1、 CENELEC EN*b3727 95 3404583 O365724 3TT I BRITISH STANDARD Photovoltaic (PV) systems Characteristics of the utility interface The European Standard EN 61727 : 1995 has the status of a British Standard Product code 00642167 ICs 31.260 BS EN 61727 : 1996 IEC 1727 : 1995 - CENELEC EN*bl1727 95 m 34045
2、83 0365725 236 m Amd.No. Date BS EN 61727 : 1996 Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee EPU47, Semiconductors, to Subcommittee EPIl47B Performance of optoelectronic semiconductor devices and liquid
3、crystal displays, upon which the following bodies were represented British Telecommunications pic Federation of the Electronics Industry Ministry of Defence National Supervising inspectorate United Kingdom Optical Sensors Collaborative Association This British Standard, having been prepared under th
4、e direction of the Electrotechnica Sector Board, was published under the authority of the Standards Board and comes into effect on Amendments issued since publication 15 January 1996 O BSI 1996 The following BSI references relate to the work on this standard: Committee reference EPU4713 Special anno
5、uncement in BSZ News February 1995 ISBN O 580 24897 6 CENELEC ENxb1727 75 3404583 0165726 172 BS EN 61727 : 1996 Contents Committees responsible National foreword Page Inside front cover u Foreword 2 Text of EN 61727 3 O BSI 1996 i CENELEC ENab3727 95 3404583 0365727 O09 m BS EN 61727 : 1996 Nationa
6、l foreword This British Standard has been prepared by Subcommittee EPY47/3 and is the English language version of EN 61727 : 1995, Photovoltaic (PV) systems. Ghamcte7-istics of the utility intetface, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical
7、with IEC 1727 : 1995 published by the International Electrotechnical Commission (IEC). Cross-references Publication referred to EN 60555-2 : 1987l) (IEC 5552 (mod) : 1982) Part 2 : 1988 Specificatwn of hamnics EN 60555-3 : 1987) EN 61173 : 1994 (IEC 1173 : 1992) Corresponding British Standard BS 540
8、6 Disturbances in supply systems caused by household appliances and similar electrical equipment Part 3 : 1988 Specifkation of vo1tugefluctwtion.s BS EN 61 173 : 1995 Overuoltcye protection for photovoltaic (PV) power generating systems. Guide (IEC 555-3 : 1982) Compliance with a British Standard do
9、es not of itself confer immunity from legal obligations. Annex ZA states that these standards have been superseded by EN 61000-3-2 and EN 61000-3-3 respectively. The corresponding British Standards are: BS EN 61000-3-2 Electromagnetic compatibility (EMC) Part 3 Limits Section 2 1995 LimitJor hamnon.
10、ic currenl emissions (equipment ,input current 5 16 A per phuse) BS EN 61000-3-3 Electromagnetic compatibility (EMC) Part 3 Limits Section 3 : 1996 Limitation of ,voltage fluctuations undjlicker in lowvoltage supply systemsfor equipment with rated cuwent 5 16 A. O BSI 1996 - CENELEC EN*kbI1727 75 H
11、3404583 Olt65728 T45 EUROPEAN STANDARD N0R;ME EUROPENNE EUROP the higher harmonic levels in- crease the potential for adverse effects on connected equipment. Acceptable levels of har- monic voltage and current depend upon distribution system characteristics, type of service, connected loads/apparatu
12、s, and established utility practice. In general, the operation of the photovoltaic system should not cause excessive distortion of the utility voltage waveform or result in excessive injection of harmonic currents into the utility system. NOTE - Total harmonic voltage distortion is defined as: n=2 T
13、HD, = Y where Vi Vn is the harmonic voltage of order n is the r.m.s. fundamental voltage The harmonic limits for static power converters are given by the local codes. Suggested design targets for voltage and current harmonic limits are 5 % total current har- monics, and 2 % total voltage harmonic di
14、stortion with a 1% maximum for individual volt- age harmonics. These values are generally applied at the peak output rating of the system (see Vol. No. 123 Electra/Revue CIGRE). 4.5 Power factor The PV system should have an average lagging power factor greater than 0,85 at the rated load or other va
15、lues fixed by local codes. When the power factor falls below this point, power-factor correction may be required. Some utilities may impose limits on lead- ing power factor. CENELEC EN*bL27 95 W 3404583 0365733 302 Page 6 EN 61727 : 1995 Average power factor (PF) is calculated by dividing the kilowa
16、tt-hours (kWh) by the square root of the sum of the squares of the kilowatt-hours and the kilovarhours (kVARh) over a period of time. Average power factor (PF) over a period of time is given by: REAL PF = where REAL is the energy in kWh and REACTIVE is the reactive energy in kVARh. 5 PV system equlp
17、ment protection and personnel safety This clause provides information and considerations for the proper and safe operation of the utility grid-connected PV systems. 5.1 Loss of utility voltage A primary safety consideration of PV systems interconnected to a utility is that the PV system shall discon
18、nect from a de-energized distribution line irrespective of connected loads or other generators within the time limits specified by the local codes. This is to prevent back-feeding to the line, which could create a hazardous situation for utility main- tenance personnel and the general public. A util
19、ity distribution line can become de-energized for several reasons. For example, a substation breaker opening due to fault conditions, or the distribution line switched out during maintenance. 5.2 Over/under voltage and frequency 5.2.1 Over/under voltage (see IEC 555-3) When the interface voltage dev
20、iates outside the conditions specified by local codes, the photovoitaic system shall disconnect from the utility. This applies to any phase of a multi- phase system. 5.2.2 Over/under frequency When the utility frequency deviates outside the conditions specified by local codes, the photovoltaic syste
21、m shall disconnect from the utility. 5.3 Utility recovery Following photovoltaic system disconnects as a result of an out-of-bounds condition, the photovoltaic system shall remain disconnected until utility service voltage has recovered to within utility acceptable voltage and frequency limits for a
22、 sufficient period of time, typi- cally 30 s to 3 min. CENELEC EN*b%727 95 1 3404583 0165734 249 1 Page 7 EN 61727 : 1995 5.4 Direct-current isolation The PV system shall not inject d.c. into the a.c. or a.c. into the d.c. interface under normal or abnormal conditions. An isolation transformer is on
23、e method that can be used to satisfy this requirement. 5.5 Grounding The PV system and utility interface equipment shall be grounded in accordance with the applicable local and national codes (see IEC 1173). 5.6 Surge protection The photovoltaic system shall have surge protection in accord with the
24、applicable local and national codes (see IEC 1173). 5.7 Short-circuit protection The photovoltaic system shall have short-circuit protection for the utility grid in accordance with the applicable local and national codes. 5.8 Safety disconnect For the safety of persons who may be exposed to contact
25、with the utility lines or equip- ment during utility maintenance or grid outages, a positive means of disconnecting the a.c. output of the PV system from the utility shall be provided. Disconnect requirements may differ due to local codes and practices. Two accepted meth- ods are as follows: a) Manu
26、al safety disconnect (figure 1) A lockable and accessible manual load-break disconnect switch between the power conditioning subsystem and the utility grid. b) Electromechanical safety disconnect (figure 2) An electrically operated contactor or circuit-breaker disconnect between the power con- ditio
27、ning subsystem and the utility grid that opens automatically for grid outages or by out-of-bounds conditions or by a utility-generated control signal. The electromechanical system may provide visual open or close status indication, and provide a means for utility personnel to determine when the powe
28、r conditioning sub- system has been disconnected from the utility grid. The system may have an accessible control switch for permissive transfer to automatic or manual open functions. CENELEC EN*bl1727 95 3404583 O365735 I185 Page 8 EN 61727 : 1995 Utility grid Manual safety disconnect switch Local
29、loads f (Alternate location) Manual safety disconnect switch (a.c.) Power conditioning subsystem System control and monitoring functions: Coordinated with the electromechanical safety disconnect subsystem (d.c.) PV array field Figure 1 - Block diagram of a grid-connected PV system with manual safety
30、 disconnect switch CENELEC ENrbL727 95 3404583 03b573b OLL .I (Alternate location) Electromechanical safety disconnect Page 9 EN 61727 : 1995 Electromechanical safety disconnect control and monitoring subsystem :. . - - . Functions to be induded in safety disconnect andlor power conditioner to autom
31、atically open safety disconnect for out-of-bounds (a.c.) : condition: _ - *a - * * - Loss of utility voltage - Overtunder frequency - Overiunder voltage v Local loads Power conditioning subsystem System control and monitoring functions: Coordinated with electromechanical safety disconnect subsystem
32、(d.c.) I . . . . . . I PVarray field I If required by the utility, a manual safety disconnect switch may be added. Figure 2 - Block diagram of a grid-connected PV system with electromechanical safety disconnect CENELEC ENrbL727 95 = 3404583 O365737 T5B * Page 10 EN 61727 : 1995 I tl )i 1- Power-cond
33、itioning subsystem I I I 1 ,-J Annex A (informative) PV system and interface The interface should include all necessary equipment and components based on good engineering design and practice to site-specific requirements. Figure A.l shows the overall system from the photovoltaic array to the utility
34、. Figure A.2 shows several subsystems that may be utilized. Some of the parts shown on the diagram may not be present in specific systems. The PV system-utility interface may include ancillary equipment such as disconnect switches and meters. Direct-current isolators and protective relaying are incl
35、uded if not a part of the power-conditioning subsystems (PCS). The interface can have several functions. These include: 1) Distribution of aiternating-current power flowing between the power-conditioning subsystem, the on-site alternating current loads, and the utility line. 2) Provision for measure
36、ment of the alternating-current energy flow (kWh) meters. 3) Provision of disconnect switches for safety and maintenance. 4) Possibility of providing for protective functions such as isolating transformers, relay- ing, fuses, and lightning protection. I PV power system -b Utility 4 ;ads I _ The PV s
37、ystem utility interface point may vary due to local codes and ownership. Figure A.l - Block and interface diagram of a photovoltaic system _ CENELEC ENmbI1727 75 I 3404583 OLb5738 974 MASTER CONTROL AND MONITORING (MCM) Page 11 EN 61727 : 1995 d.c. conditioner - Inverter + - interface Interface Inte
38、rface a.c.1a.c. d.c.1d.c. storage Auxiliary d.c. load d.c. suppy Auxiliary a.c. load Utility a.c. supply Figure A.2 - PV power-generating system major functional elements, subsystems and power-flow diagrams Annex B (informative) Bibliography IEC 1194: 1992. Characteristic parameters of stand-alone p
39、hotovoltaic (PV) systems. ANSI - IEEE 929: 1991, i Recommended Practice for Utility interface of Residential and Intermediate - Photovoltaic (f V) Sysiems. NOTE.-Harmonized as EN 61 194 : 1995 (modified) - CENELEC EN*:bL727 75 3404583 OLL5739 820 Page 12 EN 61727 : 1995 Annex ZA (normative) Normativ
40、e references to international publications with their corresponding European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed
41、hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard oniy when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. NOTE. When an international pub
42、lication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year IEC 5552 1982 (mod) IEC 555-3 1982 IEC 1173 1992 IEC 1277 1995 CIGRE 123 1992 Title ENMD Year Disturbances in supply systems caused by EN 60555-Z1) 1987 household appliances and simil
43、ar electrical equipment Part 2: Harmonics Part 3: VoltageJuctuations EN 60555-32) 1987 power generating systems Guide Terrestrial photovoltaic (PV) power generating - - systems General and guide Equipment pducng hurmonics and conditions - - governing their connection to the min power SWPb Ovetwoltag
44、e protection for photovoltaic (PV) EN 61173 1994 1 EN 605552 includes Al : 1985 to IEC 555-2; it is superseded by EN 61000-3-2 : 195, which is based on IEC 1000-3-2 : 1995 2, EN 605553 : 1987 + Al : 1991 are superseded by EN 61000-3-3 : 1995, which is based on IEC 1000-3-3 : 1994. O BSI 1996 CENELEC
45、 ENubl1727 75 3404583 0365740 542 BS EN 61727 : 1996 List of references See national foreword. CENELEC EN*bl1727 95 3404583 OLb574L 487 = BS EN 61727 : 1996 IEC 1727 : 1995 BSI 389 Chiswick High Road London w4 4AL 9601-74.35k-RTL BSI - British Standards Institution BSI is the independent national bo
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