IEC 60904-4-2019 pdf free.Photovoltaic devices – Part 4: Photovoltaic reference devices – Procedures for establishing calibration traceability.
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60904-1, Photovoltaic devices — Part 1: Measurement of photovoltaic current-voltage characteristics
IEC 60904-2. Photovoltaic devices — Part 2: Requirements for photovoltaic reference devices
IEC 60904-3, Photovoltaic devices — Part 3: Measurement principles for terrestrial photovoltaic (PV) solar devices with reference spectral irradiance data
IEC TS 61836, Solar photovoltaic energy systems — Terms, definitions and symbols
ISOIIEC Guide 98-3: 2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in measurement (GUM: 1995)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836 and the following apply.
NOTE The different reference instruments for the traceability chain of solar irradiance are defined in this clause.
Typical examples for each category are listed in Table 1. which also refers to relevant standards (where available).
Figure 1 then shows schematically the most common traceability chains linking these instruments and the relevant
standards (where available). Methods foc the implementation of this document are described in Annex A
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
. IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://wwwiso.org/obp
3.1 primary standard
standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity
Note I to entry: The concept of a primary standard is equally valid for base quantities and derived quantities.
Note 2 to entry: A primary standard is never used directly for measurement other than for comparison with other primary standards or secondary standards,
Note 3 to entry: Primary standards are usually maintained by national metrology instilutes (NMIS) or similar organizations entrusted with maintenance of standards for physical quantities. Often referred to also just as the aprimary.. the physical implementation is selected such that long-term stability, accuracy and repeatability of measurement of the quantity It represents are guaranteed to the maximum extent possible by current technology.
Note 4 to entry: The World Radiometric Reference (WRR) as realized by the World Standard Group (WSG) of cavity radiometers is the accepted primary standard for the measurement of solar irradlance.
3.2 secondary standard
device which, by periodical comparison with a primary standard, serves to maintain conformity to SI units at other places than that of the primary standard
Note I to entry: A secondary standard does not necessarily use the same technical principles as the primary standard, but strives to achieve similar long-term stability, accuracy and repeatability.
Note 2 to entry: Typical secondary standards for solar irradiance are cavity radiometers which participate periodically (normally every 5 years) in the International Pyrheliometer Comparison (IPC) with the WSG, thereby giving traceability to WRR. Direct traceability to SI radiometric scale can also be available for these instruments.
3.3 primary reference
instrument which a laboratory uses to calibrate secondary references, compared at periodic intervals to a secondary standard
Note 1 to entry: Often primary references can be realized at much lower costs than secondary standards,
Note 2 to entry: Typically, a PV cell is used as a reference device for the measurement of natural or simulated solar irradiance. Primary references are normally used by calibration and testing laboratories.
3.4 secondary reference
measurement device in use for daily routine measurements or to calibrate working references. calibrated at periodic intervals against a primary reference.IEC 60904-4 pdf free download.