Iec 61000 2 12 2003

NORME INTERNATIONALE CEI IEC INTERNATIONAL STANDARD 61000 2 12 Première édition First edition 2003 04 Compatibilité électromagnétique (CEM) – Partie 2 12 Environnement – Niveaux de compatibilité pour[.]

Définitions générales

3.1.1 perturbation (électromagnétique) tout phénomène électromagnétique qui, de par sa présence dans l’environnement électro- magnétique, peut faire dévier un équipement électrique de sa performance attendue

3.1.2 niveau de perturbation amplitude d’une perturbation électromagnétique mesurée et évaluée au moyen d’une méthode spécifiée

CEM, or Electromagnetic Compatibility, refers to the ability of a device or system to operate effectively within its electromagnetic environment while avoiding the generation of intolerable electromagnetic disturbances that could affect other entities in that environment.

Electromagnetic compatibility (EMC) is essential for ensuring that the electromagnetic environment allows all devices, equipment, and systems to operate as intended This is achieved when the level of disruptive emissions is kept low and the immunity levels are sufficiently high.

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The compatibility levels outlined in this standard are applicable at the point of common coupling for scenario (a) and at the medium-voltage terminals of the substation for scenario (b).

The referenced documents are essential for the application of this document For dated references, only the specified edition is applicable, while for undated references, the most recent edition, including any amendments, is relevant.

IEC 60071(all parts), Insulation co-ordination

IEC 60071-1, Insulation co-ordination – Part 1: Definitions, principles and rules

IEC 61000-2-2, Electromagnetic compatibility (EMC) – Part 2-2: Environment – Compatibility levels for low-frequency conducted disturbances and signalling in public low-voltage power supply systems

IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2-4: Environment – Compatibility levels in industrial plants for low-frequency conducted disturbances

IEC 61000-4-7, Electromagnetic compatibility (EMC) – Part 4-7: Testing and measurement techniques – General guide on harmonics and interharmonics measurements and instrumentation, for power supply systems and equipment connected thereto

For the purpose of this present document, the following definitions apply.

(electromagnetic) disturbance any electromagnetic phenomenon which, by being present in the electromagnetic environment, can cause electrical equipment to depart from its intended performance

3.1.2 disturbance level the amount or magnitude of an electromagnetic disturbance, measured and evaluated in a specified way

EMC (abbreviation) ability of an equipment or system to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment

Electromagnetic compatibility (EMC) refers to the state of the electromagnetic environment where disturbance emissions are kept at low levels, and immunity levels are sufficiently high This ensures that all devices, equipment, and systems function as intended without interference.

Electromagnetic compatibility is ensured only when emission and immunity levels are controlled so that the immunity levels of equipment and systems are not exceeded by the disturbance levels at any point, which result from the cumulative emissions of all sources and other factors, such as circuit impedance It is conventionally stated that electromagnetic compatibility exists if the probability of deviation from expected performance is sufficiently low Refer to Article 4 of IEC 61000-2-1 for more details.

NOTE 3 Lorsque le contexte le rend nécessaire, la compatibilité électromagnétique peut être prise en référence à une perturbation singulière ou à une classe de perturbation.

Electromagnetic compatibility refers to the field of study concerning the disrupted behaviors that materials, equipment, or systems experience due to interference from other materials, equipment, or systems, as well as from electromagnetic phenomena.

3.1.4 niveau de compatibilité (électromagnétique) niveau de perturbation électromagnétique spécifié utilisé en tant que niveau de référence dans un environnement spécifié pour la coordination des limites d’émission et d’immunité

NOTE Le niveau de compatibilité électromagnétique est choisi de telle sorte que la probabilité de dépassement de ce niveau par les perturbations réelles soit très faible.

The planning level assigned to a specific disturbance in a given environment serves as a reference for establishing applicable emission limits for high-power loads and installations This approach aims to coordinate these limits with all other standards set for equipment intended to connect to the energy distribution network.

The level of planning is specific to the location where it is applied and is utilized by those responsible for the planning and operation of the energy distribution network in that area Additional details can be found in Appendix A.

PCC point électriquement le plus proche d’une charge particulière, situé sur le réseau public de distribution d’énergie, auquel d’autres charges sont raccordées ou susceptibles de l’être

Définitions relatives aux phénomènes

Les définitions ci-dessous, relatives aux harmoniques, sont fondées sur l’analyse des systèmes de tensions ou des systèmes de courants au moyen de la Transformée de Fourier

Discrète (DFT) Il s’agit de l’application pratique de la transformée de Fourier telle que définie au VEI 101-13-09 Voir Annexe B.

The Fourier Transform applied to a time function, whether periodic or not, results in a frequency domain representation known as the frequency spectrum For periodic time functions, the spectrum consists of distinct lines or components In contrast, for non-periodic time functions, the spectrum is a continuous function that includes components at all frequencies.

Additional definitions related to harmonics or interharmonics are provided in the VEI and other standards Some of these definitions, although not utilized in this standard, are presented in Annex B.

Electromagnetic compatibility (EMC) is attained when emission and immunity levels are managed to ensure that the disturbance levels from cumulative emissions do not surpass the immunity levels of devices and systems at any given location Compatibility is typically defined by a low probability of deviation from intended performance, as outlined in Clause 4 of IEC 61000-2-1.

NOTE 3 Where the context requires it, compatibility may be understood to refer to a single disturbance or class of disturbances.

Electromagnetic compatibility (EMC) refers to the study of how devices, equipment, and systems can adversely affect one another due to electromagnetic phenomena.

(electromagnetic) compatibility level specified electromagnetic disturbance level used as a reference level in a specified environment for co-ordination in the setting of emission and immunity limits

NOTE By convention, the compatibility level is chosen so that there is only a small probability that it will be exceeded by the actual disturbance level.

The planning level for a specific disturbance in an environment serves as a reference value for establishing emission limits from large loads and installations This approach ensures that these limits are coordinated with the standards set for equipment intended to connect to the power supply system.

The planning level is tailored to local specifics and is implemented by the authorities in charge of planning and managing the power supply network in the respective region For additional details, please refer to Annex A.

PCC point on a public power supply network, electrically nearest to a particular load, at which other loads are, or could be, connected

The definitions pertaining to harmonics are derived from the analysis of system voltages or currents using the Discrete Fourier Transform (DFT) method, which serves as a practical application of the Fourier transform as outlined in IEV 101-13-09 For further details, refer to Annex B.

The Fourier Transform converts a time function, whether periodic or non-periodic, into its frequency spectrum For periodic time functions, the spectrum consists of discrete lines, while for non-periodic functions, it results in a continuous spectrum that represents components across all frequencies.

Other definitions related to harmonics or interharmonics are given in the IEV and other standards Some of those other definitions, although not used in this standard, are discussed in

The fundamental frequency is the reference frequency in the spectrum derived from the Fourier transform of a time function For the purposes of this standard, the fundamental frequency is equivalent to the frequency of the energy distribution network.

NOTE 1 Dans le cas d’une fonction périodique la fréquence fondamentale est généralement égale à celle de la fonction elle-même (Voir annexe B.1).

In cases where ambiguity may arise, the frequency of the energy distribution network can be defined based on the polarity and rotational speed of the synchronous alternators supplying the system.

3.2.2 composante fondamentale composante dont la fréquence est la fréquence fondamentale

3.2.3 fréquence harmonique fréquence multiple entier de la fréquence fondamentale Le rapport de la fréquence harmonique à la fréquence fondamentale est nommé rang harmonique (notation recom- mandộe ô h ằ)

3.2.4 composante harmonique une composante quelconque ayant une fréquence harmonique Sa valeur est normalement exprimée en valeur efficace

De faỗon concise, une telle composante peut ờtre simplement dộnommộe ô harmonique ằ

3.2.5 fréquence interharmonique n'importe quelle fréquence qui n'est pas un multiple entier de la fréquence fondamentale

NOTE 1 Par extension du rang harmonique, le rang interharmonique est le rapport de la fréquence interharmonique à la frộquence fondamentale Ce rapport n'est pas un entier (notation recommandộe ô m ằ).

NOTE 2 Dans le cas ó m < 1 le terme fréquence sous-harmonique peut être également utilisé.

3.2.6 composante interharmonique composante dont la fréquence est à une fréquence interharmonique Sa valeur est normalement exprimée en valeur efficace

De faỗon concise, une telle composante peut ờtre simplement dộnommộe ôinterharmoniqueằ

According to the IEC 61000-4-7 standard, the observation window width is defined as 10 fundamental periods for systems operating at 50 Hz or 12 fundamental periods for other frequencies.

(systèmes à 60 Hz), c'est-à-dire approximativement 200 ms En conséquence, la différence de fréquence entre deux composantes interharmoniques consécutives est approximativement 5 Hz.

3.2.7 taux de distorsion harmonique total

THD le rapport de la valeur efficace de la somme des harmoniques à la valeur efficace du fondamental La sommation est limitộe à un rang dộfini (notation recommandộe ô H ằ):

The fundamental frequency is the primary frequency in the spectrum derived from the Fourier transform of a time function, serving as a reference for all other frequencies in the spectrum In the context of this standard, the fundamental frequency is equivalent to the power supply frequency.

NOTE 1 In the case of a periodic function, the fundamental frequency is generally equal to the frequency of the function itself (See Annex B.1).

In situations where ambiguity persists, it is essential to consider the power supply frequency in relation to the polarity and rotational speed of the synchronous generator(s) supplying the system.

3.2.2 fundamental component component whose frequency is the fundamental frequency

3.2.3 harmonic frequency frequency which is an integer multiple of the fundamental frequency The ratio of the harmonic frequency to the fundamental frequency is the harmonic order (recommended notation: “h”)

3.2.4 harmonic component any of the components having a harmonic frequency Its value is normally expressed as an r.m.s value

For brevity, such a component may be referred to simply as an harmonic

3.2.5 interharmonic frequency any frequency which is not an integer multiple of the fundamental frequency

NOTE 1 By extension from harmonic order, the interharmonic order is the ratio of an interharmonic frequency to the fundamental frequency This ratio is not an integer (Recommended notation “m”).

NOTE 2 In the case where m< 1 the term subharmonic frequency may be used.

3.2.6 interharmonic component component having an interharmonic frequency Its value is normally expressed as an r.m.s. value

For brevity, such a component may be referred to simply as an “interharmonic”

According to IEC 61000-4-7, the time window for this standard is set at 10 fundamental periods for 50 Hz systems and 12 fundamental periods for 60 Hz systems, equating to roughly 200 ms Consequently, the frequency difference between two successive interharmonic components is approximately 5 Hz.

THD ratio of the r.m.s value of the sum of all the harmonic components up to a specified order

(recommended notation “H”) to the r.m.s value of the fundamental component

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Q représente soit le courant soit la tension;

Q 1 est la valeur efficace de la composante fondamentale; h est le rang harmonique;

Q h est la valeur efficace de la composante harmonique de rang h;

H est généralement égal à 50, mais peut être égal à 25 dans les cas ó le risque de résonance sur les rangs supérieurs est faible

NOTE Le THD ne prend en compte que les harmoniques Si les interharmoniques sont pris en considération, voir

Voltage imbalance occurs when the effective values of the fundamental components of phase voltages in a polyphase system, or the angles between consecutive phase voltages, are not equal The degree of inequality is typically expressed by the ratio of the inverse component to the direct component, as well as the ratio of the homopolar component to the direct component.

NOTE 1 Dans cette norme, le déséquilibre de tension ne s’applique qu’aux réseaux triphasés et n’est exprimé qu’en termes de composante inverse.

NOTE 2 Plusieurs approximations donnent des résultats suffisamment précis pour les taux de déséquilibre

(rapport des tensions inverse et directe) couramment rencontrés Par exemple:

U U U ó U 12 , U 23 et U 31 sont les trois tensions entre phases.

Généralités

The compatibility levels outlined in the following paragraphs pertain to various disturbances considered individually In practice, multiple disturbances occur simultaneously in the electromagnetic environment of equipment Specific combinations of disturbances can impair the performance of certain devices Refer to Appendix A for more details.

At the terminals of equipment powered by the medium voltage network covered by this standard, the severity of disturbances can generally be regarded as equivalent to that at the common connection point to the public network However, this is not the case in certain situations, particularly in the following instances:

• longue ligne destinée à l’alimentation d’une installation donnée;

• équipement faisant partie d’une installation très étendue;

• perturbation générée ou amplifiée dans l’installation dont l’équipement fait partie.

In medium voltage (MV) networks connected to low voltage (LV) networks, disturbance levels are typically lower in MV networks compared to LV networks, especially regarding harmonics and interharmonics Exceptions may occur due to resonance and the aggregation of disturbances from different parts of the networks Given the role of coordinating compatibility levels, it is crucial that these levels reflect the disturbances that are likely to be encountered in practice, even if the probability of occurrence is very low.

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Q represents either current or voltage

Q 1 = r.m.s value of the fundamental component h = harmonic order

Q h = r.m.s value of the harmonic component of order h

H = 50 generally, but 25 when the risk of resonance at higher orders is low.

NOTE THD takes account of harmonics only For the case where interharmonics are to be included, see B.1.2.1,

3.2.8 voltage unbalance (imbalance) condition in a polyphase system in which the r.m.s values of the line-to-line voltages

The phase angles between consecutive line-to-line voltages are not uniform, and the extent of this inequality is typically represented by the ratios of the negative and zero sequence components to the positive sequence component.

NOTE 1 In this standard, voltage unbalance is considered in relation to three-phase systems and negative phase sequence only.

NOTE 2 Several approximations give reasonably accurate results for the levels of unbalance normally encountered

(ratio of negative to positive sequence components):

U U U where U 12 , U 23 and U 31 are the three line-to-line voltages.

The compatibility levels for various disturbances are outlined individually in the following subclauses However, it is important to note that the electromagnetic environment often includes multiple disturbances at once, which can negatively impact the performance of certain equipment due to specific combinations of these disturbances For further details, refer to Annex A.

At the power input terminals of equipment connected to medium-voltage distribution systems, the severity levels of disturbances are generally consistent with those at the point of common coupling However, there are specific situations where this may not hold true.

• a long line dedicated to the supply of a particular installation;

• equipment being part of an extensive installation;

• a disturbance generated or amplified within the installation of which the equipment forms a part.

In medium voltage networks linked to low voltage networks, disturbance levels are typically lower in medium voltage systems, particularly regarding harmonics and interharmonics However, exceptions may occur due to factors like resonance and the accumulation of disturbances from other network areas It is crucial for compatibility levels to accurately represent the disturbance levels that are likely to be experienced in practice, even if the probability of such occurrences is relatively low.

Le niveau de compatibilité MT ne représente pas des conditions moyennes, mais doit prendre en compte des conditions exceptionnelles qui ont un risque significatif d’être rencontrées.

It is essential to ensure that this serves as a useful reference value for specifying immunity levels for equipment that will be connected to MT networks However, it is crucial to note that:

• les limites d’émission et d’immunité des matériels alimentés par un réseau de distribution

BT public sont coordonnées sur la base des niveaux de compatibilité BT spécifiés dans la

The limits for emissions from large loads and installations are coordinated based on planning levels, as detailed in section 3.1.6 and Appendix A Additionally, refer to IEC technical reports 61000-3-6 and 61000-3-7 for further information.

• les limites d’émission et d’immunité pour les matériels alimentés par des réseaux de distribution non public sont coordonnées sur la base des niveaux de compatibilité spécifiés dans la CEI 61000-2-4.

Therefore, although there is typically a margin between disturbance levels on MT and BT networks, this standard specifies MT compatibility levels that are identical to those outlined in IEC 61000-2-2.

Fluctuations de tension et flicker

On medium voltage networks, voltage fluctuations are caused by varying loads, the operation of transformer tap changers, or other functional adjustments within the distribution network and connected equipment.

Under normal conditions, the amplitude of rapid voltage fluctuations is restricted to 3% of the nominal supply voltage However, voltage spikes exceeding 3% may occasionally occur in the public distribution network.

Additionally, exceptional load variations or switching maneuvers can lead to voltage excursions outside normal service tolerances (for instance, ±10% of the declared supply voltage) for several seconds, until the regulators managing the high voltage/medium voltage transformers have responded.

Voltage fluctuations in medium voltage networks can lead to flicker in low voltage networks, whether these fluctuations are transmitted with or without modification For compatibility levels in low voltage networks, refer to IEC 61000-2-2.

Harmoniques

To define harmonic compatibility levels, two key factors must be considered: the increase in the number of disturbing sources and the decrease in purely resistive loads, such as heating, which serve as damping elements in the total load Consequently, we can anticipate a rise in harmonic levels in electrical networks unless harmonic emissions are effectively controlled.

The compatibility levels specified in this standard should be understood in relation to steady-state or quasi-steady-state conditions They are provided as reference values for long-term effects and for very short-term effects.

• Les effets à long terme concernent principalement les conséquences thermiques sur les câbles, les transformateurs, les moteurs, les condensateurs, etc Ils proviennent de niveaux harmoniques maintenus pendant 10 min ou plus.

The MV compatibility level is designed to address exceptional conditions with significant risk rather than average scenarios, ensuring it serves as a reliable reference for specifying immunity levels for equipment connected to MV networks.

• emission and immunity limits for equipment supplied from public low-voltage distribution systems are co-ordinated on the basis of low-voltage compatibility levels specified in

• limits for the emissions from large loads and installations are co-ordinated on the basis of planning levels – see 3.1.6 and Annex A; see also the technical reports IEC 61000-3-6 and

• emission and immunity limits for equipment supplied from non-public distribution systems are co-ordinated on the basis of compatibility levels specified in IEC 61000-2-4.

Accordingly, despite the fact that there is usually a margin between the disturbance levels on

MV and LV networks, this standard specifies MV compatibility levels that are the same as those specified in IEC 61000-2-2.

Voltage fluctuations in medium voltage networks arise from varying loads, the operation of transformer tap changers, and other adjustments made to the supply system or connected equipment.

In normal circumstances the value of rapid voltage changes is limited to 3 % of nominal supply voltage However step voltage changes exceeding 3 % can occur infrequently on the public supply network.

Following significant load changes or switching operations, voltage fluctuations beyond the normal operational tolerances (±10% of the declared supply voltage) may occur for several seconds until the on-load tap-changers on the high voltage-medium voltage transformers adjust.

Voltage fluctuations in medium voltage networks, by being transferred, with or without alteration, to low voltage networks, can cause flicker See IEC 61000-2-2 for compatibility levels in low-voltage networks.

When determining compatibility levels for harmonics, it is essential to recognize two key factors: the rising number of harmonic sources and the declining proportion of purely resistive loads, such as heating loads, which act as damping elements Consequently, power supply systems are likely to experience increasing harmonic levels until effective limits are established for harmonic emissions.

The compatibility levels outlined in this standard pertain to quasi-stationary or steady-state harmonics, serving as reference values for both long-term and very short-term effects.

• The long-term effects relate mainly to thermal effects on cables, transformers, motors, capacitors, etc They arise from harmonic levels that are sustained for 10 min or more.

• Les effets à très court terme concernent principalement la perturbation de dispositifs électroniques qui peuvent être sensibles à des niveaux harmoniques maintenus pendant

3 s ou moins Les régimes transitoires ne sont pas compris dans ces effets.

The compatibility levels for individual harmonic voltages concerning long-term effects are presented in Table 1 The total harmonic distortion (THD) level associated with this compatibility is 8%.

Tableau 1 – Niveaux de compatibilité pour les tensions harmoniques individuelles dans les réseaux moyenne tension (valeurs efficaces en pour-cent de la valeur efficace de la composante fondamentale)

The levels specified for odd harmonics that are multiples of 3 pertain to homopolar harmonics In a three-phase network without a neutral conductor or in the absence of a load connected between a phase and the ground, the values of the 3rd and 9th rank harmonics can be significantly lower than compatibility levels, depending on the network imbalance.

NOTE 2 Des valeurs plus basses sont souvent appropriées – Voir 4.1

In terms of very short-term effects, the compatibility levels of individual harmonic components of the voltage are equal to the values provided in Table 1, multiplied by a calculated coefficient \( k \).

Pour le taux de distorsion harmonique total, le niveau de compatibilité correspondant est

The compatibility levels mentioned above also apply to switching notches, as they contribute to the harmonic content of the voltage However, regarding their other effects, including their impact on the switching of other converters and their influence on equipment operating at higher spectrum ranges, a time-domain description is necessary.

– voir la norme de produits correspondante.

Interharmoniques et composantes de la tension dont la fréquence est supérieure à celle du 50 ème harmonique

L’état des connaissances concernant les interharmoniques et les composantes de tension de fréquence élevée est en cours de développement Voir l’Annexe B pour de plus amples informations.

Les niveaux de compatibilité relatifs au flicker associé à ce phénomène sur les réseaux basse tension sont donnés dans la CEI 61000-2-2.

Creux de tension et coupures brèves

Voir l’Annexe B, ainsi que la CEI 61000-2-8 pour plus d’information sur ces phénomènes.

• Very short-term effects relate mainly to disturbing effects on electronic devices that may be susceptible to harmonic levels sustained for 3 s or less Transients are not included.

Table 1 presents the compatibility levels for individual harmonic components of the voltage, highlighting the long-term effects The total harmonic distortion (THD) is noted to be 8%.

Table 1 – Compatibility levels for individual harmonic voltages in medium voltage networks (r.m.s values as percent of r.m.s value of the fundamental component)

NOTE 1 The levels given for odd harmonics that are multiples of three apply to zero sequence harmonics.

In a three-phase network lacking a neutral conductor or any load connected between the line and ground, the levels of the 3rd and 9th harmonics can be significantly lower than the established compatibility levels, influenced by the system's unbalance.

NOTE 2 Lower values are often appropriate – See 4.1

The compatibility levels for individual harmonic components of the voltage, as outlined in Table 1, are determined by multiplying the specified values by a factor \( k \).

The corresponding compatibility level for the total harmonic distortion is THD = 11 %.

Commutation notches impact harmonic levels in the supply voltage, as outlined by the compatibility levels However, to understand their additional effects, such as their influence on the commutation of other converters and their impact on equipment related to higher-order harmonic components, a time-domain description is necessary, as specified in the relevant product standard.

4.4 Interharmonics and voltage components at frequencies above that of the

Knowledge of the electromagnetic disturbance involved in interharmonic and higher frequency voltages is still developing See Annex B for further discussion.

Compatibility levels relating to the flicker effect associated with this phenomenon on low voltage networks are given in IEC 61000-2-2.

4.5 Voltage dips and short supply interruptions

For a discussion of these phenomena, see Annex B, and IEC 61000-2-8.

Déséquilibre de tension

This standard focuses on voltage imbalance specifically concerning the inverse component, which is significant when examining potential interference with equipment connected to medium voltage public distribution networks.

NOTE Pour des réseaux dont le neutre est directement relié à la terre, le déséquilibre homopolaire peut être pertinent.

The voltage imbalance caused by a single-phase load connected between two phases is nearly equal to the ratio of the power of that load to the short-circuit power of the three-phase network.

The compatibility level is inversely proportional, equating to 2% of the direct component In certain areas where high single-phase loads are common, values may reach up to 3%.

Surtensions transitoires

Ces phénomènes sont présentés à l’Annexe B.

Cette norme ne donne pas de niveau de compatibilité pour les surtensions transitoires Voir toutefois la CEI 60071 pour la coordination d’isolement.

Variations temporaires de fréquence

In public power networks, the frequency is kept as close as possible to its nominal value, primarily depending on the size of the interconnected electrical systems Typically, the variation range of the nominal frequency is less than 1 Hz When a synchronous interconnection is established on a continental scale, the frequency variations are usually much smaller However, island networks that are not synchronously connected to a larger system may experience more significant frequency fluctuations.

Le niveau de compatibilité relatif aux variations temporaires de fréquence est fixé à ±1 Hz de la fréquence nominale.

En régime permanent, l’écart entre la fréquence et la fréquence nominale est beaucoup plus faible.

NOTE Pour certains équipements, la vitesse d’évolution de la fréquence est importante.

Composantes continues

In public power supply networks governed by this standard, the voltage typically does not contain a significant direct current component However, this can occur in the presence of loads that draw asymmetrical currents.

The critical magnitude refers to the level of direct current The value of direct voltage is influenced not only by the direct current but also by other factors, particularly the resistance of the network at the specific point in question Consequently, no compatibility level is defined for the direct voltage level.

Voltage unbalance is primarily assessed through the negative phase sequence component, which is crucial for understanding potential interference with equipment linked to public medium voltage distribution systems.

NOTE For systems with the neutral point directly connected to earth, the zero-sequence unbalance ratio can be relevant.

Voltage unbalance from a single-phase load connected line-to-line is effectively represented by the ratio of the load power to the three-phase short circuit power of the network.

The compatibility level for unbalance is defined as a negative sequence component of 2% of the positive sequence component In certain regions, particularly where large single-phase loads are commonly connected, this value can rise to as much as 3%.

For a discussion of these phenomena, see Annex B.

Compatibility levels are not given for transient overvoltages in this standard However, for insulation co-ordination see IEC 60071.

In public power supply systems, maintaining the frequency close to the nominal value is crucial, with variations typically within 1 Hz for interconnected systems On a continental scale, synchronous interconnections result in even smaller frequency fluctuations However, island systems that are not connected to larger networks may experience greater frequency variations.

The compatibility level for the temporary variation of frequency from the nominal frequency is ±1Hz.

The steady-state deviation of frequency from the nominal frequency is much less.

NOTE For some equipment the rate of change of frequency is significant.

Public power supply systems typically do not exhibit a significant direct current (d.c.) component, as outlined by this standard However, the connection of certain non-symmetrically controlled loads can introduce such a component.

The critical factor in determining d.c voltage is the level of d.c current, which is influenced by various elements, particularly the resistance of the network at the relevant point Consequently, a specific compatibility level for d.c voltage cannot be established.

Systèmes de transmission de signaux sur le réseau

Public networks primarily serve to supply electricity to customers, but network managers also utilize them for signal transmission This capability is employed, for instance, to control specific types of loads, although these networks are not intended for signal transmission between private users.

Technically, remote control systems involve an interharmonic voltage source, as detailed in section 4.4 and Appendix B In this context, the signaling voltage is intentionally transmitted over a specific network segment The voltage and frequency of the emitted signal are predetermined, and the signal is broadcast at designated times.

Il est nécessaire de prendre en considération le niveau de tension des signaux de télécommande pour coordonner l’immunité des équipements raccordés aux réseaux sur lesquels ces signaux sont émis.

Il convient que la conception d’un système de transmission de signaux sur le réseau satisfasse à trois objectifs:

• assurer la compatibilité entre installations voisines;

• éviter les interférences entre le système de transmission de signaux et ses éléments ou les équipements raccordés au réseau ou faisant partie du réseau;

• empêcher le système de transmission de signaux de perturber les équipements raccordés au réseau ou faisant partie du réseau;

Quatre systèmes de transmission de signaux sur le réseau sont décrits à l’Article 10 de la

CEI 61000-2-1 (les plages de fréquence mentionnées sont nominales et sont communément utilisées).

4.10.1 Système de télécommande centralisée (de 110 Hz à 3 000 Hz)

Centralized remote control signals are transmitted as a series of pulses, with each pulse lasting between 0.1 seconds and 7 seconds The total duration of the sequence ranges from 6 seconds to 180 seconds, typically featuring a pulse duration of about 0.5 seconds and an overall sequence length of approximately 30 seconds.

These systems typically operate within a frequency range of 110 Hz to 3,000 Hz The amplitude of the injected sinusoidal signals is generally between 2% and 5% of the nominal supply voltage, depending on local practices Resonance phenomena can lead to amplification levels of up to 9% In the most recently installed systems, the signals are usually maintained within this frequency range.

In certain countries, the Meister curve, illustrated in Figure 1, is officially recognized When the Meister curve is not utilized, the amplitude of signals emitted within this frequency range must not exceed the levels specified in Table 1 for odd harmonics (non-multiples of 3).

Public networks primarily serve to supply electric energy to customers, but suppliers also utilize them for signal transmission to control specific load categories However, these networks are not intended for communication between private users.

Mains signalling generates interharmonic voltages, as detailed in section 4.4 and Annex B In this context, the signal voltage is deliberately applied to a specific section of the supply system Both the voltage and frequency of the emitted signal are predetermined, and the transmission occurs at designated times.

For co-ordination of the immunity of equipment connected to networks on which mains signals exist, the voltage levels of these signals need to be taken into account.

Design of mains signalling systems should meet three objectives:

• to assure compatibility between neighbouring installations,

• to avoid interference with the mains signalling system and its elements by equipment on or connected to the network.

• to prevent the mains signalling system from disturbing equipment on or connected to the network.

Four types of mains signalling systems are described in Clause 10 of IEC 61000-2-1 (the frequency ranges mentioned are nominal and are a matter of common practice).

4.10.1 Ripple control systems (110 Hz to 3 000 Hz)

Ripple control signals are sent as a series of pulses, typically lasting between 0.1 seconds and 7 seconds, with the overall sequence duration varying from 6 seconds to 180 seconds Commonly, each pulse lasts around 0.5 seconds, while the total sequence duration is approximately 30 seconds.

These systems typically function within a frequency range of 110 Hz to 3000 Hz, with the injected sine wave signal generally set between 2% and 5% of the nominal supply voltage, although resonance may elevate this to 9% In newer installations, the signal frequencies are commonly found between 110 Hz and 500 Hz.

In certain countries, the Meister curve, illustrated in Figure 1, is officially acknowledged In regions where the Meister curve is not utilized, the signal amplitudes within this frequency range must remain below the specified levels for odd harmonics, as outlined in Table 1.

Ni veau du si gnal Us/ U n %

Figure 1 – Courbe ô de Meister ằ pour les systốmes de tộlộcommande centralisộe dans les réseaux publics (de 100 Hz à 3 000 Hz)

4.10.2 Systèmes de courants porteurs en ligne moyenne fréquence (de 3 kHz à 20 kHz)

4.10.3 Systèmes de courants porteurs en ligne radiofréquence (de 20 kHz à 148,5 kHz)

Due to the highly heterogeneous characteristics of various systems, no general recommendations can be provided It is the responsibility of manufacturers to ensure compatibility between their systems and the power network.

Figure 1 – Meister curve for ripple control systems in public networks

4.10.2 Medium-frequency power-line carrier systems (3 kHz to 20 kHz)

4.10.3 Radio-frequency power-line carrier systems (20 kHz to 148,5 kHz)

Due to the unique features of different systems, manufacturers must ensure compatibility between their systems and the supply network, as no universal guidelines can be provided.

Rôle des niveaux de compatibilité et de planification en CEM

Besoin pour les niveaux de compatibilité

Electromagnetic compatibility (EMC) addresses the potential degradation of performance in electrical or electronic equipment caused by disturbances in the electromagnetic environment where the equipment operates To ensure compatibility, two essential conditions must be met.

• il faut que l’émission de perturbations dans l’environnement électromagnétique soit maintenue en dessous du niveau qui conduirait à une dégradation inacceptable des performances du matériel fonctionnant dans cet environnement;

• il faut que tout matériel fonctionnant dans l’environnement électromagnétique possède une immunité suffisante à toutes les perturbations, pour les niveaux qui sont les leurs dans l’environnement.

Les limites d’émission et d’immunité ne peuvent être fixées indépendamment l’une de l’autre.

Clearly, the more effectively emissions are controlled, the less stringent the immunity requirements for the equipment will be Similarly, if the equipment is highly immune to disturbances, there is no need to impose very strict emission limits.

Il est donc nécessaire de bien coordonner les limites d’émission et d’immunité C’est la principale fonction des niveaux de compatibilité indiqués dans cette norme.

The disturbances in question involve phenomena occurring on public alternative medium-voltage distribution networks Essentially, the power network, which is responsible for transporting electrical energy from production plants to consumer equipment, inadvertently also transmits electromagnetic disturbances from their sources to sensitive equipment.

Trois facteurs sont pris en compte lors de la définition des niveaux de compatibilité relatifs aux différents phénomènes:

The compatibility level refers to the degree of disturbance that may occur in the environment, with a low probability of exceeding 5% For certain disturbances, observed levels are increasing, highlighting the need for a long-term perspective.

• il s’agit d’un niveau de perturbation qui peut être maintenu en appliquant des règles d’émission réalistes;

• il s’agit du niveau de perturbation auquel un matériel fonctionnant dans l’environnement correspondant doit être immunisé, avec une marge convenable.

Relation entre niveau de compatibilité et niveau d’immunité

For each phenomenon, the compatibility level should be viewed as the potential level of disturbance that may occur in the corresponding environment Any equipment designed to operate in this environment must possess immunity that is equal to or greater than this disturbance level An appropriate margin will be maintained between the compatibility and immunity levels for the specific equipment.

The function of compatibility levels and planning levels in EMC

A.1 The need for compatibility levels

Electromagnetic compatibility (EMC) addresses the potential decline in performance of electrical and electronic devices caused by disturbances in their electromagnetic environment To ensure compatibility, two key requirements must be met.

• the emission of disturbances into the electromagnetic environment must be maintained below a level that would cause an unacceptable degradation of the performance of equipment operating in that environment;

• all equipment operating in the electromagnetic environment must have sufficient immunity from all disturbances at the levels at which they exist in the environment.

Emission limits and immunity requirements are interdependent; effective emission control allows for less stringent immunity demands on equipment Conversely, highly immune equipment reduces the necessity for strict emission limits.

There is a requirement, therefore, for close co-ordination between the limits adopted for emission and immunity That is the principal function of the compatibility levels specified in this standard.

The article discusses disturbance phenomena in medium voltage networks of public AC power supply systems It highlights that while these systems are designed to transmit electrical energy from generating stations to end-users, they inadvertently also serve as conduits for electromagnetic disturbances, affecting the connected equipment.

Three considerations have been borne in mind in setting the compatibility level for each phenomenon:

The compatibility level refers to the expected disturbance in the environment, with a small probability of exceeding 5% As the severity of certain disturbance phenomena increases, a long-term perspective becomes essential.

• it is a disturbance level which can be maintained by implementing practicable limits on emissions;

• it is the level of disturbance from which, with a suitable margin, equipment operating in the relevant environment must have immunity

A.2 Relation between compatibility level and immunity levels

It is essential to identify the compatibility level of each disturbance phenomenon, which indicates the severity that can occur in a specific environment All equipment designed for use in that environment must possess immunity that meets or exceeds this disturbance level Typically, a margin is established between the compatibility and immunity levels, tailored to the specific equipment involved.

Additionally, compatibility levels have been established for disturbances, assessed individually, and specifically for individual frequencies in the case of harmonics and interharmonics In practice, it is important to recognize that multiple disturbances typically coexist in the environment, and the performance of certain equipment may be compromised when exposed to a specific combination of disturbances, even if each one is below its respective compatibility level.

For instance, in the case of harmonics and interharmonics, specific combinations of frequencies, amplitudes, and phases can significantly alter the peak value of the voltage and/or its zero-crossing point The presence of additional disturbances can further complicate the situation.

Dans la mesure ó le nombre de combinaisons possible est infini, il est impossible de fixer des niveaux de compatibilité pour les combinaisons de perturbations.

If there is a combination of disturbances below compatibility levels that leads to a degradation in the performance of a given product, it is essential to identify this combination so that the product's immunity can be specified accordingly.

Relation entre niveau de compatibilité et limite d’émission

It is important to note that some disturbances originate from atmospheric phenomena, such as lightning, or from the normal and inevitable response of a well-designed power network to electrical faults or the switching of specific loads or equipment This category includes transient overvoltages, voltage dips, and brief power interruptions No emission limits can be defined for these phenomena since the sources of disturbance are largely uncontrollable In this case, compatibility levels reflect the severity of disturbances that can be expected in practice.

Many disturbances originate from electrical applications connected to the public grid or, to a lesser extent, from the network equipment itself These disturbances occur when such devices draw current that is not a constant or regular function of the supply voltage, exhibiting sudden variations or failing to follow the complete cycle of the voltage waveform This distorted current flows through the impedances of the power supply network, causing similar distortions in the voltage.

Although reducing network impedance is sometimes necessary to mitigate the effects of specific disturbance sources, these impedances are often determined based on factors like voltage regulation and other considerations, rather than their impact on disturbance attenuation.

Tension deformations are transmitted to other equipment that may be sensitive to them The disturbance levels at the terminals of this equipment depend on the type, number, and location of the disruptive devices operating at any given time, as well as how the disturbances from these various sources combine to produce specific levels in particular locations It is essential that these levels remain below compatibility thresholds.

Compatibility levels have been established for various disturbance phenomena, including specific frequencies for harmonics and interharmonics It is important to note that multiple disturbance phenomena often coexist in the environment, and certain combinations of these disturbances can degrade the performance of equipment, even if each individual disturbance is below the compatibility level.

Harmonics and interharmonics can significantly impact voltage peaks and zero crossing points due to specific combinations of frequency, magnitude, and phasing Additionally, the presence of other disturbances can further complicate these effects.

Because the number of permutations is infinite, it is not possible to set compatibility levels for combinations of disturbances.

To ensure optimal product performance, it is essential to identify any combinations of disturbances within the compatibility levels that may negatively impact the product This identification allows for the appropriate consideration of the product's immunity requirements.

A.3 Relation between compatibility level and emission limits

Some disturbances originate from atmospheric phenomena, particularly lightning, or from the natural responses of a well-designed supply system to electrical faults or load switching Key disturbances include transient overvoltages, voltage dips, and short supply interruptions Emission limits cannot be established for these phenomena due to the uncontrollable nature of their sources Instead, the compatibility level aims to represent the expected severity of these disturbances in practical scenarios.

Disturbances in public electricity supply often originate from the equipment used to utilize this power, as well as, to a lesser extent, from components of the supply system itself These disturbances occur when the equipment draws an irregular current that does not consistently align with the supplied voltage, leading to abrupt variations or incomplete cycles of the voltage waveform Consequently, these irregular currents pass through the supply network's impedances, resulting in voltage irregularities.

While some network impedances may be reduced to address specific disturbances, they are typically fixed due to voltage regulation and other factors unrelated to disturbance mitigation.

Voltage irregularities can disrupt various equipment, with the severity of the disturbance influenced by the types, number, and locations of emission sources The combination of emissions from these sources determines the disturbance levels at specific locations, which must remain within acceptable compatibility limits.

The relationship between compatibility levels and emission limits is more complex than that between compatibility levels and immunity levels This complexity arises from the diverse sources of disturbances and, particularly for low-frequency disturbances, the limits set for each source consider the cumulative effect of emissions from multiple similar sources, which together contribute to the overall disturbance level in the environment represented by the compatibility level Additionally, many emission limits are expressed in current, while compatibility levels are predominantly expressed in voltage for most disturbances, necessitating the consideration of network impedance.

However, the implementation of emission limits ensures that actual disturbance levels will not exceed the compatibility threshold, except in unlikely cases accepted in EMC.

Emission limits for a specific type of equipment cannot be established in isolation; they must be coordinated with the limits set for all other equipment contributing to the same disturbance This coordination ensures that when all sources adhere to their individual limits and operate simultaneously under normal environmental conditions, the resulting disturbance level remains below the compatibility threshold.

Les sources de perturbations sont extrêmement variées, mais il est utile de les diviser en deux grandes catégories:

• Equipements et installations de forte puissance

In the past, this category primarily represented the sole sources of low-frequency disturbances, such as harmonics and voltage fluctuations A key feature of these installations is that their existence is always communicated to the electricity supplier, who can then collaborate with the operator or owner to establish operating conditions that limit emissions to an acceptable level Additionally, they can define supply conditions to ensure that the disturbances produced do not affect other equipment connected to the power grid The solution is specific to the location in question.

Niveaux de planification

In the context of high-power loads and installations, the power supply network managers play a crucial role They utilize the concept of planning level, as defined in section 3.1.5, to establish the applicable emission limits for these installations.

Planning levels primarily apply to medium and high voltage networks However, low-frequency conducted disturbances propagate in both directions between low voltage networks and higher voltage levels Therefore, emission limit coordination must consider all voltage levels.

L’utilisation des niveaux de planification est décrite dans les rapports techniques

CEI 61000-3-6 et CEI 61000-3-7 Les points importants sont les suivants.

The planning level is a value determined by the entity responsible for the planning and operation of the power supply network in a specific area It is used to establish emission limits applicable to installations and high-power loads that need to be connected to the network in that area This approach aids in distributing emission limitations as fairly as possible.

The planning level cannot exceed the compatibility level, typically maintaining a margin influenced by various factors such as the type of disturbance, the design and maintenance of the power supply network, existing disturbance levels, the potential for resonance, and load profiles Therefore, it is contingent upon the specific point of consideration.

Although planning primarily focuses on high-power equipment and installations, it is essential to consider the numerous other disruptive sources, particularly the many low-power devices connected at low voltage The available margin to tolerate emissions from high-power installations practically depends on the effectiveness of the limits set for low-power devices Any challenges in this area indicate the need for stricter emission regulations for low-power devices The main objective is to ensure that the anticipated level of disturbance does not exceed the compatibility level.

Illustration des niveaux de compatibilité, d’émission, d’immunité et de

The various limits and levels of electromagnetic compatibility (EMC) are illustrated in Figure A.1 While not mathematically precise, this figure effectively demonstrates the relationships between different values Its schematic representation is intentional, particularly in showing the relative positions of the two curves, which indicate that overlap may occur but should not be interpreted as an accurate measure of the extent of that overlap.

In power supply systems for large loads and installations, those in charge play a crucial role in establishing suitable emission limits They utilize the concept of planning level, as outlined in section 3.1.5, to guide their decisions.

Currently, planning levels are mainly applicable to medium and high voltage networks Nevertheless, low frequency conducted disturbances can travel in both directions between low voltage and higher voltage networks Therefore, the coordination of emission limits must consider all voltage levels.

The use of planning levels is described in the technical reports IEC 61000-3-6 and

IEC 61000-3-7 The important points are as follows.

The planning level is a crucial value established by the authority managing the power supply system in a specific region It plays a significant role in determining emission limits for large loads and installations that intend to connect to the system This value aids in the fair distribution of emission limitation responsibilities among various entities.

The planning level must not exceed the compatibility level, typically remaining lower by a margin influenced by various factors These include the nature of the disturbance phenomenon, the design and maintenance of the supply network, background disturbance levels, resonance potential, and load profiles, making it specific to local conditions.

Effective planning for large equipment and installations must also consider various low-power devices connected at low voltage, as they can contribute to disturbances The capacity to manage emissions from larger installations is influenced by the regulation of low-power equipment Challenges in this area highlight the need for stricter emission controls on low-power devices Ultimately, the primary goal is to ensure that the anticipated disturbance levels remain within acceptable compatibility limits.

A.5 Illustration of compatibility, emission, immunity and planning levels

Figure A.1 displays the different EMC levels and limits, providing a schematic representation of their relationships While the figure is not mathematically precise, it highlights that overlap between the two curves can occur However, this overlap should not be viewed as an exact measure of its extent.

Dens ité de probabi lit é

Limites d’émission pour les sources individuelles Niveaux de planification

Niveau de perturbation sur le réseau

Figure A.1 – Relation entre les niveaux de compatibilité, d’immunité, de planification et d’émission

P robabi lit y den si ty

Emission limits individual sources Planning levels

Figure A.1 – Relation between compatibility, immunity, planning and emission levels

Tiêu đề	Part 2-12: Environment – Compatibility Levels for Low-Frequency Conducted Disturbances and Signalling in Public Medium-Voltage Power Supply Systems
Chuyên ngành	Electromagnetic Compatibility (EMC)
Thể loại	International Standard
Năm xuất bản	2003

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