General provisions
GOST establishes 11 main indicators of power quality (PQE):
1) frequency deviation;
2) steady voltage deviation;
3) the magnitude of the voltage change;
4) dose of flicker (flicker or fluctuation);
5) distortion factor of the sinusoidal voltage curve;
b) coefficient of the nth harmonic component of voltage
7) negative sequence voltage asymmetry coefficient;
8) zero-sequence voltage asymmetry coefficient;
9) duration of voltage dip;
10) pulse voltage
11) temporary overvoltage factor. In table 2.24. properties are given electrical energy, indicators that characterize them and the most likely culprits for the deterioration of CE.
Table 2.24. Properties of electrical energy, indicators and most
probable culprits for deterioration of CE
Properties of electrical energy | CE indicator | Most Likely Culprits deterioration of CE |
Voltage deviation | Steady Deviation voltage | Energy supply organization |
Voltage fluctuations | Voltage range Flicker dose | Consumer with variable load |
Non-sinusoidal voltage | Voltage curve sinusoidal distortion coefficient Coefficient nth harmonic voltage component | Consumer with nonlinear load |
Unbalance of three-phase voltage system | Negative sequence voltage asymmetry coefficient, Zero sequence voltage asymmetry coefficient | Consumer with asymmetrical load |
Frequency deviation | Frequency deviation | Energy supply organization |
Voltage dip | Voltage dip duration | Energy supply organization |
Voltage pulse | Pulse voltage | Energy supply organization |
Temporary overvoltage | Temporary overvoltage factor | Energy supply organization |
Normally permissible and maximum permissible values at the point of common connection to electrical networks with different rated voltage are given in table. 2.25.
Table 2.25 . GOST requirements for limiting the sinusoidal distortion coefficient (KU)
Normally permissible values of the coefficient of the nth harmonic component of voltage are given in table. 2.26.
In table 2.27. summary data on PKE standards is provided.
Table 2. 26 Normally acceptable coefficient valuesnth harmonic voltage component
Harmonic number of non-multiple 3, odd at, kV | Harmonic number multiple of 3*, odd at, kV | Even harmonic number at, kV |
||||||||||||
Harmonic no. | Harmonic no. | Harmonic no. | ||||||||||||
*Normally permissible values given for n equal to 3 and 9 refer to single-phase electrical networks. In three-phase three-wire electrical networks, these values are taken to be half those given in the table. |
||||||||||||||
Table 2. 27 Electrical energy quality standards
FE indicator, units. measurements | ||
normally acceptable | maximum permissible |
|
Steady-state voltage deviation, % Voltage change range, % Flicker dose, rel. units: short-term long-term Voltage curve sinusoidal distortion coefficient, % Coefficient nth harmonic component of voltage, % Negative sequence voltage asymmetry coefficient, % Zero sequence voltage asymmetry factor, % Frequency deviation, Hz Voltage dip duration, s Pulse voltage, kV Temporary overvoltage factor, rel. units | According to table 2. 25 According to table 2. 26 | According to table 2. 25 According to table 2. 26 |
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ELECTRIC ENERGY
REQUIREMENTS FOR ELECTRICAL ENERGY QUALITY IN GENERAL PURPOSE ELECTRICAL NETWORKS
Price 5 kopecks.
Official publication
USSR STATE COMMITTEE ON STANDARDS Moscow
UDC 621.311:621.332: 006.354 Group E02
STATE STANDARD OF THE USSR UNION
ELECTRIC ENERGY
Requirements for the quality of electrical energy in general purpose electrical networks GOST
Electrical energy. Requirements for quality of 13109_87
electrical energy in general-purpose electrical networks
Date of introduction 01/01/89 Failure to comply with the standard is punishable by law
The standard establishes requirements for the quality of electrical energy in general-purpose electrical networks of alternating three-phase and single-phase current with a frequency of 50 Hz at the points to which receivers or consumers of electrical energy are connected.
The standard does not establish requirements for the quality of electrical energy in electrical networks: special purpose (for example, contact traction, communications); mobile installations (eg trains, aircraft, ships); autonomous systems electricity supply; temporary appointment; connected to mobile power sources.
The terms used in the standard and their explanations are given in Appendix 1.
1. NOMENCLATURE OF ELECTRIC ENERGY QUALITY INDICATORS
1.1. Electric energy quality indicators (EPQ) are divided into two groups: main PQI and additional PQI.
Official publication
The main PKE determine the properties of electrical energy that characterize its quality. Additional PKE are forms of recording the main PKE used in other regulatory and technical documents.
Reproduction is prohibited © Standards Publishing House, 1988
Note. The voltage change ranges normalized by this standard include single voltage changes of any form with a repetition rate of more than two times per minute (1/60 Hz) and swings with a repetition frequency from two times per minute to one per hour, with an average voltage change rate of more than 0.1%/s for incandescent lamps and 0.2%/s for other electrical consumers.
1.3. The dose of voltage fluctuations (f) in percent squared is calculated using the formula
where gf is the coefficient for reducing the actual ranges of voltage changes to equivalent ones, determined in accordance with table. 2; @ - averaging time interval equal to 10 minutes; S(f,t)-frequency spectrum of the voltage change process at time t. For periodic or close to periodic voltage changes, it is possible to calculate the dose of voltage fluctuations (φ) using the formula Г VgfhUj* dt, (6) where 6Uf are the effective values of the components of the Fourier series expansion of voltage changes with a swing of 6U t, in accordance with clause 1.2 of Appendix 2). Table 3 Frequency of voltage changes, Coefficient Frequency of voltage changes, Coefficient 1.4. The coefficient of non-sinusoidality of the voltage curve (Kaeu) in percentage is calculated using the formula *HCt/=100 V 21 ^(2 R)/^nom, (7) where U(n) is the effective value of the lth harmonic component of voltage, V, kV; n-order of the harmonic component of voltage; N is the order of the last of the harmonic voltage components taken into account. 1) do not take into account harmonic components of the order of n>40 and (or) whose values are less than 0.3%; 2) calculate this PKE using the formula where (7(1) is the effective value of the fundamental frequency voltage V, kV. Note. The relative error in determining Kasi using formula (8) compared to formula (7) is numerically equal to the voltage deviation 1/(1) FROM Unom. 1.5. Coefficient lth harmonic component of voltage Kiy) in* percent is calculated by the formula where U(n) is the current nth value harmonic component of voltage V, kV. It is allowed to calculate this PKE using the formula /C i(i g=100
where U(i) is the effective value of the fundamental frequency voltage V, kV. Note. The relative error of determination using formula (10) compared to formula (9) is numerically equal to the voltage deviation 0(\) FROM Unom* 1.6. The negative sequence voltage coefficient (K 2 u) in percent is calculated using the formula where U 2 (d is the effective value of the negative sequence voltage of the fundamental frequency of the three-phase voltage system, V, kV; Ubovl - rated value of phase-to-phase voltage, V, kV. The effective value of the negative sequence voltage of the fundamental frequency (£/ 2 n>) is calculated by the formula SVP) ^AC(1) where C/vap), Vvsp ^assh are the effective values of phase-to-phase voltages of the fundamental frequency. V, kV. When determining this PQ it is allowed: 1) calculate U2(о using the approximate formula ^2(1)”®"® [^NB (1)1* O 3) where £/ nb w, Un mp) are the largest and smallest effective values of the three phase-to-phase voltages of the fundamental frequency, V, kV. Note. The relative error in determining Kj using formula (13) instead of formula (12) does not exceed ±8%; 2) use when calculating U20) instead of the effective values of phase-to-phase voltages of the fundamental frequency, the effective values of phase-to-phase voltages determined taking into account all harmonic components, if the non-sinusoidal coefficient of the voltage curve (in accordance with the requirements of clause 1.4 of Appendix 2) does not exceed 5%; Kgs;-SO ^2(1)/^1(1) O 4) where Uko is the effective value of the positive sequence voltage of the fundamental frequency. V, kV. Note. The relative error in determining Kiu using formula (14) compared to formula (11) is numerically equal to the deviation of voltage Uni) from and in ohms. 1.7. The zero sequence voltage coefficient Ko and a three-phase four-wire system in percent is calculated using the formula K oi =100 and Shch1) /and a0M "f, (15) where £/o(n-rms value of the zero sequence of the fundamental frequency B, kV; Ud, ohm-f - rated value of phase voltage V, kV. where Uyour, ^sv(1), ^Asp) are the effective values of phase-to-phase voltages of the fundamental frequency, V, kV; C/a(i>, C/b(i>) are the effective values of phase voltages of the fundamental frequency, V, kV. When determining this PQ it is allowed: 1) calculate (Jon) using an approximate formula £/0(^=0.62 [^nv.f(1) ^nm.f(1)1* O 7) where £/ nb. f(1) (^nm.f(1)” greatest and smallest effective values of three phase voltages of fundamental frequency, V, kV. and A u^aMUcs-U,)! V 3 Uв np=£VH^c-^i)/ VI «с Шг^с+^ва-)/V 3 If there is a negative sequence voltage in the phase-to-phase voltages, the values of C/NB# f(1) and Tssh.fsh are determined as the largest and smallest values of the given phase voltages (with the negative sequence voltage excluded). The given phase voltages are determined by the formula Note. The relative error in determining Koi using formula (17) instead of formula (16) does not exceed ±10%; 2) use instead of the effective values of phase-to-phase and phase-to-phase voltages of the fundamental frequency the effective values of voltages determined taking into account all harmonic components, if the coefficient of non-sinusoidality of the voltage curves does not exceed 5%; 3) calculate this PKE using the formula 100 V 3 SG 0 (1)1(/C)), (19) where L/id) is the effective value of the positive sequence voltage of the fundamental frequency. V, kV. Note. The relative error in determining Koi using formula (19) compared to formula (15) is numerically equal to the value of the deviation of voltage £/cp from U nom. 1.8. Frequency deviation (Δf) in hertz is calculated using the formula A /==/-/nom" where / is the frequency value, Hz; /nom - nominal frequency value, Hz. 1.9. The duration of the voltage dip (A/p) in seconds (Fig. 3) is calculated using the formula where /n, /k are the initial and final moments of the voltage dip, s. 1.10. Pulse voltage in relative units (fit/*imi) in accordance with the drawing. 4 is calculated by the formula a£L»imp = Dimp ~. (22) where Uimp is the value impulse voltage. V, kV. 2. Additional PKE 2.1. The amplitude modulation coefficient (/(mod) in percent in accordance with Fig. 5 is calculated using the formula ^НБ.а~^НМ.а where Unv.a, t/nm.a are the largest and smallest amplitudes of the modulated voltage. V, kV. With periodic voltage modulation, the relationship between the peak-to-peak voltage change (fit/*) and the amplitude modulation coefficient is determined by the formula bU t =2 /(mod- (24) 2.2. The unbalance coefficient of phase-to-phase voltages (/(sky) in percent is calculated using the formula where U H b* U nm is the largest and smallest effective value of the three phase-to-phase voltages. V, kV. When the voltage non-sinusoidal coefficient Kis and (determined in accordance with the requirements of clause 1.4 of Appendix 2), not exceeding 5%, the ratio between the negative sequence coefficient (Ki) and the unbalance coefficient of phase-to-phase voltages K k e b, is determined by the approximate formula K 2i = 0.62 / C„ eb. (26) Note: The relative error in calculating Kiu using formula (26) does not exceed ±8%. 2.3. The phase voltage unbalance coefficient (Kneb.f) as a percentage is calculated using the formula ^НВ, f~~^НМ. f ^nom. f where Unm.f are the largest and smallest effective values from three phase voltages. V, kV; ^nom.ph - rated value of phase voltage. V, kV. When the voltage non-sinusoidal coefficient Kis and (determined in accordance with the requirements of clause 1.4 of Appendix 2) does not exceed the 5% ratio between the zero-sequence voltage coefficient (/(oo) and the phase voltage unbalance coefficient /Snev.F, determined by approximate formula Koir=0.62 K iev. f. (28) Note. The relative error of calculating Koi according to formula (28) does not exceed ±8%. 3. Auxiliary parameters of electrical energy 3.1. The frequency of voltage changes (F), s -1, min-1, h~ 1, is calculated using the formula where /u is the number of voltage changes during time T; T - measurement time interval, s, min, h. 3.2. Time interval between voltage changes (At it t+1) in accordance with fig. 2, s, min, h, calculated by the formula where t i+ 1, fi are the initial moments of successive voltage changes, s, min, h, in accordance with the diagram. 2. If the time interval between the end of one change and the beginning of the next, occurring in the same direction, is less than 30 ms, then these changes are considered as one in accordance with the line. 2. 3.3. The depth of the voltage dip (bU a) in percent in accordance with the drawing. 3 is calculated by the formula 6th g p== .Unou7-Utt, 100| (31) where Umin is the minimum effective voltage value during a voltage dip. V, kV. TP (YG p, M p) M 3.4. The intensity of voltage dips (t#) as a percentage is calculated using the formula where t(bS/n, D*n) is the number of dips of depth 6 £/t and duration for the considered time interval Г; M is the total number of voltage dips during the considered time interval T. 3.5. The duration of the voltage pulse at the level of 0.5 of its amplitude (D*imp o.b) in microseconds, milliseconds in accordance with the drawing. 5 is calculated by the formula d ^imp o.5“^ to 1 where t Hi t K are the moments of time corresponding to the intersection of the voltage pulse curve with a horizontal line drawn at half the pulse amplitude, μs, ms. APPENDIX 9 Mandatory METHOD FOR DETERMINING THE ACCEPTANCE OF VOLTAGE FLUCTUATIONS FOR LIGHTING INSTALLATIONS The condition for the admissibility of a set of voltage change ranges, each of which does not exceed the values determined in accordance with the lines. 1, is where D* d* is the minimum permissible time interval between swings with an amplitude of 6Ut, determined by the lower scale of lines. 1; T is the total time of observation of the swings. Example. In 10 minutes, 12 peak-to-peak amplitudes of 4.8% (first group of peaks), 30 peak-to-peak amplitudes of 1.7% (second group), and 100 peak-to-peak amplitudes of 0.9% (third group) were recorded in the network. Determine the admissibility of power supply from this network of fluorescent lamps. 1. Along the curve 3 lines. 1 we determine: for 6С/l ~ 4.8% Dg d1 = 30 s, for 6С/ #2 = “1.7% D*d2 = 1 s, for bShz -0.9% A/dz-0.1 With. 2. By determining by (34) the minimum time for which a given number of swings with the specified amplitude is permissible: 12*30+30-1+100-0.1 =400 s<600 с. Conclusion. Power supply from this point of the fluorescent lamp network is acceptable. Permissible voltage ranges F - frequency of voltage changes; M d - time interval between swings Voltage fluctuations 6С/^П - range of periodic oscillations (7 ranges of voltage changes during time T p fit/81/^5 - range of non-periodic oscillations Voltage dip Periodic amplitude modulation 1.2. The main PKEs include: voltage deviation U, voltage change range bUt, dose of voltage fluctuations f, non-sinusoidal voltage curve coefficient /Cves/, coefficient of the nth harmonic component UiY), negative sequence voltage coefficient /Csi, zero-sequence voltage coefficient Koi, frequency deviation Df, voltage dip duration Dt n, pulse voltage · 100; Where U m(–) , U m(+) – power supply voltage values, less than U 0 and larger U 0 respectively, averaged over a time interval of 10 minutes in accordance with the requirements of GOST R 51317.4.30, subsection 5.12; For the above CE indicators, the following standards are established: positive and negative voltage deviations at the point of electricity transmission should not exceed 10% of the nominal or agreed voltage value for 100% of the time of the one week interval. In GOST 13109-97, the steady-state voltage deviation is calculated taking into account only the 1st voltage harmonic U (1) : δ U= (U (1) – U nom) / U nom and is characterized by normally permissible and maximum permissible values at the terminals of electrical receivers equal to ±5 and ±10%, respectively. The standards (numerical values) for permissible frequency deviations in synchronized power supply systems are the same as in GOST 13109-97: ±0.2 Hz for 95% of the time of an interval of one week and ±0.4 Hz for 100% of the time of the interval in one week. The limits for permissible frequency deviations in isolated power supply systems with stand-alone generator sets not connected to synchronized electrical power transmission systems are less stringent: ±1 Hz for 95% of the time of a one-week interval and ±5 Hz for 100% of the time of a one-week interval week. FE indicators related to the harmonic components of voltage are: The norms (numerical values) of FE indicators related to non-sinusoidality and voltage asymmetry in this standard are kept unchanged as in GOST 13109-97, but CE indicators related to voltage non-sinusoidality are measured and assessed taking into account the influence of not only higher harmonics, but also groups of closely spaced combinational (interharmonic) components in accordance with GOST R 51317.4.7-2008, subsections 3.2, 3.3. Taking into account the requirements of GOST R 51317.4.30-2008 for classes and measuring instruments of CE indicators, this standard establishes standards for CE indicators in the form of values measured over a single time interval of class A measurements, equal to 10 periods of network voltage 50 Hz (0.2 s) s averaging at each time interval of 10 minutes over a week. According to the requirements of GOST 13109-97, FE indicators must be measured over the main time interval from 0.1 to 0.5 s with averaging over a time interval of 3 s or 1 min (for voltage deviations) during every 24 hours of the weekly cycle. Thus, the estimated time interval for measuring CE indicators to assess their compliance with the requirements of the new standard is 1 week, and not 24 hours, as required by GOST 13109-97. The main differences between GOST R 54149-2010 and the European standard EN 50160: 2010 are the requirements for a number of PKE: EN 50160 does not have maximum permissible values for some of the KE indicators; an important indicator for our networks is the zero-sequence voltage asymmetry coefficient; less stringent requirements have been introduced. in comparison with GOST R 54149-2010, requirements for frequency and voltage deviations are unreasonable for Russian networks, incomplete data for CE indicators in high-voltage networks, etc. The requirements of the European standard are designed for use in electrical networks of countries that have different requirements for the design of electrical networks and a different level of condition of these networks compared to the Russian one. When revising GOST 13109-87 and developing the edition of GOST 13109-1997, CE indicators and standards were analyzed and discussed in detail and were reasonably accepted. In the period since the entry into force of GOST 13109-1997 (1999), the technical state of our networks does not yet provide grounds for revising CE standards in the direction of their mitigation and harmonization with European ones. As for the structure and content of the standard, general approaches to CE standardization and requirements for methods for measuring CE indicators, the provisions of the new domestic and European standards are quite close. The approved GOST R 54149-2010 is included in the national standardization program of the Russian Federation for its re-registration into the interstate standard of the EurAsEC organization. INTERSTATE STANDARD ELECTRIC ENERGY. COMPATIBILITY OF TECHNICAL EQUIPMENT ELECTROMAGNETIC QUALITY STANDARDS FOR ELECTRICAL ENERGY IN GENERAL PURPOSE POWER SUPPLY SYSTEMS INTERSTATE COUNCIL ON STANDARDIZATION, METROLOGY AND CERTIFICATION Preface 1 DEVELOPED by the Technical Committee for Standardization in the Field of Electromagnetic Compatibility of Technical Equipment (TK 30 EMC) INTRODUCED by Gosstandart of Russia 2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 12-97 of November 21, 1997) 3 The standard complies with international standards IEC 868, IEC 1000-3-2, IEC 1000-3-3, IEC 1000-4-1 and publications IEC 1000-2-1, IEC 1000-2-2 regarding levels of electromagnetic compatibility in systems power supply and electromagnetic interference measurement methods 4 By Decree of the State Committee of the Russian Federation for Standardization, Metrology and Certification dated August 28, 1998 No. 338, the interstate standard GOST 13109 was put into effect directly as the state standard of the Russian Federation from 01/01/1999. 5 INSTEAD GOST 13109-87 IPC Standards Publishing House, 1998 This standard cannot be fully or partially reproduced, replicated and distributed as an official publication on the territory of the Russian Federation without the permission of the State Standard of Russia INTERSTATE STANDARD Date of introduction 1999-01-01 1 AREA OF USE The standard establishes indicators and standards for the quality of electrical energy (QE) in electrical networks of general purpose power supply systems with alternating three-phase and single-phase current with a frequency of 50 Hz at points to which electrical networks owned by various consumers of electrical energy or receivers of electrical energy are connected (points of general accession). The EC limits established by this standard are electromagnetic compatibility levels for conducted electromagnetic interference in general purpose power supply systems. Subject to compliance with these standards, electromagnetic compatibility of electrical networks of general-purpose power supply systems and electrical networks of electrical energy consumers (electrical energy receivers) is ensured. The standards established by this standard are mandatory in all operating modes of general purpose power supply systems, except for modes conditioned by: Exceptional weather conditions and natural disasters (hurricane, flood, earthquake, etc.); Unforeseen situations caused by the actions of a party that is not an energy supply organization and a consumer of electricity (fire, explosion, military action, etc.); Conditions regulated by government authorities, as well as those related to the elimination of consequences caused by exceptional weather conditions and unforeseen circumstances. The standards established by this standard are subject to inclusion in the technical specifications for connecting consumers of electrical energy and in contracts for the use of electrical energy between electricity supply organizations and consumers of electrical energy. At the same time, in order to ensure the norms of the standard at points of general connection, it is allowed to establish in the technical specifications for the connection of consumers who are responsible for the deterioration of the energy efficiency, and in contracts for the use of electrical energy with such consumers, more stringent standards (with smaller ranges of change in the corresponding indicators of energy efficiency) than those established in this standard. By agreement between the energy supply organization and consumers, it is allowed to establish in the specified technical conditions and contracts requirements for CE indicators, for which standards are not established in this standard. The standards established by this standard are used in the design and operation of electrical networks, as well as in establishing the levels of noise immunity of electrical energy receivers and the levels of conducted electromagnetic interference introduced by these receivers. CE standards in electrical networks owned by consumers of electrical energy, regulated by industry standards and other regulatory documents, should not be lower than CE standards established by this standard at points of general connection. In the absence of the specified industry standards and other regulatory documents, the norms of this standard are mandatory for electrical networks of electrical energy consumers. GOST 721-77 Power supply systems, networks, sources, converters and receivers of electrical energy. Rated voltages over 1000 V GOST 19431-84 Energy and electrification. Terms and Definitions Power supply systems, networks, sources, converters and receivers of electrical energy. Rated voltages up to 1000 V GOST 30372-95 Electromagnetic compatibility of technical equipment. Terms and Definitions 3 DEFINITIONS, SYMBOLS AND ABBREVIATIONS 3.1 This standard uses the terms given in GOST 19431, GOST 30372, as well as the following: General purpose power supply system - a set of electrical installations and electrical devices of an energy supply organization designed to provide electrical energy to various consumers (receivers of electrical energy); General purpose electrical network - an electrical network of an energy supply organization designed to transmit electrical energy to various consumers (receivers of electrical energy); Power center - a generator voltage switchgear of a power plant or a secondary voltage switchgear of a step-down substation of a power system, to which the distribution networks of a given area are connected; Point of general connection - a point of a general-purpose electrical network that is electrically closest to the networks of the electrical energy consumer in question (input devices of the electrical energy receiver in question), to which the electrical networks of other consumers (input devices of other receivers) are connected or can be connected; Electric energy consumer - a legal or natural person who uses electric energy (power); Conducted electromagnetic interference in the power supply system is electromagnetic interference propagating through the elements of the electrical network; The level of electromagnetic compatibility in the power supply system is a regulated level of conducted electromagnetic interference, used as a reference for coordination between the permissible level of interference introduced by the technical means of the energy supply organization and consumers of electrical energy, and the level of interference perceived by the technical means without disrupting their normal functioning; The envelope of the rms voltage values is a step time function formed by the rms voltage values, discretely determined at each half-cycle of the fundamental frequency voltage; Flicker is a person’s subjective perception of fluctuations in the luminous flux of artificial lighting sources caused by voltage fluctuations in the electrical network supplying these sources; Flicker dose is a measure of a person’s susceptibility to the effects of flicker over a specified period of time; Flicker perception time is the minimum time for a person’s subjective perception of flicker caused by voltage fluctuations of a certain shape; Repetition frequency of voltage changes - the number of single voltage changes per unit time; The duration of the voltage change is the time interval from the beginning of a single voltage change to its final value; Voltage dip - a sudden drop in voltage at a point in the electrical network below 0.9 Un, which is followed by a restoration of the voltage to the original or close to it level after a period of time from ten milliseconds to several tens of seconds; Voltage dip duration - the time interval between the initial moment of voltage dip and the moment the voltage is restored to the original or close to it level; The frequency of voltage dips is the number of voltage dips of a certain depth and duration over a certain period of time in relation to the total number of dips over the same period of time; Voltage pulse - a sharp change in voltage at a point in the electrical network, followed by a restoration of the voltage to the original or close to it level over a period of time of up to several milliseconds; Pulse amplitude - the maximum instantaneous value of the voltage pulse; Pulse duration - the time interval between the initial moment of the voltage pulse and the moment of restoration of the instantaneous voltage value to the original or close to it level; Temporary overvoltage - an increase in voltage at a point in the electrical network above 1.1 Unom for a duration of more than 10 ms, occurring in power supply systems during switching or short circuits; Temporary overvoltage coefficient - a value equal to the ratio of the maximum value of the envelope of the amplitude voltage values during the existence of a temporary overvoltage to the amplitude of the nominal network voltage; The duration of a temporary overvoltage is the time interval between the initial moment of occurrence of a temporary overvoltage and the moment of its disappearance. 3.2 The following symbols are used in this standard: Uy - steady voltage deviation; Ut - voltage change range; Pt - flicker dose; PSt - short-term flicker dose; PLt - long-term flicker dose; KU - distortion coefficient of the sinusoidal curve of the phase-to-phase (phase) voltage; КU(n) - coefficient of the nth harmonic component of voltage; K2U - negative sequence voltage asymmetry coefficient; К0U - zero-sequence voltage asymmetry coefficient; F - frequency deviation; Tp - duration of voltage dip; Uimp - pulse voltage; KperU - temporary overvoltage coefficient; U(1)t - effective value of the interphase (phase) voltage of the fundamental frequency in the i-th observation; UAB(1)i, UBC(1)i, UCA(1)i - effective values of phase-to-phase voltages of the fundamental frequency in the i-th observation; U1 (1)i - effective value of the phase-to-phase positive sequence voltage of the fundamental frequency in the i-th observation; Uy - average voltage value; N is the number of observations; Unom - rated phase-to-phase (phase) voltage; Unom. f - rated phase voltage; Unom. mf - nominal phase-to-phase voltage; Urms - root mean square voltage value determined at the half-cycle of the fundamental frequency voltage; Ui, Ui+1 - values of extrema following one after another or extremum and horizontal section of the envelope of the root-mean-square voltage values of the fundamental frequency; Uai, Ua i+1 - values of extrema following one after another or extremum and horizontal section of the envelope of amplitude voltage values at each half-cycle of the fundamental frequency; T - measurement time interval; m is the number of voltage changes during time T; F?? Ut - repetition rate of voltage changes; ti, ti+1 - initial moments of voltage changes following one after another; Ti, i+1 - interval between adjacent voltage changes; ps - smoothed flicker level; P1s, P3s, P10s, P50s - smoothed flicker levels with an integral probability of 1.0; 3.0; 10.0; 50.0% respectively; Tsh is the time interval for measuring a short-term flicker dose; TL - time interval for measuring long-term flicker dose; n is the number of the harmonic component of voltage; РStk is a short-term flicker dose at the k-th time interval Tsh during a long observation period TL; U(n)i - effective value of the n-th harmonic component of the phase-to-phase (phase) voltage in the i-th observation; KUi is the distortion coefficient of the sinusoidality of the interphase (phase) voltage curve in the i-th observation;0 f±0
* Н с.с/=1°0 У £ ’Uf a) IU ( (8)
g P=2
^2(1)/^nom" 00
δ U (+) = [(U m(+) – U 0) / U 0 ] 100,
U 0 – voltage equal to standard rated voltage U nom or matched voltage U With.RUSSIAN AND EUROPEAN STANDARDS
LITERATURE