BS 7484:1991

Committees responsible
National foreword
1. Scope
2. Normative references
3. Definitions
4. Purpose of specifying electromagnetic compatibility
     levels
5. Harmonics
6. Interharmonics
7. Voltage fluctuations
8. Voltage dips and short supply interruptions
9. Voltage unbalance
10. Mains signalling
11. Power frequency variation
12. D.C. components
Figures
1. Coordination between the disturbance level in the
     environment, the compatibility level, the immunity
     level, the susceptibility level
2. Superposition of harmonic currents
3. Sinusoidal voltage fluctuation of 10 Hz frequency
4. Illustration of peak voltage changes
5. Some illustrations of voltage fluctuation waveforms
6. Illustration of a voltage dip (triangle U1) or a
     voltage interruption (triangle U2 = 100%)

Describes conducted disturbances in the frequency range up to 10 kHz with an extension for mains signalling systems. Separate sections give numerical compatibility levels for different system voltage levels. Does not deal with the application of compatibility levels to assess, the permissible interference emission from specific items of equipment or installations. Does not prejudge the specification of immunity levels by the product committees but merely provides a guide. Phenomena considered are harmonics, inter-harmonics, voltage fluctuations, voltage dips and short supply interruptions, voltage unbalance, mains signalling, power frequency variation and d.c. components.

This section of IEC 1000-2 is concerned with conducted disturbances in the frequency range up to 10 kHz with an extension for mains signalling systems. Separate sections give numerical compatibility levels for different system voltage levels.

This section does not deal with the application of compatibility levels to assess, for example, the permissible interference emission from specific items of equipment or installations, because other system parameters, such as its impedance as a function of frequency, have also to be considered. Furthermore, it does not prejudge the specification of immunity levels by the product committees but merely provides a guide.

The disturbance phenomena considered are:

• harmonics;

• inter-harmonics;

• voltage fluctuations;

• voltage dips and short supply interruptions;

• voltage unbalance;

• mains signalling;

• power frequency variation;

• d.c. components.

The object of this section is to give information on the various types of disturbances that can be expected on public power supply systems. It is a reference document for those associated parts that give values of compatibility level.