SIST EN 50160:2011

Voltage characteristics of electricity supplied by public distribution networks

This European Standard defines, describes and specifies the main characteristics of the voltage at a network user's supply terminals in public low voltage, medium and high voltage AC electricity networks under normal operating conditions. This standard describes the limits or values within which the voltage characteristics can be expected to remain at any supply terminal in public European electricity networks and does not describe the average situation usually experienced by an individual network user. NOTE 1   For the definitions of low, medium and high voltage see 3 (Definitions). This European Standard does not apply under abnormal operating conditions, including the following: a)   a temporary supply arrangement to keep network users supplied during conditions arising as a result of a fault, maintenance and construction work, or to minimize the extent and duration of a loss of supply; b)   in the case of non-compliance of a network user's installation or equipment with the relevant standards or with the technical requirements for connection, established either by the public authorities or the network operator, including the limits for the emission of conducted disturbances; NOTE 2   A network user’s installation may include load and generation. c)   in exceptional situations, in particular, 1)   exceptional weather conditions and other natural disasters;  2)   third party interference; 3)   acts by public authorities;  4)   industrial actions (subject to legal requirements);  5)   force majeure;  6)   power shortages resulting from external events. The voltage characteristics given in this standard are not intended to be used as electromagnetic compatibility (EMC) levels or user emission limits for conducted disturbances in public electricity networks. The voltage characteristics given in this standard are not intended to be used to specify requirements in equipment product standards and in installation standards. NOTE 3   The performance of equipment might be impaired if it is subjected to supply conditions which are not specified in the equipment product standard. This standard may be superseded in total or in part by the terms of a contract between the individual network user and the network operator. NOTE 4   The sharing of complaint management and problem mitigation costs between the involved parties is outside the scope of EN 50160. Measurement methods to be applied in this standard are described in EN 61000-4-30.

Merkmale der Spannung in öffentlichen Elektrizitätsversorgungsnetzen

Caractéristiques de la tension fournie par les réseaux publics de distribution

Cette Norme Européenne définit, décrit et spécifie, au point de livraison de l’utilisateur du réseau, les caractéristiques principales de tension fournie par un réseau public basse tension, moyenne tension et haute tension AC dans des conditions normales d'exploitation. Cette norme décrit les limites ou les valeurs des caractéristiques de la tension qui peuvent être attendues en chaque point de livraison du réseau public et ne décrit pas la situation moyenne habituellement rencontrée par un utilisateur du réseau. NOTE 1   Voir les définitions de la basse tension, moyenne tension et haute tension de 3 (Définitions). Cette Norme Européenne ne s'applique pas dans les situations d'exploitation anormales, y compris dans les cas suivants: a)   conditions d'alimentation provisoires pour maintenir les utilisateurs du réseau alimentés suite à une avarie, pendant les travaux d'entretien ou de construction sur le réseau ou pour limiter l'étendue et la durée d'une interruption d'alimentation; b)   non conformité de l'installation ou des équipements de l’utilisateur du réseau aux normes applicables ou aux exigences techniques de raccordement de charges établies soit par l'administration, soit par le gestionnaire de réseau incluant les limites d'émission de perturbations conduites; NOTE 2   L'installation d’un utilisateur du réseau peut inclure des charges et de la production. c)   dans les situations exceptionnelles, en particulier, 1)   conditions climatiques exceptionnelles et autres catastrophes naturelles,  2)   faits provenant de tiers, 3)   décisions officielles,  4)   faits de grève (soumises à des exigences légales),  5)   force majeure,  6)   interruptions dues à des causes externes. Les caractéristiques de la tension données dans cette norme ne sont pas destinées à être utilisées comme des niveaux de compatibilité électromagnétique (CEM) ou comme des limitations d’émission de l'utilisateur pour les perturbations conduites dans les réseaux publics de distribution. Elles ne sont pas non plus destinées à être utilisées pour définir les exigences dans les normes de produit des équipements et les normes d’installation. NOTE 3   Les performances d’un équipement peuvent être dégradées si les conditions d’alimentation ne sont pas celles spécifiées dans la norme produit correspondante. Cette norme peut être en tout ou en partie remplacée par les termes d'un contrat conclu entre un utilisateur du réseau et le gestionnaire de réseau. NOTE 4   Le partage entre les parties de la gestion des réclamations et des coûts liés à l’atténuation des problèmes est hors du domaine d’application de l’EN 50160. Les méthodes de mesure appliquées dans la présente norme sont décrites dans l’EN 61000-4-30.

Značilnosti napetosti v javnih razdelilnih omrežjih

Ta evropski standard opredeljuje, opisuje in določa glavne značilnosti napetosti pri napajalnih terminalih uporabnikov omrežja v javnih električnih omrežjih nizke, srednje in visoke izmenične napetosti pod normalnimi pogoji delovanja. Ta standard opisuje meje oziroma vrednosti, v okviru katerih lahko pričakujemo, da bodo značilnosti napetosti ostale na katerem koli napajalnem terminalu v javnih evropskih električnih omrežjih, in ne opisuje povprečnega stanja, ki ga običajno občuti posamezen mrežni uporabnik. Ta evropski standard ne velja pod nenormalnimi pogoji delovanja, vključno z naslednjim: a) začasni dobavni režim, da se zagotovi dobava mrežnim uporabnikom med pogoji, ki so nastali zaradi okvare, vzdrževalnih ali gradbenih del, ali za zmanjšanje obsega in trajanja izgube dobave; b) pri neskladnosti inštalacije ali opreme mrežnih uporabnikov s pomembnimi standardi ali s tehničnimi zahtevami za povezavo, ki jo vzpostavijo državni organi ali omrežni operater, vključno z mejami za emisije opravljenih motenj; c) v izrednih okoliščinah, še posebej, 1) izredni vremenski pogojih in druge naravne katastrofe; 2) motnje, ki jih povzroči tretja oseba; 3) zakoni državnih organov 4) industrijski vplivi (ki so predmet pravnih zahtev); 5) višja sila; 6) pomanjkanje električne energije zaradi zunanjih dogodkov. Značilnosti napetosti, podane v tem standardu, niso namenjene uporabi kot stopnje elektromagnetne skladnosti (EMC) ali meje emisij uporabnikov za izvedene motnje v javnih električnih omrežjih. Značilnosti napetosti, podane v tem standardu, niso namenjene določevanju zahtev proizvodnih standardov za opremo in standardov za inštalacijo.

General Information

• Status: Withdrawn
• Public Enquiry End Date: 30-Jun-2008
• Publication Date: 08-Feb-2011
• Withdrawal Date: 01-Dec-2025
• ICS: 29.240.01 - Power transmission and distribution networks in general
• Technical Committee: NTF - Electricity energy supply systems
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 21-Nov-2025
• Due Date: 14-Dec-2025
• Completion Date: 02-Dec-2025
• Mandate: M/490 - Standardisation mandate to the European Standardisation Organisations (ESOs) to support European Smart Grid deployment
• Ref Project: EN 50160:2010 - Voltage characteristics of electricity supplied by public electricity networks

Relations

• Replaces: SIST EN 50160:2008 - Voltage characteristics of electricity supplied by public distribution networks
• Effective Date: 28-Jan-2023
• Replaced By: SIST EN 50160:2023 - Voltage characteristics of electricity supplied by public distribution networks
• Effective Date: 20-Dec-2022
• Corrected By: SIST EN 50160:2011/AC:2013 - Voltage characteristics of electricity supplied by public electricity networks
• Effective Date: 28-Jan-2023
• Revised: SIST EN 50160:2008 - Voltage characteristics of electricity supplied by public distribution networks
• Effective Date: 05-Mar-2013

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Merkmale der Spannung in öffentlichen ElektrizitätsversorgungsnetzenCaractéristiques de la tension fournie par les réseaux publics de distributionVoltage characteristics of electricity supplied by public distribution networks29.240.01Power transmission and distribution networks in generalICS:Ta slovenski standard je istoveten z:EN 50160:2010SIST EN 50160:2011en,fr,de01-marec-2011SIST EN 50160:2011SLOVENSKI
STANDARDSIST EN 50160:20081DGRPHãþD

EUROPEAN STANDARDEN 50160 NORME EUROPÉENNE EUROPÄISCHE NORM July 2010
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2010 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 50160:2010 E
ICS 29.020 Supersedes EN 50160:2007
English version
Voltage characteristics of electricity supplied by public electricity networks
Caractéristiques de la tension fournie par les réseaux publics de distribution
Merkmale der Spannung in öffentlichen Elektrizitätsversorgungsnetzen
This European Standard was approved by CENELEC on 2010-03-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
This European Standard was prepared by Working Group 1, Physical characteristics of electrical energy, of the Technical Committee CENELEC TC 8X, System aspects of electrical energy supply. It was submitted to the formal vote and was approved by CENELEC as EN 50160 on 2010-03-01. This document is the result of an intensive cooperation between CENELEC and CEER, with involvement of CEER experts in TC 8X WG1 as well as in related Task Forces. This document supersedes EN 50160:2007. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights. The following dates were fixed: – latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement
(dop)
2011-03-01 – latest date by which the national standards conflicting with the EN have to be withdrawn
(dow)
2015-03-01 The main differences from EN 50160:2007 are: – new organization of the document by grouping clauses related to events and continuous phenomena; – modification of some definitions and completion by some new definitions; – new Clause 6 relevant to voltage characteristics in high voltage networks. This work has been deemed so important, that before submission for vote, a CENELEC enquiry has been made, where NCs had the opportunity to respond to the most essential questions resulting from the WG discussions. This enquiry resulted in an extensive number of valuable comments, which have been carefully examined for possible consideration either for the voting draft in particular or for further work within WG1 on some main issues. Following that, the draft has been revised in depth, considering in particular the comments received on: – the subclauses relevant to supply voltage changes, where a new formulation (capable of encompassing the needs expressed by the vast majority of the NCs) has been introduced, – the new Clause 6, relevant to voltage characteristics in high voltage networks, where limits for harmonics and unbalance have been changed into indicative values, as new measurement surveys are taking place in several European countries, and it has been recognized as appropriate to wait for the relevant results before considering the setting of limits. SIST EN 50160:2011

– 3 – EN 50160:2010 Contents 1Scope and object . 41.1Scope . 41.2Object . 42Normative references . 53Terms and definitions . 54Low-voltage supply characteristics . 104.1 General . 10 4.2 Continuous phenomena . 11 4.3 Voltage events . 14 5Medium-voltage supply characteristics . 165.1 General . 16 5.2 Continuous phenomena . 17 5.3 Voltage events . 20 6High-voltage supply characteristics . 226.1 General . 22 6.2 Continuous phenomena . 23 6.3 Voltage events . 25 Annex A
(informative)
Special nature of electricity . 28Annex B
(informative)
Indicative values for voltage events and single rapid voltage changes . 30 B.1 Long interruptions of the supply voltage . 30 B.2 Short interruptions of the supply voltage . 30 B.3 Voltage dips and swells . 30 B.4 Swells (temporary power frequency overvoltages) between live conductors
and earth . 32 B.5 Magnitude of rapid voltage changes . 32 Bibliography . 33Figures Figure 1
Voltage levels of signal frequencies in percent of Un used in public LV networks . 13 Figure 2
Voltage levels of signal frequencies in percent of Uc used in public MV networks . 20 Tables Table 1
Values of individual harmonic voltages at the supply terminals
for orders up to 25 given in percent of the fundamental voltage U1 . 13 Table 2
Classification of dips according to residual voltage and duration . 15 Table 3
Classification of swells according to maximum voltage and duration . 16 Table 4
Values of individual harmonic voltages at the supply terminals for orders up to 25 given in percent of the fundamental voltage U1 . 19 Table 5
Classification of dips according to residual voltage and duration . 21 Table 6
Classification of swells according to maximum voltage and duration . 22 Table 7
Indicative values of individual harmonic voltages at the supply terminals for orders up to 25 given in percent of the fundamental voltage U1 . 24 Table 8
Classification of dips according to residual voltage and duration . 26 Table 9
Classification of swells according to maximum voltage and duration . 26 SIST EN 50160:2011

1.1 Scope This European Standard defines, describes and specifies the main characteristics of the voltage at a network user's supply terminals in public low voltage, medium and high voltage AC electricity networks under normal operating conditions. This standard describes the limits or values within which the voltage characteristics can be expected to remain at any supply terminal in public European electricity networks and does not describe the average situation usually experienced by an individual network user. NOTE 1
For the definitions of low, medium and high voltage see 3 (Definitions). This European Standard does not apply under abnormal operating conditions, including the following: a) a temporary supply arrangement to keep network users supplied during conditions arising as a result of a fault, maintenance and construction work, or to minimize the extent and duration of a loss of supply; b) in the case of non-compliance of a network user's installation or equipment with the relevant standards or with the technical requirements for connection, established either by the public authorities or the network operator, including the limits for the emission of conducted disturbances; NOTE 2
A network user’s installation may include load and generation. c) in exceptional situations, in particular, 1) exceptional weather conditions and other natural disasters;
2) third party interference; 3) acts by public authorities;
4) industrial actions (subject to legal requirements);
5) force majeure;
6) power shortages resulting from external events. The voltage characteristics given in this standard are not intended to be used as electromagnetic compatibility (EMC) levels or user emission limits for conducted disturbances in public electricity networks. The voltage characteristics given in this standard are not intended to be used to specify requirements in equipment product standards and in installation standards. NOTE 3
The performance of equipment might be impaired if it is subjected to supply conditions which are not specified in the equipment product standard. This standard may be superseded in total or in part by the terms of a contract between the individual network user and the network operator. NOTE 4
The sharing of complaint management and problem mitigation costs between the involved parties is outside the scope of EN 50160. Measurement methods to be applied in this standard are described in EN 61000-4-30. 1.2 Object
The object of this European Standard is to define, describe and specify the characteristics of the supply voltage concerning: a) frequency; b) magnitude; c) waveform; d) symmetry of the line voltages. SIST EN 50160:2011

– 5 – EN 50160:2010
These characteristics are subject to variations during the normal operation of a supply system due to changes of load, disturbances generated by certain equipment and the occurrence of faults which are mainly caused by external events.
The characteristics vary in a manner which is random in time, with reference to any specific supply terminal, and random in location, with reference to any given instant of time. Because of these variations, the values given in this standard for the characteristics can be expected to be exceeded on a small number of occasions.
Some of the phenomena affecting the voltage are particularly unpredictable, which make it very difficult to give useful definite values for the corresponding characteristics. The values given in this standard for the voltage characteristics associated with such phenomena, e.g. voltage dips and voltage interruptions, shall be interpreted accordingly.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 60664-1 2007 Insulation coordination for equipment within low-voltage systems – Part 1: Principles, requirements and tests (IEC 60664-1:2007) EN 61000-3-3 2008 Electromagnetic compatibility (EMC) –
Part 3-3: Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ≤ 16 A per phase and not subject to conditional connection (IEC 61000-3-3:2008) EN 61000-4-30 2009 Electromagnetic compatibility (EMC) –
Part 4-30: Testing and measurement techniques – Power quality measurement methods (IEC 61000-4-30:2008) IEC 60364-5-53 + A1 2001 2002 Electrical installations of buildings –
Part 5-53: Selection and erection of electrical equipment – Isolation, switching and control IEC/TR 61000-2-8 2002 Electromagnetic compatibility (EMC) –
Part 2-8: Environment – Voltage dips and short interruptions on public electric power supply systems with statistical measurement results IEC/TR 61000-3-7 2008 Electromagnetic compatibility (EMC) –
Part 3-7: Assessment of emission limits for fluctuating loads in MV and HV power systems
3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 conducted disturbance electromagnetic phenomenon propagated along the line conductors of a supply network
NOTE In some cases an electromagnetic phenomenon is propagated across transformer windings and hence between networks of different voltage levels. These disturbances may degrade the performance of a device, equipment or system or they may cause damage. 3.2 declared supply voltage
Uc supply voltage Uc agreed by the network operator and the network user NOTE Generally declared supply voltage Uc is the nominal voltage Un but it may be different according to the agreement between the network operator and the network user.
NOTE Application: Harmonic voltages can be evaluated: – individually by their relative amplitude (uh) which is the harmonic voltage related to the fundamental voltage u1, where h is the order of the harmonic; – globally, for example by the total harmonic distortion factor THD, calculated using the following expression: ∑==4022)(hhuTHD NOTE Harmonics of the supply voltage are caused mainly by network users' non-linear loads connected to all voltage levels of the supply network. Harmonic currents flowing through the network impedance give rise to harmonic voltages. Harmonic currents and network impedances and thus the harmonic voltages at the supply terminals vary in time. 3.7 high voltage
HV voltage whose nominal r.m.s. value is 36 kV < Un ≤ 150 kV NOTE
Because of existing network structures, in some countries the boundary between MV and HV can be different. 3.8 interharmonic voltage sinusoidal voltage with a frequency not equal to an integer multiple of the fundamental NOTE
Interharmonic voltages at closely adjacent frequencies can appear at the same time forming a wide band spectrum. SIST EN 50160:2011

– 7 – EN 50160:2010 3.9 low voltage
LV voltage whose nominal r.m.s. value is Un ≤ 1 kV 3.10 mains signalling voltage signal superimposed on the supply voltage for the purpose of transmission of information in the public supply network and to network users' premises.
NOTE Classification: three types of signals in the public supply network can be classified: – ripple control signals: superimposed sinusoidal voltage signals in the frequency range 110 Hz to 3 000 Hz; – power-line-carrier signals: superimposed sinusoidal voltage signals in the frequency range 3 kHz to 148,5 kHz; – mains marking signals: superimposed short time alterations (transients) at selected points of the voltage waveform 3.11 medium voltage
MV voltage whose nominal r.m.s. value is 1 kV < Un ≤ 36 kV NOTE
Because of existing network structures, in some countries the boundary between MV and HV can be different. 3.12 network user party being supplied by or supplying to an electricity supply network
NOTE
In several countries, the term network user includes network operators connected to a supply network with the same or higher voltage level. 3.13 network operator
party responsible for operating, ensuring the maintenance of, and if necessary developing, the supply network in a given area and responsible for ensuring the long term ability of the network to meet reasonable demands for electricity supply 3.14 nominal frequency nominal value of the frequency of the supply voltage 3.15 normal operating condition operating condition for an electricity network, where load and generation demands are met, system switching operations are made and faults are cleared by automatic protection systems, in the absence of
exceptional circumstances, i.e.: a) temporary supply arrangement; b) in the case of non-compliance of a network user’s installation or equipment with the relevant standards or with the technical requirements for connection; c) exceptional situations, such as: 1) exceptional weather conditions and other natural disasters; 2) third party interference; 3) acts by public authorities; 4) industrial actions (subject to legal requirements); SIST EN 50160:2011

Un voltage by which a supply network is designated or identified and to which certain operating characteristics are referred 3.17 rapid voltage change single rapid variation of the r.m.s. value of a voltage between two consecutive levels which are sustained for definite but unspecified durations
NOTE For more information see EN 61000-3-3. 3.18 reference voltage (for interruptions, voltage dips and voltage swells evaluation) a value specified as the base on which residual voltage, thresholds and other values are expressed in per unit or percentage terms
NOTE
For the purpose of this standard, the reference voltage is the nominal or declared voltage of the supply system. 3.19 supply interruption condition in which the voltage at the supply terminals is lower than 5 % of the reference voltage NOTE 1 Classification: a supply interruption can be classified as: a) prearranged, when network users are informed in advance; or b) accidental, caused by permanent or transient faults, mostly related to external events, equipment failures or interference. An accidental interruption is classified as: 1) a long interruption (longer than 3 min); 2) a short interruption (up to and including 3 min). NOTE 2
Normally, interruptions are caused by the operation of switches or protective devices. NOTE 3
The effect of a prearranged interruption can be minimized by network users by taking appropriate measures. NOTE 4
Prearranged interruptions are typically due to the execution of scheduled works on the electricity network. NOTE 5
Accidental supply interruptions are unpredictable, largely random events. NOTE 6
For polyphase systems, an interruption occurs when the voltage falls below 5 % of the reference voltage on all phases (otherwise, it is considered to be a dip). NOTE 7
In some countries, the term Very Short Interruptions (VSI) or transitory interruptions are used to classify interruptions with duration shorter than 1 s to 5 s. Such interruptions are related to automatic reclosing device operation. 3.20 supply terminal point in a public supply network designated as such and contractually fixed, at which electrical energy is exchanged between contractual partners NOTE
This point can differ from, for example, the electricity metering point or the point of common coupling. 3.21 supply voltage r.m.s. value of the voltage at a given time at the supply terminal, measured over a given interval SIST EN 50160:2011

– 9 – EN 50160:2010 3.22 transient overvoltage short duration oscillatory or non-oscillatory overvoltage usually highly damped and with a duration of a few milliseconds or less [IEV 604-03-13, modified] NOTE Transient overvoltages are usually caused by lightning, switching or operation of fuses. The rise time of a transient overvoltage can vary from less than a microsecond up to a few milliseconds. 3.23 voltage dip temporary reduction of the r.m.s. voltage at a point in the electrical supply system below a specified start threshold
NOTE 1 Application: for the purpose of this standard, the dip start threshold is equal to 90 % of the reference voltage. NOTE 2 Typically, a dip is associated with the occurrence and termination of a short circuit or other extreme current increase on the system or installations connected to it. NOTE 3 For the purpose of this standard, a voltage dip is a two dimensional electromagnetic disturbance, the level of which is determined by both voltage and time (duration). 3.24 voltage dip duration
time between the instant at which the r.m.s. voltage at a particular point of an electricity supply system falls below the start threshold and the instant at which it rises to the end threshold NOTE 1 Application: for the purpose of the standard, the duration of a voltage dip is from 10 ms up to and including 1 min. NOTE 2 For polyphase events, a dip begins when one voltage falls below the dip start threshold and ends when all voltages are equal to or above the dip end threshold. 3.25 voltage dip end threshold
r.m.s. value of the voltage on an electricity supply system specified for the purpose of defining the end of a voltage dip
3.26 voltage dip residual voltage minimum value of r.m.s. voltage recorded during a voltage dip NOTE
For the purpose of this standard, the residual voltage is expressed as a percentage of the reference voltage. 3.27 voltage dip start threshold r.m.s. value of the voltage on an electricity supply system specified for the purpose of defining the start of a voltage dip 3.28 voltage fluctuation series of voltage changes or a cyclic variation of the voltage envelope [IEV 161-08-05] 3.29 voltage swell
temporary power frequency overvoltage temporary increase of the r.m.s. voltage at a point in the electrical supply system above a specified start threshold NOTE 1 Application: for the purpose of this standard, the swell start threshold is equal to the 110 % of the reference voltage (see CLC/TR 50422, Clause 3, for more information). SIST EN 50160:2011

r.m.s. value of the voltage on an electricity supply system specified for the purpose of defining the start of a voltage swell 3.33 voltage unbalance condition in a polyphase system in which the r.m.s. values of the line-to-line voltages (fundamental component), or the phase angles between consecutive line voltages, are not all equal [IEV 161-08-09, modified] NOTE 1
The degree of the inequality is usually expressed as the ratios of the negative and zero sequence components to the positive sequence component. NOTE 2
In this European Standard, voltage unbalance is considered in relation to three-phase systems and negative phase sequence only. 3.34 voltage variation increase or decrease of r.m.s. voltage normally due to load variations 4 Low-voltage supply characteristics
4.1 General
This clause describes the voltage characteristics of electricity supplied by public low voltage networks. In the following, a distinction is made between – continuous phenomena, i.e. deviations from the nominal value that occur continuously over time. Such phenomena occur mainly due to load pattern, changes of load or nonlinear loads, – voltage events, i.e. sudden and significant deviations from normal or desired wave shape. Voltage events typically occur due to unpredictable events (e.g. faults) or to external causes (e.g. weather conditions, third party actions).
For some continuous phenomena, limits are specified 1) 2); for voltage events, only indicative values can be given at present (see Annex B).
The standard nominal voltage Un for public low voltage is Un = 230 V, either between phase and neutral, or between phases.
– for four-wire three phase systems: Un = 230 V between phase and neutral;
1) For single rapid voltage changes, only indicative values are given for the time being. 2) For some specific parameters, in some national regulations stricter limits may exist. SIST EN 50160:2011

– 11 – EN 50160:2010
– for three-wire three phase systems: Un = 230 V between phases.
NOTE In low voltage systems declared and nominal voltage are equal.
4.2 Continuous phenomena
4.2.1 Power frequency
The nominal frequency of the supply voltage shall be 50 Hz. Under normal operating conditions the mean value of the fundamental frequency measured over 10 s shall be within a range of:
– for systems with synchronous connection to an interconnected system: 50 Hz ± 1 % (i.e. 49,5 Hz. 50,5 Hz) during 99,5 % of a year; 50 Hz + 4 % / - 6 % (i.e. 47 Hz. 52 Hz)
during 100 % of the time;
– for systems with no synchronous connection to an interconnected system (e.g. supply systems on certain islands): 50 Hz ± 2 %
(i.e. 49 Hz. 51 Hz) during 95 % of a week; 50 Hz ± 15 %
(i.e. 42,5 Hz. 57,5 Hz) during 100 % of the time.
NOTE
Related monitoring is usually done by the Control Area Operator. 4.2.2 Supply voltage variations
4.2.2.1 Requirements
Under normal operating conditions excluding the periods with interruptions, supply voltage variations should not exceed ± 10 % of the nominal voltage Un.
In cases of electricity supplies in networks not interconnected with transmission systems or for special remote network users, voltage variations should not exceed + 10 % / - 15 % of Un. Network users should be informed of the conditions. NOTE 1
The actual power consumption required by individual network users is not fully predictable, in terms of amount and of contemporaneity. As a consequence, networks are generally designed on a probabilistic basis. If, following a complaint, measurements carried out by the network operator according to 4.2.2.2 indicate that the magnitude of the supply voltage departs beyond the limits given in 4.2.2.2 causing negative consequences for the network user, the network operator should take remedial action in collaboration with the network user(s) depending on a risk assessment. Temporarily, for the time needed to solve the problem, voltage variations should be within the range + 10 % / - 15 % of Un, unless otherwise agreed with the network users. NOTE 2
In accordance with relevant product and installation standards and application of IEC 60038, network users’ appliances are typically designed to tolerate supply voltages of ± 10 % around the nominal system voltage, which is sufficient to cover an overwhelming majority of supply conditions. Generally, appliances do not need to be designed to handle wider voltage variations.
NOTE 3
Identification of what is a "special remote network user" can vary between countries, taking into account different characteristics of national electric systems as, for instance, limitation of power on the supply terminal and/or power factor limits. 4.2.2.2 Test method
Under normal operating conditions:
− during each period of one week 95 % of the 10 min mean r.m.s. values of the supply voltage shall be within the range of Un ± 10 %; and − all 10 min mean r.m.s. values of the supply voltage shall be within the range of Un + 10 % / - 15 %.
Rapid voltage changes of the supply voltage are mainly caused either by load changes in the network users' installations, by switching in the system, or by faults.
If the voltage during a change crosses the voltage dip and/or the voltage swell threshold, the event is classified as a voltage dip and/or swell rather than a rapid voltage change.
NOTE
Reference can be made to EN 61000-2-2; some indicative values can be found in Annex B. 4.2.3.2 Flicker severity
Under normal operating conditions, during each period of one week the long term flicker severity Plt caused by voltage fluctuation should be less than or equal to 1 for 95 % of the time. NOTE
Reaction to flicker is subjective and can vary depending on the perceived cause of the flicker and the period over which it persists. In some cases Plt = 1 gives rise to annoyance, whereas in other cases higher levels of Plt are noticed without annoyance. 4.2.4 Supply voltage unbalance
Under normal operating conditions, during each period of one week, 95 % of the 10 min mean r.m.s. values of the negative phase sequence component (fundamental) of the supply voltage shall be within the range 0 % to 2 % of the positive phase sequence component (fundamental).
NOTE 1
In some areas with partly single phase or two phase connected network users' installations, unbalances up to about 3 % at three-phase supply terminals occur. NOTE 2
In this European Standard only values for the negative sequence component are given because this component is the relevant one for the possible interference of appliances connected to the system.
4.2.5 Harmonic voltage
Under normal operating conditions, during each period of one week, 95 % of the 10 min mean r.m.s. values of each individual harmonic voltage shall be less than or equal to the values given in Table 1. Resonances may cause higher voltages for an individual harmonic.
Moreover, the THD of the supply voltage (including all harmonics up to the order 40) shall be less than or equal to 8 %.
NOTE The limitation to order 40 is conventional.
– 13 – EN 50160:2010 Table 1
Values of individual harmonic voltages at the supply terminals
for orders up to 25 given in percent of the fundamental voltage u1 Odd harmonics Even harmonics Not multiples of 3 Multiples of 3 Order h Relative amplitude
uh Order h Relative amplitude
uh Order h Relative amplitude uh 5 6,0 % 3 5,0 % 2
2,0 % 7 5,0 % 9 1,5 % 4
1,0 % 11 3,5 % 15 0,5 % 6 … 24 0,5 % 13 3,0 % 21 0,5 %
17 2,0 %
19 1,5 %
23 1,5 %
25 1,5 %
NOTE
No values are given for harmonics of order higher than 25, as they are usually small, but largely unpredictable due to resonance effects.
4.2.6 Interharmonic voltages
The level of interharmonics is increasing due to the development of frequency converters and similar control equipment. Levels are under consideration, pending more experience.
In certain cases interharmonics, even at low levels, give rise to flicker (see 4.2.3.2), or cause interference in ripple control systems.
4.2.7 Mains signalling voltages
In some countries the public networks may be used by the network operators for the transmission of signals. For 99 % of a day the 3 s mean value of signal voltages shall be less than or equal to the values given in Figure 1. Frequency in kHzVoltage level in percent
Figure 1
Voltage levels of signal frequencies in percent of Un used in public LV networks
NOTE 1
Power line carrier signalling with frequencies in the range from 95 kHz to 148,5 kHz may be used in network users' installations. Though the use of the public LV network is not permitted for the transmission of signals between network users, voltages of these frequencies up to 1,4 V r.m.s. in the public LV network have to be taken into account. Because of the possibility of mutual influences of neighbouring network users’ signalling systems, the network user may need to apply protection or appropriate mitigation measures for his signalling installation. SIST EN 50160:2011

For PLC purposes, in some networks also frequencies above 148,5 kHz are used. 4.3 Voltage events
4.3.1 Interruptions of the supply voltage
Interruptions are, by their nature, very unpredictable and variable from place to place and from time to time. For the time being, it is not possible to give fully representative statistical results of measurements of interruption frequency covering the whole of European networks. A reference for actual values recorded in European networks concerning interruptions is given in Annex B.
4.3.2 Supply voltage dips/swells 4.3.2.1 General
Voltage dips are typically originated by faults occurring in the public network or in network users’ installations. Voltage swells are typically caused by switching operations and load disconnections. Both phenomena are unpredictable and largely random. The annual frequency varies greatly depending on the type of supply system and on the point of observation. Moreover, the distribution over the year can be very irregular. 4.3.2.2 Voltage dip/swell measurement and detection
If statistics are collected, voltage dips/swells shall be measured and detected according to EN 61000-4-30, using as reference the nominal supply voltage. The voltage dips/swells characteristics of interest for this standard are residual voltage (maximum r.m.s. voltage for swells) and duration 3). On LV networks, for four-wire three phase systems, the line to neutral voltages shall be considered; for three-wire three phase systems the line to line voltages shall be considered; in the case of a single phase connection, the supply voltage (line to line or line to neutral, according to the network user connection) shall be considered.
Conventionally, the dip start threshold is equal to 90 % of the nominal voltage; the start threshold for swells is equal to the 110 % of the nominal voltage. The hysteresis is typically 2 %; reference rules for hysteresis are given in 5.4.2.1 of EN 61000-4-30:2009. NOTE
For polyphase measurements, it is recommended that the number of phases affected by each event are detected and stored. 4.3.2.3 Voltage dips evaluation
Evaluation of voltage dips shall be in accordance with EN 61000-4-30. The method of analyzing the voltage dips (post treatment) depends on the purpose of the evaluation.
Typically, on LV networks: − if a three-phase system is considered, polyphase aggregation shall be applied; polyphase aggregation consists of defining an equivalent event characterized by a single duration and a single residual voltage; − time aggregation applies; time aggregation consists of defining an equivalent event in the case of multiple successive events; the method used for the aggregation of multiple events can be set according to the final use of data; some reference rules are given in IEC/TR 61000-2-8.
3) In this standard, values are expressed in percentage terms of the reference voltage. SIST EN 50160:2011

– 15 – EN 50160:2010 4.3.2.4 Voltage dips classification
If statistics are collected, voltage dips shall be classified according to the table 2. The figures to be put in the cells refer to the number of equivalent events (see in 4.3.2.3) 4). NOTE
For existing measurement equipment and/or monitoring systems, Table 2 is to be taken as a recommendation. Table 2
Classification of dips according to residual voltage and duration
Residual voltage u
% Duration t ms 10 ≤≤≤≤ t ≤≤≤≤ 200 200 < t ≤≤≤≤
500 500 < t ≤≤≤≤
1 0001 000 < t ≤≤≤≤
5 000 5 000 < t ≤≤≤≤
60 00090 > u ≥ 80 CELL A1 CELL A2 CELL A3 CELL A4 CELL A5 80 > u ≥ 70 CELL B1 CELL B2 CELL B3 CELL B4 CELL B5 70 > u ≥
40 CELL C1 CELL C2 CELL C3 CELL C4 CELL C5 40 > u ≥
5 CELL D1 CELL D2 CELL D3 CELL D4 CELL D5 5 > u CELL X1 CELL X2 CELL X3 CELL X4 CELL X5
Voltage dips are, by their nature, very unpredictable and variable from place to place and from time to time. For the time being, it is not possible to give fully representative statistical results of measurements of voltage dip frequency covering the whole of European networks. A reference for actual values recorded in the European networks concerning dips is given in Annex B.
It should be noted that, due to the measurement method adopted, measurement uncertainty affecting the results has to be taken into account: this is particularly relevant for shorter events. Measurement uncertainty is addressed in EN 61000-4-30.
Generally, the duration of a voltage dip depends on the protection strategy adopted on the network, which may differ from network to network depending on network structure and on neutral earthing. As a consequence, typical durations do not necessarily match the boundaries of the columns in Table 2. 4.3.2.5 Voltage swells evaluation
Evaluation of voltage swells shall be in accordance with EN 61000-4-30. The method of analyzing the voltage swells (post treatment) depends on the purpose of the evaluation.
Typically, on LV networks: − if a three phase system is considered, polyphase aggregation shall be applied; polyphase aggregation consists of defining an equivalent event characterized by a single duration and a single maximum r.m.s. voltage; − time aggregation applies; time aggregation consists of defining an equivalent event in the case of multiple successive events; the method used for the aggregation of multiple events can be set according to the final use of data; some reference rules are given in IEC/TR 61000-2-8. 4.3.2.6 Voltage swells classification
If statistics are collected, voltage swells shall be classified according to the following table. The figures to be put in the cells refer to the number of equivalent events (see 4.3.2.5) 5).
4) This table reflects the polyphase network performance. Further information is needed to consider events affecting an individual single-phase voltage in three-phase systems. To calculate the latter, a different evaluation method has to be applied. 5) This table reflects the polyphase network performance. Further information is needed to consider events affecting an individual single phase voltage in three-phase systems. To calculate the latter, a different evaluation method has to be applied. SIST EN 50160:2011

For existing measurement equipment and/or monitoring systems, Table 3 is to be taken as a recommendation. Table 3
Classification of swells according to maximum voltage and duration Swell voltage u % Duration tms 10 ≤≤≤≤ t ≤≤≤≤ 500 500 < t ≤≤≤≤
5 000 5 000 < t ≤≤≤≤
60 000 u ≥ 120 CELL S1CELL S2CELL S3120 > u > 110 CELL T1CELL T2CELL T3 NOTE 2
Typically, faults in the public LV network or in a network user's installation give rise to temporary power frequency overvoltages between live conductors and earth; such overvoltages disappear when the fault is cleared. Some indicative values are given in Annex B. NOTE 3
For the classification of swells between live conductors and earth, reference can be made to IEC 60364-4-44. 4.3.3 Transient overvoltages
Transient overvoltages at the supply terminals are generally caused by lightning (induced overvoltage) or by switching in the system. NOTE 1
The rise time can cover a wide range from milliseconds down to much less than a microsecond. However, for physical reasons, transients of longer durations usually have much lower amplitudes. Therefore, the coincidence of a high amplitude and a long rise time is extremely unlikely. NOTE 2
The energy content of a transient overvoltage varies considerably according to the origin. An induced overvoltage due to lightning generally has a higher amplitude but lower energy content than an overvoltage caused by switching, because of the generally longer duration of such switching overvoltages. NOTE 3
For withstanding transient overvoltages in the vast majority of cases, LV Installations and end users’ appliances are designed according to EN 60664-1. Where necessary (see IEC 60364-4-44), surge protective devices should be selected according to IEC 60364-5-53, to take account of the actual situations. This is assumed to cover also induced over-voltages due to both lightning and switching.
5 Medium-voltage supply characteristics
5.1 General
Network users with demands exceeding the capacity of the LV network are generally connected to networks at nominal voltages above 1 kV. This clause applies to such electricity supplies at nominal voltages up to and including 36 kV. NOTE
Network users may also be supplied at this voltage level to satisfy special requirements or to mitigate conducted disturbances emitted by their equipment. This clause describes the voltage characteristics of electricity supplied by public medium voltage networks. In the following, a distinction is made between: – continuous phenomena, i.e. deviations from the nominal value that occur continuously over time. Such phenomena occur mainly due to load pattern, changes of load or nonlinear loads; – voltage events, i.e. sudden and significant deviations from normal or desired wave shape. Voltage events typically occur due to unpredictable events (e.g. faults) or to external causes (e.g. weather conditions, third party actions).
For some continuous phenomena, limits are specified 6) 7); for voltage events, only indicative values can be given at present (see Annex B).
The magnitude of voltage is given by the declared supply voltage Uc.
6) For single rapid voltage changes, only indicative values are given. 7) For some specific parameters, in some national regulations stricter limits may exist. SIST EN 50160:2011

– 17 – EN 50160:2010 5.2 Continuous phenomena
5.2.1 Power frequency
The nominal frequency of the supply voltage shall be 50 Hz. Under normal operating conditions the mean value of the fundamen
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