex B;

• calculate the arithmetic average of the measured values from the DFT time windows, over the entire observation period as defined in 6.2.4.

The value of the input power to be used for the calculation of limits shall be determined as follows:

• measure the 1,5 s smoothed active input power in each DFT time window;

• determine the maximum of the measured values of power from the DFT time windows over the entire duration of the test.

NOTE The active input power supplied to the smoothing section of the measuring instrument as defined in Annex В is the active input power in each DFT time window.

The harmonic currents and the active input power shall be measured under the same test conditions but need not be measured simultaneously

.In order not to use a value of power at which limits change abruptly, thus giving rise to doubt as to which limits apply, the manufacturer may specify any value which is within ±10% of the actual measured value and use it for determining the limits for the original manufacturer’s conformity assessment test. The measured and specified values of power, as defined in this clause, shall be documented in the test report.

If the value of the power found by measurement during emission tests other than the original manufacturer’s conformity assessment test, measured according to the terms of this clause, is not less than 90 % nor greater than 110 % of the value for power specified by the manufacturer in the test report (see 6.2.3.5), the specified value shall be used to establish the limits. If the measured value is outside of this tolerance band around the specified value, the measured power shall be used to establish the limits.

For Class C equipment, the fundamental current and power factor, specified by the manufacturer, shall be used for the calculation of limits (see 3.10). The fundamental component of the current and the power factor are measured and specified by the manufacturer in the same way as the power is measured and specified for the calculation of Class D limits. The value used for the power factor shall be obtained from the same DFT measurement window as the value for the fundamental component of current.

The repeatability (see 3.19) of the average value for the individual harmonic currents over the entire test observation period shall be better than ±5 % of the applicable limit, when the following conditions are met:

• the same equipment under test (EUT) (not another of the same type, however similar);

• identical test conditions;

• the same test system;

• identical climatic conditions, if relevant.

NOTE This repeatability requirement serves the purpose of defining the necessary observation period, see 6.2.4. It is not intended to serve as a pass/fail criterion for the assessment of compliance with the requirements of this standard.

The reproducibility (see 3.20) of measurements on the same EUT with different test systems cannot be definitively calculated so as to apply to all possible combinations of EUT, harmonics meter and test supply, but can be estimated to be better than ± (1 % + 10 mA), where the 1 % is 1 % of the average value of the total input current taken over the entire test observation period. Therefore, differences in results which are less than that value of current are deemed negligible, but in some cases a higher value may occur.

For the avoidance of doubt in such cases, test results, obtained at different locations or on different occasions, that show that all the relevant limits are met shall be accepted as demonstrating compliance, even though the results may differ more than the values for repeatability and reproducibility, given above.

NOTE The variability (see 3.21) of measurements on different EUTs of the same type, having no intentional differences, can be increased by practical component tolerances and other effects, such as possible interactions between the characteristics of the EUT and the measuring instrument or the power supply. The results of these effects cannot be quantified in this standard, for the same reasons as for reproducibility. The second paragraph of 6.2.3.2 also applies in the case of variability.

A regulatory concession in respect of limit values to allow for possible variability is recommended but outside the scope of this standard.

When a piece of equipment is brought into operation or is taken out of operation, manually or automatically, harmonic currents and power are not taken into account for the first 10 s following the switching event.

The equipment under test shall not be in stand-by mode (see 3.18) for more than 10 % of any observation period.

The average values for the individual harmonic currents, taken over the entire test observation period shall be less than or equal to the applicable limits.

For each harmonic order, all 1,5 s smoothed r.m.s. harmonic current values, as defined in 6.2.2, shall be either:

1. less than or equal to 150 % of the applicable limits, or

2. less than or equal to 200 % of the applicable limits under the following conditions, which apply all together:

1. the EUT belongs to Class A for harmonics;

2. the excursion beyond 150% of the applicable limits lasts less than 10% of the test observation period or in total 10 min (within the test observation period), whichever is smaller, and

3. the average value of the harmonic current, taken over the entire test observation period, is less than 90 % of the applicable limits.

Harmonic currents less than 0,6 % of the input current measured under the test conditions, or less than 5 mA, whichever is greater, are disregarded.

For the 21^st and higher odd order harmonics, the average value obtained for each individual odd harmonic over the full observation period, calculated from the 1,5 s smoothed r.m.s. values according to 6.2.2, may exceed the applicable limits by 50 % provided that the following conditions are met:

• the measured partial odd harmonic current does not exceed the partial odd harmonic current which can be calculated from the applicable limits;

• all 1,5 s smoothed r.m.s. individual harmonic current values shall be less than or equal to 150 % of the applicable limits.

NOTE These exemptions (the use of the partial odd harmonic current for the average values and the 200 % short term limit for single 1,5 s smoothed values) are mutually exclusive and cannot be used together.

6.2.3.5 Test report

The test report may be based on information supplied by the manufacturer to a testing facility, or be a document recording details of the manufacturer’s own tests. It shall include all relevant information for the test conditions, the test observation period, and, when applicable for establishing the limits, the active power or fundamental current and power factor.

6.2.4 Test observation period

Observation periods (T_obs) for four different types of equipment behaviour are considered and described in Table 4.

6.3 Equipment in a rack or case

Where individual self-contained items of equipment are installed in a rack or case, they are regarded as being individually connected to the mains supply. The rack or case need not be tested as a whole.

7 Harmonic current limits

The procedure for applying the limits and assessing the results is shown in Figure 1.

For the following categories of equipment, limits are not specified in this standard:

NOTE 1 Limits may be defined in a future amendment or revision of the standard.

• equipment with a rated power of 75 W or less, other than lighting equipment;

NOTE 2 This value may be reduced from 75 W to 50 W in the future, subject to approval by National Committees at that time.

• professional equipment with a total rated power greater than 1 kW;

• symmetrically controlled heating elements with a rated power less than or equal to 200 W;

• independent dimmers for incandescent lamps with a rated power less than or equal to 1 kW.

NOTE 3 See also C.5.3

.

Figure 1 - Flowchart for determining conformity

NOTE /p(abs) is the higher absolute value of/_p+and/p.

Figure 2 - Illustration of the relative phase angle
and current parameters described in 7.3 b)

For Class A equipment, the harmonics of the input current shall not exceed the values given in Table 1.

Audio amplifiers shall be tested according to Clause C.3. Dimmers for incandescent lamps shall be tested according to Clause C.6.

For Class В equipment, the harmonics of the input current shall not exceed the values given in Table 1 multiplied by a factor of 1,5.

1. Active input power > 25 W

For lighting equipment having an active input power greater than 25 W, the harmonic currents shall not exceed the relative limits given in Table 2.

However, the limits given in Table 1 apply to incandescent lighting equipment that has built- in dimmers or consists of dimmers built in an enclosure.

For discharge lighting equipment that has built-in dimmers or consists of independent dimmers or dimmers built in an enclosure, the following conditions apply:

• the harmonic current values for the maximum load condition derived from the percentage limits given in Table 2 shall not be exceeded;

• in any dimming position, the harmonic current shall not exceed the value of current allowed in the maximum load condition;the equipment shall be tested according to the conditions given in Clause C.5 (see the last paragraph of C.5.3).

2. Active input power < 25 W

Discharge lighting equipment having an active input power smaller than or equal to 25 W shall comply with one of the following two sets of requirements:

• the harmonic currents shall not exceed the power-related limits of Table 3, column 2, or:

• the third harmonic current, expressed as a percentage of the fundamental current, shall not exceed 86 % and the fifth harmonic current shall not exceed 61 %. Also, the waveform of the input current shall be such that it reaches the 5 % current threshold before or at 60°, has its peak value before or at 65° and does not fall below the 5 % current threshold before 90°, referenced to any zero crossing of the fundamental supply voltage. The current threshold is 5 % of the highest absolute peak value that occurs in the measurement window, and the phase angle measurements are made on the cycle that includes this absolute peak value. See Figure 2.

If the discharge lighting equipment has a built-in dimming device, measurement is made only in the full load condition.

For Class D equipment, the harmonic currents and the power shall be measured as defined in 6.2.2. The input currents at harmonic frequencies shall not exceed the values that can be derived from Table 3 according to the requirements specified in 6.2.3 and 6.2.4.

Table 1 - Limits for Class A equipment

Table 2 - Limits for Class C equipment

Table 3 - Limits for Class D equipment

Table 4 - Test observation period

Annex A
(normative)

Measurement circuit and supply source

A.1 Test circuit

The measured harmonic values shall be compared with the limits given in Clause 7. The harmonic currents of the equipment under test (EUT) shall be measured in accordance with the circuits given in the following figures:

• Figure A.1 for single-phase equipment;

• Figure A.2 for three-phase equipment.

Measurement equipment complying with Annex В shall be used. Test conditions for the EUT are given in Annex C.

A.2 Supply source

While the measurements are being made, the test voltage (U) at the terminals of the equipment under test, when operated according to Annex C, shall meet the following requirements.

1. The test voltage (U) shall be the rated voltage of the equipment. In the case of a voltage range, the test voltage shall be 230 V or 400 V for single-phase or three-phase supplies respectively. The test voltage shall be maintained within ±2,0 % and the frequency within ±0,5 % of the nominal value.

2. In the case of a three-phase supply, the angle between the fundamental voltage on each pair of phases of a three-phase source shall be 120° ± 1,5°.

3. The harmonic ratios of the test voltage (U) shall not exceed the following values with the EUT connected as in normal operation:

0,9 % for harmonic of order 3;

0,4 % for harmonic of order 5;

0,3 % for harmonic of order 7;

0,2 % for harmonic of order 9;

0,2 % for even harmonics of order from 2 to 10;

0,1 % for harmonics of order from 11 to 40.

4. The peak value of the test voltage shall be within 1,40 times and 1,42 times its r.m.s. value and shall be reached within 87° to 93° after the zero crossing. This requirement does not apply when Class A or В equipment is tested.

Key

Z

S power supply source

M measurement equipment EUT equipment under test U test voltage

ІЕС 1462/14

_M input impedance of measurement equipment

Z_s internal impedance of the supply source

!„ harmonic component of order n of the line current

G open-loop voltage of the supply source

NOTE 1 Z_s and Z_M are not specified, but must be sufficiently low for the requirements of Clause A.2 to be met. This is checked by measuring the properties of the supply voltage at the point of connection of the EUT to the measurement equipment. More information can be found in IEC 61000-4-7.

NOTE 2 In some special cases, particular care may be necessary to avoid resonance between the internal inductance of the source and the capacitances of the equipment under test.

NOTE 3 For some types of equipment, such as single-phase uncontrolled rectifiers, the harmonic amplitudes vary greatly with the supply voltage. To minimize variability, it is recommended to maintain the voltage at the point of connection of the EUT to the measurement equipment to 230 V or 400 V within ±1,0 V, evaluated over the same 200 ms observation window, used for harmonic assessment.

Figure A.1 - Measurement circuit for single-phase equipment

Key

S power supply source

M measurement equipment

EUT equipment under test

G open-loop voltage of the supply source

Z_M input impedance of the measurement equipment

Z_s internal impedance of the supply source

/_п harmonic component of order of the line current

U test voltage (shown as an example between phases L1 and L2)

NOTE 1 Z_s and Z_M are not specified, but must be sufficiently low for the requirements of Clause A.2 to be met. This is checked by measuring the properties of the supply voltage at the point of connection of the EUT to the measurement equipment. More information can be found in IEC 61000-4-7.

NOTE 2 In some special cases, particular care may be necessary to avoid resonance between the internal inductance of the source and the capacitances of the equipment under test.

NOTE 3 For some types of equipment, such as single-phase uncontrolled rectifiers, the harmonic amplitudes vary greatly with the supply voltage. To minimize variability, it is recommended to maintain the voltage at the point of connection of the EUT to the measurement equipment to 230 V or 400 V within ±1,0 V, evaluated over the same 200 ms observation window, used for harmonic assessment

Figure A.2 - Measurement circuit for three-phase equipment

Annex В
(normative)

Requirements for measurement equipment

The requirements for measurement equipment are defined in IEC 61000-4-7.Annex С
(normative)

Type test conditions

C.1 General

The test conditions for the measurement of harmonic currents associated with some types of equipment are given in the following clauses.

NOTE Product committees are invited to submit proposals for defined test conditions for specific products to IEC SC 77A, for inclusion in this Annex.

C.2 Test conditions for television (TV) receivers

C.2.1 General conditions

Measurements shall include the loading of any auxiliary circuits included in the receiver, but exclude the loading of any peripheral equipment powered from the receiver.

C.2.2 Conditions for measurement

A radio-frequency signal modulated in accordance with C.2.2.1 shall be supplied by a test generator, and the receiver shall be adjusted to display a picture with appropriate settings for brightness, contrast and sound level in accordance with C.2.2.2.