{"id":9775,"date":"2026-09-24T09:01:52","date_gmt":"2026-09-24T01:01:52","guid":{"rendered":"https:\/\/www.yantaisensor.com\/?p=9775"},"modified":"2026-10-16T10:04:41","modified_gmt":"2026-10-16T02:04:41","slug":"solar-pr-calculation-guide","status":"publish","type":"post","link":"https:\/\/www.yantaisensor.com\/zh\/blog\/solar-pr-calculation-guide","title":{"rendered":"\u592a\u9633\u80fdPR\u8ba1\u7b97\u6307\u5357\uff1a\u5229\u7528\u8f90\u7167\u5ea6\u6570\u636e\u8ba1\u7b97PR"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

For PV operators and project engineers, a solar PR calculation may show an unexpected result even when the plant appears to be operating normally. The problem is not always the PV system itself. Incorrect POA irradiance<\/mark><\/a> measurement, sensor misalignment, soiling, calibration drift, missing data, or mismatched timestamps can all affect the reference yield used for PR. Because PV performance ratio relates actual energy production to the solar resource received by the array, reliable irradiance data is essential for meaningful results.<\/p>\n\n\n\n

In practice, the key question is not simply how to calculate PR, but whether the irradiance data used in the calculation truly represents the PV array conditions. This guide explains how to use POA irradiance for PR calculation using irradiance data, shows the calculation formula with a practical PV example, and then examines sensor installation, data quality, and common measurement errors that can distort the result. It also covers practical irradiance sensor considerations for long-term PV performance monitoring.For more insight into how ultraviolet radiation affects module materials, power output, and long-term reliability, read [UV Impact on Solar Panels<\/mark><\/a>].<\/p>\n\n\n\n

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\"TBQ-2C<\/figure>\n\n\n\n
\"SAUT<\/figure>\n<\/figure>\n\n\n\n

What Is PV Performance Ratio and How Is It Calculated?<\/h2>\n\n\n\n

PV Performance Ratio (PR)<\/mark><\/a> is a normalized indicator that compares the actual energy produced by a PV system with the energy expected from the solar resource received by the PV array.<\/p>\n\n\n\n

What Does PR Measure?<\/h3>\n\n\n\n

PR reflects how effectively a PV system converts the available solar resource into electricity. Unlike total energy output, it accounts for both the PV system capacity and the solar irradiation received during the evaluation period.<\/p>\n\n\n\n

Solar PR Calculation Formula<\/h3>\n\n\n\n

The basic solar PR calculation is:<\/p>\n\n\n\n

PR = Actual Energy Yield \u00f7 Reference Yield \u00d7 100%<\/strong><\/p>\n\n\n\n

The actual energy yield is calculated from the PV system’s AC energy output and installed DC capacity. The reference yield is calculated from the POA irradiation measured on the PV array plane and the reference irradiance.<\/p>\n\n\n\n

Therefore, POA irradiance data is a key input for PR calculation. The measured irradiance is accumulated over the evaluation period to obtain the irradiation used in the calculation.<\/p>\n\n\n\n

IEC 61724-1 provides the standard framework for PV system performance monitoring and PR evaluation.<\/p>\n\n\n\n

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\"Environmental<\/figure>\n\n\n\n
\"PV<\/figure>\n\n\n\n
\"Solar<\/figure>\n<\/figure>\n\n\n\n

How to Calculate PR Using POA Irradiance Data?<\/h2>\n\n\n\n

For a PR calculation using irradiance data, two datasets need to match: the energy generated by the PV system and the solar irradiation received by the array. In practice, we use POA irradiance because the sensor is measuring sunlight on the same plane as the modules. The calculation is then based on the measured solar resource and the actual energy output over the same period.<\/p>\n\n\n\n

Why POA Irradiance Is Used?<\/h3>\n\n\n\n

POA (Plane of Array) irradiance is measured on the plane of the PV array. Because module tilt and orientation affect the radiation received by the modules, POA data is more suitable for PV performance monitoring than horizontal irradiance.<\/p>\n\n\n\n

Irradiance<\/td>Measurement Plane<\/td>Typical Use<\/td><\/tr>
GHI<\/td>Horizontal plane<\/td>Solar resource assessment<\/td><\/tr>
POA<\/td>PV array plane<\/td>PV performance monitoring<\/td><\/tr>
DNI<\/td>Normal to the sun<\/td>Direct radiation measurement<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

For a PV performance ratio calculation, the POA measurement should represent the same array conditions as the PV system being evaluated.<\/p>\n\n\n\n

Five Steps for Solar PR Calculation<\/h3>\n\n\n\n