AS NZS 61724.1:2020 pdf free.Photovoltaic system performance Part 1: Monitoring (IEC 61724-1:2017/ MOD).
4 Monitoring system classification
The required accuracy and complexity of the monitoring system depends on the PV system size and user objectives. This document defines three classifications of monitoring systems providing varying levels of accuracy, as listed in Table 1.
The monitoring system classification shall be stated in any conformity declarations to this standard. The monitoring system classification may be referenced either by its letter code (A, B, C) or its name (high accuracy, medium accuracy, basic accuracy) as indicated in Table 1 In this document, the letter codes are used for convenience.
Class A or Class B would be most appropriate for large PV systems, such as utility-scale and large commercial installations, while Class B or Class C would be most appropriate for small systems, such as smaller commercial and residential installations. However, users of the standard may specify any classification appropriate to their application, regardless of PV system size.
Throughout this document, some requirements are designated as applying to a particular classification. Where no designation is given, the requirements apply to all classifications.
Measurement uncertainties can be calculated as outlined in ISO/IEC Guide 98-1 and ISO/IEC Guide 98-3.
5.2 Calibration
Sensors and signal-conditioning electronics used in the monitoring system shall be calibrated prior to the start of monitoring.
Recalibration of sensors and signal-conditioning electronics is to be performed as required by the manufacturer or at more frequent intervals where specified.
It is recommended to perform periodic cross-checks of each sensor against sister sensors or reference devices in order to identify out-of-calibration sensors.
5.3 Repeated elements
Depending on system size and user requirements, the monitoring system may include redundancy in sensors and/or repetition of sensor elements for different components or subsections of the full PV system. Accordingly, the measured and calculated parameters defined in this document may have multiple instances, each corresponding to a subsection or subcomponent of the PV system.
5.4 Power consumption
The parasitic power drawn by tracking, monitoring, and other ancillary systems required for operation of the PV plant shall be considered a power loss of the plant, not a load supplied by the plant.
5.5 Documentation
Specifications of all components of the monitoring system, including sensors and signal-
conditioning electronics, shall be documented.
User guides shall be provided for the monitoring system software.
All system maintenance, including cleaning of sensors, PV modules, or other soed surfaces, shall be documented.
A log should be kept to record unusual events, component changes, sensor recalibration, changes to the data acquisition system, changes to the overall system operation, failures, faults, or accidents.
When a conformity declaration is made, documentation shall demonstrate consistency with the indicated class A, B, or C.AS NZS 61724.1 pdf download.