What is the main purpose of this standard?

To provide a standardized methodology for evaluating the energy performance of a grid-connected PV system, primarily by calculating the Performance Ratio (PR).

What is Performance Ratio (PR)?

PR is the ratio of the final (actual) AC energy yield to the reference (ideal) yield. It quantifies the overall effect of system losses on the rated output. (Clause 5.4)

What are the minimum instruments required for performance evaluation?

A pyranometer (or reference cell) for solar irradiance, an energy meter for AC energy output, and temperature sensors for module and ambient temperature. (Clause 7, Table 1)

What is the difference between Array Yield (Ya) and Final Yield (Yf)?

Array Yield (Ya) is the DC energy output per kWp of the array, while Final Yield (Yf) is the AC energy output per kWp delivered to the grid. The difference represents Balance-of-System (BOS) losses. (Clause 5.6, 5.7)

IS 16302

: 2016

Photovoltaic (PV) systems - Evaluation of performance

CurrentEssentialTesting MethodBIMMEP · Solar and Renewable Energy Installations

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This standard specifies the procedure for measuring and analyzing the energy performance of grid-connected photovoltaic (PV) systems. It defines key metrics like Performance Ratio (PR) and system yields, and details the requirements for instrumentation, data acquisition, and reporting to verify a plant's operational efficiency.

Specifies methods for evaluating and reporting the energy performance of photovoltaic (PV) systems, including measurement and data analysis.

Quick Reference Values

Standard Test Condition (STC) Irradiance1000 W/m²

Standard Test Condition (STC) Cell Temperature25 °C

Standard Test Condition (STC) Air MassAM 1.5

Recommended Data Acquisition Interval≤ 15 minutes

Typical Target Performance Ratio (PR) Range75% to 85%

Key Formulas

PR = Yf / Yr — Performance Ratio, where Yf is Final Yield and Yr is Reference Yield

Yf = E_AC / P_peak — Final PV System Yield (kWh/kWp)

Yr = H_t / G_ref — Reference Yield (h)

Lc = Yr - Ya — Array Capture Losses

Ls = Ya - Yf — System (BOS) Losses

Practical Notes

Accurate PR calculation heavily depends on correct data filtering to exclude periods of grid outage, inverter downtime, or sensor malfunction.

Soiling on pyranometers and PV modules is a major source of error; regular cleaning and maintenance of sensors are critical for reliable data.

Ensure the 'as-built' peak power (P_peak) of the array is accurately determined and used for calculations, as it can differ from the sum of module nameplate ratings.