AS/NZS 61000.3.3:2012 PDF – Electromagnetic compatibility (EMC) Part 3.3: Limits—Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems

AS/NZS 61000.3.3:2012 PDF – Electromagnetic compatibility (EMC) Part 3.3: Limits—Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems
1 Scope
This part of IEC 61 000 is concerned with the limitation of voltage fluctuations and flicker impressed on the public low-voltage system. It specifies limits of voltage changes which may be produced by an equipment tested under specified conditions and gives guidance on methods of assessment. This part of IEC 61 000 is applicable to electrical and electronic equipment having an input current equal to or less than 1 6 A per phase, intended to be connected to public low-voltage distribution systems of between 220 V and 250 V line to neutral at 50 Hz, and not subject to conditional connection. Equipment which does not comply with the limits of this part of IEC 61 000 when tested with the reference impedance Z ref of 6.4, and which therefore cannot be declared compliant with this part, may be retested or evaluated to show conformity with IEC 61 000-3-1 1 . Part 3-1 1 is applicable to equipment with rated input current ≤75 A per phase and subject to conditional connection. The tests according to this part are type tests. Particular test conditions are given in annex A and the test circuit is shown in Figure 1 . NOTE The limits in this part of IEC 61 000 are based mainly on the subjective severity of flicker imposed on the light from 230 V/60 W coiled-coil filament lamps by fluctuations of the supply voltage. For systems with nominal voltage less than 220 V line to neutral and/or frequency of 60 Hz, the limits and reference circuit values are under consideration.
6.2 Measurement accuracy
The magnitude of the current shall be measured with an accuracy of ±1 % or better. If instead of active and reactive current the phase angle is used, its error shall not exceed ±2°. The relative voltage change “d” shall be determined with a total accuracy better than ±8 % with reference to the maximum value d max . The total impedance of the circuit, excluding the appliance under test, but including the internal impedance of the supply source, shall be equal to the reference impedance. The stability and tolerance of this total impedance shall be adequate to ensure that the overall accuracy of ±8 % is achieved during the whole assessment procedure. NOTE The following method is not recommended where the measured values are close to the limits. When the source impedance is not well defined, for example where the source impedance is subject to unpredictable variations, an impedance having resistance and inductance equal to the reference impedance may be connected between the supply and the terminals of the equipment under test. Measurements can then be made of the voltages at the source side of the reference impedance and at the equipment terminals. In that case, the maximum relative voltage change, d max , measured at the supply terminals shall be less than 20 % of the maximum value d max measured at the equipment terminals.

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