IEC 61724-1:2017 — Photovoltaic System Performance — Part 1: Monitoring — defines data collection, parameter calculations, and Performance Ratio methodology for PV plant monitoring and O&M reporting. | Solarpedia Standards

Scope

IEC 61724-1:2017 specifies the minimum data to be recorded, parameters to be computed, and reporting methods for assessing the performance of grid-connected PV systems. It is the reference standard for all PR calculations, widely referenced in Indian PPA O&M contracts.

Key defined metrics

Reference yield (Y_r): In-plane irradiation (kWh/m²) ÷ 1 kW/m²
Final yield (Y_f): AC energy ÷ installed capacity
Performance Ratio (PR) = Y_f / Y_r
Temperature-corrected PR: PR adjusted for ambient temperature deviations from 25°C

Measurement system classes

Class A: Pyranometers, calibrated sensors — required for bankable yield assessments
Class B: Reference cells — standard for commercial/industrial O&M contracts
Class C: Weather station irradiance — acceptable for small rooftop monitoring

India O&M context

Most O&M contracts above 1 MW in India require IEC 61724-1 Class B monitoring, monthly PR reporting, and temperature-corrected PR annual reporting.

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Photovoltaic System Performance — Part 1: Monitoring — defines data collection, parameter calculations, and Performance Ratio methodology for PV plant monitoring and O&M reporting.

Scope

Key defined metrics

Measurement system classes

India O&M context

Key requirements