IEC TS 62257-6:2015

IEC TS 62257-6 ®
Edition 2.0 2015-12
TECHNICAL
SPECIFICATION
Recommendations for renewable energy and hybrid systems for rural
electrification –
Part 6: Acceptance, operation, maintenance and replacement
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IEC TS 62257-6 ®
Edition 2.0 2015-12
TECHNICAL
SPECIFICATION
Recommendations for renewable energy and hybrid systems for rural

electrification –
Part 6: Acceptance, operation, maintenance and replacement

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-3069-5

– 2 – IEC TS 62257-6:2015  IEC 2015
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative reference . 6
3 Terms and definitions . 7
4 General aspects . 7
4.1 Introduction to AOMR actions . 7
4.2 Conditions impacting AOMR actions and guidelines . 10
4.2.1 Characteristics of the project/systems to be managed . 10
4.2.2 Organization of AOMR personnel and responsibilities . 10
4.2.3 Needed technical capabilities of AOMR participants . 11
4.3 Training . 12
5 Rules for systems . 12
5.1 System identification and operational data record keeping . 12
5.2 Organizational issues . 13
5.2.1 System limit definition of the AOMR domain . 13
5.2.2 Planning of AOMR actions . 13
5.2.3 Traceability of AOMR actions . 14
5.3 Technical issues . 14
5.4 Acceptance issues . 15
5.5 Recommended practices for intervention . 15
5.6 Maintenance actions . 15
5.7 Replacement factors . 16
5.8 Analysis of the conformity of the delivered service to the contractual
commitments . 16
6 Rules for electric equipment . 17
6.1 General aspects . 17
6.2 Specific aspects related to electric equipment . 17
6.2.1 General . 17
6.2.2 Acceptance test . 18
6.2.3 Recommended practices for intervention . 18
6.2.4 Maintenance actions . 18
6.2.5 Replacement factors . 18
Bibliography . 20

Table 1 – AOMR actions . 8
Table 2 – System acceptance process description . 9
Table 3 – AOMR participant involvement . 10
Table 4 – Levels of skill for safety . 12
Table 5 – Levels of general skill . 12
Table 6 – Maintenance actions planning -example . 14
Table 7 – Voltage domains . 14
Table 8 – Verification of the adherence to commitments . 17

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RECOMMENDATIONS FOR RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 6: Acceptance, operation, maintenance and replacement

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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The main task of IEC technical committees is to prepare International Standards. In
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• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 62257-6, which is a technical specification, has been prepared by IEC technical
committee 82: Solar photovoltaic energy systems.

– 4 – IEC TS 62257-6:2015  IEC 2015
This second edition cancels and replaces the first edition issued in 2005. It constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– redefine the maximum AC voltage from 500 V to 1 000 V as well as the maximum DC
voltage from 750 V to 1 500 V; and
– removal of the limitation of the 100 kVA system size. Hence the removal of the word “small”
with regard to the title and related references in this document.
This technical specification is to be used in conjunction with the IEC 62257 series.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
82/951/DTS 82/1002A/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62257 series, published under the general title Recommendations
for renewable energy and hybrid systems for rural electrification, can be found on the IEC
website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

INTRODUCTION
The IEC 62257 series intends to provide to different players involved in rural electrification
projects (such as project implementers, project contractors, project supervisors, installers,
etc.) documents for the setting up of renewable energy and hybrid systems with AC voltage
below 1 000 V and DC voltage below 1 500 V.
These documents are recommendations:
• to choose the right system for the right place;
• to design the system;
• to operate and maintain the system.
These documents are focused only on rural electrification concentrating on, but not specific to,
developing countries. They should not be considered as all inclusive to rural electrification.
The documents try to promote the use of renewable energies in rural electrification; they do
not deal with clean mechanisms developments at this time (CO emission, carbon credit, etc.).
Further developments in this field could be introduced in future steps.
This consistent set of documents is best considered as a whole with different parts
corresponding to items for safety as well as sustainability of systems aiming at the lowest life
cycle cost as possible. One of the main objectives is to provide the minimum sufficient
requirements, relevant to the field of application, that is: renewable energy and hybrid off-grid
systems.
The purpose of this technical specification is to propose a methodology to achieve the best
technical and economic conditions for acceptance, operation, maintenance and replacement
of equipment and complete system life cycle.

– 6 – IEC TS 62257-6:2015  IEC 2015
RECOMMENDATIONS FOR RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 6: Acceptance, operation, maintenance and replacement

1 Scope
This part of IEC 62257, which is a technical specification, intends to describe the various
rules to be applied for acceptance, operation, maintenance and replacement (AOMR) of
decentralized rural electrification systems (DRES) which are designed to supply electric
power for sites which are not connected to a large interconnected system, or a national grid,
in order to meet basic needs.
The majority of these sites are:
• isolated dwellings;
• village houses;
• community services (public lighting, pumping, health centers, places of worship or cultural
activities, administrative buildings, etc.);
• economic activities (workshops, micro-industry, etc.).
This technical specification proposes a methodology to achieve the best technical and
economic conditions for acceptance, operation, maintenance and replacement of equipment
and complete system life cycle.
It does not substitute for technical manuals provided by manufacturers for each equipment.
The complexity of the system and application will dictate the level of required AOMR
documentation.
2 Normative reference
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62257 (all parts), Recommendations for renewable energy and hybrid systems for rural
electrification
IEC TS 62257-1, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 1: General introduction to IEC 62257 series and rural electrification
IEC TS 62257-2, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 2: From requirements to a range of electrification systems
IEC TS 62257-3, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 3: Project development and management
IEC TS 62257-4, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 4: System selection and design

IEC TS 62257-7, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 7: Generators
IEC TS 62257-8, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 8: Batteries and converters
IEC TS 62257-9 (all parts), Recommendations for renewable energy and hybrid systems for
rural electrification – Part 9-XX: Integrated systems
IEC TS 62257-12-1, Recommendations for renewable energy and hybrid systems for rural
electrification – Part 12-1: Selection of lamps and lighting appliances for off-grid electricity
systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
AOMR actions
acceptance, operation, maintenance and replacement actions
key processes that are required for the overall successful implementation of an isolated
electrification system
3.2
implementation contract
contract between project developer and project implementer usually the result of a
competitive sollicitation for proposals developed by the project developer on the basis of the
general specification
3.3
electric equipment
item used for such puposes as generation, conversion, transmission, distribution or utilization
of electric energy, such as electric machines, transformers, switchgear and controlgear,
measuring instruments, protective devices, wiring systems, current-using equipment
[SOURCE: IEC 60050-826:2004, 826-16-01]
3.4
REN
renewable energy
energy from a source that is not depleted when used
[SOURCE: IEC TS 62257-2:2015, 3.1]
4 General aspects
4.1 Introduction to AOMR actions
Isolated electrification systems are designed to supply power to those individuals,
communities or loads located in remote areas not connected to national grids.
These systems can be broken down into three categories:
• process electrification systems (for instance for pumping);
• individual electrification systems (IES) (single user, load or application);

– 8 – IEC TS 62257-6:2015  IEC 2015
• collective electrification systems (CES) (multiple user load or application).
In order to satisfy the various energy requirements both in terms of quality and quantity, six
types of isolated micropower systems have been identified (see IEC 62257-2).
AOMR actions are introduced in Table 1.
A basic system acceptance process description is given in Table 2.
Table 1 – AOMR actions
• checking the process to ensure that the system installation meets the requirement set forth
Acceptance
in the implementation contract between the project developer and the project implementer
• testing the process to ensure that the micropower system operates according to the

functional part of the implementation contract
• once the parties have come to agreement, transfer the responsibility of the system

• managing the business of system operation
Operation
• monitoring "normal" system operation

("normal" operation = system supplies the power complying with all the characteristics of
the expected service, with the original designed configuration)
• managing system electrical operation = executing actions on electrical circuits

(configuration changes)
• response to abnormal operating conditions = to provide service outside of the boundaries of

the implementation contract (prolonged absence of REN sources)
• response to abnormal system operation

corrective actions (manual or automatic), troubleshooting and repair system or system
components (diagnosing the cause(s) for failure); fault finding = to service the plant and
restore its operating conditions following an unpredictable failure
• guaranteeing safety while performing (servicing) actions on the plant

• performing analysis and retrofit of the system to account for new operating conditions

• preventive maintenance: keeping and maintaining the system to its «normal» operating
Maintenance
state
• corrective maintenance: adjusting, fixing or replacing components after fault recognition

• conducting periodic tests and inspection

• replacing the equipment on «normal» life cycle completion
Replacement
• replacing the equipment for upgrading purposes

• dismantling and recycling at end of life cycle

Table 2 – System acceptance process description
Acceptance process Objective Responsible Implementers Content of a suggested data sheet
party
Phase 1 Preparation To collect all information on Project Project List of contractual documents to be provided
the system implementer implementer/
subcontractor
Phase 2 Check of existing To check that all non Project Consultant List of contractual documents to be provided
documentation, contract operational contractual developer engineer
clauses requirements are met:
Documentation, manuals,
spare parts, drawings,
procedures, warranty
contracts, etc.
Phase 3 Commissioning step 1: To check that the equipment Project Consultant Equipment list:
Evaluation of the conformity of complies with the contractual developer engineer
Initial design list/as built list/comments
the installed system with the accepted design and that any
accepted design differences are explained
Commissioning step 2: To check that the system is Project Project Letter
Evaluation of qualification of ready to be operated implementer implementer/
the installation subcontractor
Commissioning step 3: To test that the system Project Consultant Component by component, verification:
Preliminary tests components operate correctly developer engineer
Proper type and reference according to the as built list
Proper installation: check list of key points
Proper operation: list of tests with targeted performances
to be obtained
Commissioning step 4: To check all the operating Project Consultant List of system tests with targeted performances to be
Performance testing performances of the whole developer engineer obtained
system
Phase 4 Agreement Transfer of responsibility Project Letter of acceptance
implementer/
developer/
operator/
owner
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