Session 11

Grid Tied PV Systems – Part 1

Standards and Codes

October 01, 2015

Session 11 content

Standards and CodesoPurpose, utilityoExamples

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Learning Outcomes

• Introduction to the idea of standards and codes in engineering design

• Recognition of the importance of standards and codes to the safe operation of PV systems

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PV Systems - Applicable standards and codes

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• Photovoltaic systems, like all engineered systems, must meet a variety of codes and standards, especially in the area of system safetyo Safety for homeowners (in residential PV

systems)o Safety for utility service workerso Safety for firefighters and other first

responders

PV Systems - Applicable standards and codes

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• The codes and standards applicable to PV systems also ensure several other characteristics, including:

o Protection against the elements and tampering

o Durability and structural integrityo Uniformity in construction and utilization

PV Systems - Applicable standards and codes

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• The American Society of Mechanical Engineers (ASME) lists these definitions on their webpage:o A Standard can be defined as a set of technical definitions

and guidelines that function as instructions for designers, manufacturers, operators, or users of equipment.o Standards are written by professionals who are members of a

regulating organizationo They are generally voluntary and are not enforceable by law

o A standard becomes a Code when it has been adopted by one or more governmental bodies and is enforceable by law, or when it has been incorporated into a business contract

PV Systems - Applicable standards and codes

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• Standards and Codes generally have these requirements.

o Suitable for repetitive use o Enforceable – an auditor can easily see whether it is being followedo Definite – it contains specific instructionso Realistic – it is not excessively restrictiveo Authoritative – it is technically correct o Complete o Clearo Consistent – it does not contradict other standards and codeso Focused

PV Systems - Applicable standards and codes

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• The technical issues related to connecting a PV system to the grid were essentially understood in 1999

• The IEEE adopted Standard 929 in 2000 which listed performance criteria for grid-tied systems.

• If a PV system met the criteria of Standard 929 using inverters that were listed under UL 1741 and if it were installed in accordance with the current National Electrical Code (NEC), it automatically met all established performance criteria

• The IEEE adopted Standard 1547 in 2003. Among other things, it contains some revisions from Standard 929 related to PV power quality and PV disconnect issues. It is a functional standard, not a prescriptive one. That is, it specifies specific functions that must be performed, but does not tell how to satisfy the functional requirements

PV Systems - Applicable standards and codes

Partial Listing of PV Standards and Codes

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PV Systems - Applicable standards and codes

Partial Listing of PV Standards and Codes, cont.

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PV Systems - Applicable standards and codes

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• The National Electrical Code is published by the National Fire Protection Association and is updated every three years.

• It was first published in 1897. The current NEC to be followed is the 2014 edition, available since November, 2013

• The NEC is a collection of articles pertaining to wiring methods, grounding, switches and fuses, etc., relevant to the overall electrical safety of the system

• It is not US law, but is mandated by state or local jurisdictions

PV Systems - Applicable standards and codes

NEC Article 690

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PV Systems - Applicable standards and codes

Regulating Organizations

• NEC – National Electrical Code

• IEEE – Institute of Electrical and Electronic Engineers

• IEC – International Electrotechnical Commission

• ISO – International Organization for Standardization

• UL – Underwriters Laboratories

• ANSI – American National Standards Institutes

• ASCE – American Society of Civil Engineers

• ASTM – American Society for Testing and Materials

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Important Resources

• IEEE Standards:o http://ieeexplore.ieee.org/xpl/standards.jsp

• National Electrical Code:o http://en.wikipedia.org/wiki/National_Electrical_C

ode

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