Difference between revisions of "Technical Standards for Solar Home Systems (SHS)"

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<span id="fck_dom_range_temp_1248088806816_809" />To assure the quality of a photovoltaic power system and&nbsp;its correct functioning&nbsp;and guarantee costumers' satisfaction it is important that the components of the system and the system as a whole meet certain requirements.
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[[Portal:Solar|►Back to Solar Portal]]
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= Overview =
  
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The GTZ prepared a publication which&nbsp;gives an overview of&nbsp;different standardisation activities and&nbsp;existing standards that are relevant for Solar Home Systems (SHS) and&nbsp; Rural Health Power Supply Systems (RHS):
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To assure the quality of a [[Photovoltaic (PV)|photovoltaic]] power system and its correct functioning and guarantee costumers' satisfaction it is important that the components of the system and the system as a whole meet certain requirements.
  
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[http://www.gtz.de/de/dokumente/en-gtz-pvquality.pdf GTZ, Division 44, Environmental Management, Water, Energy, Transport: Quality Standards for Solar Home Systems and Rural Health Power Supply. Photovoltaic Systems in Developing Countries, February 2000.]
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= Introduction =
  
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The following Wiki-Page is an extract of the publication regarding SHS.  
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'''Photovoltaic (PV) '''systems for applications in developing countries have been tested, optimised and disseminated throughout the world over the last 20 years. A wide variety of demands have been made of the components and systems, partly for reasons due to country specific characteristics or regional availability, but also because there were no binding standards, or if there were, they were often not known.
  
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= Introduction  =
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The project activities in technical and financial co-operation at bilateral and multilateral level have moved away from the pilot phase and towards the dissemination of PV systems. Yet, secure technical standards are required for dissemination in order to minimise the need for adjustments after the fact and the related costs in the case of large unit numbers.
  
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PV systems for applications in developing countries have been tested, optimised and disseminated throughout the world over the last 20 years. A wide variety of demands have been made of the components and systems, partly for reasons due to countryspecific characteristics or regional availability, but also because there were no binding standards, or if there were, they were often not known.  
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An international survey carried out in preparation for this publication showed that several different standardisation activities are in progress. Probably the most interesting international project is the so-called "Global Approval Program for Photovoltaics (PV GAP)", but also technical specifications such as those that have been proposed by the World Bank or the University of Madrid have already been elaborated in great detail.
  
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The project activities in technical and financial co-operation at bilateral and multilateral level have moved away from the pilot phase and towards the dissemination of PV systems. Yet, secure technical standards are required for dissemination in order to minimise the need for adjustments after the fact and the related costs in the case of large unit numbers.
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= Global Approval Program for Photovoltaics =
  
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An international survey carried out in preparation for this publication showed that several different standardisation activities are in progress. Probably the most interesting international project is the so-called "Global Approval Program for Photovoltaics (PV GAP)", but also technical specifications such as those that have been proposed by the World Bank or the University of Madrid have already been elaborated in great detail.  
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The publication provides an overview of standards that are relevant for '''Solar Home Systems (SHS)''' and in '''Rural Health Power Supply Systems (RHS)'''. It is intended to facilitate the selection of PV systems and components, especially in tenders, and to provide the impetus for a standardisation of PV systems on a scale that is as broad as possible. Moreover, it also identifies those components for which there is still a need for technical specifications.<br/>
  
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The publication provides an overview of standards that are relevant for Solar Home Systems (SHS) and in Rural Health Power Supply Systems (RHS). It is intended to facilitate the selection of PV systems and components, especially in tenders, and to provide the impetus for a standardisation of PV systems on a scale that is as broad as possible. Moreover, it also identifies those components for which there is still a need for technical specifications.  
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This should lead, in the long term or better yet in the medium term, to binding, internationally recognised technical standards, especially for the use of photovoltaic systems in developing countries.
  
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This should lead, in the long term or better yet in the medium term, to binding, internationally recognised technical standards, especially for the use of photovoltaic systems in developing countries.  
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In preparing this publication, all of the well-known national and international institutions concerned with standardisation activities in the field of photovoltaics were contacted in writing. The existing photovoltaics projects of GTZ were also included in the survey.
  
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In preparing this publication, all of the well-known national and international institutions concerned with standardisation activities in the field of photovoltaics were contacted in writing. The existing photovoltaics projects of GTZ were also included in the survey.  
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In the course of the survey, information and documentation obtained from the World Bank, the '''World Health Organization (WHO)''', the international standardisation institution IEC, the European standardisation institution CENELEC, the U.S. standardisation office IEEE, as well as a series of projects, firms and experts, were compiled and evaluated.<br/>
  
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In the course of the survey, information and documentation obtained from the World Bank, the World Health Organization (WHO), the international standardisation institution IEC, the European standardisation institution CENELEC, the U.S. standardisation office IEEE, as well as a series of projects, firms and experts, were compiled and evaluated.  
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The available PV-relevant standards were evaluated and summarised in the form of a table with a breakdown by components.
  
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The available PV-relevant standards were evaluated and summarised in the form of a table with a breakdown by components.  
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The list of standard specifications for tenders for SHS and RHS forms the largest part of the publication. Eleven different documents with specifications for PV systems and their components were evaluated for this purpose and summarised in a table. These documents varied widely in terms of quality and scope; some of them were intended for the specification of individual components, others as tender documents for whole systems.
  
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The list of standard specifications for tenders for SHS and RHS forms the largest part of the publication. Eleven different documents with specifications for PV systems and their components were evaluated for this purpose and summarised in a table. These documents varied widely in terms of quality and scope; some of them were intended for the specification of individual components, others as tender documents for whole systems.  
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Based on these documents, standard specifications were prepared that can be used directly as text modules for international tenders. The minimum requirements were chosen in such a way that a reliably functioning Solar Home System can be set up according to the current state-of-the-art.
  
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Based on these documents, standard specifications were prepared that can be used directly as text modules for international tenders. The minimum requirements were chosen in such a way that a reliably functioning Solar Home System can be set up according to the current state-of-the-art.  
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Systems and components that are used for power supply to '''[[Energy_for_Rural_Health_Centers|rural health stations (RHS)]]''' have to meet higher standards as a matter of principle. The available experience with PV systems in this area of application to date as well as a series of documents, especially from WHO, were evaluated and condensed. A separate list of specifications was compiled for the RHS sector.<br/>
  
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Systems and components that are used for power supply to rural health stations (RHS) have to meet higher standards as a matter of principle. The available experience with PV systems in this area of application to date as well as a series of documents, especially from WHO, were evaluated and condensed. A separate list of specifications was compiled for the RHS sector.
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A separate set of standard texts for tenders for '''[[Photovoltaic_(PV)_Pumping|Photovoltaic Pumping Systems (PVP)]]''' entitled "Proposal for Tender Documents for the Procurement of Photovoltaic Pumping Systems (PVP)" is also available from GTZ, Div. 44, Sustainable Energy Systems.
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= Current Status of Standardisation Activities for Solar Home Systems =
  
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A separate set of standard texts for tenders for Photovoltaic Pumping Systems (PVP) entitled "Proposal for Tender Documents for the Procurement of Photovoltaic Pumping Systems (PVP)" is also available from GTZ, Div. 44, Sustainable Energy Systems.
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For an overview of quality standards for solar home systems , see [[Quality_Standards_for_Solar_Home_Systems_(SHS)|Quality Standards for Solar Home Systems (SHS)]]
  
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<br>
 
  
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= IEC Draft Standard for Small-Scale PV Systems =
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= Overview of Specifications for Solar Home Systems and Rural Health Power Supply =
  
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In June 1997, the Technical Committee TC 82 WG 3 of IEC drafted its first standard with the title "PV Stand-Alone Systems - Design Qualification and Type Approval". This draft refers to individual home application with a solar generator with a maximum of 1000 Wpeak and electrical loads like lamps, radio, TV, refrigerator and telecommunication facilities. In this draft test procedures are described that can be used to determine the electrical and technical operating characteristics of PV systems and their components.  
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In the framework of the international survey, various documents with specifications for Solar Home Systems and their components were evaluated and summarised in the form of a table.<br/>
  
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The current draft, however, is more or less a loose collection of individual documents, and is by far not yet complete for an international standard. Important information such as minimum requirements, system layout, installation, etc., are still missing or are extremely incomplete. In the meantime, there are indications that this draft will be replaced by a new proposal of a European group of experts with representatives of the French GENEC, the Spanish CIAMAT, the German TÜV-Rheinland and the European joint research institute ISPRA.
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<u>The specifications in the table were subdivided into the following categories:</u><br/>
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*[[Solar Cells and Modules|PV generator]]
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*[[Standards_for_the_Module_Support_Structure|Support structure]]
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*[[Batteries|Battery]]
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*[[Charge_Controllers|Charge regulator]]
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*[[Lamps_and_Electric_Appliances|Lamp, ballast]]
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*[[Solar_Systems_-_Wiring_and_Fitting|Wiring, installation]]
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*[[Solar_Home_Systems_(SHS)_-_Quality_Standards_for_Documentation|Documentation]]
  
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<br>
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<br/>
  
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= The Global Approval Program for Photovoltaics (PV GAP) =
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<u>The following 11 documents were evaluated. Not all of the documents did include all components:</u>
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#Madrid “Universal Technical Standard for Solar Home Systems”, Instituto de Energía Solar, Universidad Politécnica de Sdrid, European Commission, Thermie B: SUP-995-96, EC-DGXVII,1998<ref>The specifications from Madrid University additionally contain a three-tier classification of the criteria according to compulsory (C), recommended (R) and suggested (S).</ref><br/>
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#FHG-ISE ´94 “Ladereglertest”, Fraunhofer Institut für Solare Energiesysteme, for GTZ OE 4150, Energie und Transport, 1994<br/>
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#GTZ ´93 “Standards für SHS-Laderegler” und “Vorläufige Grundanforderungen an elektronische Vorschaltgeräte”, GTZ, 1993<br/>
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#PSE Tunisia “Lastenheft Laderegler und elektronische Vorschaltgeräte für Photovoltaische Kleinsysteme”, c. 1994<br/>
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#Steca Midi “Datenblatt, Solarix Midi & Mini”, Steca Solarelektronik, c. 1993<br/>
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#SEP Marocco “Proposition d’un standard technique pour les systémes photovoltaiques familiaux”, CDER, Morocco, 1997<br/>
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#Namibia Health ”Tender: Okavango Clinics: Photovoltaic Systems”, GTZ, Department of Works, Namibia, 1997<br/>
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#Namibia SHS “Tender Annex B: Specifications for Solar Home Systems (50Wp)”, GTZ, Ministry of Mines and Energy Namibia, 1997<br/>
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#TÜV/CENELEC Standard Proposals: “Test Procedures for Charge Regulators and Lighting Systems in Solar Home Systems”, CENELEC CLC BTTF 86-2, 1998<br/>
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#Philippines ‘94 “Material Specification for Solar Home Systems”, GTZ SEP Philippinen, 1994<br/>
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#World Bank “Indonesia: Solar Home Systems Project, Specifications”, World Bank, 1996<br/>
  
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In the interest of world-wide quality assurance and as a reaction to the lack of standards up to now, various PV producers, lending institutions (e.g. the World Bank) and governmental as well as private organisations came out in favour of a world-wide programme for quality assurance of small-scale PV systems. At the 14th PV Conference in Barcelona, Spain in July 1997, the “Global Approval Program for PV (PV GAP)” was launched. The founding members established the following mission as the goal of PV GAP:
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<br/>
  
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''PV GAP is a global, PV industry-driven organisation that strives to promote and maintain a set of quality standards and certification procedures for the performance of PV products and systems, to ensure high quality, reliability and durability.''
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The results of the evaluation are listed in Annex A2. There is a separate table for each component.<ref>The table can be made available by e-mail as an Excel file upon request.</ref> (To view the tables [http://www.gtz.de/de/dokumente/en-gtz-pvquality.pdf downolad] the whole text.)
  
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PV GAP is domiciled at the Central Office of the IEC in Geneva, Switzerland, and works closely together with the IEC and its suborganisation, IEC’s Quality Assessment System for Electronic Components (IECQ). Existing IEC standards for quality approval and certification of components and systems are the basis of its work, and progress is being made on the development of new standards that are still lacking. As long as there are no binding standards for certain components, recommendations are made (Recommended Standards) for the interim, which are generally based on national or regional standards.  
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The specifications table can be used to get an initial overview of which criteria and corresponding components are mentioned in the respective documents.
  
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Furthermore, test laboratories are identified world-wide, also in the developing countries, which can carry out the type tests on the components described in the standards, reliably and reproducibly.  
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The table for charge regulators is the most comprehensive; charge regulators are included in all 11 documents. Due to the variety of requirements, local conditions, personal preferences and, last but not least, the different purposes for which the documents are used, a total of 91 criteria were identified for charge regulators, some of which complement each other, or also conflict with one another, and in many cases can be summarised into more general criteria.
  
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A Reference Manual was put together, which came out in the first edition in January 1998, and can be purchased from PV GAP for 175 US$. The manual first describes in detail the ideas, the organisation and the planned procedures for a quality assurance of PV components in the framework of PV GAP. The technical part essentially consists of a list of standards that may be relevant for PV components. A comprehensive training manual entitled "Quality Management in Photovoltaics" was published in August 1999 which contains specific quality assurance standards for PV components as well as an updated list of relevant IEC standards. It also comprises proposed standards that are currently in progress (IEC TC 82 Work in Progress) <sup>3</sup>.  
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At the same time, however, this variety of criteria also shows that there is an urgent need for standardisation, especially of the main components charge regulator and lamp/ballast. On the other hand, if one considers the table for PV generators, for example, one finds that many criteria are already covered by the reference “Qualified according to IEC 61215”.
  
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Moreover, a quality seal of approval is given for PV components that were tested under PV GAP conditions. This quality seal of approval is to become established if at all possible in international tenders as the prerequisite for the approval of components and systems. Qualified and recognised producers, sales and installation companies or system integrators have the right to display the quality seal of approval for PV components and systems.
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<br/>
  
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The organisational structure of PV GAP provides for the following working groups:
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= Specifications for Tenders of SHS and RHS =
  
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'''Organization Working Group: '''To develop a permanent legal entity for PV GAP and a "Seal of Quality." This group will develop a PV GAP organizational structure. This group will work on an interface with the Switzerland-based International Electrotechnical Commission Quality Assurance Program (IECQ), along with the criteria for awarding the "GAP Seal."
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The most up-to-date, comprehensive and best elaborated documents from the previous chapter 4 have been used as the basis for the proposed specifications of SHS and RHS.
  
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'''Standardization Working Group:''' PV GAP will not write standards, but will accept and promote globally the IEC standards. If no IEC standard is available, then, based on peer review, PV GAP will accept existing or future standards of other bodies as "GAP Temporary Standards (GAP TS)," and promote their use globally. These GAP TS will then be submitted to IEC TC 82 to develop them into permanent IEC standards, which, when completed, will replace the GAP TS.
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<u>Specifically, these are:</u><br/>
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*the tender documents of the World Bank for 200,000 SHS in Indonesia (and similarly 30,000 SHS in Sri Lanka) [11]
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*two tender documents for SHS [8] and RHS [7] in Namibia (which are partly based on the World Bank specifications)
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*the proposal by the University of Madrid for a “Universal Standard” [1]
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*the CENELEC draft standards for charge regulators and lamps/ballasts of the TÜVRheinland and FHG-ISE [9]
  
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'''Handbook Working Group:''' A PV GAP Handbook will be established, combining inputs from the many other organizations that already have developed a handbook or parts thereof. This PV GAP Handbook then will be promoted globally. The Handbook will incorporate all of the PV GAP-approved standards.
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<br/>
  
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'''Testing Laboratories Working Group:''' This group will establish criteria and compile a list of testing laboratories to be qualified to test PV components and systems according to IEC and PV GAP Temporary Standards. Reciprocity of test results from PV GAP-qualified Testing Laboratories will be established.  
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The specifications which, in the author's opinion, gave the best technical description were selected from these documents, revised and compiled according to component and topic. These can be used directly as text modules for international tenders. The minimum requirements in each case were selected in such a way that a reliably functioning system can be set up according to the technical state of the art<ref name="null">A separate compilation of tender documents for photovoltaic pumping systems (PVP) entitled “Proposal for Tender Documents for the Procurement of Photovoltaic Pumping-Systems (PVP)” is available from GTZ, Div. 44.</ref>.
  
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'''PV GAP Membership:''' PV-related industrial and commercial organisations, their representatives, producers, system suppliers, traders/retailers, installation companies as well as supporting organisations and individuals can become members of PV GAP. They must abide by the principles of PV GAP, especially in regard to the established quality standards. The advantages of membership are primarily the better marketing of products that have the PV GAP quality seal. As far as governmental and internationally financed projects are concerned, especially in development co-operation, preference will in all likelihood be given to the use of products that meet the PV GAP specifications. Moreover, members benefit from diverse information services and discounts on purchases of IEC and PV GAP publications and standards as well as the PV Reference Manual.
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<br/>
  
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'''Sponsors and Partnerships of PV GAP (as at 10/98):''' Chairman: Dr. P. Varadi, P/V Enterprises, USA Secretary: Mr. R. Kay (acting) - IECQ - Switzerland Treasurer: Mr. M. Real - Alpha Real - Switzerland
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<u>'''Tender Specifications for Solar Home Systems and Rural Health Power Supply Systems'''</u>:<br/>
  
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Organisations represented on the PV GAP Executive Board:  
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Some of the texts proposed for the specifications presented here include additional notes marked <u>“Optional”</u>, <u>“Health”</u> and/or <u>''“Comment”''</u>:
  
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<u>Board Members:</u> JEMA – Japan; EPIA – Belgium; NREL – USA; SEIA – USA; Newcastle Photovoltaic Applications Centre – UK; UNDP – USA; JRC, Ispra – Italy; JQAO – Japan.
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<u>Optional:</u> Optional specifications for higher requirements, alternative equipment or special environmental conditions
  
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<u>Advisory Board Members:</u> PowerMark – USA; WIP – Germany; Fraunhofer Institute – Germany; NOVEM - The Netherlands; EDF – France; ISPMA – India; National Technical University, Athens – Greece.
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<u>Health:</u> Additional or alternative specifications for Rural Health Power Supply Systems (RHS) with stricter requirements
  
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It remains to be seen how PV GAP develops in the future and whether offices issuing tenders and international donor organisations refer to the quality standards made by PV GAP. As the example of the Training Manual prepared for the World Bank in 1999 shows, however, the PV GAP’s quality assurance function has already met with international interest. If these standards become established in future tender procedures, tests according to PV GAP standards will be binding on the suppliers.
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''<u>Comment:</u> Explanation of the reason for choosing a certain specification or a personal opinion of the author''
  
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<br>
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<br/>
  
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= Reliability  =
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== Photovoltaic Generator (PV Modules) ==
  
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SHS reliability, in the sense of lack of failures, depends not only on the reliability of the components, but also on some other features of the system which can directly affect the lifetime of batteries and lamps, such as size, the voltage thresholds of the charge regulator, the quality of installation, etc. Each component of the system must fulfil similar quality and reliability requirements because, if there is only one bad component in an otherwise perfect system, this will limit the quality of the whole.  
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For information about the PV Generators, see [[Standards_for_the_PV_Generator|Standards for the PV Generator]].
  
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<br>
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== Module Support Structure ==
  
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= PV Generator  =
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For Information about module support Structure , see [[Standards_for_the_Module_Support_Structure|Standards for the Module Support Structure]].
  
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*''PV modules certified according to the international standard IEC-61215 or to the national standard of PV modules used by the relevant country. '''(R)'''''
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== Battery ==
  
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This requirement currently excludes thin-film PV modules, although certification procedures for such modules are also available (IEC-61646, SERI/TR-213-3624). Thin film modules are permitted in some projects supported by the World Bank and promising new modules are emerging onto international markets but until now the field experience with commercially available thin-film modules has been rather discouraging <sup>6,7</sup>. Their use in largescale programmes is therefore still considered to be extremely risky and it is recommended that they should only be accepted if supported by comprehensive long term guarantees.
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For more information about the technical standard for the battery, see [[Battery_in_a_Photovoltaic_Power_Supply_System_-_Standards|Battery in a Photovoltaic Power Supply System - Standards]]
  
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[6] M.J.Manimala. "Solar Photovoltaic Lanterns in rural India: a socio-economic evaluation of the schema as implemented in the state of Maharashtra in India". 12th EC PV Solar Energy Conference. Amsterdam. 1994
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== Charge Regulator ==
  
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[7] E. Dunlop et al. "Electrical Characterisation and Analysis of Operating Conditions of Amorphous Silicon Building Integrated Photovoltaic Modules". 14th EC PV Conference. Barcelona. 1997
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For information about the charge regulator, see [[Standards_for_the_Charge_Regulator|Standards for the Charge Regulator]].
  
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<br>
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== Loads ==
  
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= Support Structure  =
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For information about the load , see [[Standards_for_the_Load|Standards for the Load]].
  
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*''Support structures should be able to resist, at least, 10 years of outdoor exposure without appreciable corrosion or fatigue. '''(C)'''''
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== System installation and wiring ==
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*''Support structures must withstand winds of 120 km/h. '''(R)'''''
 
  
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Several materials can be used for support structures, including stainless steel, aluminium, galvanised iron with a protective layer of about 30 μm, treated wood, etc.
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For standards on system installation and wiring, see [[Standards_for_System_Installation_and_Wiring|Standards for System Installation and Wiring]]
  
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*''In the case of framed PV modules, only stainless steel fasteners (screws, nuts, rings, etc.) may be used for attaching them to support. '''(C)'''''
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== Grounding, Lightning Protection ==
  
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It is worth mentioning that frameless PV modules bonded to a frame with suitable adhesive products, while today scarcely used onto SHS market, are performing well in general PV applications and can also be accepted.
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For standards on lightning protection , see [[Standards_for_Grounding_and_Lightning_Protection|Standards for Grounding and Lightning Protection]]
  
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*''Tilt angle should be selected to optimise the energy collection during the worst month, i.e., the month with the lowest ratio of monthly mean daily irradiation to the monthly mean daily load. Generally, constant user load can be assumed. Then, the following formula can be used'' <br>''Tilt (°) = max {|Φ|} + 10°}'' <br>''where Φ is the latitude of the installation. '''(R)'''''
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== Documentation ==
  
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This formula leads to a minimum tilt angle of 10°, which is sufficient to allow rainwater to drain off the surface. It may also be useful to note that slight azimuth deviations from south/north (+/- 30°) and in the tilt angle (+/- 10°) have a relatively small influence on the energy output of a PV array.
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For documents on solar home systems, see [[Solar_Home_Systems_(SHS)_-_Quality_Standards_for_Documentation|Solar Home Systems (SHS) - Quality Standards for Documentation]]
  
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Most of the consulted experts are opposed to manual tracking because it implies a risk of damage to the modules, and a risk of energy lost through poor or no adjustment. However, it has been used in some places with positive results not only in terms of energy gain, but also in terms of user participation. Naturally, adequate training is needed and the tracking features, including any hinges and other coupling devices needed to allow the modules to be moved, must also meet the requirements specified above. Hence:
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= Further Information =
  
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*''Static support structures are generally preferable to tracking-ones '''(R)'''''
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*[[Publication_-_Pico-PV_Quality_Standards|Publication - Pico-PV Quality Standards]]‎; Lighting Global 2018
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*''In the case where manual tracking (2 or 3 positions per day, moving from East to West) is used, all of its features must meet the support structure requirements specified above '''(C)'''.''
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*[https://sun-connect-news.org/fileadmin/DATEIEN/Dateien/New/Solar_Home_System_Design_Guideline_Final_2019_2.pdf World Bank: System Design Guidelines (2019)]
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*[[:File:Gtz quality standards for solar home systems and rural health power supply.pdf|Gtz quality standards for solar home systems and rural health power supply.pdf]]
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*[[Portal:Solar|Solar portal on energypedia]]
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*[[Solar Home Systems (SHS)|Solar Home Systems]]
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*[[Market for Solar Home Systems (SHS)|Market for Solar Home Systems (SHS)]]
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*[[Monitoring of Solar Home System (SHS)|Monitoring of Solar Home System (SHS)]]
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*[[Solar Home System (SHS) Costs|Solar Home System (SHS) Costs]]
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*[[Solar Home Systems: Costs, Financing, Business and Operation Models|Financing solar home systems]]
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*[[Planning, Installation and Maintenance of Solar Home System|Planning, Installation and Maintenance of Solar Home System]]<br/>
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= References =
  
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&nbsp;
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The GTZ prepared a publication which gives an overview of different standardisation activities and existing standards that are relevant for '''[[Solar Home Systems (SHS)|solar home systems]] (SHS)''' and '''rural health power supply systems (RHS)''':
  
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= Battery  =
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[[:File:Gtz_quality_standards_for_solar_home_systems_and_rural_health_power_supply.pdf|GTZ, Division 44, Environmental Management, Water, Energy, Transport: Quality Standards for Solar Home Systems and Rural Health Power Supply. Photovoltaic Systems in Developing Countries, February 2000.]]
  
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For the battery, the most important feature of its operation in SHSs is cycling. During the daily cycle, the battery is charged during the day and 11 discharged by the night-time load. Superimposed onto the daily cycle is the seasonal cycle, which is associated with periods of reduced radiation availability. This, together with other operating parameters (ambient temperature, current, voltages, etc.) affects the battery life and maintenance requirements. In order to maximise the lifetime of lead acid batteries, the following operating conditions must be avoided<sup>8</sup>:
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<br/>This article is an extract of the publication mainly regarding Solar Home Systems (SHS).<br/>
  
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*High voltages during charging (to prevent against corrosion and loss of water)
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<references /><br/>
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*Low voltages during discharge (corrosion)
 
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*Deep discharge (sulphation, growth of dentrites)
 
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*Extended periods without a fully charging (sulphation)
 
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*High battery temperatures (all ageing processes are accelerated)
 
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*Stratification of the electrolyte (sulphation)
 
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*Very low charge currents (sulphation)
 
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These rules lead to specifications for sizing (both battery and PV generator) and for battery protection procedures (charge regulator). However, it must be pointed out that some of the rules are generally in contradiction with each other (e.g. full charging needs high voltages but high voltages accelerate corrosion), so compromises must be found taking into account the particular local conditions: solar radiation, PV module and battery prices duties and taxes, local manufacturing, recycling infrastructure, etc. Perhaps this explains the lack of consensus on this issue among the different information sources (standards, experts, etc.) that have been consulted during the preparation of this standard, and the requirements given below should therefore be adapted to suit the local circumstances.
 
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The need to prevent excessive discharge leads to the need to limit the maximum depth of discharge to a certain value, PD<sub>MAX</sub>, which usually ranges from 0.3 to 0.6, but can approach 0.8 according to the type of battery. The supply to the load must be cut when this limit is reached. The available or useful capacity, C<sub>U</sub>, is therefore less than the nominal capacity, C<sub>B</sub>, (which refers to the whole charge that could be extracted from the battery if no particular limitations were imposed) and equal to the product C<sub>B</sub> x PD<sub>MAX</sub>, , such that:
 
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<br>[8] G. Bopp et al., "Energy Storage in Photovoltaic stand alone energy supply systems". Progress in Photovoltaics (to be published).
 
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= The charge regulator  =
 
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= The loads (mainly lighting)  =
 
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= The wiring  =
 
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Source: [http://www.taqsolre.net/doc/Standard_IngV2.pdf Universal technical standard for solar home systems, Version 2, Thermie B SUP 995-96, EC-DGXVII, 1998, updated in 2001].
 
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[[Category:Solar_Home_Systems_(SHS)]]
 
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Latest revision as of 14:35, 29 September 2021

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Overview

To assure the quality of a photovoltaic power system and its correct functioning and guarantee costumers' satisfaction it is important that the components of the system and the system as a whole meet certain requirements.

Introduction

Photovoltaic (PV) systems for applications in developing countries have been tested, optimised and disseminated throughout the world over the last 20 years. A wide variety of demands have been made of the components and systems, partly for reasons due to country specific characteristics or regional availability, but also because there were no binding standards, or if there were, they were often not known.

The project activities in technical and financial co-operation at bilateral and multilateral level have moved away from the pilot phase and towards the dissemination of PV systems. Yet, secure technical standards are required for dissemination in order to minimise the need for adjustments after the fact and the related costs in the case of large unit numbers.

An international survey carried out in preparation for this publication showed that several different standardisation activities are in progress. Probably the most interesting international project is the so-called "Global Approval Program for Photovoltaics (PV GAP)", but also technical specifications such as those that have been proposed by the World Bank or the University of Madrid have already been elaborated in great detail.

Global Approval Program for Photovoltaics

The publication provides an overview of standards that are relevant for Solar Home Systems (SHS) and in Rural Health Power Supply Systems (RHS). It is intended to facilitate the selection of PV systems and components, especially in tenders, and to provide the impetus for a standardisation of PV systems on a scale that is as broad as possible. Moreover, it also identifies those components for which there is still a need for technical specifications.

This should lead, in the long term or better yet in the medium term, to binding, internationally recognised technical standards, especially for the use of photovoltaic systems in developing countries.

In preparing this publication, all of the well-known national and international institutions concerned with standardisation activities in the field of photovoltaics were contacted in writing. The existing photovoltaics projects of GTZ were also included in the survey.

In the course of the survey, information and documentation obtained from the World Bank, the World Health Organization (WHO), the international standardisation institution IEC, the European standardisation institution CENELEC, the U.S. standardisation office IEEE, as well as a series of projects, firms and experts, were compiled and evaluated.

The available PV-relevant standards were evaluated and summarised in the form of a table with a breakdown by components.

The list of standard specifications for tenders for SHS and RHS forms the largest part of the publication. Eleven different documents with specifications for PV systems and their components were evaluated for this purpose and summarised in a table. These documents varied widely in terms of quality and scope; some of them were intended for the specification of individual components, others as tender documents for whole systems.

Based on these documents, standard specifications were prepared that can be used directly as text modules for international tenders. The minimum requirements were chosen in such a way that a reliably functioning Solar Home System can be set up according to the current state-of-the-art.

Systems and components that are used for power supply to rural health stations (RHS) have to meet higher standards as a matter of principle. The available experience with PV systems in this area of application to date as well as a series of documents, especially from WHO, were evaluated and condensed. A separate list of specifications was compiled for the RHS sector.

A separate set of standard texts for tenders for Photovoltaic Pumping Systems (PVP) entitled "Proposal for Tender Documents for the Procurement of Photovoltaic Pumping Systems (PVP)" is also available from GTZ, Div. 44, Sustainable Energy Systems.

Current Status of Standardisation Activities for Solar Home Systems

For an overview of quality standards for solar home systems , see Quality Standards for Solar Home Systems (SHS)


Overview of Specifications for Solar Home Systems and Rural Health Power Supply

In the framework of the international survey, various documents with specifications for Solar Home Systems and their components were evaluated and summarised in the form of a table.

The specifications in the table were subdivided into the following categories:


The following 11 documents were evaluated. Not all of the documents did include all components:

  1. Madrid “Universal Technical Standard for Solar Home Systems”, Instituto de Energía Solar, Universidad Politécnica de Sdrid, European Commission, Thermie B: SUP-995-96, EC-DGXVII,1998[1]
  2. FHG-ISE ´94 “Ladereglertest”, Fraunhofer Institut für Solare Energiesysteme, for GTZ OE 4150, Energie und Transport, 1994
  3. GTZ ´93 “Standards für SHS-Laderegler” und “Vorläufige Grundanforderungen an elektronische Vorschaltgeräte”, GTZ, 1993
  4. PSE Tunisia “Lastenheft Laderegler und elektronische Vorschaltgeräte für Photovoltaische Kleinsysteme”, c. 1994
  5. Steca Midi “Datenblatt, Solarix Midi & Mini”, Steca Solarelektronik, c. 1993
  6. SEP Marocco “Proposition d’un standard technique pour les systémes photovoltaiques familiaux”, CDER, Morocco, 1997
  7. Namibia Health ”Tender: Okavango Clinics: Photovoltaic Systems”, GTZ, Department of Works, Namibia, 1997
  8. Namibia SHS “Tender Annex B: Specifications for Solar Home Systems (50Wp)”, GTZ, Ministry of Mines and Energy Namibia, 1997
  9. TÜV/CENELEC Standard Proposals: “Test Procedures for Charge Regulators and Lighting Systems in Solar Home Systems”, CENELEC CLC BTTF 86-2, 1998
  10. Philippines ‘94 “Material Specification for Solar Home Systems”, GTZ SEP Philippinen, 1994
  11. World Bank “Indonesia: Solar Home Systems Project, Specifications”, World Bank, 1996


The results of the evaluation are listed in Annex A2. There is a separate table for each component.[2] (To view the tables downolad the whole text.)

The specifications table can be used to get an initial overview of which criteria and corresponding components are mentioned in the respective documents.

The table for charge regulators is the most comprehensive; charge regulators are included in all 11 documents. Due to the variety of requirements, local conditions, personal preferences and, last but not least, the different purposes for which the documents are used, a total of 91 criteria were identified for charge regulators, some of which complement each other, or also conflict with one another, and in many cases can be summarised into more general criteria.

At the same time, however, this variety of criteria also shows that there is an urgent need for standardisation, especially of the main components charge regulator and lamp/ballast. On the other hand, if one considers the table for PV generators, for example, one finds that many criteria are already covered by the reference “Qualified according to IEC 61215”.


Specifications for Tenders of SHS and RHS

The most up-to-date, comprehensive and best elaborated documents from the previous chapter 4 have been used as the basis for the proposed specifications of SHS and RHS.

Specifically, these are:

  • the tender documents of the World Bank for 200,000 SHS in Indonesia (and similarly 30,000 SHS in Sri Lanka) [11]
  • two tender documents for SHS [8] and RHS [7] in Namibia (which are partly based on the World Bank specifications)
  • the proposal by the University of Madrid for a “Universal Standard” [1]
  • the CENELEC draft standards for charge regulators and lamps/ballasts of the TÜVRheinland and FHG-ISE [9]


The specifications which, in the author's opinion, gave the best technical description were selected from these documents, revised and compiled according to component and topic. These can be used directly as text modules for international tenders. The minimum requirements in each case were selected in such a way that a reliably functioning system can be set up according to the technical state of the art[3].


Tender Specifications for Solar Home Systems and Rural Health Power Supply Systems:

Some of the texts proposed for the specifications presented here include additional notes marked “Optional”, “Health” and/or “Comment”:

Optional: Optional specifications for higher requirements, alternative equipment or special environmental conditions

Health: Additional or alternative specifications for Rural Health Power Supply Systems (RHS) with stricter requirements

Comment: Explanation of the reason for choosing a certain specification or a personal opinion of the author


Photovoltaic Generator (PV Modules)

For information about the PV Generators, see Standards for the PV Generator.

Module Support Structure

For Information about module support Structure , see Standards for the Module Support Structure.

Battery

For more information about the technical standard for the battery, see Battery in a Photovoltaic Power Supply System - Standards

Charge Regulator

For information about the charge regulator, see Standards for the Charge Regulator.

Loads

For information about the load , see Standards for the Load.

System installation and wiring

For standards on system installation and wiring, see Standards for System Installation and Wiring

Grounding, Lightning Protection

For standards on lightning protection , see Standards for Grounding and Lightning Protection

Documentation

For documents on solar home systems, see Solar Home Systems (SHS) - Quality Standards for Documentation

Further Information

References

The GTZ prepared a publication which gives an overview of different standardisation activities and existing standards that are relevant for solar home systems (SHS) and rural health power supply systems (RHS):

GTZ, Division 44, Environmental Management, Water, Energy, Transport: Quality Standards for Solar Home Systems and Rural Health Power Supply. Photovoltaic Systems in Developing Countries, February 2000.


This article is an extract of the publication mainly regarding Solar Home Systems (SHS).

  1. ↑ The specifications from Madrid University additionally contain a three-tier classification of the criteria according to compulsory (C), recommended (R) and suggested (S).
  2. ↑ The table can be made available by e-mail as an Excel file upon request.
  3. ↑ A separate compilation of tender documents for photovoltaic pumping systems (PVP) entitled “Proposal for Tender Documents for the Procurement of Photovoltaic Pumping-Systems (PVP)” is available from GTZ, Div. 44.


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